draft-lafon-rfc2616bis-03.txt   draft-lafon-rfc2616bis-04.txt 
Network Working Group R. Fielding Network Working Group R. Fielding
Internet-Draft Day Software Internet-Draft Day Software
Obsoletes: 2616 (if approved) J. Gettys Obsoletes: 2616 (if approved) J. Gettys
Intended status: Standards Track J. Mogul Intended status: Standards Track One Laptop per Child
Expires: January 1, 2008 HP Expires: May 21, 2008 J. Mogul
HP
H. Frystyk H. Frystyk
Microsoft Microsoft
L. Masinter L. Masinter
Adobe Systems Adobe Systems
P. Leach P. Leach
Microsoft Microsoft
T. Berners-Lee T. Berners-Lee
W3C/MIT W3C/MIT
Y. Lafon, Ed. Y. Lafon, Ed.
W3C W3C
J. Reschke, Ed. J. Reschke, Ed.
greenbytes greenbytes
June 30, 2007 November 18, 2007
Hypertext Transfer Protocol -- HTTP/1.1 Hypertext Transfer Protocol -- HTTP/1.1
draft-lafon-rfc2616bis-03 draft-lafon-rfc2616bis-04
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 48 skipping to change at page 1, line 49
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 1, 2008. This Internet-Draft will expire on May 21, 2008.
Abstract Abstract
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information protocol for distributed, collaborative, hypermedia information
systems. It is a generic, stateless, protocol which can be used for systems. It is a generic, stateless, protocol which can be used for
many tasks beyond its use for hypertext, such as name servers and many tasks beyond its use for hypertext, such as name servers and
distributed object management systems, through extension of its distributed object management systems, through extension of its
request methods, error codes and headers [RFC2324]. A feature of request methods, error codes and headers [RFC2324]. A feature of
HTTP is the typing and negotiation of data representation, allowing HTTP is the typing and negotiation of data representation, allowing
skipping to change at page 4, line 7 skipping to change at page 4, line 7
text in word wrapping, page breaks, list formatting, reference text in word wrapping, page breaks, list formatting, reference
formatting, whitespace usage and appendix numbering. Otherwise, it formatting, whitespace usage and appendix numbering. Otherwise, it
is supposed to contain an accurate copy of the original specification is supposed to contain an accurate copy of the original specification
text. See <http://www.w3.org/Protocols/HTTP/1.1/ text. See <http://www.w3.org/Protocols/HTTP/1.1/
rfc2616bis-00-from-rfc2616.diff.html> for a comparison between both rfc2616bis-00-from-rfc2616.diff.html> for a comparison between both
documents, as generated by "rfcdiff" documents, as generated by "rfcdiff"
(<http://tools.ietf.org/tools/rfcdiff/>). (<http://tools.ietf.org/tools/rfcdiff/>).
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 12
1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . . 11 1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 11 1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 12
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . 12 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . 13
1.4. Overall Operation . . . . . . . . . . . . . . . . . . . 16 1.4. Overall Operation . . . . . . . . . . . . . . . . . . . 17
2. Notational Conventions and Generic Grammar . . . . . . . . . 19 2. Notational Conventions and Generic Grammar . . . . . . . . . 20
2.1. Augmented BNF . . . . . . . . . . . . . . . . . . . . . 19 2.1. Augmented BNF . . . . . . . . . . . . . . . . . . . . . 20
2.2. Basic Rules . . . . . . . . . . . . . . . . . . . . . . 21 2.2. Basic Rules . . . . . . . . . . . . . . . . . . . . . . 22
3. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 23 3. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 24
3.1. HTTP Version . . . . . . . . . . . . . . . . . . . . . . 23 3.1. HTTP Version . . . . . . . . . . . . . . . . . . . . . . 24
3.2. Uniform Resource Identifiers . . . . . . . . . . . . . . 24 3.2. Uniform Resource Identifiers . . . . . . . . . . . . . . 25
3.2.1. General Syntax . . . . . . . . . . . . . . . . . . . 24 3.2.1. General Syntax . . . . . . . . . . . . . . . . . . . 25
3.2.2. http URL . . . . . . . . . . . . . . . . . . . . . . 25 3.2.2. http URL . . . . . . . . . . . . . . . . . . . . . . 26
3.2.3. URI Comparison . . . . . . . . . . . . . . . . . . . 25 3.2.3. URI Comparison . . . . . . . . . . . . . . . . . . . 26
3.3. Date/Time Formats . . . . . . . . . . . . . . . . . . . 26 3.3. Date/Time Formats . . . . . . . . . . . . . . . . . . . 27
3.3.1. Full Date . . . . . . . . . . . . . . . . . . . . . 26 3.3.1. Full Date . . . . . . . . . . . . . . . . . . . . . 27
3.3.2. Delta Seconds . . . . . . . . . . . . . . . . . . . 27 3.3.2. Delta Seconds . . . . . . . . . . . . . . . . . . . 28
3.4. Character Sets . . . . . . . . . . . . . . . . . . . . . 27 3.4. Character Sets . . . . . . . . . . . . . . . . . . . . . 28
3.4.1. Missing Charset . . . . . . . . . . . . . . . . . . 28 3.4.1. Missing Charset . . . . . . . . . . . . . . . . . . 29
3.5. Content Codings . . . . . . . . . . . . . . . . . . . . 29 3.5. Content Codings . . . . . . . . . . . . . . . . . . . . 30
3.6. Transfer Codings . . . . . . . . . . . . . . . . . . . . 30 3.6. Transfer Codings . . . . . . . . . . . . . . . . . . . . 31
3.6.1. Chunked Transfer Coding . . . . . . . . . . . . . . 31 3.6.1. Chunked Transfer Coding . . . . . . . . . . . . . . 32
3.7. Media Types . . . . . . . . . . . . . . . . . . . . . . 32 3.7. Media Types . . . . . . . . . . . . . . . . . . . . . . 33
3.7.1. Canonicalization and Text Defaults . . . . . . . . . 33 3.7.1. Canonicalization and Text Defaults . . . . . . . . . 34
3.7.2. Multipart Types . . . . . . . . . . . . . . . . . . 33 3.7.2. Multipart Types . . . . . . . . . . . . . . . . . . 34
3.8. Product Tokens . . . . . . . . . . . . . . . . . . . . . 34 3.8. Product Tokens . . . . . . . . . . . . . . . . . . . . . 35
3.9. Quality Values . . . . . . . . . . . . . . . . . . . . . 35 3.9. Quality Values . . . . . . . . . . . . . . . . . . . . . 36
3.10. Language Tags . . . . . . . . . . . . . . . . . . . . . 35 3.10. Language Tags . . . . . . . . . . . . . . . . . . . . . 36
3.11. Entity Tags . . . . . . . . . . . . . . . . . . . . . . 36 3.11. Entity Tags . . . . . . . . . . . . . . . . . . . . . . 37
3.12. Range Units . . . . . . . . . . . . . . . . . . . . . . 36 3.12. Range Units . . . . . . . . . . . . . . . . . . . . . . 37
4. HTTP Message . . . . . . . . . . . . . . . . . . . . . . . . 38 4. HTTP Message . . . . . . . . . . . . . . . . . . . . . . . . 39
4.1. Message Types . . . . . . . . . . . . . . . . . . . . . 38 4.1. Message Types . . . . . . . . . . . . . . . . . . . . . 39
4.2. Message Headers . . . . . . . . . . . . . . . . . . . . 38 4.2. Message Headers . . . . . . . . . . . . . . . . . . . . 39
4.3. Message Body . . . . . . . . . . . . . . . . . . . . . . 39 4.3. Message Body . . . . . . . . . . . . . . . . . . . . . . 40
4.4. Message Length . . . . . . . . . . . . . . . . . . . . . 40 4.4. Message Length . . . . . . . . . . . . . . . . . . . . . 41
4.5. General Header Fields . . . . . . . . . . . . . . . . . 41 4.5. General Header Fields . . . . . . . . . . . . . . . . . 42
5. Request . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5. Request . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.1. Request-Line . . . . . . . . . . . . . . . . . . . . . . 43 5.1. Request-Line . . . . . . . . . . . . . . . . . . . . . . 44
5.1.1. Method . . . . . . . . . . . . . . . . . . . . . . . 43 5.1.1. Method . . . . . . . . . . . . . . . . . . . . . . . 44
5.1.2. Request-URI . . . . . . . . . . . . . . . . . . . . 44 5.1.2. Request-URI . . . . . . . . . . . . . . . . . . . . 45
5.2. The Resource Identified by a Request . . . . . . . . . . 45 5.2. The Resource Identified by a Request . . . . . . . . . . 46
5.3. Request Header Fields . . . . . . . . . . . . . . . . . 46 5.3. Request Header Fields . . . . . . . . . . . . . . . . . 47
6. Response . . . . . . . . . . . . . . . . . . . . . . . . . . 47 6. Response . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1. Status-Line . . . . . . . . . . . . . . . . . . . . . . 47 6.1. Status-Line . . . . . . . . . . . . . . . . . . . . . . 48
6.1.1. Status Code and Reason Phrase . . . . . . . . . . . 47 6.1.1. Status Code and Reason Phrase . . . . . . . . . . . 48
6.2. Response Header Fields . . . . . . . . . . . . . . . . . 50 6.2. Response Header Fields . . . . . . . . . . . . . . . . . 51
7. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
7.1. Entity Header Fields . . . . . . . . . . . . . . . . . . 51 7.1. Entity Header Fields . . . . . . . . . . . . . . . . . . 52
7.2. Entity Body . . . . . . . . . . . . . . . . . . . . . . 51 7.2. Entity Body . . . . . . . . . . . . . . . . . . . . . . 52
7.2.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 52 7.2.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 53
7.2.2. Entity Length . . . . . . . . . . . . . . . . . . . 52 7.2.2. Entity Length . . . . . . . . . . . . . . . . . . . 53
8. Connections . . . . . . . . . . . . . . . . . . . . . . . . . 53 8. Connections . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.1. Persistent Connections . . . . . . . . . . . . . . . . . 53 8.1. Persistent Connections . . . . . . . . . . . . . . . . . 54
8.1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . 53 8.1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . 54
8.1.2. Overall Operation . . . . . . . . . . . . . . . . . 53 8.1.2. Overall Operation . . . . . . . . . . . . . . . . . 54
8.1.3. Proxy Servers . . . . . . . . . . . . . . . . . . . 55 8.1.3. Proxy Servers . . . . . . . . . . . . . . . . . . . 56
8.1.4. Practical Considerations . . . . . . . . . . . . . . 55 8.1.4. Practical Considerations . . . . . . . . . . . . . . 56
8.2. Message Transmission Requirements . . . . . . . . . . . 56 8.2. Message Transmission Requirements . . . . . . . . . . . 57
8.2.1. Persistent Connections and Flow Control . . . . . . 56 8.2.1. Persistent Connections and Flow Control . . . . . . 57
8.2.2. Monitoring Connections for Error Status Messages . . 56 8.2.2. Monitoring Connections for Error Status Messages . . 57
8.2.3. Use of the 100 (Continue) Status . . . . . . . . . . 57 8.2.3. Use of the 100 (Continue) Status . . . . . . . . . . 58
8.2.4. Client Behavior if Server Prematurely Closes 8.2.4. Client Behavior if Server Prematurely Closes
Connection . . . . . . . . . . . . . . . . . . . . . 59 Connection . . . . . . . . . . . . . . . . . . . . . 60
9. Method Definitions . . . . . . . . . . . . . . . . . . . . . 60 9. Method Definitions . . . . . . . . . . . . . . . . . . . . . 61
9.1. Safe and Idempotent Methods . . . . . . . . . . . . . . 60 9.1. Safe and Idempotent Methods . . . . . . . . . . . . . . 61
9.1.1. Safe Methods . . . . . . . . . . . . . . . . . . . . 60 9.1.1. Safe Methods . . . . . . . . . . . . . . . . . . . . 61
9.1.2. Idempotent Methods . . . . . . . . . . . . . . . . . 60 9.1.2. Idempotent Methods . . . . . . . . . . . . . . . . . 61
9.2. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . 61 9.2. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . 62
9.3. GET . . . . . . . . . . . . . . . . . . . . . . . . . . 62 9.3. GET . . . . . . . . . . . . . . . . . . . . . . . . . . 63
9.4. HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . 62 9.4. HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . 63
9.5. POST . . . . . . . . . . . . . . . . . . . . . . . . . . 63 9.5. POST . . . . . . . . . . . . . . . . . . . . . . . . . . 64
9.6. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . 64 9.6. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . 64
9.7. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . 65 9.7. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . 66
9.8. TRACE . . . . . . . . . . . . . . . . . . . . . . . . . 65 9.8. TRACE . . . . . . . . . . . . . . . . . . . . . . . . . 66
9.9. CONNECT . . . . . . . . . . . . . . . . . . . . . . . . 66 9.9. CONNECT . . . . . . . . . . . . . . . . . . . . . . . . 66
10. Status Code Definitions . . . . . . . . . . . . . . . . . . . 67 10. Status Code Definitions . . . . . . . . . . . . . . . . . . . 67
10.1. Informational 1xx . . . . . . . . . . . . . . . . . . . 67 10.1. Informational 1xx . . . . . . . . . . . . . . . . . . . 67
10.1.1. 100 Continue . . . . . . . . . . . . . . . . . . . . 67 10.1.1. 100 Continue . . . . . . . . . . . . . . . . . . . . 67
10.1.2. 101 Switching Protocols . . . . . . . . . . . . . . 67 10.1.2. 101 Switching Protocols . . . . . . . . . . . . . . 67
10.2. Successful 2xx . . . . . . . . . . . . . . . . . . . . . 68 10.2. Successful 2xx . . . . . . . . . . . . . . . . . . . . . 68
10.2.1. 200 OK . . . . . . . . . . . . . . . . . . . . . . . 68 10.2.1. 200 OK . . . . . . . . . . . . . . . . . . . . . . . 68
10.2.2. 201 Created . . . . . . . . . . . . . . . . . . . . 68 10.2.2. 201 Created . . . . . . . . . . . . . . . . . . . . 68
10.2.3. 202 Accepted . . . . . . . . . . . . . . . . . . . . 68 10.2.3. 202 Accepted . . . . . . . . . . . . . . . . . . . . 68
10.2.4. 203 Non-Authoritative Information . . . . . . . . . 69 10.2.4. 203 Non-Authoritative Information . . . . . . . . . 69
skipping to change at page 9, line 4 skipping to change at page 9, line 4
15.4. Location Headers and Spoofing . . . . . . . . . . . . . 165 15.4. Location Headers and Spoofing . . . . . . . . . . . . . 165
15.5. Content-Disposition Issues . . . . . . . . . . . . . . . 166 15.5. Content-Disposition Issues . . . . . . . . . . . . . . . 166
15.6. Authentication Credentials and Idle Clients . . . . . . 166 15.6. Authentication Credentials and Idle Clients . . . . . . 166
15.7. Proxies and Caching . . . . . . . . . . . . . . . . . . 166 15.7. Proxies and Caching . . . . . . . . . . . . . . . . . . 166
15.7.1. Denial of Service Attacks on Proxies . . . . . . . . 167 15.7.1. Denial of Service Attacks on Proxies . . . . . . . . 167
16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 168 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 168
16.1. (RFC2616) . . . . . . . . . . . . . . . . . . . . . . . 168 16.1. (RFC2616) . . . . . . . . . . . . . . . . . . . . . . . 168
16.2. (This Document) . . . . . . . . . . . . . . . . . . . . 169 16.2. (This Document) . . . . . . . . . . . . . . . . . . . . 169
17. References . . . . . . . . . . . . . . . . . . . . . . . . . 170 17. References . . . . . . . . . . . . . . . . . . . . . . . . . 170
17.1. References (to be classified) . . . . . . . . . . . . . 170 17.1. References (to be classified) . . . . . . . . . . . . . 170
17.2. Informative References . . . . . . . . . . . . . . . . . 173 17.2. Normative References . . . . . . . . . . . . . . . . . . 170
17.3. Informative References . . . . . . . . . . . . . . . . . 171
Appendix A. Internet Media Type message/http and Appendix A. Internet Media Type message/http and
application/http . . . . . . . . . . . . . . . . . . 176 application/http . . . . . . . . . . . . . . . . . . 176
Appendix B. Internet Media Type multipart/byteranges . . . . . . 178 Appendix B. Internet Media Type multipart/byteranges . . . . . . 178
Appendix C. Tolerant Applications . . . . . . . . . . . . . . . 180 Appendix C. Tolerant Applications . . . . . . . . . . . . . . . 180
Appendix D. Differences Between HTTP Entities and RFC 2045 Appendix D. Differences Between HTTP Entities and RFC 2045
Entities . . . . . . . . . . . . . . . . . . . . . . 181 Entities . . . . . . . . . . . . . . . . . . . . . . 181
D.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . 181 D.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . 181
D.2. Conversion to Canonical Form . . . . . . . . . . . . . . 181 D.2. Conversion to Canonical Form . . . . . . . . . . . . . . 181
D.3. Conversion of Date Formats . . . . . . . . . . . . . . . 182 D.3. Conversion of Date Formats . . . . . . . . . . . . . . . 182
D.4. Introduction of Content-Encoding . . . . . . . . . . . . 182 D.4. Introduction of Content-Encoding . . . . . . . . . . . . 182
skipping to change at page 9, line 33 skipping to change at page 9, line 34
Conserve IP Addresses . . . . . . . . . . . . . . . 185 Conserve IP Addresses . . . . . . . . . . . . . . . 185
F.2. Compatibility with HTTP/1.0 Persistent Connections . . . 186 F.2. Compatibility with HTTP/1.0 Persistent Connections . . . 186
F.3. Changes from RFC 2068 . . . . . . . . . . . . . . . . . 187 F.3. Changes from RFC 2068 . . . . . . . . . . . . . . . . . 187
F.4. Changes from RFC 2616 . . . . . . . . . . . . . . . . . 189 F.4. Changes from RFC 2616 . . . . . . . . . . . . . . . . . 189
Appendix G. Change Log (to be removed by RFC Editor before Appendix G. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 191 publication) . . . . . . . . . . . . . . . . . . . . 191
G.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . 191 G.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . 191
G.2. Since draft-lafon-rfc2616bis-00 . . . . . . . . . . . . 191 G.2. Since draft-lafon-rfc2616bis-00 . . . . . . . . . . . . 191
G.3. Since draft-lafon-rfc2616bis-01 . . . . . . . . . . . . 191 G.3. Since draft-lafon-rfc2616bis-01 . . . . . . . . . . . . 191
G.4. Since draft-lafon-rfc2616bis-02 . . . . . . . . . . . . 191 G.4. Since draft-lafon-rfc2616bis-02 . . . . . . . . . . . . 191
G.5. Since draft-lafon-rfc2616bis-03 . . . . . . . . . . . . 192
Appendix H. Resolved issues (to be removed by RFC Editor Appendix H. Resolved issues (to be removed by RFC Editor
before publication) . . . . . . . . . . . . . . . . 193 before publication) . . . . . . . . . . . . . . . . 194
H.1. i45-rfc977-reference . . . . . . . . . . . . . . . . . . 193 H.1. unneeded_references . . . . . . . . . . . . . . . . . . 194
H.2. i46-rfc1700_remove . . . . . . . . . . . . . . . . . . . 193 H.2. consistent-reason-phrases . . . . . . . . . . . . . . . 194
H.3. i47-inconsistency-in-date-format-explanation . . . . . . 193 H.3. i66-iso8859-1-reference . . . . . . . . . . . . . . . . 194
H.4. i49-connection-header-text . . . . . . . . . . . . . . . 194 H.4. abnf-edit . . . . . . . . . . . . . . . . . . . . . . . 195
H.5. i48-date-reference-typo . . . . . . . . . . . . . . . . 194 H.5. rfc1766_normative . . . . . . . . . . . . . . . . . . . 195
H.6. i86-normative-up-to-date-references . . . . . . . . . . 195
H.7. i68-encoding-references-normative . . . . . . . . . . . 196
H.8. rfc2396_normative . . . . . . . . . . . . . . . . . . . 196
H.9. usascii_normative . . . . . . . . . . . . . . . . . . . 196
H.10. i65-informative-references . . . . . . . . . . . . . . . 196
H.11. i31-qdtext-bnf . . . . . . . . . . . . . . . . . . . . . 197
H.12. i62-whitespace-in-quoted-pair . . . . . . . . . . . . . 198
H.13. i26-import-query-bnf . . . . . . . . . . . . . . . . . . 198
H.14. i47-inconsistency-in-date-format-explanation . . . . . . 199
H.15. media-reg . . . . . . . . . . . . . . . . . . . . . . . 199
H.16. i84-redundant-cross-references . . . . . . . . . . . . . 200
H.17. i87-typo-in-13.2.2 . . . . . . . . . . . . . . . . . . . 200
H.18. i25-accept-encoding-bnf . . . . . . . . . . . . . . . . 201
H.19. remove-CTE-abbrev . . . . . . . . . . . . . . . . . . . 202
Appendix I. Open issues (to be removed by RFC Editor prior to Appendix I. Open issues (to be removed by RFC Editor prior to
publication) . . . . . . . . . . . . . . . . . . . . 196 publication) . . . . . . . . . . . . . . . . . . . . 203
I.1. rfc2616bis . . . . . . . . . . . . . . . . . . . . . . . 196 I.1. rfc2616bis . . . . . . . . . . . . . . . . . . . . . . . 203
I.2. unneeded_references . . . . . . . . . . . . . . . . . . 196 I.2. i35-split-normative-and-informative-references . . . . . 203
I.3. edit . . . . . . . . . . . . . . . . . . . . . . . . . . 196 I.3. i40-header-registration . . . . . . . . . . . . . . . . 203
I.4. i66-iso8859-1-reference . . . . . . . . . . . . . . . . 196 I.4. edit . . . . . . . . . . . . . . . . . . . . . . . . . . 203
I.5. abnf . . . . . . . . . . . . . . . . . . . . . . . . . . 196 I.5. abnf . . . . . . . . . . . . . . . . . . . . . . . . . . 203
I.6. rfc2048_informative_and_obsolete . . . . . . . . . . . . 197 I.6. rfc2048_informative_and_obsolete . . . . . . . . . . . . 204
I.7. i34-updated-reference-for-uris . . . . . . . . . . . . . 197 I.7. i34-updated-reference-for-uris . . . . . . . . . . . . . 204
I.8. i50-misc-typos . . . . . . . . . . . . . . . . . . . . . 197 I.8. i50-misc-typos . . . . . . . . . . . . . . . . . . . . . 204
I.9. i65-informative-references . . . . . . . . . . . . . . . 197 I.9. i52-sort-1.3-terminology . . . . . . . . . . . . . . . . 205
I.10. i52-sort-1.3-terminology . . . . . . . . . . . . . . . . 198 I.10. i63-header-length-limit-with-encoded-words . . . . . . . 205
I.11. i63-header-length-limit-with-encoded-words . . . . . . . 199 I.11. i74-character-encodings-for-headers . . . . . . . . . . 206
I.12. i31-qdtext-bnf . . . . . . . . . . . . . . . . . . . . . 199 I.12. i64-ws-in-quoted-pair . . . . . . . . . . . . . . . . . 206
I.13. i62-whitespace-in-quoted-pair . . . . . . . . . . . . . 199 I.13. i75-rfc2145-normative . . . . . . . . . . . . . . . . . 207
I.14. i58-what-identifies-an-http-resource . . . . . . . . . . 200 I.14. i82-rel_path-not-used . . . . . . . . . . . . . . . . . 207
I.15. i51-http-date-vs-rfc1123-date . . . . . . . . . . . . . 200 I.15. i58-what-identifies-an-http-resource . . . . . . . . . . 208
I.16. i67-quoting-charsets . . . . . . . . . . . . . . . . . . 200 I.16. i51-http-date-vs-rfc1123-date . . . . . . . . . . . . . 208
I.17. media-reg . . . . . . . . . . . . . . . . . . . . . . . 201 I.17. i73-clarification-of-the-term-deflate . . . . . . . . . 209
I.18. languagetag . . . . . . . . . . . . . . . . . . . . . . 201 I.18. i67-quoting-charsets . . . . . . . . . . . . . . . . . . 209
I.19. i56-6.1.1-can-be-misread-as-a-complete-list . . . . . . 201 I.19. i20-default-charsets-for-text-media-types . . . . . . . 209
I.20. i57-status-code-and-reason-phrase . . . . . . . . . . . 202 I.20. languagetag . . . . . . . . . . . . . . . . . . . . . . 211
I.21. i59-status-code-registry . . . . . . . . . . . . . . . . 202 I.21. i85-custom-ranges . . . . . . . . . . . . . . . . . . . 211
I.22. i21-put-side-effects . . . . . . . . . . . . . . . . . . 202 I.22. i30-header-lws . . . . . . . . . . . . . . . . . . . . . 212
I.23. i54-definition-of-1xx-warn-codes . . . . . . . . . . . . 203 I.23. i77-line-folding . . . . . . . . . . . . . . . . . . . . 212
I.24. i60-13.5.1-and-13.5.2 . . . . . . . . . . . . . . . . . 203 I.24. i19-bodies-on-GET . . . . . . . . . . . . . . . . . . . 213
I.25. i53-allow-is-not-in-13.5.2 . . . . . . . . . . . . . . . 203 I.25. i28-connection-closing . . . . . . . . . . . . . . . . . 213
I.26. i25-accept-encoding-bnf . . . . . . . . . . . . . . . . 204 I.26. i32-options-asterisk . . . . . . . . . . . . . . . . . . 213
I.27. i61-redirection-vs-location . . . . . . . . . . . . . . 204 I.27. i83-options-asterisk-and-proxies . . . . . . . . . . . . 214
I.28. fragment-combination . . . . . . . . . . . . . . . . . . 204 I.28. i56-6.1.1-can-be-misread-as-a-complete-list . . . . . . 215
I.29. i55-updating-to-rfc4288 . . . . . . . . . . . . . . . . 205 I.29. i57-status-code-and-reason-phrase . . . . . . . . . . . 215
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 I.30. i59-status-code-registry . . . . . . . . . . . . . . . . 216
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 218 I.31. i72-request-method-registry . . . . . . . . . . . . . . 216
Intellectual Property and Copyright Statements . . . . . . . . . 221 I.32. i21-put-side-effects . . . . . . . . . . . . . . . . . . 216
I.33. i27-put-idempotency . . . . . . . . . . . . . . . . . . 217
I.34. i79-content-headers-vs-put . . . . . . . . . . . . . . . 218
I.35. i33-trace-security-considerations . . . . . . . . . . . 218
I.36. i69-clarify-requested-variant . . . . . . . . . . . . . 219
I.37. i70-cacheability-of-303 . . . . . . . . . . . . . . . . 220
I.38. i76-deprecate-305-use-proxy . . . . . . . . . . . . . . 222
I.39. i78-relationship-between-401-authorization-and-www-authe 222
I.40. i24-requiring-allow-in-405-responses . . . . . . . . . . 223
I.41. i81-content-negotiation-for-media-types . . . . . . . . 223
I.42. i54-definition-of-1xx-warn-codes . . . . . . . . . . . . 225
I.43. i29-age-calculation . . . . . . . . . . . . . . . . . . 225
I.44. i71-examples-for-etag-matching . . . . . . . . . . . . . 226
I.45. i60-13.5.1-and-13.5.2 . . . . . . . . . . . . . . . . . 227
I.46. i53-allow-is-not-in-13.5.2 . . . . . . . . . . . . . . . 227
I.47. i37-vary-and-non-existant-headers . . . . . . . . . . . 227
I.48. i38-mismatched-vary . . . . . . . . . . . . . . . . . . 228
I.49. i39-etag-uniqueness . . . . . . . . . . . . . . . . . . 228
I.50. i23-no-store-invalidation . . . . . . . . . . . . . . . 228
I.51. i80-content-location-is-not-special . . . . . . . . . . 229
I.52. i22-etag-and-other-metadata-in-status-messages . . . . . 230
I.53. i61-redirection-vs-location . . . . . . . . . . . . . . 230
I.54. fragment-combination . . . . . . . . . . . . . . . . . . 230
I.55. i41-security-considerations . . . . . . . . . . . . . . 231
I.56. i55-updating-to-rfc4288 . . . . . . . . . . . . . . . . 231
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 244
Intellectual Property and Copyright Statements . . . . . . . . . 247
1. Introduction 1. Introduction
1.1. Purpose 1.1. Purpose
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information protocol for distributed, collaborative, hypermedia information
systems. HTTP has been in use by the World-Wide Web global systems. HTTP has been in use by the World-Wide Web global
information initiative since 1990. The first version of HTTP, information initiative since 1990. The first version of HTTP,
referred to as HTTP/0.9, was a simple protocol for raw data transfer referred to as HTTP/0.9, was a simple protocol for raw data transfer
skipping to change at page 11, line 36 skipping to change at page 12, line 36
This protocol includes more stringent requirements than HTTP/1.0 in This protocol includes more stringent requirements than HTTP/1.0 in
order to ensure reliable implementation of its features. order to ensure reliable implementation of its features.
Practical information systems require more functionality than simple Practical information systems require more functionality than simple
retrieval, including search, front-end update, and annotation. HTTP retrieval, including search, front-end update, and annotation. HTTP
allows an open-ended set of methods and headers that indicate the allows an open-ended set of methods and headers that indicate the
purpose of a request [RFC2324]. It builds on the discipline of purpose of a request [RFC2324]. It builds on the discipline of
reference provided by the Uniform Resource Identifier (URI) reference provided by the Uniform Resource Identifier (URI)
[RFC1630], as a location (URL) [RFC1738] or name (URN) [RFC1737], for [RFC1630], as a location (URL) [RFC1738] or name (URN) [RFC1737], for
indicating the resource to which a method is to be applied. Messages indicating the resource to which a method is to be applied. Messages
are passed in a format similar to that used by Internet mail [RFC822] are passed in a format similar to that used by Internet mail
as defined by the Multipurpose Internet Mail Extensions (MIME) [RFC2822] as defined by the Multipurpose Internet Mail Extensions
[RFC2045]. (MIME) [RFC2045].
HTTP is also used as a generic protocol for communication between HTTP is also used as a generic protocol for communication between
user agents and proxies/gateways to other Internet systems, including user agents and proxies/gateways to other Internet systems, including
those supported by the SMTP [RFC821], NNTP [RFC3977], FTP [RFC959], those supported by the SMTP [RFC2821], NNTP [RFC3977], FTP [RFC959],
Gopher [RFC1436], and WAIS [WAIS] protocols. In this way, HTTP Gopher [RFC1436], and WAIS [WAIS] protocols. In this way, HTTP
allows basic hypermedia access to resources available from diverse allows basic hypermedia access to resources available from diverse
applications. applications.
1.2. Requirements 1.2. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
skipping to change at page 19, line 11 skipping to change at page 20, line 11
request/response exchange. In HTTP/1.1, a connection may be used for request/response exchange. In HTTP/1.1, a connection may be used for
one or more request/response exchanges, although connections may be one or more request/response exchanges, although connections may be
closed for a variety of reasons (see Section 8.1). closed for a variety of reasons (see Section 8.1).
2. Notational Conventions and Generic Grammar 2. Notational Conventions and Generic Grammar
2.1. Augmented BNF 2.1. Augmented BNF
All of the mechanisms specified in this document are described in All of the mechanisms specified in this document are described in
both prose and an augmented Backus-Naur Form (BNF) similar to that both prose and an augmented Backus-Naur Form (BNF) similar to that
used by [RFC822]. Implementors will need to be familiar with the used by [RFC822ABNF]. Implementors will need to be familiar with the
notation in order to understand this specification. The augmented notation in order to understand this specification. The augmented
BNF includes the following constructs: BNF includes the following constructs:
name = definition name = definition
The name of a rule is simply the name itself (without any The name of a rule is simply the name itself (without any
enclosing "<" and ">") and is separated from its definition by the enclosing "<" and ">") and is separated from its definition by the
equal "=" character. White space is only significant in that equal "=" character. White space is only significant in that
indentation of continuation lines is used to indicate a rule indentation of continuation lines is used to indicate a rule
definition that spans more than one line. Certain basic rules are definition that spans more than one line. Certain basic rules are
skipping to change at page 21, line 13 skipping to change at page 22, line 13
separators) MUST exist between any two tokens (for the definition separators) MUST exist between any two tokens (for the definition
of "token" below), since they would otherwise be interpreted as a of "token" below), since they would otherwise be interpreted as a
single token. single token.
2.2. Basic Rules 2.2. Basic Rules
The following rules are used throughout this specification to The following rules are used throughout this specification to
describe basic parsing constructs. The US-ASCII coded character set describe basic parsing constructs. The US-ASCII coded character set
is defined by ANSI X3.4-1986 [USASCII]. is defined by ANSI X3.4-1986 [USASCII].
OCTET = <any 8-bit sequence of data> OCTET = <any 8-bit sequence of data>
CHAR = <any US-ASCII character (octets 0 - 127)> CHAR = <any US-ASCII character (octets 0 - 127)>
UPALPHA = <any US-ASCII uppercase letter "A".."Z"> UPALPHA = <any US-ASCII uppercase letter "A".."Z">
LOALPHA = <any US-ASCII lowercase letter "a".."z"> LOALPHA = <any US-ASCII lowercase letter "a".."z">
ALPHA = UPALPHA | LOALPHA ALPHA = UPALPHA | LOALPHA
DIGIT = <any US-ASCII digit "0".."9"> DIGIT = <any US-ASCII digit "0".."9">
CTL = <any US-ASCII control character CTL = <any US-ASCII control character
(octets 0 - 31) and DEL (127)> (octets 0 - 31) and DEL (127)>
CR = <US-ASCII CR, carriage return (13)> CR = <US-ASCII CR, carriage return (13)>
LF = <US-ASCII LF, linefeed (10)> LF = <US-ASCII LF, linefeed (10)>
SP = <US-ASCII SP, space (32)> SP = <US-ASCII SP, space (32)>
HT = <US-ASCII HT, horizontal-tab (9)> HT = <US-ASCII HT, horizontal-tab (9)>
<"> = <US-ASCII double-quote mark (34)> <"> = <US-ASCII double-quote mark (34)>
HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all
protocol elements except the entity-body (see Appendix C for tolerant protocol elements except the entity-body (see Appendix C for tolerant
applications). The end-of-line marker within an entity-body is applications). The end-of-line marker within an entity-body is
defined by its associated media type, as described in Section 3.7. defined by its associated media type, as described in Section 3.7.
CRLF = CR LF CRLF = CR LF
HTTP/1.1 header field values can be folded onto multiple lines if the HTTP/1.1 header field values can be folded onto multiple lines if the
continuation line begins with a space or horizontal tab. All linear continuation line begins with a space or horizontal tab. All linear
white space, including folding, has the same semantics as SP. A white space, including folding, has the same semantics as SP. A
recipient MAY replace any linear white space with a single SP before recipient MAY replace any linear white space with a single SP before
interpreting the field value or forwarding the message downstream. interpreting the field value or forwarding the message downstream.
LWS = [CRLF] 1*( SP | HT ) LWS = [CRLF] 1*( SP | HT )
The TEXT rule is only used for descriptive field contents and values The TEXT rule is only used for descriptive field contents and values
that are not intended to be interpreted by the message parser. Words that are not intended to be interpreted by the message parser. Words
of *TEXT MAY contain characters from character sets other than ISO- of *TEXT MAY contain characters from character sets other than ISO-
8859-1 [ISO-8859-1] only when encoded according to the rules of 8859-1 [ISO-8859-1] only when encoded according to the rules of
[RFC2047]. [RFC2047].
TEXT = <any OCTET except CTLs, TEXT = <any OCTET except CTLs,
but including LWS> but including LWS>
A CRLF is allowed in the definition of TEXT only as part of a header A CRLF is allowed in the definition of TEXT only as part of a header
field continuation. It is expected that the folding LWS will be field continuation. It is expected that the folding LWS will be
replaced with a single SP before interpretation of the TEXT value. replaced with a single SP before interpretation of the TEXT value.
Hexadecimal numeric characters are used in several protocol elements. Hexadecimal numeric characters are used in several protocol elements.
HEX = "A" | "B" | "C" | "D" | "E" | "F" HEX = "A" | "B" | "C" | "D" | "E" | "F"
| "a" | "b" | "c" | "d" | "e" | "f" | DIGIT | "a" | "b" | "c" | "d" | "e" | "f" | DIGIT
Many HTTP/1.1 header field values consist of words separated by LWS Many HTTP/1.1 header field values consist of words separated by LWS
or special characters. These special characters MUST be in a quoted or special characters. These special characters MUST be in a quoted
string to be used within a parameter value (as defined in string to be used within a parameter value (as defined in
Section 3.6). Section 3.6).
token = 1*<any CHAR except CTLs or separators> token = 1*<any CHAR except CTLs or separators>
separators = "(" | ")" | "<" | ">" | "@" separators = "(" | ")" | "<" | ">" | "@"
| "," | ";" | ":" | "\" | <"> | "," | ";" | ":" | "\" | <">
| "/" | "[" | "]" | "?" | "=" | "/" | "[" | "]" | "?" | "="
| "{" | "}" | SP | HT | "{" | "}" | SP | HT
Comments can be included in some HTTP header fields by surrounding Comments can be included in some HTTP header fields by surrounding
the comment text with parentheses. Comments are only allowed in the comment text with parentheses. Comments are only allowed in
fields containing "comment" as part of their field value definition. fields containing "comment" as part of their field value definition.
In all other fields, parentheses are considered part of the field In all other fields, parentheses are considered part of the field
value. value.
comment = "(" *( ctext | quoted-pair | comment ) ")" comment = "(" *( ctext | quoted-pair | comment ) ")"
ctext = <any TEXT excluding "(" and ")"> ctext = <any TEXT excluding "(" and ")">
A string of text is parsed as a single word if it is quoted using A string of text is parsed as a single word if it is quoted using
double-quote marks. double-quote marks.
quoted-string = ( <"> *(qdtext | quoted-pair ) <"> ) quoted-string = ( <"> *(qdtext | quoted-pair ) <"> )
qdtext = <any TEXT except <">> qdtext = <any TEXT excluding <"> and "\">
The backslash character ("\") MAY be used as a single-character The backslash character ("\") MAY be used as a single-character
quoting mechanism only within quoted-string and comment constructs. quoting mechanism only within quoted-string and comment constructs.
quoted-pair = "\" CHAR quoted-pair = "\" CHAR
3. Protocol Parameters 3. Protocol Parameters
3.1. HTTP Version 3.1. HTTP Version
HTTP uses a "<major>.<minor>" numbering scheme to indicate versions HTTP uses a "<major>.<minor>" numbering scheme to indicate versions
of the protocol. The protocol versioning policy is intended to allow of the protocol. The protocol versioning policy is intended to allow
the sender to indicate the format of a message and its capacity for the sender to indicate the format of a message and its capacity for
understanding further HTTP communication, rather than the features understanding further HTTP communication, rather than the features
obtained via that communication. No change is made to the version obtained via that communication. No change is made to the version
skipping to change at page 23, line 26 skipping to change at page 24, line 26
The <minor> number is incremented when the changes made to the The <minor> number is incremented when the changes made to the
protocol add features which do not change the general message parsing protocol add features which do not change the general message parsing
algorithm, but which may add to the message semantics and imply algorithm, but which may add to the message semantics and imply
additional capabilities of the sender. The <major> number is additional capabilities of the sender. The <major> number is
incremented when the format of a message within the protocol is incremented when the format of a message within the protocol is
changed. See [RFC2145] for a fuller explanation. changed. See [RFC2145] for a fuller explanation.
The version of an HTTP message is indicated by an HTTP-Version field The version of an HTTP message is indicated by an HTTP-Version field
in the first line of the message. in the first line of the message.
HTTP-Version = "HTTP" "/" 1*DIGIT "." 1*DIGIT HTTP-Version = "HTTP" "/" 1*DIGIT "." 1*DIGIT
Note that the major and minor numbers MUST be treated as separate Note that the major and minor numbers MUST be treated as separate
integers and that each MAY be incremented higher than a single digit. integers and that each MAY be incremented higher than a single digit.
Thus, HTTP/2.4 is a lower version than HTTP/2.13, which in turn is Thus, HTTP/2.4 is a lower version than HTTP/2.13, which in turn is
lower than HTTP/12.3. Leading zeros MUST be ignored by recipients lower than HTTP/12.3. Leading zeros MUST be ignored by recipients
and MUST NOT be sent. and MUST NOT be sent.
An application that sends a request or response message that includes An application that sends a request or response message that includes
HTTP-Version of "HTTP/1.1" MUST be at least conditionally compliant HTTP-Version of "HTTP/1.1" MUST be at least conditionally compliant
with this specification. Applications that are at least with this specification. Applications that are at least
skipping to change at page 24, line 34 skipping to change at page 25, line 34
3.2.1. General Syntax 3.2.1. General Syntax
URIs in HTTP can be represented in absolute form or relative to some URIs in HTTP can be represented in absolute form or relative to some
known base URI [RFC1808], depending upon the context of their use. known base URI [RFC1808], depending upon the context of their use.
The two forms are differentiated by the fact that absolute URIs The two forms are differentiated by the fact that absolute URIs
always begin with a scheme name followed by a colon. For definitive always begin with a scheme name followed by a colon. For definitive
information on URL syntax and semantics, see "Uniform Resource information on URL syntax and semantics, see "Uniform Resource
Identifiers (URI): Generic Syntax and Semantics," [RFC2396] (which Identifiers (URI): Generic Syntax and Semantics," [RFC2396] (which
replaces [RFC1738] and [RFC1808]). This specification adopts the replaces [RFC1738] and [RFC1808]). This specification adopts the
definitions of "URI-reference", "absoluteURI", "relativeURI", "port", definitions of "URI-reference", "absoluteURI", "relativeURI", "port",
"host", "abs_path", "rel_path", and "authority" from that "host", "abs_path", "rel_path", "query", and "authority" from that
specification. specification.
The HTTP protocol does not place any a priori limit on the length of The HTTP protocol does not place any a priori limit on the length of
a URI. Servers MUST be able to handle the URI of any resource they a URI. Servers MUST be able to handle the URI of any resource they
serve, and SHOULD be able to handle URIs of unbounded length if they serve, and SHOULD be able to handle URIs of unbounded length if they
provide GET-based forms that could generate such URIs. A server provide GET-based forms that could generate such URIs. A server
SHOULD return 414 (Request-URI Too Long) status if a URI is longer SHOULD return 414 (Request-URI Too Long) status if a URI is longer
than the server can handle (see Section 10.4.15). than the server can handle (see Section 10.4.15).
Note: Servers ought to be cautious about depending on URI lengths Note: Servers ought to be cautious about depending on URI lengths
above 255 bytes, because some older client or proxy above 255 bytes, because some older client or proxy
implementations might not properly support these lengths. implementations might not properly support these lengths.
3.2.2. http URL 3.2.2. http URL
The "http" scheme is used to locate network resources via the HTTP The "http" scheme is used to locate network resources via the HTTP
protocol. This section defines the scheme-specific syntax and protocol. This section defines the scheme-specific syntax and
semantics for http URLs. semantics for http URLs.
http_URL = "http:" "//" host [ ":" port ] [ abs_path [ "?" query ]] http_URL = "http:" "//" host [ ":" port ] [ abs_path [ "?" query ]]
If the port is empty or not given, port 80 is assumed. The semantics If the port is empty or not given, port 80 is assumed. The semantics
are that the identified resource is located at the server listening are that the identified resource is located at the server listening
for TCP connections on that port of that host, and the Request-URI for TCP connections on that port of that host, and the Request-URI
for the resource is abs_path (Section 5.1.2). The use of IP for the resource is abs_path (Section 5.1.2). The use of IP
addresses in URLs SHOULD be avoided whenever possible (see addresses in URLs SHOULD be avoided whenever possible (see
[RFC1900]). If the abs_path is not present in the URL, it MUST be [RFC1900]). If the abs_path is not present in the URL, it MUST be
given as "/" when used as a Request-URI for a resource given as "/" when used as a Request-URI for a resource
(Section 5.1.2). If a proxy receives a host name which is not a (Section 5.1.2). If a proxy receives a host name which is not a
fully qualified domain name, it MAY add its domain to the host name fully qualified domain name, it MAY add its domain to the host name
skipping to change at page 26, line 13 skipping to change at page 27, line 13
http://EXAMPLE.com:/%7esmith/home.html http://EXAMPLE.com:/%7esmith/home.html
3.3. Date/Time Formats 3.3. Date/Time Formats
3.3.1. Full Date 3.3.1. Full Date
HTTP applications have historically allowed three different formats HTTP applications have historically allowed three different formats
for the representation of date/time stamps: for the representation of date/time stamps:
Sun, 06 Nov 1994 08:49:37 GMT ; [RFC822], updated by [RFC1123] Sun, 06 Nov 1994 08:49:37 GMT ; [RFC822], updated by [RFC1123]
Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by [RFC1036] Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
The first format is preferred as an Internet standard and represents The first format is preferred as an Internet standard and represents
a fixed-length subset of that defined by [RFC1123] (an update to a fixed-length subset of that defined by [RFC1123] (an update to
[RFC822]). The second format is in common use, but is based on the [RFC822]). The other formats are described here only for
obsolete RFC 1036 date format [RFC1036] and lacks a four-digit year. compatibility with obsolete implementations. HTTP/1.1 clients and
HTTP/1.1 clients and servers that parse the date value MUST accept servers that parse the date value MUST accept all three formats (for
all three formats (for compatibility with HTTP/1.0), though they MUST compatibility with HTTP/1.0), though they MUST only generate the RFC
only generate the RFC 1123 format for representing HTTP-date values 1123 format for representing HTTP-date values in header fields. See
in header fields. See Appendix C for further information. Appendix C for further information.
Note: Recipients of date values are encouraged to be robust in Note: Recipients of date values are encouraged to be robust in
accepting date values that may have been sent by non-HTTP accepting date values that may have been sent by non-HTTP
applications, as is sometimes the case when retrieving or posting applications, as is sometimes the case when retrieving or posting
messages via proxies/gateways to SMTP or NNTP. messages via proxies/gateways to SMTP or NNTP.
All HTTP date/time stamps MUST be represented in Greenwich Mean Time All HTTP date/time stamps MUST be represented in Greenwich Mean Time
(GMT), without exception. For the purposes of HTTP, GMT is exactly (GMT), without exception. For the purposes of HTTP, GMT is exactly
equal to UTC (Coordinated Universal Time). This is indicated in the equal to UTC (Coordinated Universal Time). This is indicated in the
first two formats by the inclusion of "GMT" as the three-letter first two formats by the inclusion of "GMT" as the three-letter
abbreviation for time zone, and MUST be assumed when reading the abbreviation for time zone, and MUST be assumed when reading the
asctime format. HTTP-date is case sensitive and MUST NOT include asctime format. HTTP-date is case sensitive and MUST NOT include
additional LWS beyond that specifically included as SP in the additional LWS beyond that specifically included as SP in the
grammar. grammar.
HTTP-date = rfc1123-date | rfc850-date | asctime-date HTTP-date = rfc1123-date | rfc850-date | asctime-date
rfc1123-date = wkday "," SP date1 SP time SP "GMT" rfc1123-date = wkday "," SP date1 SP time SP "GMT"
rfc850-date = weekday "," SP date2 SP time SP "GMT" rfc850-date = weekday "," SP date2 SP time SP "GMT"
asctime-date = wkday SP date3 SP time SP 4DIGIT asctime-date = wkday SP date3 SP time SP 4DIGIT
date1 = 2DIGIT SP month SP 4DIGIT date1 = 2DIGIT SP month SP 4DIGIT
; day month year (e.g., 02 Jun 1982) ; day month year (e.g., 02 Jun 1982)
date2 = 2DIGIT "-" month "-" 2DIGIT date2 = 2DIGIT "-" month "-" 2DIGIT
; day-month-year (e.g., 02-Jun-82) ; day-month-year (e.g., 02-Jun-82)
date3 = month SP ( 2DIGIT | ( SP 1DIGIT )) date3 = month SP ( 2DIGIT | ( SP 1DIGIT ))
; month day (e.g., Jun 2) ; month day (e.g., Jun 2)
time = 2DIGIT ":" 2DIGIT ":" 2DIGIT time = 2DIGIT ":" 2DIGIT ":" 2DIGIT
; 00:00:00 - 23:59:59 ; 00:00:00 - 23:59:59
wkday = "Mon" | "Tue" | "Wed" wkday = "Mon" | "Tue" | "Wed"
| "Thu" | "Fri" | "Sat" | "Sun" | "Thu" | "Fri" | "Sat" | "Sun"
weekday = "Monday" | "Tuesday" | "Wednesday" weekday = "Monday" | "Tuesday" | "Wednesday"
| "Thursday" | "Friday" | "Saturday" | "Sunday" | "Thursday" | "Friday" | "Saturday" | "Sunday"
month = "Jan" | "Feb" | "Mar" | "Apr" month = "Jan" | "Feb" | "Mar" | "Apr"
| "May" | "Jun" | "Jul" | "Aug" | "May" | "Jun" | "Jul" | "Aug"
| "Sep" | "Oct" | "Nov" | "Dec" | "Sep" | "Oct" | "Nov" | "Dec"
Note: HTTP requirements for the date/time stamp format apply only to Note: HTTP requirements for the date/time stamp format apply only to
their usage within the protocol stream. Clients and servers are not their usage within the protocol stream. Clients and servers are not
required to use these formats for user presentation, request logging, required to use these formats for user presentation, request logging,
etc. etc.
3.3.2. Delta Seconds 3.3.2. Delta Seconds
Some HTTP header fields allow a time value to be specified as an Some HTTP header fields allow a time value to be specified as an
integer number of seconds, represented in decimal, after the time integer number of seconds, represented in decimal, after the time
that the message was received. that the message was received.
delta-seconds = 1*DIGIT delta-seconds = 1*DIGIT
3.4. Character Sets 3.4. Character Sets
HTTP uses the same definition of the term "character set" as that HTTP uses the same definition of the term "character set" as that
described for MIME: described for MIME:
The term "character set" is used in this document to refer to a The term "character set" is used in this document to refer to a
method used with one or more tables to convert a sequence of octets method used with one or more tables to convert a sequence of octets
into a sequence of characters. Note that unconditional conversion in into a sequence of characters. Note that unconditional conversion in
the other direction is not required, in that not all characters may the other direction is not required, in that not all characters may
skipping to change at page 28, line 17 skipping to change at page 29, line 17
Note: This use of the term "character set" is more commonly Note: This use of the term "character set" is more commonly
referred to as a "character encoding." However, since HTTP and referred to as a "character encoding." However, since HTTP and
MIME share the same registry, it is important that the terminology MIME share the same registry, it is important that the terminology
also be shared. also be shared.
HTTP character sets are identified by case-insensitive tokens. The HTTP character sets are identified by case-insensitive tokens. The
complete set of tokens is defined by the IANA Character Set registry complete set of tokens is defined by the IANA Character Set registry
(<http://www.iana.org/assignments/character-sets>). (<http://www.iana.org/assignments/character-sets>).
charset = token charset = token
Although HTTP allows an arbitrary token to be used as a charset Although HTTP allows an arbitrary token to be used as a charset
value, any token that has a predefined value within the IANA value, any token that has a predefined value within the IANA
Character Set registry MUST represent the character set defined by Character Set registry MUST represent the character set defined by
that registry. Applications SHOULD limit their use of character sets that registry. Applications SHOULD limit their use of character sets
to those defined by the IANA registry. to those defined by the IANA registry.
HTTP uses charset in two contexts: within an Accept-Charset request HTTP uses charset in two contexts: within an Accept-Charset request
header (in which the charset value is an unquoted token) and as the header (in which the charset value is an unquoted token) and as the
value of a parameter in a Content-Type header (within a request or value of a parameter in a Content-Type header (within a request or
response), in which case the parameter value of the charset parameter response), in which case the parameter value of the charset parameter
may be quoted. may be quoted.
Implementors should be aware of IETF character set requirements Implementors should be aware of IETF character set requirements
[RFC2279] [RFC2277]. [RFC3629] [RFC2277].
3.4.1. Missing Charset 3.4.1. Missing Charset
Some HTTP/1.0 software has interpreted a Content-Type header without Some HTTP/1.0 software has interpreted a Content-Type header without
charset parameter incorrectly to mean "recipient should guess." charset parameter incorrectly to mean "recipient should guess."
Senders wishing to defeat this behavior MAY include a charset Senders wishing to defeat this behavior MAY include a charset
parameter even when the charset is ISO-8859-1 and SHOULD do so when parameter even when the charset is ISO-8859-1 and SHOULD do so when
it is known that it will not confuse the recipient. it is known that it will not confuse the recipient.
Unfortunately, some older HTTP/1.0 clients did not deal properly with Unfortunately, some older HTTP/1.0 clients did not deal properly with
skipping to change at page 29, line 14 skipping to change at page 30, line 14
3.5. Content Codings 3.5. Content Codings
Content coding values indicate an encoding transformation that has Content coding values indicate an encoding transformation that has
been or can be applied to an entity. Content codings are primarily been or can be applied to an entity. Content codings are primarily
used to allow a document to be compressed or otherwise usefully used to allow a document to be compressed or otherwise usefully
transformed without losing the identity of its underlying media type transformed without losing the identity of its underlying media type
and without loss of information. Frequently, the entity is stored in and without loss of information. Frequently, the entity is stored in
coded form, transmitted directly, and only decoded by the recipient. coded form, transmitted directly, and only decoded by the recipient.
content-coding = token content-coding = token
All content-coding values are case-insensitive. HTTP/1.1 uses All content-coding values are case-insensitive. HTTP/1.1 uses
content-coding values in the Accept-Encoding (Section 14.3) and content-coding values in the Accept-Encoding (Section 14.3) and
Content-Encoding (Section 14.11) header fields. Although the value Content-Encoding (Section 14.11) header fields. Although the value
describes the content-coding, what is more important is that it describes the content-coding, what is more important is that it
indicates what decoding mechanism will be required to remove the indicates what decoding mechanism will be required to remove the
encoding. encoding.
The Internet Assigned Numbers Authority (IANA) acts as a registry for The Internet Assigned Numbers Authority (IANA) acts as a registry for
content-coding value tokens. Initially, the registry contains the content-coding value tokens. Initially, the registry contains the
skipping to change at page 30, line 23 skipping to change at page 31, line 23
conform to the purpose of content coding defined in this section. conform to the purpose of content coding defined in this section.
3.6. Transfer Codings 3.6. Transfer Codings
Transfer-coding values are used to indicate an encoding Transfer-coding values are used to indicate an encoding
transformation that has been, can be, or may need to be applied to an transformation that has been, can be, or may need to be applied to an
entity-body in order to ensure "safe transport" through the network. entity-body in order to ensure "safe transport" through the network.
This differs from a content coding in that the transfer-coding is a This differs from a content coding in that the transfer-coding is a
property of the message, not of the original entity. property of the message, not of the original entity.
transfer-coding = "chunked" | transfer-extension transfer-coding = "chunked" | transfer-extension
transfer-extension = token *( ";" parameter ) transfer-extension = token *( ";" parameter )
Parameters are in the form of attribute/value pairs. Parameters are in the form of attribute/value pairs.
parameter = attribute "=" value parameter = attribute "=" value
attribute = token attribute = token
value = token | quoted-string value = token | quoted-string
All transfer-coding values are case-insensitive. HTTP/1.1 uses All transfer-coding values are case-insensitive. HTTP/1.1 uses
transfer-coding values in the TE header field (Section 14.39) and in transfer-coding values in the TE header field (Section 14.39) and in
the Transfer-Encoding header field (Section 14.41). the Transfer-Encoding header field (Section 14.41).
Whenever a transfer-coding is applied to a message-body, the set of Whenever a transfer-coding is applied to a message-body, the set of
transfer-codings MUST include "chunked", unless the message is transfer-codings MUST include "chunked", unless the message is
terminated by closing the connection. When the "chunked" transfer- terminated by closing the connection. When the "chunked" transfer-
coding is used, it MUST be the last transfer-coding applied to the coding is used, it MUST be the last transfer-coding applied to the
message-body. The "chunked" transfer-coding MUST NOT be applied more message-body. The "chunked" transfer-coding MUST NOT be applied more
skipping to change at page 31, line 14 skipping to change at page 32, line 14
The Internet Assigned Numbers Authority (IANA) acts as a registry for The Internet Assigned Numbers Authority (IANA) acts as a registry for
transfer-coding value tokens. Initially, the registry contains the transfer-coding value tokens. Initially, the registry contains the
following tokens: "chunked" (Section 3.6.1), "gzip" (Section 3.5), following tokens: "chunked" (Section 3.6.1), "gzip" (Section 3.5),
"compress" (Section 3.5), and "deflate" (Section 3.5). "compress" (Section 3.5), and "deflate" (Section 3.5).
New transfer-coding value tokens SHOULD be registered in the same way New transfer-coding value tokens SHOULD be registered in the same way
as new content-coding value tokens (Section 3.5). as new content-coding value tokens (Section 3.5).
A server which receives an entity-body with a transfer-coding it does A server which receives an entity-body with a transfer-coding it does
not understand SHOULD return 501 (Unimplemented), and close the not understand SHOULD return 501 (Not Implemented), and close the
connection. A server MUST NOT send transfer-codings to an HTTP/1.0 connection. A server MUST NOT send transfer-codings to an HTTP/1.0
client. client.
3.6.1. Chunked Transfer Coding 3.6.1. Chunked Transfer Coding
The chunked encoding modifies the body of a message in order to The chunked encoding modifies the body of a message in order to
transfer it as a series of chunks, each with its own size indicator, transfer it as a series of chunks, each with its own size indicator,
followed by an OPTIONAL trailer containing entity-header fields. followed by an OPTIONAL trailer containing entity-header fields.
This allows dynamically produced content to be transferred along with This allows dynamically produced content to be transferred along with
the information necessary for the recipient to verify that it has the information necessary for the recipient to verify that it has
received the full message. received the full message.
Chunked-Body = *chunk Chunked-Body = *chunk
last-chunk last-chunk
trailer trailer
CRLF CRLF
chunk = chunk-size [ chunk-extension ] CRLF chunk = chunk-size [ chunk-extension ] CRLF
chunk-data CRLF chunk-data CRLF
chunk-size = 1*HEX chunk-size = 1*HEX
last-chunk = 1*("0") [ chunk-extension ] CRLF last-chunk = 1*("0") [ chunk-extension ] CRLF
chunk-extension= *( ";" chunk-ext-name [ "=" chunk-ext-val ] ) chunk-extension= *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
chunk-ext-name = token chunk-ext-name = token
chunk-ext-val = token | quoted-string chunk-ext-val = token | quoted-string
chunk-data = chunk-size(OCTET) chunk-data = chunk-size(OCTET)
trailer = *(entity-header CRLF) trailer = *(entity-header CRLF)
The chunk-size field is a string of hex digits indicating the size of The chunk-size field is a string of hex digits indicating the size of
the chunk-data in octets. The chunked encoding is ended by any chunk the chunk-data in octets. The chunked encoding is ended by any chunk
whose size is zero, followed by the trailer, which is terminated by whose size is zero, followed by the trailer, which is terminated by
an empty line. an empty line.
The trailer allows the sender to include additional HTTP header The trailer allows the sender to include additional HTTP header
fields at the end of the message. The Trailer header field can be fields at the end of the message. The Trailer header field can be
used to indicate which header fields are included in a trailer (see used to indicate which header fields are included in a trailer (see
Section 14.40). Section 14.40).
skipping to change at page 32, line 36 skipping to change at page 33, line 36
An example process for decoding a Chunked-Body is presented in An example process for decoding a Chunked-Body is presented in
Appendix D.6. Appendix D.6.
All HTTP/1.1 applications MUST be able to receive and decode the All HTTP/1.1 applications MUST be able to receive and decode the
"chunked" transfer-coding, and MUST ignore chunk-extension extensions "chunked" transfer-coding, and MUST ignore chunk-extension extensions
they do not understand. they do not understand.
3.7. Media Types 3.7. Media Types
HTTP uses Internet Media Types [RFC1590] in the Content-Type HTTP uses Internet Media Types [RFC2048] in the Content-Type
(Section 14.17) and Accept (Section 14.1) header fields in order to (Section 14.17) and Accept (Section 14.1) header fields in order to
provide open and extensible data typing and type negotiation. provide open and extensible data typing and type negotiation.
media-type = type "/" subtype *( ";" parameter ) media-type = type "/" subtype *( ";" parameter )
type = token type = token
subtype = token subtype = token
Parameters MAY follow the type/subtype in the form of attribute/value Parameters MAY follow the type/subtype in the form of attribute/value
pairs (as defined in Section 3.6). pairs (as defined in Section 3.6).
The type, subtype, and parameter attribute names are case- The type, subtype, and parameter attribute names are case-
insensitive. Parameter values might or might not be case-sensitive, insensitive. Parameter values might or might not be case-sensitive,
depending on the semantics of the parameter name. Linear white space depending on the semantics of the parameter name. Linear white space
(LWS) MUST NOT be used between the type and subtype, nor between an (LWS) MUST NOT be used between the type and subtype, nor between an
attribute and its value. The presence or absence of a parameter attribute and its value. The presence or absence of a parameter
might be significant to the processing of a media-type, depending on might be significant to the processing of a media-type, depending on
its definition within the media type registry. its definition within the media type registry.
Note that some older HTTP applications do not recognize media type Note that some older HTTP applications do not recognize media type
parameters. When sending data to older HTTP applications, parameters. When sending data to older HTTP applications,
implementations SHOULD only use media type parameters when they are implementations SHOULD only use media type parameters when they are
required by that type/subtype definition. required by that type/subtype definition.
Media-type values are registered with the Internet Assigned Number Media-type values are registered with the Internet Assigned Number
Authority (IANA). The media type registration process is outlined in Authority (IANA). The media type registration process is outlined in
[RFC1590]. Use of non-registered media types is discouraged. [RFC2048]. Use of non-registered media types is discouraged.
3.7.1. Canonicalization and Text Defaults 3.7.1. Canonicalization and Text Defaults
Internet media types are registered with a canonical form. An Internet media types are registered with a canonical form. An
entity-body transferred via HTTP messages MUST be represented in the entity-body transferred via HTTP messages MUST be represented in the
appropriate canonical form prior to its transmission except for appropriate canonical form prior to its transmission except for
"text" types, as defined in the next paragraph. "text" types, as defined in the next paragraph.
When in canonical form, media subtypes of the "text" type use CRLF as When in canonical form, media subtypes of the "text" type use CRLF as
the text line break. HTTP relaxes this requirement and allows the the text line break. HTTP relaxes this requirement and allows the
skipping to change at page 34, line 33 skipping to change at page 35, line 33
body do not have any significance to HTTP beyond that defined by body do not have any significance to HTTP beyond that defined by
their MIME semantics. their MIME semantics.
In general, an HTTP user agent SHOULD follow the same or similar In general, an HTTP user agent SHOULD follow the same or similar
behavior as a MIME user agent would upon receipt of a multipart type. behavior as a MIME user agent would upon receipt of a multipart type.
If an application receives an unrecognized multipart subtype, the If an application receives an unrecognized multipart subtype, the
application MUST treat it as being equivalent to "multipart/mixed". application MUST treat it as being equivalent to "multipart/mixed".
Note: The "multipart/form-data" type has been specifically defined Note: The "multipart/form-data" type has been specifically defined
for carrying form data suitable for processing via the POST for carrying form data suitable for processing via the POST
request method, as described in RFC 1867 [RFC1867]. request method, as described in [RFC2388].
3.8. Product Tokens 3.8. Product Tokens
Product tokens are used to allow communicating applications to Product tokens are used to allow communicating applications to
identify themselves by software name and version. Most fields using identify themselves by software name and version. Most fields using
product tokens also allow sub-products which form a significant part product tokens also allow sub-products which form a significant part
of the application to be listed, separated by white space. By of the application to be listed, separated by white space. By
convention, the products are listed in order of their significance convention, the products are listed in order of their significance
for identifying the application. for identifying the application.
product = token ["/" product-version] product = token ["/" product-version]
product-version = token product-version = token
Examples: Examples:
User-Agent: CERN-LineMode/2.15 libwww/2.17b3 User-Agent: CERN-LineMode/2.15 libwww/2.17b3
Server: Apache/0.8.4 Server: Apache/0.8.4
Product tokens SHOULD be short and to the point. They MUST NOT be Product tokens SHOULD be short and to the point. They MUST NOT be
used for advertising or other non-essential information. Although used for advertising or other non-essential information. Although
any token character MAY appear in a product-version, this token any token character MAY appear in a product-version, this token
SHOULD only be used for a version identifier (i.e., successive SHOULD only be used for a version identifier (i.e., successive
skipping to change at page 35, line 24 skipping to change at page 36, line 24
HTTP content negotiation (Section 12) uses short "floating point" HTTP content negotiation (Section 12) uses short "floating point"
numbers to indicate the relative importance ("weight") of various numbers to indicate the relative importance ("weight") of various
negotiable parameters. A weight is normalized to a real number in negotiable parameters. A weight is normalized to a real number in
the range 0 through 1, where 0 is the minimum and 1 the maximum the range 0 through 1, where 0 is the minimum and 1 the maximum
value. If a parameter has a quality value of 0, then content with value. If a parameter has a quality value of 0, then content with
this parameter is `not acceptable' for the client. HTTP/1.1 this parameter is `not acceptable' for the client. HTTP/1.1
applications MUST NOT generate more than three digits after the applications MUST NOT generate more than three digits after the
decimal point. User configuration of these values SHOULD also be decimal point. User configuration of these values SHOULD also be
limited in this fashion. limited in this fashion.
qvalue = ( "0" [ "." 0*3DIGIT ] ) qvalue = ( "0" [ "." 0*3DIGIT ] )
| ( "1" [ "." 0*3("0") ] ) | ( "1" [ "." 0*3("0") ] )
"Quality values" is a misnomer, since these values merely represent "Quality values" is a misnomer, since these values merely represent
relative degradation in desired quality. relative degradation in desired quality.
3.10. Language Tags 3.10. Language Tags
A language tag identifies a natural language spoken, written, or A language tag identifies a natural language spoken, written, or
otherwise conveyed by human beings for communication of information otherwise conveyed by human beings for communication of information
to other human beings. Computer languages are explicitly excluded. to other human beings. Computer languages are explicitly excluded.
HTTP uses language tags within the Accept-Language and Content- HTTP uses language tags within the Accept-Language and Content-
Language fields. Language fields.
The syntax and registry of HTTP language tags is the same as that The syntax and registry of HTTP language tags is the same as that
defined by [RFC1766]. In summary, a language tag is composed of 1 or defined by [RFC1766]. In summary, a language tag is composed of 1 or
more parts: A primary language tag and a possibly empty series of more parts: A primary language tag and a possibly empty series of
subtags: subtags:
language-tag = primary-tag *( "-" subtag ) language-tag = primary-tag *( "-" subtag )
primary-tag = 1*8ALPHA primary-tag = 1*8ALPHA
subtag = 1*8ALPHA subtag = 1*8ALPHA
White space is not allowed within the tag and all tags are case- White space is not allowed within the tag and all tags are case-
insensitive. The name space of language tags is administered by the insensitive. The name space of language tags is administered by the
IANA. Example tags include: IANA. Example tags include:
en, en-US, en-cockney, i-cherokee, x-pig-latin en, en-US, en-cockney, i-cherokee, x-pig-latin
where any two-letter primary-tag is an ISO-639 language abbreviation where any two-letter primary-tag is an ISO-639 language abbreviation
and any two-letter initial subtag is an ISO-3166 country code. (The and any two-letter initial subtag is an ISO-3166 country code. (The
last three tags above are not registered tags; all but the last are last three tags above are not registered tags; all but the last are
skipping to change at page 36, line 20 skipping to change at page 37, line 20
3.11. Entity Tags 3.11. Entity Tags
Entity tags are used for comparing two or more entities from the same Entity tags are used for comparing two or more entities from the same
requested resource. HTTP/1.1 uses entity tags in the ETag requested resource. HTTP/1.1 uses entity tags in the ETag
(Section 14.19), If-Match (Section 14.24), If-None-Match (Section 14.19), If-Match (Section 14.24), If-None-Match
(Section 14.26), and If-Range (Section 14.27) header fields. The (Section 14.26), and If-Range (Section 14.27) header fields. The
definition of how they are used and compared as cache validators is definition of how they are used and compared as cache validators is
in Section 13.3.3. An entity tag consists of an opaque quoted in Section 13.3.3. An entity tag consists of an opaque quoted
string, possibly prefixed by a weakness indicator. string, possibly prefixed by a weakness indicator.
entity-tag = [ weak ] opaque-tag entity-tag = [ weak ] opaque-tag
weak = "W/" weak = "W/"
opaque-tag = quoted-string opaque-tag = quoted-string
A "strong entity tag" MAY be shared by two entities of a resource A "strong entity tag" MAY be shared by two entities of a resource
only if they are equivalent by octet equality. only if they are equivalent by octet equality.
A "weak entity tag," indicated by the "W/" prefix, MAY be shared by A "weak entity tag," indicated by the "W/" prefix, MAY be shared by
two entities of a resource only if the entities are equivalent and two entities of a resource only if the entities are equivalent and
could be substituted for each other with no significant change in could be substituted for each other with no significant change in
semantics. A weak entity tag can only be used for weak comparison. semantics. A weak entity tag can only be used for weak comparison.
An entity tag MUST be unique across all versions of all entities An entity tag MUST be unique across all versions of all entities
skipping to change at page 36, line 47 skipping to change at page 37, line 47
entities. entities.
3.12. Range Units 3.12. Range Units
HTTP/1.1 allows a client to request that only part (a range of) the HTTP/1.1 allows a client to request that only part (a range of) the
response entity be included within the response. HTTP/1.1 uses range response entity be included within the response. HTTP/1.1 uses range
units in the Range (Section 14.35) and Content-Range (Section 14.16) units in the Range (Section 14.35) and Content-Range (Section 14.16)
header fields. An entity can be broken down into subranges according header fields. An entity can be broken down into subranges according
to various structural units. to various structural units.
range-unit = bytes-unit | other-range-unit range-unit = bytes-unit | other-range-unit
bytes-unit = "bytes" bytes-unit = "bytes"
other-range-unit = token other-range-unit = token
The only range unit defined by HTTP/1.1 is "bytes". HTTP/1.1 The only range unit defined by HTTP/1.1 is "bytes". HTTP/1.1
implementations MAY ignore ranges specified using other units. implementations MAY ignore ranges specified using other units.
HTTP/1.1 has been designed to allow implementations of applications HTTP/1.1 has been designed to allow implementations of applications
that do not depend on knowledge of ranges. that do not depend on knowledge of ranges.
4. HTTP Message 4. HTTP Message
4.1. Message Types 4.1. Message Types
HTTP messages consist of requests from client to server and responses HTTP messages consist of requests from client to server and responses
from server to client. from server to client.
HTTP-message = Request | Response ; HTTP/1.1 messages HTTP-message = Request | Response ; HTTP/1.1 messages
Request (Section 5) and Response (Section 6) messages use the generic Request (Section 5) and Response (Section 6) messages use the generic
message format of [RFC822] for transferring entities (the payload of message format of [RFC2822] for transferring entities (the payload of
the message). Both types of message consist of a start-line, zero or the message). Both types of message consist of a start-line, zero or
more header fields (also known as "headers"), an empty line (i.e., a more header fields (also known as "headers"), an empty line (i.e., a
line with nothing preceding the CRLF) indicating the end of the line with nothing preceding the CRLF) indicating the end of the
header fields, and possibly a message-body. header fields, and possibly a message-body.
generic-message = start-line generic-message = start-line
*(message-header CRLF) *(message-header CRLF)
CRLF CRLF
[ message-body ] [ message-body ]
start-line = Request-Line | Status-Line start-line = Request-Line | Status-Line
In the interest of robustness, servers SHOULD ignore any empty In the interest of robustness, servers SHOULD ignore any empty
line(s) received where a Request-Line is expected. In other words, line(s) received where a Request-Line is expected. In other words,
if the server is reading the protocol stream at the beginning of a if the server is reading the protocol stream at the beginning of a
message and receives a CRLF first, it should ignore the CRLF. message and receives a CRLF first, it should ignore the CRLF.
Certain buggy HTTP/1.0 client implementations generate extra CRLF's Certain buggy HTTP/1.0 client implementations generate extra CRLF's
after a POST request. To restate what is explicitly forbidden by the after a POST request. To restate what is explicitly forbidden by the
BNF, an HTTP/1.1 client MUST NOT preface or follow a request with an BNF, an HTTP/1.1 client MUST NOT preface or follow a request with an
extra CRLF. extra CRLF.
4.2. Message Headers 4.2. Message Headers
HTTP header fields, which include general-header (Section 4.5), HTTP header fields, which include general-header (Section 4.5),
request-header (Section 5.3), response-header (Section 6.2), and request-header (Section 5.3), response-header (Section 6.2), and
entity-header (Section 7.1) fields, follow the same generic format as entity-header (Section 7.1) fields, follow the same generic format as
that given in Section 3.1 of [RFC822]. Each header field consists of that given in Section 2.1 of [RFC2822]. Each header field consists
a name followed by a colon (":") and the field value. Field names of a name followed by a colon (":") and the field value. Field names
are case-insensitive. The field value MAY be preceded by any amount are case-insensitive. The field value MAY be preceded by any amount
of LWS, though a single SP is preferred. Header fields can be of LWS, though a single SP is preferred. Header fields can be
extended over multiple lines by preceding each extra line with at extended over multiple lines by preceding each extra line with at
least one SP or HT. Applications ought to follow "common form", least one SP or HT. Applications ought to follow "common form",
where one is known or indicated, when generating HTTP constructs, where one is known or indicated, when generating HTTP constructs,
since there might exist some implementations that fail to accept since there might exist some implementations that fail to accept
anything beyond the common forms. anything beyond the common forms.
message-header = field-name ":" [ field-value ] message-header = field-name ":" [ field-value ]
field-name = token field-name = token
field-value = *( field-content | LWS ) field-value = *( field-content | LWS )
field-content = <the OCTETs making up the field-value field-content = <the OCTETs making up the field-value
and consisting of either *TEXT or combinations and consisting of either *TEXT or combinations
of token, separators, and quoted-string> of token, separators, and quoted-string>
The field-content does not include any leading or trailing LWS: The field-content does not include any leading or trailing LWS:
linear white space occurring before the first non-whitespace linear white space occurring before the first non-whitespace
character of the field-value or after the last non-whitespace character of the field-value or after the last non-whitespace
character of the field-value. Such leading or trailing LWS MAY be character of the field-value. Such leading or trailing LWS MAY be
removed without changing the semantics of the field value. Any LWS removed without changing the semantics of the field value. Any LWS
that occurs between field-content MAY be replaced with a single SP that occurs between field-content MAY be replaced with a single SP
before interpreting the field value or forwarding the message before interpreting the field value or forwarding the message
downstream. downstream.
skipping to change at page 39, line 45 skipping to change at page 40, line 45
change the order of these field values when a message is forwarded. change the order of these field values when a message is forwarded.
4.3. Message Body 4.3. Message Body
The message-body (if any) of an HTTP message is used to carry the The message-body (if any) of an HTTP message is used to carry the
entity-body associated with the request or response. The message- entity-body associated with the request or response. The message-
body differs from the entity-body only when a transfer-coding has body differs from the entity-body only when a transfer-coding has
been applied, as indicated by the Transfer-Encoding header field been applied, as indicated by the Transfer-Encoding header field
(Section 14.41). (Section 14.41).
message-body = entity-body message-body = entity-body
| <entity-body encoded as per Transfer-Encoding> | <entity-body encoded as per Transfer-Encoding>
Transfer-Encoding MUST be used to indicate any transfer-codings Transfer-Encoding MUST be used to indicate any transfer-codings
applied by an application to ensure safe and proper transfer of the applied by an application to ensure safe and proper transfer of the
message. Transfer-Encoding is a property of the message, not of the message. Transfer-Encoding is a property of the message, not of the
entity, and thus MAY be added or removed by any application along the entity, and thus MAY be added or removed by any application along the
request/response chain. (However, Section 3.6 places restrictions on request/response chain. (However, Section 3.6 places restrictions on
when certain transfer-codings may be used.) when certain transfer-codings may be used.)
The rules for when a message-body is allowed in a message differ for The rules for when a message-body is allowed in a message differ for
requests and responses. requests and responses.
skipping to change at page 40, line 23 skipping to change at page 41, line 23
(Section 5.1.1) does not allow sending an entity-body in requests. A (Section 5.1.1) does not allow sending an entity-body in requests. A
server SHOULD read and forward a message-body on any request; if the server SHOULD read and forward a message-body on any request; if the
request method does not include defined semantics for an entity-body, request method does not include defined semantics for an entity-body,
then the message-body SHOULD be ignored when handling the request. then the message-body SHOULD be ignored when handling the request.
For response messages, whether or not a message-body is included with For response messages, whether or not a message-body is included with
a message is dependent on both the request method and the response a message is dependent on both the request method and the response
status code (Section 6.1.1). All responses to the HEAD request status code (Section 6.1.1). All responses to the HEAD request
method MUST NOT include a message-body, even though the presence of method MUST NOT include a message-body, even though the presence of
entity-header fields might lead one to believe they do. All 1xx entity-header fields might lead one to believe they do. All 1xx
(informational), 204 (no content), and 304 (not modified) responses (informational), 204 (No Content), and 304 (Not Modified) responses
MUST NOT include a message-body. All other responses do include a MUST NOT include a message-body. All other responses do include a
message-body, although it MAY be of zero length. message-body, although it MAY be of zero length.
4.4. Message Length 4.4. Message Length
The transfer-length of a message is the length of the message-body as The transfer-length of a message is the length of the message-body as
it appears in the message; that is, after any transfer-codings have it appears in the message; that is, after any transfer-codings have
been applied. When a message-body is included with a message, the been applied. When a message-body is included with a message, the
transfer-length of that body is determined by one of the following transfer-length of that body is determined by one of the following
(in order of precedence): (in order of precedence):
skipping to change at page 41, line 28 skipping to change at page 42, line 28
5. By the server closing the connection. (Closing the connection 5. By the server closing the connection. (Closing the connection
cannot be used to indicate the end of a request body, since that cannot be used to indicate the end of a request body, since that
would leave no possibility for the server to send back a would leave no possibility for the server to send back a
response.) response.)
For compatibility with HTTP/1.0 applications, HTTP/1.1 requests For compatibility with HTTP/1.0 applications, HTTP/1.1 requests
containing a message-body MUST include a valid Content-Length header containing a message-body MUST include a valid Content-Length header
field unless the server is known to be HTTP/1.1 compliant. If a field unless the server is known to be HTTP/1.1 compliant. If a
request contains a message-body and a Content-Length is not given, request contains a message-body and a Content-Length is not given,
the server SHOULD respond with 400 (bad request) if it cannot the server SHOULD respond with 400 (Bad Request) if it cannot
determine the length of the message, or with 411 (length required) if determine the length of the message, or with 411 (Length Required) if
it wishes to insist on receiving a valid Content-Length. it wishes to insist on receiving a valid Content-Length.
All HTTP/1.1 applications that receive entities MUST accept the All HTTP/1.1 applications that receive entities MUST accept the
"chunked" transfer-coding (Section 3.6), thus allowing this mechanism "chunked" transfer-coding (Section 3.6), thus allowing this mechanism
to be used for messages when the message length cannot be determined to be used for messages when the message length cannot be determined
in advance. in advance.
Messages MUST NOT include both a Content-Length header field and a Messages MUST NOT include both a Content-Length header field and a
transfer-coding. If the message does include a transfer-coding, the transfer-coding. If the message does include a transfer-coding, the
Content-Length MUST be ignored. Content-Length MUST be ignored.
skipping to change at page 42, line 5 skipping to change at page 43, line 5
the message-body. HTTP/1.1 user agents MUST notify the user when an the message-body. HTTP/1.1 user agents MUST notify the user when an
invalid length is received and detected. invalid length is received and detected.
4.5. General Header Fields 4.5. General Header Fields
There are a few header fields which have general applicability for There are a few header fields which have general applicability for
both request and response messages, but which do not apply to the both request and response messages, but which do not apply to the
entity being transferred. These header fields apply only to the entity being transferred. These header fields apply only to the
message being transmitted. message being transmitted.
general-header = Cache-Control ; Section 14.9 general-header = Cache-Control ; Section 14.9
| Connection ; Section 14.10 | Connection ; Section 14.10
| Date ; Section 14.18 | Date ; Section 14.18
| Pragma ; Section 14.32 | Pragma ; Section 14.32
| Trailer ; Section 14.40 | Trailer ; Section 14.40
| Transfer-Encoding ; Section 14.41 | Transfer-Encoding ; Section 14.41
| Upgrade ; Section 14.42 | Upgrade ; Section 14.42
| Via ; Section 14.45 | Via ; Section 14.45
| Warning ; Section 14.46 | Warning ; Section 14.46
General-header field names can be extended reliably only in General-header field names can be extended reliably only in
combination with a change in the protocol version. However, new or combination with a change in the protocol version. However, new or
experimental header fields may be given the semantics of general experimental header fields may be given the semantics of general
header fields if all parties in the communication recognize them to header fields if all parties in the communication recognize them to
be general-header fields. Unrecognized header fields are treated as be general-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
5. Request 5. Request
A request message from a client to a server includes, within the A request message from a client to a server includes, within the
first line of that message, the method to be applied to the resource, first line of that message, the method to be applied to the resource,
the identifier of the resource, and the protocol version in use. the identifier of the resource, and the protocol version in use.
Request = Request-Line ; Section 5.1 Request = Request-Line ; Section 5.1
*(( general-header ; Section 4.5 *(( general-header ; Section 4.5
| request-header ; Section 5.3 | request-header ; Section 5.3
| entity-header ) CRLF) ; Section 7.1 | entity-header ) CRLF) ; Section 7.1
CRLF CRLF
[ message-body ] ; Section 4.3 [ message-body ] ; Section 4.3
5.1. Request-Line 5.1. Request-Line
The Request-Line begins with a method token, followed by the Request- The Request-Line begins with a method token, followed by the Request-
URI and the protocol version, and ending with CRLF. The elements are URI and the protocol version, and ending with CRLF. The elements are
separated by SP characters. No CR or LF is allowed except in the separated by SP characters. No CR or LF is allowed except in the
final CRLF sequence. final CRLF sequence.
Request-Line = Method SP Request-URI SP HTTP-Version CRLF Request-Line = Method SP Request-URI SP HTTP-Version CRLF
5.1.1. Method 5.1.1. Method
The Method token indicates the method to be performed on the resource The Method token indicates the method to be performed on the resource
identified by the Request-URI. The method is case-sensitive. identified by the Request-URI. The method is case-sensitive.
Method = "OPTIONS" ; Section 9.2 Method = "OPTIONS" ; Section 9.2
| "GET" ; Section 9.3 | "GET" ; Section 9.3
| "HEAD" ; Section 9.4 | "HEAD" ; Section 9.4
| "POST" ; Section 9.5 | "POST" ; Section 9.5
| "PUT" ; Section 9.6 | "PUT" ; Section 9.6
| "DELETE" ; Section 9.7 | "DELETE" ; Section 9.7
| "TRACE" ; Section 9.8 | "TRACE" ; Section 9.8
| "CONNECT" ; Section 9.9 | "CONNECT" ; Section 9.9
| extension-method | extension-method
extension-method = token extension-method = token
The list of methods allowed by a resource can be specified in an The list of methods allowed by a resource can be specified in an
Allow header field (Section 14.7). The return code of the response Allow header field (Section 14.7). The return code of the response
always notifies the client whether a method is currently allowed on a always notifies the client whether a method is currently allowed on a
resource, since the set of allowed methods can change dynamically. resource, since the set of allowed methods can change dynamically.
An origin server SHOULD return the status code 405 (Method Not An origin server SHOULD return the status code 405 (Method Not
Allowed) if the method is known by the origin server but not allowed Allowed) if the method is known by the origin server but not allowed
for the requested resource, and 501 (Not Implemented) if the method for the requested resource, and 501 (Not Implemented) if the method
is unrecognized or not implemented by the origin server. The methods is unrecognized or not implemented by the origin server. The methods
GET and HEAD MUST be supported by all general-purpose servers. All GET and HEAD MUST be supported by all general-purpose servers. All
other methods are OPTIONAL; however, if the above methods are other methods are OPTIONAL; however, if the above methods are
implemented, they MUST be implemented with the same semantics as implemented, they MUST be implemented with the same semantics as
those specified in Section 9. those specified in Section 9.
5.1.2. Request-URI 5.1.2. Request-URI
The Request-URI is a Uniform Resource Identifier (Section 3.2) and The Request-URI is a Uniform Resource Identifier (Section 3.2) and
identifies the resource upon which to apply the request. identifies the resource upon which to apply the request.
Request-URI = "*" Request-URI = "*"
| absoluteURI | absoluteURI
| abs_path [ "?" query ] | abs_path [ "?" query ]
| authority | authority
The four options for Request-URI are dependent on the nature of the The four options for Request-URI are dependent on the nature of the
request. The asterisk "*" means that the request does not apply to a request. The asterisk "*" means that the request does not apply to a
particular resource, but to the server itself, and is only allowed particular resource, but to the server itself, and is only allowed
when the method used does not necessarily apply to a resource. One when the method used does not necessarily apply to a resource. One
example would be example would be
OPTIONS * HTTP/1.1 OPTIONS * HTTP/1.1
The absoluteURI form is REQUIRED when the request is being made to a The absoluteURI form is REQUIRED when the request is being made to a
skipping to change at page 46, line 19 skipping to change at page 47, line 19
exact resource is being requested. exact resource is being requested.
5.3. Request Header Fields 5.3. Request Header Fields
The request-header fields allow the client to pass additional The request-header fields allow the client to pass additional
information about the request, and about the client itself, to the information about the request, and about the client itself, to the
server. These fields act as request modifiers, with semantics server. These fields act as request modifiers, with semantics
equivalent to the parameters on a programming language method equivalent to the parameters on a programming language method
invocation. invocation.
request-header = Accept ; Section 14.1 request-header = Accept ; Section 14.1
| Accept-Charset ; Section 14.2 | Accept-Charset ; Section 14.2
| Accept-Encoding ; Section 14.3 | Accept-Encoding ; Section 14.3
| Accept-Language ; Section 14.4 | Accept-Language ; Section 14.4
| Authorization ; Section 14.8 | Authorization ; Section 14.8
| Expect ; Section 14.20 | Expect ; Section 14.20
| From ; Section 14.22 | From ; Section 14.22
| Host ; Section 14.23 | Host ; Section 14.23
| If-Match ; Section 14.24 | If-Match ; Section 14.24
| If-Modified-Since ; Section 14.25 | If-Modified-Since ; Section 14.25
| If-None-Match ; Section 14.26 | If-None-Match ; Section 14.26
| If-Range ; Section 14.27 | If-Range ; Section 14.27
| If-Unmodified-Since ; Section 14.28 | If-Unmodified-Since ; Section 14.28
| Max-Forwards ; Section 14.31 | Max-Forwards ; Section 14.31
| Proxy-Authorization ; Section 14.34 | Proxy-Authorization ; Section 14.34
| Range ; Section 14.35 | Range ; Section 14.35
| Referer ; Section 14.36 | Referer ; Section 14.36
| TE ; Section 14.39 | TE ; Section 14.39
| User-Agent ; Section 14.43 | User-Agent ; Section 14.43
Request-header field names can be extended reliably only in Request-header field names can be extended reliably only in
combination with a change in the protocol version. However, new or combination with a change in the protocol version. However, new or
experimental header fields MAY be given the semantics of request- experimental header fields MAY be given the semantics of request-
header fields if all parties in the communication recognize them to header fields if all parties in the communication recognize them to
be request-header fields. Unrecognized header fields are treated as be request-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
6. Response 6. Response
After receiving and interpreting a request message, a server responds After receiving and interpreting a request message, a server responds
with an HTTP response message. with an HTTP response message.
Response = Status-Line ; Section 6.1 Response = Status-Line ; Section 6.1
*(( general-header ; Section 4.5 *(( general-header ; Section 4.5
| response-header ; Section 6.2 | response-header ; Section 6.2
| entity-header ) CRLF) ; Section 7.1 | entity-header ) CRLF) ; Section 7.1
CRLF CRLF
[ message-body ] ; Section 7.2 [ message-body ] ; Section 7.2
6.1. Status-Line 6.1. Status-Line
The first line of a Response message is the Status-Line, consisting The first line of a Response message is the Status-Line, consisting
of the protocol version followed by a numeric status code and its of the protocol version followed by a numeric status code and its
associated textual phrase, with each element separated by SP associated textual phrase, with each element separated by SP
characters. No CR or LF is allowed except in the final CRLF characters. No CR or LF is allowed except in the final CRLF
sequence. sequence.
Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF
6.1.1. Status Code and Reason Phrase 6.1.1. Status Code and Reason Phrase
The Status-Code element is a 3-digit integer result code of the The Status-Code element is a 3-digit integer result code of the
attempt to understand and satisfy the request. These codes are fully attempt to understand and satisfy the request. These codes are fully
defined in Section 10. The Reason-Phrase is intended to give a short defined in Section 10. The Reason-Phrase is intended to give a short
textual description of the Status-Code. The Status-Code is intended textual description of the Status-Code. The Status-Code is intended
for use by automata and the Reason-Phrase is intended for the human for use by automata and the Reason-Phrase is intended for the human
user. The client is not required to examine or display the Reason- user. The client is not required to examine or display the Reason-
Phrase. Phrase.
skipping to change at page 49, line 5 skipping to change at page 50, line 5
o 5xx: Server Error - The server failed to fulfill an apparently o 5xx: Server Error - The server failed to fulfill an apparently
valid request valid request
The individual values of the numeric status codes defined for The individual values of the numeric status codes defined for
HTTP/1.1, and an example set of corresponding Reason-Phrase's, are HTTP/1.1, and an example set of corresponding Reason-Phrase's, are
presented below. The reason phrases listed here are only presented below. The reason phrases listed here are only
recommendations -- they MAY be replaced by local equivalents without recommendations -- they MAY be replaced by local equivalents without
affecting the protocol. affecting the protocol.
Status-Code = Status-Code =
"100" ; Section 10.1.1: Continue "100" ; Section 10.1.1: Continue
| "101" ; Section 10.1.2: Switching Protocols | "101" ; Section 10.1.2: Switching Protocols
| "200" ; Section 10.2.1: OK | "200" ; Section 10.2.1: OK
| "201" ; Section 10.2.2: Created | "201" ; Section 10.2.2: Created
| "202" ; Section 10.2.3: Accepted | "202" ; Section 10.2.3: Accepted
| "203" ; Section 10.2.4: Non-Authoritative Information | "203" ; Section 10.2.4: Non-Authoritative Information
| "204" ; Section 10.2.5: No Content | "204" ; Section 10.2.5: No Content
| "205" ; Section 10.2.6: Reset Content | "205" ; Section 10.2.6: Reset Content
| "206" ; Section 10.2.7: Partial Content | "206" ; Section 10.2.7: Partial Content
| "300" ; Section 10.3.1: Multiple Choices | "300" ; Section 10.3.1: Multiple Choices
| "301" ; Section 10.3.2: Moved Permanently | "301" ; Section 10.3.2: Moved Permanently
| "302" ; Section 10.3.3: Found | "302" ; Section 10.3.3: Found
| "303" ; Section 10.3.4: See Other | "303" ; Section 10.3.4: See Other
| "304" ; Section 10.3.5: Not Modified | "304" ; Section 10.3.5: Not Modified
| "305" ; Section 10.3.6: Use Proxy | "305" ; Section 10.3.6: Use Proxy
| "307" ; Section 10.3.8: Temporary Redirect | "307" ; Section 10.3.8: Temporary Redirect
| "400" ; Section 10.4.1: Bad Request | "400" ; Section 10.4.1: Bad Request
| "401" ; Section 10.4.2: Unauthorized | "401" ; Section 10.4.2: Unauthorized
| "402" ; Section 10.4.3: Payment Required | "402" ; Section 10.4.3: Payment Required
| "403" ; Section 10.4.4: Forbidden | "403" ; Section 10.4.4: Forbidden
| "404" ; Section 10.4.5: Not Found | "404" ; Section 10.4.5: Not Found
| "405" ; Section 10.4.6: Method Not Allowed | "405" ; Section 10.4.6: Method Not Allowed
| "406" ; Section 10.4.7: Not Acceptable | "406" ; Section 10.4.7: Not Acceptable
| "407" ; Section 10.4.8: Proxy Authentication Required | "407" ; Section 10.4.8: Proxy Authentication Required
| "408" ; Section 10.4.9: Request Time-out | "408" ; Section 10.4.9: Request Time-out
| "409" ; Section 10.4.10: Conflict | "409" ; Section 10.4.10: Conflict
| "410" ; Section 10.4.11: Gone | "410" ; Section 10.4.11: Gone
| "411" ; Section 10.4.12: Length Required | "411" ; Section 10.4.12: Length Required
| "412" ; Section 10.4.13: Precondition Failed | "412" ; Section 10.4.13: Precondition Failed
| "413" ; Section 10.4.14: Request Entity Too Large | "413" ; Section 10.4.14: Request Entity Too Large
| "414" ; Section 10.4.15: Request-URI Too Large | "414" ; Section 10.4.15: Request-URI Too Large
| "415" ; Section 10.4.16: Unsupported Media Type | "415" ; Section 10.4.16: Unsupported Media Type
| "416" ; Section 10.4.17: Requested range not satisfiable | "416" ; Section 10.4.17: Requested range not satisfiable
| "417" ; Section 10.4.18: Expectation Failed | "417" ; Section 10.4.18: Expectation Failed
| "500" ; Section 10.5.1: Internal Server Error | "500" ; Section 10.5.1: Internal Server Error
| "501" ; Section 10.5.2: Not Implemented | "501" ; Section 10.5.2: Not Implemented
| "502" ; Section 10.5.3: Bad Gateway | "502" ; Section 10.5.3: Bad Gateway
| "503" ; Section 10.5.4: Service Unavailable | "503" ; Section 10.5.4: Service Unavailable
| "504" ; Section 10.5.5: Gateway Time-out | "504" ; Section 10.5.5: Gateway Time-out
| "505" ; Section 10.5.6: HTTP Version not supported | "505" ; Section 10.5.6: HTTP Version not supported
| extension-code | extension-code
extension-code = 3DIGIT extension-code = 3DIGIT
Reason-Phrase = *<TEXT, excluding CR, LF> Reason-Phrase = *<TEXT, excluding CR, LF>
HTTP status codes are extensible. HTTP applications are not required HTTP status codes are extensible. HTTP applications are not required
to understand the meaning of all registered status codes, though such to understand the meaning of all registered status codes, though such
understanding is obviously desirable. However, applications MUST understanding is obviously desirable. However, applications MUST
understand the class of any status code, as indicated by the first understand the class of any status code, as indicated by the first
digit, and treat any unrecognized response as being equivalent to the digit, and treat any unrecognized response as being equivalent to the
x00 status code of that class, with the exception that an x00 status code of that class, with the exception that an
unrecognized response MUST NOT be cached. For example, if an unrecognized response MUST NOT be cached. For example, if an
unrecognized status code of 431 is received by the client, it can unrecognized status code of 431 is received by the client, it can
safely assume that there was something wrong with its request and safely assume that there was something wrong with its request and
skipping to change at page 50, line 23 skipping to change at page 51, line 23
with the response, since that entity is likely to include human- with the response, since that entity is likely to include human-
readable information which will explain the unusual status. readable information which will explain the unusual status.
6.2. Response Header Fields 6.2. Response Header Fields
The response-header fields allow the server to pass additional The response-header fields allow the server to pass additional
information about the response which cannot be placed in the Status- information about the response which cannot be placed in the Status-
Line. These header fields give information about the server and Line. These header fields give information about the server and
about further access to the resource identified by the Request-URI. about further access to the resource identified by the Request-URI.
response-header = Accept-Ranges ; Section 14.5 response-header = Accept-Ranges ; Section 14.5
| Age ; Section 14.6 | Age ; Section 14.6
| ETag ; Section 14.19 | ETag ; Section 14.19
| Location ; Section 14.30 | Location ; Section 14.30
| Proxy-Authenticate ; Section 14.33 | Proxy-Authenticate ; Section 14.33
| Retry-After ; Section 14.37 | Retry-After ; Section 14.37
| Server ; Section 14.38 | Server ; Section 14.38
| Vary ; Section 14.44 | Vary ; Section 14.44
| WWW-Authenticate ; Section 14.47 | WWW-Authenticate ; Section 14.47
Response-header field names can be extended reliably only in Response-header field names can be extended reliably only in
combination with a change in the protocol version. However, new or combination with a change in the protocol version. However, new or
experimental header fields MAY be given the semantics of response- experimental header fields MAY be given the semantics of response-
header fields if all parties in the communication recognize them to header fields if all parties in the communication recognize them to
be response-header fields. Unrecognized header fields are treated as be response-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
7. Entity 7. Entity
skipping to change at page 51, line 22 skipping to change at page 52, line 22
In this section, both sender and recipient refer to either the client In this section, both sender and recipient refer to either the client
or the server, depending on who sends and who receives the entity. or the server, depending on who sends and who receives the entity.
7.1. Entity Header Fields 7.1. Entity Header Fields
Entity-header fields define metainformation about the entity-body or, Entity-header fields define metainformation about the entity-body or,
if no body is present, about the resource identified by the request. if no body is present, about the resource identified by the request.
Some of this metainformation is OPTIONAL; some might be REQUIRED by Some of this metainformation is OPTIONAL; some might be REQUIRED by
portions of this specification. portions of this specification.
entity-header = Allow ; Section 14.7 entity-header = Allow ; Section 14.7
| Content-Encoding ; Section 14.11 | Content-Encoding ; Section 14.11
| Content-Language ; Section 14.12 | Content-Language ; Section 14.12
| Content-Length ; Section 14.13 | Content-Length ; Section 14.13
| Content-Location ; Section 14.14 | Content-Location ; Section 14.14
| Content-MD5 ; Section 14.15 | Content-MD5 ; Section 14.15
| Content-Range ; Section 14.16 | Content-Range ; Section 14.16
| Content-Type ; Section 14.17 | Content-Type ; Section 14.17
| Expires ; Section 14.21 | Expires ; Section 14.21
| Last-Modified ; Section 14.29 | Last-Modified ; Section 14.29
| extension-header | extension-header
extension-header = message-header extension-header = message-header
The extension-header mechanism allows additional entity-header fields The extension-header mechanism allows additional entity-header fields
to be defined without changing the protocol, but these fields cannot to be defined without changing the protocol, but these fields cannot
be assumed to be recognizable by the recipient. Unrecognized header be assumed to be recognizable by the recipient. Unrecognized header
fields SHOULD be ignored by the recipient and MUST be forwarded by fields SHOULD be ignored by the recipient and MUST be forwarded by
transparent proxies. transparent proxies.
7.2. Entity Body 7.2. Entity Body
The entity-body (if any) sent with an HTTP request or response is in The entity-body (if any) sent with an HTTP request or response is in
a format and encoding defined by the entity-header fields. a format and encoding defined by the entity-header fields.
entity-body = *OCTET entity-body = *OCTET
An entity-body is only present in a message when a message-body is An entity-body is only present in a message when a message-body is
present, as described in Section 4.3. The entity-body is obtained present, as described in Section 4.3. The entity-body is obtained
from the message-body by decoding any Transfer-Encoding that might from the message-body by decoding any Transfer-Encoding that might
have been applied to ensure safe and proper transfer of the message. have been applied to ensure safe and proper transfer of the message.
7.2.1. Type 7.2.1. Type
When an entity-body is included with a message, the data type of that When an entity-body is included with a message, the data type of that
body is determined via the header fields Content-Type and Content- body is determined via the header fields Content-Type and Content-
skipping to change at page 63, line 49 skipping to change at page 64, line 49
If a resource has been created on the origin server, the response If a resource has been created on the origin server, the response
SHOULD be 201 (Created) and contain an entity which describes the SHOULD be 201 (Created) and contain an entity which describes the
status of the request and refers to the new resource, and a Location status of the request and refers to the new resource, and a Location
header (see Section 14.30). header (see Section 14.30).
Responses to this method are not cacheable, unless the response Responses to this method are not cacheable, unless the response
includes appropriate Cache-Control or Expires header fields. includes appropriate Cache-Control or Expires header fields.
However, the 303 (See Other) response can be used to direct the user However, the 303 (See Other) response can be used to direct the user
agent to retrieve a cacheable resource. agent to retrieve a cacheable resource.
POST requests MUST obey the message transmission requirements set out
in Section 8.2.
See Section 15.1.3 for security considerations.
9.6. PUT 9.6. PUT
The PUT method requests that the enclosed entity be stored under the The PUT method requests that the enclosed entity be stored under the
supplied Request-URI. If the Request-URI refers to an already supplied Request-URI. If the Request-URI refers to an already
existing resource, the enclosed entity SHOULD be considered as a existing resource, the enclosed entity SHOULD be considered as a
modified version of the one residing on the origin server. If the modified version of the one residing on the origin server. If the
Request-URI does not point to an existing resource, and that URI is Request-URI does not point to an existing resource, and that URI is
capable of being defined as a new resource by the requesting user capable of being defined as a new resource by the requesting user
agent, the origin server can create the resource with that URI. If a agent, the origin server can create the resource with that URI. If a
new resource is created, the origin server MUST inform the user agent new resource is created, the origin server MUST inform the user agent
skipping to change at page 64, line 51 skipping to change at page 65, line 46
A single resource MAY be identified by many different URIs. For A single resource MAY be identified by many different URIs. For
example, an article might have a URI for identifying "the current example, an article might have a URI for identifying "the current
version" which is separate from the URI identifying each particular version" which is separate from the URI identifying each particular
version. In this case, a PUT request on a general URI might result version. In this case, a PUT request on a general URI might result
in several other URIs being defined by the origin server. in several other URIs being defined by the origin server.
HTTP/1.1 does not define how a PUT method affects the state of an HTTP/1.1 does not define how a PUT method affects the state of an
origin server. origin server.
PUT requests MUST obey the message transmission requirements set out
in Section 8.2.
Unless otherwise specified for a particular entity-header, the Unless otherwise specified for a particular entity-header, the
entity-headers in the PUT request SHOULD be applied to the resource entity-headers in the PUT request SHOULD be applied to the resource
created or modified by the PUT. created or modified by the PUT.
9.7. DELETE 9.7. DELETE
The DELETE method requests that the origin server delete the resource The DELETE method requests that the origin server delete the resource
identified by the Request-URI. This method MAY be overridden by identified by the Request-URI. This method MAY be overridden by
human intervention (or other means) on the origin server. The client human intervention (or other means) on the origin server. The client
cannot be guaranteed that the operation has been carried out, even if cannot be guaranteed that the operation has been carried out, even if
skipping to change at page 70, line 42 skipping to change at page 70, line 42
If the 206 response is the result of an If-Range request, the If the 206 response is the result of an If-Range request, the
response SHOULD NOT include other entity-headers. Otherwise, the response SHOULD NOT include other entity-headers. Otherwise, the
response MUST include all of the entity-headers that would have been response MUST include all of the entity-headers that would have been
returned with a 200 (OK) response to the same request. returned with a 200 (OK) response to the same request.
A cache MUST NOT combine a 206 response with other previously cached A cache MUST NOT combine a 206 response with other previously cached
content if the ETag or Last-Modified headers do not match exactly, content if the ETag or Last-Modified headers do not match exactly,
see 13.5.4. see 13.5.4.
A cache that does not support the Range and Content-Range headers A cache that does not support the Range and Content-Range headers
MUST NOT cache 206 (Partial) responses. MUST NOT cache 206 (Partial Content) responses.
10.3. Redirection 3xx 10.3. Redirection 3xx
This class of status code indicates that further action needs to be This class of status code indicates that further action needs to be
taken by the user agent in order to fulfill the request. The action taken by the user agent in order to fulfill the request. The action
required MAY be carried out by the user agent without interaction required MAY be carried out by the user agent without interaction
with the user if and only if the method used in the second request is with the user if and only if the method used in the second request is
GET or HEAD. A client SHOULD detect infinite redirection loops, GET or HEAD. A client SHOULD detect infinite redirection loops,
since such loops generate network traffic for each redirection. since such loops generate network traffic for each redirection.
skipping to change at page 86, line 39 skipping to change at page 86, line 39
the origin server so specifies, it is the freshness requirement the origin server so specifies, it is the freshness requirement
of the origin server alone. If a stored response is not "fresh of the origin server alone. If a stored response is not "fresh
enough" by the most restrictive freshness requirement of both the enough" by the most restrictive freshness requirement of both the
client and the origin server, in carefully considered client and the origin server, in carefully considered
circumstances the cache MAY still return the response with the circumstances the cache MAY still return the response with the
appropriate Warning header (see Section 13.1.5 and 14.46), unless appropriate Warning header (see Section 13.1.5 and 14.46), unless
such a response is prohibited (e.g., by a "no-store" cache- such a response is prohibited (e.g., by a "no-store" cache-
directive, or by a "no-cache" cache-request-directive; see directive, or by a "no-cache" cache-request-directive; see
Section 14.9). Section 14.9).
3. It is an appropriate 304 (Not Modified), 305 (Proxy Redirect), or 3. It is an appropriate 304 (Not Modified), 305 (Use Proxy), or
error (4xx or 5xx) response message. error (4xx or 5xx) response message.
If the cache can not communicate with the origin server, then a If the cache can not communicate with the origin server, then a
correct cache SHOULD respond as above if the response can be correct cache SHOULD respond as above if the response can be
correctly served from the cache; if not it MUST return an error or correctly served from the cache; if not it MUST return an error or
warning indicating that there was a communication failure. warning indicating that there was a communication failure.
If a cache receives a response (either an entire response, or a 304 If a cache receives a response (either an entire response, or a 304
(Not Modified) response) that it would normally forward to the (Not Modified) response) that it would normally forward to the
requesting client, and the received response is no longer fresh, the requesting client, and the received response is no longer fresh, the
skipping to change at page 91, line 6 skipping to change at page 91, line 6
and history mechanisms. and history mechanisms.
13.2.2. Heuristic Expiration 13.2.2. Heuristic Expiration
Since origin servers do not always provide explicit expiration times, Since origin servers do not always provide explicit expiration times,
HTTP caches typically assign heuristic expiration times, employing HTTP caches typically assign heuristic expiration times, employing
algorithms that use other header values (such as the Last-Modified algorithms that use other header values (such as the Last-Modified
time) to estimate a plausible expiration time. The HTTP/1.1 time) to estimate a plausible expiration time. The HTTP/1.1
specification does not provide specific algorithms, but does impose specification does not provide specific algorithms, but does impose
worst-case constraints on their results. Since heuristic expiration worst-case constraints on their results. Since heuristic expiration
times might compromise semantic transparency, they ought to used times might compromise semantic transparency, they ought to be used
cautiously, and we encourage origin servers to provide explicit cautiously, and we encourage origin servers to provide explicit
expiration times as much as possible. expiration times as much as possible.
13.2.3. Age Calculations 13.2.3. Age Calculations
In order to know if a cached entry is fresh, a cache needs to know if In order to know if a cached entry is fresh, a cache needs to know if
its age exceeds its freshness lifetime. We discuss how to calculate its age exceeds its freshness lifetime. We discuss how to calculate
the latter in Section 13.2.4; this section describes how to calculate the latter in Section 13.2.4; this section describes how to calculate
the age of a response or cache entry. the age of a response or cache entry.
skipping to change at page 111, line 20 skipping to change at page 111, line 20
sends and who receives the entity. sends and who receives the entity.
14.1. Accept 14.1. Accept
The Accept request-header field can be used to specify certain media The Accept request-header field can be used to specify certain media
types which are acceptable for the response. Accept headers can be types which are acceptable for the response. Accept headers can be
used to indicate that the request is specifically limited to a small used to indicate that the request is specifically limited to a small
set of desired types, as in the case of a request for an in-line set of desired types, as in the case of a request for an in-line
image. image.
Accept = "Accept" ":" Accept = "Accept" ":"
#( media-range [ accept-params ] ) #( media-range [ accept-params ] )
media-range = ( "*/*" media-range = ( "*/*"
| ( type "/" "*" ) | ( type "/" "*" )
| ( type "/" subtype ) | ( type "/" subtype )
) *( ";" parameter ) ) *( ";" parameter )
accept-params = ";" "q" "=" qvalue *( accept-extension ) accept-params = ";" "q" "=" qvalue *( accept-extension )
accept-extension = ";" token [ "=" ( token | quoted-string ) ] accept-extension = ";" token [ "=" ( token | quoted-string ) ]
The asterisk "*" character is used to group media types into ranges, The asterisk "*" character is used to group media types into ranges,
with "*/*" indicating all media types and "type/*" indicating all with "*/*" indicating all media types and "type/*" indicating all
subtypes of that type. The media-range MAY include media type subtypes of that type. The media-range MAY include media type
parameters that are applicable to that range. parameters that are applicable to that range.
Each media-range MAY be followed by one or more accept-params, Each media-range MAY be followed by one or more accept-params,
beginning with the "q" parameter for indicating a relative quality beginning with the "q" parameter for indicating a relative quality
factor. The first "q" parameter (if any) separates the media-range factor. The first "q" parameter (if any) separates the media-range
parameter(s) from the accept-params. Quality factors allow the user parameter(s) from the accept-params. Quality factors allow the user
skipping to change at page 112, line 13 skipping to change at page 112, line 13
The example The example
Accept: audio/*; q=0.2, audio/basic Accept: audio/*; q=0.2, audio/basic
SHOULD be interpreted as "I prefer audio/basic, but send me any audio SHOULD be interpreted as "I prefer audio/basic, but send me any audio
type if it is the best available after an 80% mark-down in quality." type if it is the best available after an 80% mark-down in quality."
If no Accept header field is present, then it is assumed that the If no Accept header field is present, then it is assumed that the
client accepts all media types. If an Accept header field is client accepts all media types. If an Accept header field is
present, and if the server cannot send a response which is acceptable present, and if the server cannot send a response which is acceptable
according to the combined Accept field value, then the server SHOULD according to the combined Accept field value, then the server SHOULD
send a 406 (not acceptable) response. send a 406 (Not Acceptable) response.
A more elaborate example is A more elaborate example is
Accept: text/plain; q=0.5, text/html, Accept: text/plain; q=0.5, text/html,
text/x-dvi; q=0.8, text/x-c text/x-dvi; q=0.8, text/x-c
Verbally, this would be interpreted as "text/html and text/x-c are Verbally, this would be interpreted as "text/html and text/x-c are
the preferred media types, but if they do not exist, then send the the preferred media types, but if they do not exist, then send the
text/x-dvi entity, and if that does not exist, send the text/plain text/x-dvi entity, and if that does not exist, send the text/plain
entity." entity."
skipping to change at page 113, line 19 skipping to change at page 113, line 19
default set ought to be configurable by the user. default set ought to be configurable by the user.
14.2. Accept-Charset 14.2. Accept-Charset
The Accept-Charset request-header field can be used to indicate what The Accept-Charset request-header field can be used to indicate what
character sets are acceptable for the response. This field allows character sets are acceptable for the response. This field allows
clients capable of understanding more comprehensive or special- clients capable of understanding more comprehensive or special-
purpose character sets to signal that capability to a server which is purpose character sets to signal that capability to a server which is
capable of representing documents in those character sets. capable of representing documents in those character sets.
Accept-Charset = "Accept-Charset" ":" Accept-Charset = "Accept-Charset" ":"
1#( ( charset | "*" )[ ";" "q" "=" qvalue ] ) 1#( ( charset | "*" ) [ ";" "q" "=" qvalue ] )
Character set values are described in Section 3.4. Each charset MAY Character set values are described in Section 3.4. Each charset MAY
be given an associated quality value which represents the user's be given an associated quality value which represents the user's
preference for that charset. The default value is q=1. An example preference for that charset. The default value is q=1. An example
is is
Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
The special value "*", if present in the Accept-Charset field, The special value "*", if present in the Accept-Charset field,
matches every character set (including ISO-8859-1) which is not matches every character set (including ISO-8859-1) which is not
mentioned elsewhere in the Accept-Charset field. If no "*" is mentioned elsewhere in the Accept-Charset field. If no "*" is
present in an Accept-Charset field, then all character sets not present in an Accept-Charset field, then all character sets not
explicitly mentioned get a quality value of 0, except for ISO-8859-1, explicitly mentioned get a quality value of 0, except for ISO-8859-1,
which gets a quality value of 1 if not explicitly mentioned. which gets a quality value of 1 if not explicitly mentioned.
If no Accept-Charset header is present, the default is that any If no Accept-Charset header is present, the default is that any
character set is acceptable. If an Accept-Charset header is present, character set is acceptable. If an Accept-Charset header is present,
and if the server cannot send a response which is acceptable and if the server cannot send a response which is acceptable
according to the Accept-Charset header, then the server SHOULD send according to the Accept-Charset header, then the server SHOULD send
an error response with the 406 (not acceptable) status code, though an error response with the 406 (Not Acceptable) status code, though
the sending of an unacceptable response is also allowed. the sending of an unacceptable response is also allowed.
14.3. Accept-Encoding 14.3. Accept-Encoding
The Accept-Encoding request-header field is similar to Accept, but The Accept-Encoding request-header field is similar to Accept, but
restricts the content-codings (Section 3.5) that are acceptable in restricts the content-codings (Section 3.5) that are acceptable in
the response. the response.
Accept-Encoding = "Accept-Encoding" ":" Accept-Encoding = "Accept-Encoding" ":"
1#( codings [ ";" "q" "=" qvalue ] ) #( codings [ ";" "q" "=" qvalue ] )
codings = ( content-coding | "*" ) codings = ( content-coding | "*" )
Examples of its use are: Examples of its use are:
Accept-Encoding: compress, gzip Accept-Encoding: compress, gzip
Accept-Encoding: Accept-Encoding:
Accept-Encoding: * Accept-Encoding: *
Accept-Encoding: compress;q=0.5, gzip;q=1.0 Accept-Encoding: compress;q=0.5, gzip;q=1.0
Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
A server tests whether a content-coding is acceptable, according to A server tests whether a content-coding is acceptable, according to
skipping to change at page 115, line 16 skipping to change at page 115, line 16
Note: Most HTTP/1.0 applications do not recognize or obey qvalues Note: Most HTTP/1.0 applications do not recognize or obey qvalues
associated with content-codings. This means that qvalues will not associated with content-codings. This means that qvalues will not
work and are not permitted with x-gzip or x-compress. work and are not permitted with x-gzip or x-compress.
14.4. Accept-Language 14.4. Accept-Language
The Accept-Language request-header field is similar to Accept, but The Accept-Language request-header field is similar to Accept, but
restricts the set of natural languages that are preferred as a restricts the set of natural languages that are preferred as a
response to the request. Language tags are defined in Section 3.10. response to the request. Language tags are defined in Section 3.10.
Accept-Language = "Accept-Language" ":" Accept-Language = "Accept-Language" ":"
1#( language-range [ ";" "q" "=" qvalue ] ) 1#( language-range [ ";" "q" "=" qvalue ] )
language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" ) language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" )
Each language-range MAY be given an associated quality value which Each language-range MAY be given an associated quality value which
represents an estimate of the user's preference for the languages represents an estimate of the user's preference for the languages
specified by that range. The quality value defaults to "q=1". For specified by that range. The quality value defaults to "q=1". For
example, example,
Accept-Language: da, en-gb;q=0.8, en;q=0.7 Accept-Language: da, en-gb;q=0.8, en;q=0.7
would mean: "I prefer Danish, but will accept British English and would mean: "I prefer Danish, but will accept British English and
other types of English." A language-range matches a language-tag if other types of English." A language-range matches a language-tag if
skipping to change at page 116, line 28 skipping to change at page 116, line 28
might assume that on selecting "en-gb", they will be served any might assume that on selecting "en-gb", they will be served any
kind of English document if British English is not available. A kind of English document if British English is not available. A
user agent might suggest in such a case to add "en" to get the user agent might suggest in such a case to add "en" to get the
best matching behavior. best matching behavior.
14.5. Accept-Ranges 14.5. Accept-Ranges
The Accept-Ranges response-header field allows the server to indicate The Accept-Ranges response-header field allows the server to indicate
its acceptance of range requests for a resource: its acceptance of range requests for a resource:
Accept-Ranges = "Accept-Ranges" ":" acceptable-ranges Accept-Ranges = "Accept-Ranges" ":" acceptable-ranges
acceptable-ranges = 1#range-unit | "none" acceptable-ranges = 1#range-unit | "none"
Origin servers that accept byte-range requests MAY send Origin servers that accept byte-range requests MAY send
Accept-Ranges: bytes Accept-Ranges: bytes
but are not required to do so. Clients MAY generate byte-range but are not required to do so. Clients MAY generate byte-range
requests without having received this header for the resource requests without having received this header for the resource
involved. Range units are defined in Section 3.12. involved. Range units are defined in Section 3.12.
Servers that do not accept any kind of range request for a resource Servers that do not accept any kind of range request for a resource
skipping to change at page 117, line 6 skipping to change at page 117, line 6
to advise the client not to attempt a range request. to advise the client not to attempt a range request.
14.6. Age 14.6. Age
The Age response-header field conveys the sender's estimate of the The Age response-header field conveys the sender's estimate of the
amount of time since the response (or its revalidation) was generated amount of time since the response (or its revalidation) was generated
at the origin server. A cached response is "fresh" if its age does at the origin server. A cached response is "fresh" if its age does
not exceed its freshness lifetime. Age values are calculated as not exceed its freshness lifetime. Age values are calculated as
specified in Section 13.2.3. specified in Section 13.2.3.
Age = "Age" ":" age-value Age = "Age" ":" age-value
age-value = delta-seconds age-value = delta-seconds
Age values are non-negative decimal integers, representing time in Age values are non-negative decimal integers, representing time in
seconds. seconds.
If a cache receives a value larger than the largest positive integer If a cache receives a value larger than the largest positive integer
it can represent, or if any of its age calculations overflows, it it can represent, or if any of its age calculations overflows, it
MUST transmit an Age header with a value of 2147483648 (2^31). An MUST transmit an Age header with a value of 2147483648 (2^31). An
HTTP/1.1 server that includes a cache MUST include an Age header HTTP/1.1 server that includes a cache MUST include an Age header
field in every response generated from its own cache. Caches SHOULD field in every response generated from its own cache. Caches SHOULD
use an arithmetic type of at least 31 bits of range. use an arithmetic type of at least 31 bits of range.
14.7. Allow 14.7. Allow
The Allow entity-header field lists the set of methods supported by The Allow entity-header field lists the set of methods supported by
the resource identified by the Request-URI. The purpose of this the resource identified by the Request-URI. The purpose of this
field is strictly to inform the recipient of valid methods associated field is strictly to inform the recipient of valid methods associated
with the resource. An Allow header field MUST be present in a 405 with the resource. An Allow header field MUST be present in a 405
(Method Not Allowed) response. (Method Not Allowed) response.
Allow = "Allow" ":" #Method Allow = "Allow" ":" #Method
Example of use: Example of use:
Allow: GET, HEAD, PUT Allow: GET, HEAD, PUT
This field cannot prevent a client from trying other methods. This field cannot prevent a client from trying other methods.
However, the indications given by the Allow header field value SHOULD However, the indications given by the Allow header field value SHOULD
be followed. The actual set of allowed methods is defined by the be followed. The actual set of allowed methods is defined by the
origin server at the time of each request. origin server at the time of each request.
skipping to change at page 118, line 9 skipping to change at page 118, line 9
14.8. Authorization 14.8. Authorization
A user agent that wishes to authenticate itself with a server-- A user agent that wishes to authenticate itself with a server--
usually, but not necessarily, after receiving a 401 response--does so usually, but not necessarily, after receiving a 401 response--does so
by including an Authorization request-header field with the request. by including an Authorization request-header field with the request.
The Authorization field value consists of credentials containing the The Authorization field value consists of credentials containing the
authentication information of the user agent for the realm of the authentication information of the user agent for the realm of the
resource being requested. resource being requested.
Authorization = "Authorization" ":" credentials Authorization = "Authorization" ":" credentials
HTTP access authentication is described in "HTTP Authentication: HTTP access authentication is described in "HTTP Authentication:
Basic and Digest Access Authentication" [RFC2617]. If a request is Basic and Digest Access Authentication" [RFC2617]. If a request is
authenticated and a realm specified, the same credentials SHOULD be authenticated and a realm specified, the same credentials SHOULD be
valid for all other requests within this realm (assuming that the valid for all other requests within this realm (assuming that the
authentication scheme itself does not require otherwise, such as authentication scheme itself does not require otherwise, such as
credentials that vary according to a challenge value or using credentials that vary according to a challenge value or using
synchronized clocks). synchronized clocks).
When a shared cache (see Section 13.7) receives a request containing When a shared cache (see Section 13.7) receives a request containing
skipping to change at page 119, line 30 skipping to change at page 119, line 30
cache-request-directive = cache-request-directive =
"no-cache" ; Section 14.9.1 "no-cache" ; Section 14.9.1
| "no-store" ; Section 14.9.2 | "no-store" ; Section 14.9.2
| "max-age" "=" delta-seconds ; Section 14.9.3, 14.9.4 | "max-age" "=" delta-seconds ; Section 14.9.3, 14.9.4
| "max-stale" [ "=" delta-seconds ] ; Section 14.9.3 | "max-stale" [ "=" delta-seconds ] ; Section 14.9.3
| "min-fresh" "=" delta-seconds ; Section 14.9.3 | "min-fresh" "=" delta-seconds ; Section 14.9.3
| "no-transform" ; Section 14.9.5 | "no-transform" ; Section 14.9.5
| "only-if-cached" ; Section 14.9.4 | "only-if-cached" ; Section 14.9.4
| cache-extension ; Section 14.9.6 | cache-extension ; Section 14.9.6
cache-response-directive = cache-response-directive =
"public" ; Section 14.9.1 "public" ; Section 14.9.1
| "private" [ "=" <"> 1#field-name <"> ] ; Section 14.9.1 | "private" [ "=" <"> 1#field-name <"> ] ; Section 14.9.1
| "no-cache" [ "=" <"> 1#field-name <"> ]; Section 14.9.1 | "no-cache" [ "=" <"> 1#field-name <"> ]; Section 14.9.1
| "no-store" ; Section 14.9.2 | "no-store" ; Section 14.9.2
| "no-transform" ; Section 14.9.5 | "no-transform" ; Section 14.9.5
| "must-revalidate" ; Section 14.9.4 | "must-revalidate" ; Section 14.9.4
| "proxy-revalidate" ; Section 14.9.4 | "proxy-revalidate" ; Section 14.9.4
| "max-age" "=" delta-seconds ; Section 14.9.3 | "max-age" "=" delta-seconds ; Section 14.9.3
| "s-maxage" "=" delta-seconds ; Section 14.9.3 | "s-maxage" "=" delta-seconds ; Section 14.9.3
| cache-extension ; Section 14.9.6 | cache-extension ; Section 14.9.6
cache-extension = token [ "=" ( token | quoted-string ) ] cache-extension = token [ "=" ( token | quoted-string ) ]
When a directive appears without any 1#field-name parameter, the When a directive appears without any 1#field-name parameter, the
directive applies to the entire request or response. When such a directive applies to the entire request or response. When such a
directive appears with a 1#field-name parameter, it applies only to directive appears with a 1#field-name parameter, it applies only to
the named field or fields, and not to the rest of the request or the named field or fields, and not to the rest of the request or
response. This mechanism supports extensibility; implementations of response. This mechanism supports extensibility; implementations of
future versions of the HTTP protocol might apply these directives to future versions of the HTTP protocol might apply these directives to
header fields not defined in HTTP/1.1. header fields not defined in HTTP/1.1.
skipping to change at page 128, line 20 skipping to change at page 128, line 20
correct even if the cache does not understand the extension(s). correct even if the cache does not understand the extension(s).
14.10. Connection 14.10. Connection
The Connection general-header field allows the sender to specify The Connection general-header field allows the sender to specify
options that are desired for that particular connection and MUST NOT options that are desired for that particular connection and MUST NOT
be communicated by proxies over further connections. be communicated by proxies over further connections.
The Connection header has the following grammar: The Connection header has the following grammar:
Connection = "Connection" ":" 1#(connection-token) Connection = "Connection" ":" 1#(connection-token)
connection-token = token connection-token = token
HTTP/1.1 proxies MUST parse the Connection header field before a HTTP/1.1 proxies MUST parse the Connection header field before a
message is forwarded and, for each connection-token in this field, message is forwarded and, for each connection-token in this field,
remove any header field(s) from the message with the same name as the remove any header field(s) from the message with the same name as the
connection-token. Connection options are signaled by the presence of connection-token. Connection options are signaled by the presence of
a connection-token in the Connection header field, not by any a connection-token in the Connection header field, not by any
corresponding additional header field(s), since the additional header corresponding additional header field(s), since the additional header
field may not be sent if there are no parameters associated with that field may not be sent if there are no parameters associated with that
connection option. connection option.
skipping to change at page 129, line 22 skipping to change at page 129, line 22
14.11. Content-Encoding 14.11. Content-Encoding
The Content-Encoding entity-header field is used as a modifier to the The Content-Encoding entity-header field is used as a modifier to the
media-type. When present, its value indicates what additional media-type. When present, its value indicates what additional
content codings have been applied to the entity-body, and thus what content codings have been applied to the entity-body, and thus what
decoding mechanisms must be applied in order to obtain the media-type decoding mechanisms must be applied in order to obtain the media-type
referenced by the Content-Type header field. Content-Encoding is referenced by the Content-Type header field. Content-Encoding is
primarily used to allow a document to be compressed without losing primarily used to allow a document to be compressed without losing
the identity of its underlying media type. the identity of its underlying media type.
Content-Encoding = "Content-Encoding" ":" 1#content-coding Content-Encoding = "Content-Encoding" ":" 1#content-coding
Content codings are defined in Section 3.5. An example of its use is Content codings are defined in Section 3.5. An example of its use is
Content-Encoding: gzip Content-Encoding: gzip
The content-coding is a characteristic of the entity identified by The content-coding is a characteristic of the entity identified by
the Request-URI. Typically, the entity-body is stored with this the Request-URI. Typically, the entity-body is stored with this
encoding and is only decoded before rendering or analogous usage. encoding and is only decoded before rendering or analogous usage.
However, a non-transparent proxy MAY modify the content-coding if the However, a non-transparent proxy MAY modify the content-coding if the
new coding is known to be acceptable to the recipient, unless the new coding is known to be acceptable to the recipient, unless the
skipping to change at page 130, line 6 skipping to change at page 130, line 6
Additional information about the encoding parameters MAY be provided Additional information about the encoding parameters MAY be provided
by other entity-header fields not defined by this specification. by other entity-header fields not defined by this specification.
14.12. Content-Language 14.12. Content-Language
The Content-Language entity-header field describes the natural The Content-Language entity-header field describes the natural
language(s) of the intended audience for the enclosed entity. Note language(s) of the intended audience for the enclosed entity. Note
that this might not be equivalent to all the languages used within that this might not be equivalent to all the languages used within
the entity-body. the entity-body.
Content-Language = "Content-Language" ":" 1#language-tag Content-Language = "Content-Language" ":" 1#language-tag
Language tags are defined in Section 3.10. The primary purpose of Language tags are defined in Section 3.10. The primary purpose of
Content-Language is to allow a user to identify and differentiate Content-Language is to allow a user to identify and differentiate
entities according to the user's own preferred language. Thus, if entities according to the user's own preferred language. Thus, if
the body content is intended only for a Danish-literate audience, the the body content is intended only for a Danish-literate audience, the
appropriate field is appropriate field is
Content-Language: da Content-Language: da
If no Content-Language is specified, the default is that the content If no Content-Language is specified, the default is that the content
skipping to change at page 130, line 45 skipping to change at page 130, line 45
Content-Language MAY be applied to any media type -- it is not Content-Language MAY be applied to any media type -- it is not
limited to textual documents. limited to textual documents.
14.13. Content-Length 14.13. Content-Length
The Content-Length entity-header field indicates the size of the The Content-Length entity-header field indicates the size of the
entity-body, in decimal number of OCTETs, sent to the recipient or, entity-body, in decimal number of OCTETs, sent to the recipient or,
in the case of the HEAD method, the size of the entity-body that in the case of the HEAD method, the size of the entity-body that
would have been sent had the request been a GET. would have been sent had the request been a GET.
Content-Length = "Content-Length" ":" 1*DIGIT Content-Length = "Content-Length" ":" 1*DIGIT
An example is An example is
Content-Length: 3495 Content-Length: 3495
Applications SHOULD use this field to indicate the transfer-length of Applications SHOULD use this field to indicate the transfer-length of
the message-body, unless this is prohibited by the rules in the message-body, unless this is prohibited by the rules in
Section 4.4. Section 4.4.
Any Content-Length greater than or equal to zero is a valid value. Any Content-Length greater than or equal to zero is a valid value.
skipping to change at page 131, line 30 skipping to change at page 131, line 30
The Content-Location entity-header field MAY be used to supply the The Content-Location entity-header field MAY be used to supply the
resource location for the entity enclosed in the message when that resource location for the entity enclosed in the message when that
entity is accessible from a location separate from the requested entity is accessible from a location separate from the requested
resource's URI. A server SHOULD provide a Content-Location for the resource's URI. A server SHOULD provide a Content-Location for the
variant corresponding to the response entity; especially in the case variant corresponding to the response entity; especially in the case
where a resource has multiple entities associated with it, and those where a resource has multiple entities associated with it, and those
entities actually have separate locations by which they might be entities actually have separate locations by which they might be
individually accessed, the server SHOULD provide a Content-Location individually accessed, the server SHOULD provide a Content-Location
for the particular variant which is returned. for the particular variant which is returned.
Content-Location = "Content-Location" ":" Content-Location = "Content-Location" ":"
( absoluteURI | relativeURI ) ( absoluteURI | relativeURI )
The value of Content-Location also defines the base URI for the The value of Content-Location also defines the base URI for the
entity. entity.
The Content-Location value is not a replacement for the original The Content-Location value is not a replacement for the original
requested URI; it is only a statement of the location of the resource requested URI; it is only a statement of the location of the resource
corresponding to this particular entity at the time of the request. corresponding to this particular entity at the time of the request.
Future requests MAY specify the Content-Location URI as the request- Future requests MAY specify the Content-Location URI as the request-
URI if the desire is to identify the source of that particular URI if the desire is to identify the source of that particular
entity. entity.
skipping to change at page 132, line 16 skipping to change at page 132, line 16
undefined; servers are free to ignore it in those cases. undefined; servers are free to ignore it in those cases.
14.15. Content-MD5 14.15. Content-MD5
The Content-MD5 entity-header field, as defined in [RFC1864], is an The Content-MD5 entity-header field, as defined in [RFC1864], is an
MD5 digest of the entity-body for the purpose of providing an end-to- MD5 digest of the entity-body for the purpose of providing an end-to-
end message integrity check (MIC) of the entity-body. (Note: a MIC end message integrity check (MIC) of the entity-body. (Note: a MIC
is good for detecting accidental modification of the entity-body in is good for detecting accidental modification of the entity-body in
transit, but is not proof against malicious attacks.) transit, but is not proof against malicious attacks.)
Content-MD5 = "Content-MD5" ":" md5-digest Content-MD5 = "Content-MD5" ":" md5-digest
md5-digest = <base64 of 128 bit MD5 digest as per [RFC1864]> md5-digest = <base64 of 128 bit MD5 digest as per [RFC1864]>
The Content-MD5 header field MAY be generated by an origin server or The Content-MD5 header field MAY be generated by an origin server or
client to function as an integrity check of the entity-body. Only client to function as an integrity check of the entity-body. Only
origin servers or clients MAY generate the Content-MD5 header field; origin servers or clients MAY generate the Content-MD5 header field;
proxies and gateways MUST NOT generate it, as this would defeat its proxies and gateways MUST NOT generate it, as this would defeat its
value as an end-to-end integrity check. Any recipient of the entity- value as an end-to-end integrity check. Any recipient of the entity-
body, including gateways and proxies, MAY check that the digest value body, including gateways and proxies, MAY check that the digest value
in this header field matches that of the entity-body as received. in this header field matches that of the entity-body as received.
The MD5 digest is computed based on the content of the entity-body, The MD5 digest is computed based on the content of the entity-body,
skipping to change at page 133, line 26 skipping to change at page 133, line 26
the digest is the transmission byte order defined for the type. the digest is the transmission byte order defined for the type.
Lastly, HTTP allows transmission of text types with any of several Lastly, HTTP allows transmission of text types with any of several
line break conventions and not just the canonical form using CRLF. line break conventions and not just the canonical form using CRLF.
14.16. Content-Range 14.16. Content-Range
The Content-Range entity-header is sent with a partial entity-body to The Content-Range entity-header is sent with a partial entity-body to
specify where in the full entity-body the partial body should be specify where in the full entity-body the partial body should be
applied. Range units are defined in Section 3.12. applied. Range units are defined in Section 3.12.
Content-Range = "Content-Range" ":" content-range-spec Content-Range = "Content-Range" ":" content-range-spec
content-range-spec = byte-content-range-spec content-range-spec = byte-content-range-spec
byte-content-range-spec = bytes-unit SP byte-content-range-spec = bytes-unit SP
byte-range-resp-spec "/" byte-range-resp-spec "/"
( instance-length | "*" ) ( instance-length | "*" )
byte-range-resp-spec = (first-byte-pos "-" last-byte-pos) byte-range-resp-spec = (first-byte-pos "-" last-byte-pos)
| "*" | "*"
instance-length = 1*DIGIT instance-length = 1*DIGIT
The header SHOULD indicate the total length of the full entity-body, The header SHOULD indicate the total length of the full entity-body,
unless this length is unknown or difficult to determine. The unless this length is unknown or difficult to determine. The
asterisk "*" character means that the instance-length is unknown at asterisk "*" character means that the instance-length is unknown at
the time when the response was generated. the time when the response was generated.
Unlike byte-ranges-specifier values (see Section 14.35.1), a byte- Unlike byte-ranges-specifier values (see Section 14.35.1), a byte-
range-resp-spec MUST only specify one range, and MUST contain range-resp-spec MUST only specify one range, and MUST contain
absolute byte positions for both the first and last byte of the absolute byte positions for both the first and last byte of the
range. range.
skipping to change at page 134, line 37 skipping to change at page 134, line 37
o The last 500 bytes: o The last 500 bytes:
bytes 734-1233/1234 bytes 734-1233/1234
When an HTTP message includes the content of a single range (for When an HTTP message includes the content of a single range (for
example, a response to a request for a single range, or to a request example, a response to a request for a single range, or to a request
for a set of ranges that overlap without any holes), this content is for a set of ranges that overlap without any holes), this content is
transmitted with a Content-Range header, and a Content-Length header transmitted with a Content-Range header, and a Content-Length header
showing the number of bytes actually transferred. For example, showing the number of bytes actually transferred. For example,
HTTP/1.1 206 Partial content HTTP/1.1 206 Partial Content
Date: Wed, 15 Nov 1995 06:25:24 GMT Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-Range: bytes 21010-47021/47022 Content-Range: bytes 21010-47021/47022
Content-Length: 26012 Content-Length: 26012
Content-Type: image/gif Content-Type: image/gif
When an HTTP message includes the content of multiple ranges (for When an HTTP message includes the content of multiple ranges (for
example, a response to a request for multiple non-overlapping example, a response to a request for multiple non-overlapping
ranges), these are transmitted as a multipart message. The multipart ranges), these are transmitted as a multipart message. The multipart
media type used for this purpose is "multipart/byteranges" as defined media type used for this purpose is "multipart/byteranges" as defined
skipping to change at page 135, line 35 skipping to change at page 135, line 35
range not satisfiable) response instead of a 200 (OK) response for range not satisfiable) response instead of a 200 (OK) response for
an unsatisfiable Range request-header, since not all servers an unsatisfiable Range request-header, since not all servers
implement this request-header. implement this request-header.
14.17. Content-Type 14.17. Content-Type
The Content-Type entity-header field indicates the media type of the The Content-Type entity-header field indicates the media type of the
entity-body sent to the recipient or, in the case of the HEAD method, entity-body sent to the recipient or, in the case of the HEAD method,
the media type that would have been sent had the request been a GET. the media type that would have been sent had the request been a GET.
Content-Type = "Content-Type" ":" media-type Content-Type = "Content-Type" ":" media-type
Media types are defined in Section 3.7. An example of the field is Media types are defined in Section 3.7. An example of the field is
Content-Type: text/html; charset=ISO-8859-4 Content-Type: text/html; charset=ISO-8859-4
Further discussion of methods for identifying the media type of an Further discussion of methods for identifying the media type of an
entity is provided in Section 7.2.1. entity is provided in Section 7.2.1.
14.18. Date 14.18. Date
The Date general-header field represents the date and time at which The Date general-header field represents the date and time at which
the message was originated, having the same semantics as orig-date in the message was originated, having the same semantics as orig-date in
RFC 822. The field value is an HTTP-date, as described in [RFC2822]. The field value is an HTTP-date, as described in
Section 3.3.1; it MUST be sent in rfc1123-date format. Section 3.3.1; it MUST be sent in rfc1123-date format.
Date = "Date" ":" HTTP-date Date = "Date" ":" HTTP-date
An example is An example is
Date: Tue, 15 Nov 1994 08:12:31 GMT Date: Tue, 15 Nov 1994 08:12:31 GMT
Origin servers MUST include a Date header field in all responses, Origin servers MUST include a Date header field in all responses,
except in these cases: except in these cases:
1. If the response status code is 100 (Continue) or 101 (Switching 1. If the response status code is 100 (Continue) or 101 (Switching
Protocols), the response MAY include a Date header field, at the Protocols), the response MAY include a Date header field, at the
server's option. server's option.
2. If the response status code conveys a server error, e.g. 500 2. If the response status code conveys a server error, e.g. 500
(Internal Server Error) or 503 (Service Unavailable), and it is (Internal Server Error) or 503 (Service Unavailable), and it is
inconvenient or impossible to generate a valid Date. inconvenient or impossible to generate a valid Date.
3. If the server does not have a clock that can provide a reasonable 3. If the server does not have a clock that can provide a reasonable
approximation of the current time, its responses MUST NOT include approximation of the current time, its responses MUST NOT include
a Date header field. In this case, the rules in Section 14.18.1 a Date header field. In this case, the rules in Section 14.18.1
MUST be followed. MUST be followed.
A received message that does not have a Date header field MUST be A received message that does not have a Date header field MUST be
assigned one by the recipient if the message will be cached by that assigned one by the recipient if the message will be cached by that
skipping to change at page 137, line 17 skipping to change at page 137, line 17
resource). resource).
14.19. ETag 14.19. ETag
The ETag response-header field provides the current value of the The ETag response-header field provides the current value of the
entity tag for the requested variant. The headers used with entity entity tag for the requested variant. The headers used with entity
tags are described in Sections 14.24, 14.26 and 14.44. The entity tags are described in Sections 14.24, 14.26 and 14.44. The entity
tag MAY be used for comparison with other entities from the same tag MAY be used for comparison with other entities from the same
resource (see Section 13.3.3). resource (see Section 13.3.3).
ETag = "ETag" ":" entity-tag ETag = "ETag" ":" entity-tag
Examples: Examples:
ETag: "xyzzy" ETag: "xyzzy"
ETag: W/"xyzzy" ETag: W/"xyzzy"
ETag: "" ETag: ""
14.20. Expect 14.20. Expect
The Expect request-header field is used to indicate that particular The Expect request-header field is used to indicate that particular
server behaviors are required by the client. server behaviors are required by the client.
Expect = "Expect" ":" 1#expectation Expect = "Expect" ":" 1#expectation
expectation = "100-continue" | expectation-extension expectation = "100-continue" | expectation-extension
expectation-extension = token [ "=" ( token | quoted-string ) expectation-extension = token [ "=" ( token | quoted-string )
*expect-params ] *expect-params ]
expect-params = ";" token [ "=" ( token | quoted-string ) ] expect-params = ";" token [ "=" ( token | quoted-string ) ]
A server that does not understand or is unable to comply with any of A server that does not understand or is unable to comply with any of
the expectation values in the Expect field of a request MUST respond the expectation values in the Expect field of a request MUST respond
with appropriate error status. The server MUST respond with a 417 with appropriate error status. The server MUST respond with a 417
(Expectation Failed) status if any of the expectations cannot be met (Expectation Failed) status if any of the expectations cannot be met
or, if there are other problems with the request, some other 4xx or, if there are other problems with the request, some other 4xx
status. status.
This header field is defined with extensible syntax to allow for This header field is defined with extensible syntax to allow for
future extensions. If a server receives a request containing an future extensions. If a server receives a request containing an
skipping to change at page 138, line 14 skipping to change at page 138, line 14
The Expect mechanism is hop-by-hop: that is, an HTTP/1.1 proxy MUST The Expect mechanism is hop-by-hop: that is, an HTTP/1.1 proxy MUST
return a 417 (Expectation Failed) status if it receives a request return a 417 (Expectation Failed) status if it receives a request
with an expectation that it cannot meet. However, the Expect with an expectation that it cannot meet. However, the Expect
request-header itself is end-to-end; it MUST be forwarded if the request-header itself is end-to-end; it MUST be forwarded if the
request is forwarded. request is forwarded.
Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Many older HTTP/1.0 and HTTP/1.1 applications do not understand the
Expect header. Expect header.
See Section 8.2.3 for the use of the 100 (continue) status. See Section 8.2.3 for the use of the 100 (Continue) status.
14.21. Expires 14.21. Expires
The Expires entity-header field gives the date/time after which the The Expires entity-header field gives the date/time after which the
response is considered stale. A stale cache entry may not normally response is considered stale. A stale cache entry may not normally
be returned by a cache (either a proxy cache or a user agent cache) be returned by a cache (either a proxy cache or a user agent cache)
unless it is first validated with the origin server (or with an unless it is first validated with the origin server (or with an
intermediate cache that has a fresh copy of the entity). See intermediate cache that has a fresh copy of the entity). See
Section 13.2 for further discussion of the expiration model. Section 13.2 for further discussion of the expiration model.
The presence of an Expires field does not imply that the original The presence of an Expires field does not imply that the original
resource will change or cease to exist at, before, or after that resource will change or cease to exist at, before, or after that
time. time.
The format is an absolute date and time as defined by HTTP-date in The format is an absolute date and time as defined by HTTP-date in
Section 3.3.1; it MUST be in rfc1123-date format: Section 3.3.1; it MUST be in rfc1123-date format:
Expires = "Expires" ":" HTTP-date Expires = "Expires" ":" HTTP-date
An example of its use is An example of its use is
Expires: Thu, 01 Dec 1994 16:00:00 GMT Expires: Thu, 01 Dec 1994 16:00:00 GMT
Note: if a response includes a Cache-Control field with the max- Note: if a response includes a Cache-Control field with the max-
age directive (see Section 14.9.3), that directive overrides the age directive (see Section 14.9.3), that directive overrides the
Expires field. Expires field.
HTTP/1.1 clients and caches MUST treat other invalid date formats, HTTP/1.1 clients and caches MUST treat other invalid date formats,
skipping to change at page 139, line 16 skipping to change at page 139, line 16
The presence of an Expires header field with a date value of some The presence of an Expires header field with a date value of some
time in the future on a response that otherwise would by default be time in the future on a response that otherwise would by default be
non-cacheable indicates that the response is cacheable, unless non-cacheable indicates that the response is cacheable, unless
indicated otherwise by a Cache-Control header field (Section 14.9). indicated otherwise by a Cache-Control header field (Section 14.9).
14.22. From 14.22. From
The From request-header field, if given, SHOULD contain an Internet The From request-header field, if given, SHOULD contain an Internet
e-mail address for the human user who controls the requesting user e-mail address for the human user who controls the requesting user
agent. The address SHOULD be machine-usable, as defined by "mailbox" agent. The address SHOULD be machine-usable, as defined by "mailbox"
in [RFC822] as updated by [RFC1123]: in Section 3.4 of [RFC2822]:
From = "From" ":" mailbox From = "From" ":" mailbox
An example is: An example is:
From: webmaster@w3.org From: webmaster@w3.org
This header field MAY be used for logging purposes and as a means for This header field MAY be used for logging purposes and as a means for
identifying the source of invalid or unwanted requests. It SHOULD identifying the source of invalid or unwanted requests. It SHOULD
NOT be used as an insecure form of access protection. The NOT be used as an insecure form of access protection. The
interpretation of this field is that the request is being performed interpretation of this field is that the request is being performed
on behalf of the person given, who accepts responsibility for the on behalf of the person given, who accepts responsibility for the
skipping to change at page 140, line 7 skipping to change at page 140, line 7
The Host request-header field specifies the Internet host and port The Host request-header field specifies the Internet host and port
number of the resource being requested, as obtained from the original number of the resource being requested, as obtained from the original
URI given by the user or referring resource (generally an HTTP URL, URI given by the user or referring resource (generally an HTTP URL,
as described in Section 3.2.2). The Host field value MUST represent as described in Section 3.2.2). The Host field value MUST represent
the naming authority of the origin server or gateway given by the the naming authority of the origin server or gateway given by the
original URL. This allows the origin server or gateway to original URL. This allows the origin server or gateway to
differentiate between internally-ambiguous URLs, such as the root "/" differentiate between internally-ambiguous URLs, such as the root "/"
URL of a server for multiple host names on a single IP address. URL of a server for multiple host names on a single IP address.
Host = "Host" ":" host [ ":" port ] ; Section 3.2.2 Host = "Host" ":" host [ ":" port ] ; Section 3.2.2
A "host" without any trailing port information implies the default A "host" without any trailing port information implies the default
port for the service requested (e.g., "80" for an HTTP URL). For port for the service requested (e.g., "80" for an HTTP URL). For
example, a request on the origin server for example, a request on the origin server for
<http://www.example.org/pub/WWW/> would properly include: <http://www.example.org/pub/WWW/> would properly include:
GET /pub/WWW/ HTTP/1.1 GET /pub/WWW/ HTTP/1.1
Host: www.example.org Host: www.example.org
A client MUST include a Host header field in all HTTP/1.1 request A client MUST include a Host header field in all HTTP/1.1 request
skipping to change at page 140, line 42 skipping to change at page 140, line 42
conditional. A client that has one or more entities previously conditional. A client that has one or more entities previously
obtained from the resource can verify that one of those entities is obtained from the resource can verify that one of those entities is
current by including a list of their associated entity tags in the current by including a list of their associated entity tags in the
If-Match header field. Entity tags are defined in Section 3.11. The If-Match header field. Entity tags are defined in Section 3.11. The
purpose of this feature is to allow efficient updates of cached purpose of this feature is to allow efficient updates of cached
information with a minimum amount of transaction overhead. It is information with a minimum amount of transaction overhead. It is
also used, on updating requests, to prevent inadvertent modification also used, on updating requests, to prevent inadvertent modification
of the wrong version of a resource. As a special case, the value "*" of the wrong version of a resource. As a special case, the value "*"
matches any current entity of the resource. matches any current entity of the resource.
If-Match = "If-Match" ":" ( "*" | 1#entity-tag ) If-Match = "If-Match" ":" ( "*" | 1#entity-tag )
If any of the entity tags match the entity tag of the entity that If any of the entity tags match the entity tag of the entity that
would have been returned in the response to a similar GET request would have been returned in the response to a similar GET request
(without the If-Match header) on that resource, or if "*" is given (without the If-Match header) on that resource, or if "*" is given
and any current entity exists for that resource, then the server MAY and any current entity exists for that resource, then the server MAY
perform the requested method as if the If-Match header field did not perform the requested method as if the If-Match header field did not
exist. exist.
A server MUST use the strong comparison function (see Section 13.3.3) A server MUST use the strong comparison function (see Section 13.3.3)
to compare the entity tags in If-Match. to compare the entity tags in If-Match.
skipping to change at page 141, line 43 skipping to change at page 141, line 43
The result of a request having both an If-Match header field and The result of a request having both an If-Match header field and
either an If-None-Match or an If-Modified-Since header fields is either an If-None-Match or an If-Modified-Since header fields is
undefined by this specification. undefined by this specification.
14.25. If-Modified-Since 14.25. If-Modified-Since
The If-Modified-Since request-header field is used with a method to The If-Modified-Since request-header field is used with a method to
make it conditional: if the requested variant has not been modified make it conditional: if the requested variant has not been modified
since the time specified in this field, an entity will not be since the time specified in this field, an entity will not be
returned from the server; instead, a 304 (not modified) response will returned from the server; instead, a 304 (Not Modified) response will
be returned without any message-body. be returned without any message-body.
If-Modified-Since = "If-Modified-Since" ":" HTTP-date If-Modified-Since = "If-Modified-Since" ":" HTTP-date
An example of the field is: An example of the field is:
If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT
A GET method with an If-Modified-Since header and no Range header A GET method with an If-Modified-Since header and no Range header
requests that the identified entity be transferred only if it has requests that the identified entity be transferred only if it has
been modified since the date given by the If-Modified-Since header. been modified since the date given by the If-Modified-Since header.
The algorithm for determining this includes the following cases: The algorithm for determining this includes the following cases:
skipping to change at page 143, line 24 skipping to change at page 143, line 24
current by including a list of their associated entity tags in the current by including a list of their associated entity tags in the
If-None-Match header field. The purpose of this feature is to allow If-None-Match header field. The purpose of this feature is to allow
efficient updates of cached information with a minimum amount of efficient updates of cached information with a minimum amount of
transaction overhead. It is also used to prevent a method (e.g. transaction overhead. It is also used to prevent a method (e.g.
PUT) from inadvertently modifying an existing resource when the PUT) from inadvertently modifying an existing resource when the
client believes that the resource does not exist. client believes that the resource does not exist.
As a special case, the value "*" matches any current entity of the As a special case, the value "*" matches any current entity of the
resource. resource.
If-None-Match = "If-None-Match" ":" ( "*" | 1#entity-tag ) If-None-Match = "If-None-Match" ":" ( "*" | 1#entity-tag )
If any of the entity tags match the entity tag of the entity that If any of the entity tags match the entity tag of the entity that
would have been returned in the response to a similar GET request would have been returned in the response to a similar GET request
(without the If-None-Match header) on that resource, or if "*" is (without the If-None-Match header) on that resource, or if "*" is
given and any current entity exists for that resource, then the given and any current entity exists for that resource, then the
server MUST NOT perform the requested method, unless required to do server MUST NOT perform the requested method, unless required to do
so because the resource's modification date fails to match that so because the resource's modification date fails to match that
supplied in an If-Modified-Since header field in the request. supplied in an If-Modified-Since header field in the request.
Instead, if the request method was GET or HEAD, the server SHOULD Instead, if the request method was GET or HEAD, the server SHOULD
respond with a 304 (Not Modified) response, including the cache- respond with a 304 (Not Modified) response, including the cache-
skipping to change at page 144, line 40 skipping to change at page 144, line 40
either or both of If-Unmodified-Since and If-Match.) However, if the either or both of If-Unmodified-Since and If-Match.) However, if the
condition fails because the entity has been modified, the client condition fails because the entity has been modified, the client
would then have to make a second request to obtain the entire current would then have to make a second request to obtain the entire current
entity-body. entity-body.
The If-Range header allows a client to "short-circuit" the second The If-Range header allows a client to "short-circuit" the second
request. Informally, its meaning is `if the entity is unchanged, request. Informally, its meaning is `if the entity is unchanged,
send me the part(s) that I am missing; otherwise, send me the entire send me the part(s) that I am missing; otherwise, send me the entire
new entity'. new entity'.
If-Range = "If-Range" ":" ( entity-tag | HTTP-date ) If-Range = "If-Range" ":" ( entity-tag | HTTP-date )
If the client has no entity tag for an entity, but does have a Last- If the client has no entity tag for an entity, but does have a Last-
Modified date, it MAY use that date in an If-Range header. (The Modified date, it MAY use that date in an If-Range header. (The
server can distinguish between a valid HTTP-date and any form of server can distinguish between a valid HTTP-date and any form of
entity-tag by examining no more than two characters.) The If-Range entity-tag by examining no more than two characters.) The If-Range
header SHOULD only be used together with a Range header, and MUST be header SHOULD only be used together with a Range header, and MUST be
ignored if the request does not include a Range header, or if the ignored if the request does not include a Range header, or if the
server does not support the sub-range operation. server does not support the sub-range operation.
If the entity tag given in the If-Range header matches the current If the entity tag given in the If-Range header matches the current
entity tag for the entity, then the server SHOULD provide the entity tag for the entity, then the server SHOULD provide the
specified sub-range of the entity using a 206 (Partial content) specified sub-range of the entity using a 206 (Partial Content)
response. If the entity tag does not match, then the server SHOULD response. If the entity tag does not match, then the server SHOULD
return the entire entity using a 200 (OK) response. return the entire entity using a 200 (OK) response.
14.28. If-Unmodified-Since 14.28. If-Unmodified-Since
The If-Unmodified-Since request-header field is used with a method to The If-Unmodified-Since request-header field is used with a method to
make it conditional. If the requested resource has not been modified make it conditional. If the requested resource has not been modified
since the time specified in this field, the server SHOULD perform the since the time specified in this field, the server SHOULD perform the
requested operation as if the If-Unmodified-Since header were not requested operation as if the If-Unmodified-Since header were not
present. present.
If the requested variant has been modified since the specified time, If the requested variant has been modified since the specified time,
the server MUST NOT perform the requested operation, and MUST return the server MUST NOT perform the requested operation, and MUST return
a 412 (Precondition Failed). a 412 (Precondition Failed).
If-Unmodified-Since = "If-Unmodified-Since" ":" HTTP-date If-Unmodified-Since = "If-Unmodified-Since" ":" HTTP-date
An example of the field is: An example of the field is:
If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT
If the request normally (i.e., without the If-Unmodified-Since If the request normally (i.e., without the If-Unmodified-Since
header) would result in anything other than a 2xx or 412 status, the header) would result in anything other than a 2xx or 412 status, the
If-Unmodified-Since header SHOULD be ignored. If-Unmodified-Since header SHOULD be ignored.
If the specified date is invalid, the header is ignored. If the specified date is invalid, the header is ignored.
The result of a request having both an If-Unmodified-Since header The result of a request having both an If-Unmodified-Since header
field and either an If-None-Match or an If-Modified-Since header field and either an If-None-Match or an If-Modified-Since header
fields is undefined by this specification. fields is undefined by this specification.
14.29. Last-Modified 14.29. Last-Modified
The Last-Modified entity-header field indicates the date and time at The Last-Modified entity-header field indicates the date and time at
which the origin server believes the variant was last modified. which the origin server believes the variant was last modified.
Last-Modified = "Last-Modified" ":" HTTP-date Last-Modified = "Last-Modified" ":" HTTP-date
An example of its use is An example of its use is
Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT
The exact meaning of this header field depends on the implementation The exact meaning of this header field depends on the implementation
of the origin server and the nature of the original resource. For of the origin server and the nature of the original resource. For
files, it may be just the file system last-modified time. For files, it may be just the file system last-modified time. For
entities with dynamically included parts, it may be the most recent entities with dynamically included parts, it may be the most recent
of the set of last-modify times for its component parts. For of the set of last-modify times for its component parts. For
skipping to change at page 146, line 32 skipping to change at page 146, line 32
14.30. Location 14.30. Location
The Location response-header field is used to redirect the recipient The Location response-header field is used to redirect the recipient
to a location other than the Request-URI for completion of the to a location other than the Request-URI for completion of the
request or identification of a new resource. For 201 (Created) request or identification of a new resource. For 201 (Created)
responses, the Location is that of the new resource which was created responses, the Location is that of the new resource which was created
by the request. For 3xx responses, the location SHOULD indicate the by the request. For 3xx responses, the location SHOULD indicate the
server's preferred URI for automatic redirection to the resource. server's preferred URI for automatic redirection to the resource.
The field value consists of a single absolute URI. The field value consists of a single absolute URI.
Location = "Location" ":" absoluteURI [ "#" fragment ] Location = "Location" ":" absoluteURI [ "#" fragment ]
An example is: An example is:
Location: http://www.example.org/pub/WWW/People.html Location: http://www.example.org/pub/WWW/People.html
Note: The Content-Location header field (Section 14.14) differs Note: The Content-Location header field (Section 14.14) differs
from Location in that the Content-Location identifies the original from Location in that the Content-Location identifies the original
location of the entity enclosed in the request. It is therefore location of the entity enclosed in the request. It is therefore
possible for a response to contain header fields for both Location possible for a response to contain header fields for both Location
and Content-Location. Also see Section 13.10 for cache and Content-Location. Also see Section 13.10 for cache
skipping to change at page 147, line 20 skipping to change at page 147, line 20
14.31. Max-Forwards 14.31. Max-Forwards
The Max-Forwards request-header field provides a mechanism with the The Max-Forwards request-header field provides a mechanism with the
TRACE (Section 9.8) and OPTIONS (Section 9.2) methods to limit the TRACE (Section 9.8) and OPTIONS (Section 9.2) methods to limit the
number of proxies or gateways that can forward the request to the number of proxies or gateways that can forward the request to the
next inbound server. This can be useful when the client is next inbound server. This can be useful when the client is
attempting to trace a request chain which appears to be failing or attempting to trace a request chain which appears to be failing or
looping in mid-chain. looping in mid-chain.
Max-Forwards = "Max-Forwards" ":" 1*DIGIT Max-Forwards = "Max-Forwards" ":" 1*DIGIT
The Max-Forwards value is a decimal integer indicating the remaining The Max-Forwards value is a decimal integer indicating the remaining
number of times this request message may be forwarded. number of times this request message may be forwarded.
Each proxy or gateway recipient of a TRACE or OPTIONS request Each proxy or gateway recipient of a TRACE or OPTIONS request
containing a Max-Forwards header field MUST check and update its containing a Max-Forwards header field MUST check and update its
value prior to forwarding the request. If the received value is zero value prior to forwarding the request. If the received value is zero
(0), the recipient MUST NOT forward the request; instead, it MUST (0), the recipient MUST NOT forward the request; instead, it MUST
respond as the final recipient. If the received Max-Forwards value respond as the final recipient. If the received Max-Forwards value
is greater than zero, then the forwarded message MUST contain an is greater than zero, then the forwarded message MUST contain an
skipping to change at page 147, line 45 skipping to change at page 147, line 45
it is not explicitly referred to as part of that method definition. it is not explicitly referred to as part of that method definition.
14.32. Pragma 14.32. Pragma
The Pragma general-header field is used to include implementation- The Pragma general-header field is used to include implementation-
specific directives that might apply to any recipient along the specific directives that might apply to any recipient along the
request/response chain. All pragma directives specify optional request/response chain. All pragma directives specify optional
behavior from the viewpoint of the protocol; however, some systems behavior from the viewpoint of the protocol; however, some systems
MAY require that behavior be consistent with the directives. MAY require that behavior be consistent with the directives.
Pragma = "Pragma" ":" 1#pragma-directive Pragma = "Pragma" ":" 1#pragma-directive
pragma-directive = "no-cache" | extension-pragma pragma-directive = "no-cache" | extension-pragma
extension-pragma = token [ "=" ( token | quoted-string ) ] extension-pragma = token [ "=" ( token | quoted-string ) ]
When the no-cache directive is present in a request message, an When the no-cache directive is present in a request message, an
application SHOULD forward the request toward the origin server even application SHOULD forward the request toward the origin server even
if it has a cached copy of what is being requested. This pragma if it has a cached copy of what is being requested. This pragma
directive has the same semantics as the no-cache cache-directive (see directive has the same semantics as the no-cache cache-directive (see
Section 14.9) and is defined here for backward compatibility with Section 14.9) and is defined here for backward compatibility with
HTTP/1.0. Clients SHOULD include both header fields when a no-cache HTTP/1.0. Clients SHOULD include both header fields when a no-cache
request is sent to a server not known to be HTTP/1.1 compliant. request is sent to a server not known to be HTTP/1.1 compliant.
Pragma directives MUST be passed through by a proxy or gateway Pragma directives MUST be passed through by a proxy or gateway
skipping to change at page 148, line 30 skipping to change at page 148, line 30
header field is not actually specified, it does not provide a header field is not actually specified, it does not provide a
reliable replacement for "Cache-Control: no-cache" in a response reliable replacement for "Cache-Control: no-cache" in a response
14.33. Proxy-Authenticate 14.33. Proxy-Authenticate
The Proxy-Authenticate response-header field MUST be included as part The Proxy-Authenticate response-header field MUST be included as part
of a 407 (Proxy Authentication Required) response. The field value of a 407 (Proxy Authentication Required) response. The field value
consists of a challenge that indicates the authentication scheme and consists of a challenge that indicates the authentication scheme and
parameters applicable to the proxy for this Request-URI. parameters applicable to the proxy for this Request-URI.
Proxy-Authenticate = "Proxy-Authenticate" ":" 1#challenge Proxy-Authenticate = "Proxy-Authenticate" ":" 1#challenge
The HTTP access authentication process is described in "HTTP The HTTP access authentication process is described in "HTTP
Authentication: Basic and Digest Access Authentication" [RFC2617]. Authentication: Basic and Digest Access Authentication" [RFC2617].
Unlike WWW-Authenticate, the Proxy-Authenticate header field applies Unlike WWW-Authenticate, the Proxy-Authenticate header field applies
only to the current connection and SHOULD NOT be passed on to only to the current connection and SHOULD NOT be passed on to
downstream clients. However, an intermediate proxy might need to downstream clients. However, an intermediate proxy might need to
obtain its own credentials by requesting them from the downstream obtain its own credentials by requesting them from the downstream
client, which in some circumstances will appear as if the proxy is client, which in some circumstances will appear as if the proxy is
forwarding the Proxy-Authenticate header field. forwarding the Proxy-Authenticate header field.
14.34. Proxy-Authorization 14.34. Proxy-Authorization
The Proxy-Authorization request-header field allows the client to The Proxy-Authorization request-header field allows the client to
identify itself (or its user) to a proxy which requires identify itself (or its user) to a proxy which requires
authentication. The Proxy-Authorization field value consists of authentication. The Proxy-Authorization field value consists of
credentials containing the authentication information of the user credentials containing the authentication information of the user
agent for the proxy and/or realm of the resource being requested. agent for the proxy and/or realm of the resource being requested.
Proxy-Authorization = "Proxy-Authorization" ":" credentials Proxy-Authorization = "Proxy-Authorization" ":" credentials
The HTTP access authentication process is described in "HTTP The HTTP access authentication process is described in "HTTP
Authentication: Basic and Digest Access Authentication" [RFC2617]. Authentication: Basic and Digest Access Authentication" [RFC2617].
Unlike Authorization, the Proxy-Authorization header field applies Unlike Authorization, the Proxy-Authorization header field applies
only to the next outbound proxy that demanded authentication using only to the next outbound proxy that demanded authentication using
the Proxy-Authenticate field. When multiple proxies are used in a the Proxy-Authenticate field. When multiple proxies are used in a
chain, the Proxy-Authorization header field is consumed by the first chain, the Proxy-Authorization header field is consumed by the first
outbound proxy that was expecting to receive credentials. A proxy outbound proxy that was expecting to receive credentials. A proxy
MAY relay the credentials from the client request to the next proxy MAY relay the credentials from the client request to the next proxy
if that is the mechanism by which the proxies cooperatively if that is the mechanism by which the proxies cooperatively
skipping to change at page 149, line 29 skipping to change at page 149, line 29
of bytes, the concept of a byte range is meaningful for any HTTP of bytes, the concept of a byte range is meaningful for any HTTP
entity. (However, not all clients and servers need to support byte- entity. (However, not all clients and servers need to support byte-
range operations.) range operations.)
Byte range specifications in HTTP apply to the sequence of bytes in Byte range specifications in HTTP apply to the sequence of bytes in
the entity-body (not necessarily the same as the message-body). the entity-body (not necessarily the same as the message-body).
A byte range operation MAY specify a single range of bytes, or a set A byte range operation MAY specify a single range of bytes, or a set
of ranges within a single entity. of ranges within a single entity.
ranges-specifier = byte-ranges-specifier ranges-specifier = byte-ranges-specifier
byte-ranges-specifier = bytes-unit "=" byte-range-set byte-ranges-specifier = bytes-unit "=" byte-range-set
byte-range-set = 1#( byte-range-spec | suffix-byte-range-spec ) byte-range-set = 1#( byte-range-spec | suffix-byte-range-spec )
byte-range-spec = first-byte-pos "-" [last-byte-pos] byte-range-spec = first-byte-pos "-" [last-byte-pos]
first-byte-pos = 1*DIGIT first-byte-pos = 1*DIGIT
last-byte-pos = 1*DIGIT last-byte-pos = 1*DIGIT
The first-byte-pos value in a byte-range-spec gives the byte-offset The first-byte-pos value in a byte-range-spec gives the byte-offset
of the first byte in a range. The last-byte-pos value gives the of the first byte in a range. The last-byte-pos value gives the
byte-offset of the last byte in the range; that is, the byte byte-offset of the last byte in the range; that is, the byte
positions specified are inclusive. Byte offsets start at zero. positions specified are inclusive. Byte offsets start at zero.
If the last-byte-pos value is present, it MUST be greater than or If the last-byte-pos value is present, it MUST be greater than or
equal to the first-byte-pos in that byte-range-spec, or the byte- equal to the first-byte-pos in that byte-range-spec, or the byte-
range-spec is syntactically invalid. The recipient of a byte-range- range-spec is syntactically invalid. The recipient of a byte-range-
set that includes one or more syntactically invalid byte-range-spec set that includes one or more syntactically invalid byte-range-spec
skipping to change at page 150, line 8 skipping to change at page 150, line 8
set. set.
If the last-byte-pos value is absent, or if the value is greater than If the last-byte-pos value is absent, or if the value is greater than
or equal to the current length of the entity-body, last-byte-pos is or equal to the current length of the entity-body, last-byte-pos is
taken to be equal to one less than the current length of the entity- taken to be equal to one less than the current length of the entity-
body in bytes. body in bytes.
By its choice of last-byte-pos, a client can limit the number of By its choice of last-byte-pos, a client can limit the number of
bytes retrieved without knowing the size of the entity. bytes retrieved without knowing the size of the entity.
suffix-byte-range-spec = "-" suffix-length suffix-byte-range-spec = "-" suffix-length
suffix-length = 1*DIGIT suffix-length = 1*DIGIT
A suffix-byte-range-spec is used to specify the suffix of the entity- A suffix-byte-range-spec is used to specify the suffix of the entity-
body, of a length given by the suffix-length value. (That is, this body, of a length given by the suffix-length value. (That is, this
form specifies the last N bytes of an entity-body.) If the entity is form specifies the last N bytes of an entity-body.) If the entity is
shorter than the specified suffix-length, the entire entity-body is shorter than the specified suffix-length, the entire entity-body is
used. used.
If a syntactically valid byte-range-set includes at least one byte- If a syntactically valid byte-range-set includes at least one byte-
range-spec whose first-byte-pos is less than the current length of range-spec whose first-byte-pos is less than the current length of
the entity-body, or at least one suffix-byte-range-spec with a non- the entity-body, or at least one suffix-byte-range-spec with a non-
skipping to change at page 151, line 5 skipping to change at page 151, line 5
bytes=500-600,601-999 bytes=500-600,601-999
bytes=500-700,601-999 bytes=500-700,601-999
14.35.2. Range Retrieval Requests 14.35.2. Range Retrieval Requests
HTTP retrieval requests using conditional or unconditional GET HTTP retrieval requests using conditional or unconditional GET
methods MAY request one or more sub-ranges of the entity, instead of methods MAY request one or more sub-ranges of the entity, instead of
the entire entity, using the Range request header, which applies to the entire entity, using the Range request header, which applies to
the entity returned as the result of the request: the entity returned as the result of the request:
Range = "Range" ":" ranges-specifier Range = "Range" ":" ranges-specifier
A server MAY ignore the Range header. However, HTTP/1.1 origin A server MAY ignore the Range header. However, HTTP/1.1 origin
servers and intermediate caches ought to support byte ranges when servers and intermediate caches ought to support byte ranges when
possible, since Range supports efficient recovery from partially possible, since Range supports efficient recovery from partially
failed transfers, and supports efficient partial retrieval of large failed transfers, and supports efficient partial retrieval of large
entities. entities.
If the server supports the Range header and the specified range or If the server supports the Range header and the specified range or
ranges are appropriate for the entity: ranges are appropriate for the entity:
skipping to change at page 151, line 49 skipping to change at page 151, line 49
The Referer[sic] request-header field allows the client to specify, The Referer[sic] request-header field allows the client to specify,
for the server's benefit, the address (URI) of the resource from for the server's benefit, the address (URI) of the resource from
which the Request-URI was obtained (the "referrer", although the which the Request-URI was obtained (the "referrer", although the
header field is misspelled.) The Referer request-header allows a header field is misspelled.) The Referer request-header allows a
server to generate lists of back-links to resources for interest, server to generate lists of back-links to resources for interest,
logging, optimized caching, etc. It also allows obsolete or mistyped logging, optimized caching, etc. It also allows obsolete or mistyped
links to be traced for maintenance. The Referer field MUST NOT be links to be traced for maintenance. The Referer field MUST NOT be
sent if the Request-URI was obtained from a source that does not have sent if the Request-URI was obtained from a source that does not have
its own URI, such as input from the user keyboard. its own URI, such as input from the user keyboard.
Referer = "Referer" ":" ( absoluteURI | relativeURI ) Referer = "Referer" ":" ( absoluteURI | relativeURI )
Example: Example:
Referer: http://www.example.org/hypertext/Overview.html Referer: http://www.example.org/hypertext/Overview.html
If the field value is a relative URI, it SHOULD be interpreted If the field value is a relative URI, it SHOULD be interpreted
relative to the Request-URI. The URI MUST NOT include a fragment. relative to the Request-URI. The URI MUST NOT include a fragment.
See Section 15.1.3 for security considerations. See Section 15.1.3 for security considerations.
14.37. Retry-After 14.37. Retry-After
The Retry-After response-header field can be used with a 503 (Service The Retry-After response-header field can be used with a 503 (Service
Unavailable) response to indicate how long the service is expected to Unavailable) response to indicate how long the service is expected to
be unavailable to the requesting client. This field MAY also be used be unavailable to the requesting client. This field MAY also be used
with any 3xx (Redirection) response to indicate the minimum time the with any 3xx (Redirection) response to indicate the minimum time the
user-agent is asked wait before issuing the redirected request. The user-agent is asked wait before issuing the redirected request. The
value of this field can be either an HTTP-date or an integer number value of this field can be either an HTTP-date or an integer number
of seconds (in decimal) after the time of the response. of seconds (in decimal) after the time of the response.
Retry-After = "Retry-After" ":" ( HTTP-date | delta-seconds ) Retry-After = "Retry-After" ":" ( HTTP-date | delta-seconds )
Two examples of its use are Two examples of its use are
Retry-After: Fri, 31 Dec 1999 23:59:59 GMT Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
Retry-After: 120 Retry-After: 120
In the latter example, the delay is 2 minutes. In the latter example, the delay is 2 minutes.
14.38. Server 14.38. Server
The Server response-header field contains information about the The Server response-header field contains information about the
software used by the origin server to handle the request. The field software used by the origin server to handle the request. The field
can contain multiple product tokens (Section 3.8) and comments can contain multiple product tokens (Section 3.8) and comments
identifying the server and any significant subproducts. The product identifying the server and any significant subproducts. The product
tokens are listed in order of their significance for identifying the tokens are listed in order of their significance for identifying the
application. application.
Server = "Server" ":" 1*( product | comment ) Server = "Server" ":" 1*( product | comment )
Example: Example:
Server: CERN/3.0 libwww/2.17 Server: CERN/3.0 libwww/2.17
If the response is being forwarded through a proxy, the proxy If the response is being forwarded through a proxy, the proxy
application MUST NOT modify the Server response-header. Instead, it application MUST NOT modify the Server response-header. Instead, it
MUST include a Via field (as described in Section 14.45). MUST include a Via field (as described in Section 14.45).
Note: Revealing the specific software version of the server might Note: Revealing the specific software version of the server might
skipping to change at page 153, line 15 skipping to change at page 153, line 15
14.39. TE 14.39. TE
The TE request-header field indicates what extension transfer-codings The TE request-header field indicates what extension transfer-codings
it is willing to accept in the response and whether or not it is it is willing to accept in the response and whether or not it is
willing to accept trailer fields in a chunked transfer-coding. Its willing to accept trailer fields in a chunked transfer-coding. Its
value may consist of the keyword "trailers" and/or a comma-separated value may consist of the keyword "trailers" and/or a comma-separated
list of extension transfer-coding names with optional accept list of extension transfer-coding names with optional accept
parameters (as described in Section 3.6). parameters (as described in Section 3.6).
TE = "TE" ":" #( t-codings ) TE = "TE" ":" #( t-codings )
t-codings = "trailers" | ( transfer-extension [ accept-params ] ) t-codings = "trailers" | ( transfer-extension [ accept-params ] )
The presence of the keyword "trailers" indicates that the client is The presence of the keyword "trailers" indicates that the client is
willing to accept trailer fields in a chunked transfer-coding, as willing to accept trailer fields in a chunked transfer-coding, as
defined in Section 3.6.1. This keyword is reserved for use with defined in Section 3.6.1. This keyword is reserved for use with
transfer-coding values even though it does not itself represent a transfer-coding values even though it does not itself represent a
transfer-coding. transfer-coding.
Examples of its use are: Examples of its use are:
TE: deflate TE: deflate
skipping to change at page 154, line 21 skipping to change at page 154, line 21
If the TE field-value is empty or if no TE field is present, the only If the TE field-value is empty or if no TE field is present, the only
transfer-coding is "chunked". A message with no transfer-coding is transfer-coding is "chunked". A message with no transfer-coding is
always acceptable. always acceptable.
14.40. Trailer 14.40. Trailer
The Trailer general field value indicates that the given set of The Trailer general field value indicates that the given set of
header fields is present in the trailer of a message encoded with header fields is present in the trailer of a message encoded with
chunked transfer-coding. chunked transfer-coding.
Trailer = "Trailer" ":" 1#field-name Trailer = "Trailer" ":" 1#field-name
An HTTP/1.1 message SHOULD include a Trailer header field in a An HTTP/1.1 message SHOULD include a Trailer header field in a
message using chunked transfer-coding with a non-empty trailer. message using chunked transfer-coding with a non-empty trailer.
Doing so allows the recipient to know which header fields to expect Doing so allows the recipient to know which header fields to expect
in the trailer. in the trailer.
If no Trailer header field is present, the trailer SHOULD NOT include If no Trailer header field is present, the trailer SHOULD NOT include
any header fields. See Section 3.6.1 for restrictions on the use of any header fields. See Section 3.6.1 for restrictions on the use of
trailer fields in a "chunked" transfer-coding. trailer fields in a "chunked" transfer-coding.
skipping to change at page 155, line 23 skipping to change at page 155, line 23
Encoding header. Encoding header.
14.42. Upgrade 14.42. Upgrade
The Upgrade general-header allows the client to specify what The Upgrade general-header allows the client to specify what
additional communication protocols it supports and would like to use additional communication protocols it supports and would like to use
if the server finds it appropriate to switch protocols. The server if the server finds it appropriate to switch protocols. The server
MUST use the Upgrade header field within a 101 (Switching Protocols) MUST use the Upgrade header field within a 101 (Switching Protocols)
response to indicate which protocol(s) are being switched. response to indicate which protocol(s) are being switched.
Upgrade = "Upgrade" ":" 1#product Upgrade = "Upgrade" ":" 1#product
For example, For example,
Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11 Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
The Upgrade header field is intended to provide a simple mechanism The Upgrade header field is intended to provide a simple mechanism
for transition from HTTP/1.1 to some other, incompatible protocol. for transition from HTTP/1.1 to some other, incompatible protocol.
It does so by allowing the client to advertise its desire to use It does so by allowing the client to advertise its desire to use
another protocol, such as a later version of HTTP with a higher major another protocol, such as a later version of HTTP with a higher major
version number, even though the current request has been made using version number, even though the current request has been made using
skipping to change at page 156, line 30 skipping to change at page 156, line 30
user agent originating the request. This is for statistical user agent originating the request. This is for statistical
purposes, the tracing of protocol violations, and automated purposes, the tracing of protocol violations, and automated
recognition of user agents for the sake of tailoring responses to recognition of user agents for the sake of tailoring responses to
avoid particular user agent limitations. User agents SHOULD include avoid particular user agent limitations. User agents SHOULD include
this field with requests. The field can contain multiple product this field with requests. The field can contain multiple product
tokens (Section 3.8) and comments identifying the agent and any tokens (Section 3.8) and comments identifying the agent and any
subproducts which form a significant part of the user agent. By subproducts which form a significant part of the user agent. By
convention, the product tokens are listed in order of their convention, the product tokens are listed in order of their
significance for identifying the application. significance for identifying the application.
User-Agent = "User-Agent" ":" 1*( product | comment ) User-Agent = "User-Agent" ":" 1*( product | comment )
Example: Example:
User-Agent: CERN-LineMode/2.15 libwww/2.17b3 User-Agent: CERN-LineMode/2.15 libwww/2.17b3
14.44. Vary 14.44. Vary
The Vary field value indicates the set of request-header fields that The Vary field value indicates the set of request-header fields that
fully determines, while the response is fresh, whether a cache is fully determines, while the response is fresh, whether a cache is
permitted to use the response to reply to a subsequent request permitted to use the response to reply to a subsequent request
without revalidation. For uncacheable or stale responses, the Vary without revalidation. For uncacheable or stale responses, the Vary
field value advises the user agent about the criteria that were used field value advises the user agent about the criteria that were used
to select the representation. A Vary field value of "*" implies that to select the representation. A Vary field value of "*" implies that
a cache cannot determine from the request headers of a subsequent a cache cannot determine from the request headers of a subsequent
request whether this response is the appropriate representation. See request whether this response is the appropriate representation. See
Section 13.6 for use of the Vary header field by caches. Section 13.6 for use of the Vary header field by caches.
Vary = "Vary" ":" ( "*" | 1#field-name ) Vary = "Vary" ":" ( "*" | 1#field-name )
An HTTP/1.1 server SHOULD include a Vary header field with any An HTTP/1.1 server SHOULD include a Vary header field with any
cacheable response that is subject to server-driven negotiation. cacheable response that is subject to server-driven negotiation.
Doing so allows a cache to properly interpret future requests on that Doing so allows a cache to properly interpret future requests on that
resource and informs the user agent about the presence of negotiation resource and informs the user agent about the presence of negotiation
on that resource. A server MAY include a Vary header field with a on that resource. A server MAY include a Vary header field with a
non-cacheable response that is subject to server-driven negotiation, non-cacheable response that is subject to server-driven negotiation,
since this might provide the user agent with useful information about since this might provide the user agent with useful information about
the dimensions over which the response varies at the time of the the dimensions over which the response varies at the time of the
skipping to change at page 157, line 37 skipping to change at page 157, line 37
client), play a role in the selection of the response representation. client), play a role in the selection of the response representation.
The "*" value MUST NOT be generated by a proxy server; it may only be The "*" value MUST NOT be generated by a proxy server; it may only be
generated by an origin server. generated by an origin server.
14.45. Via 14.45. Via
The Via general-header field MUST be used by gateways and proxies to The Via general-header field MUST be used by gateways and proxies to
indicate the intermediate protocols and recipients between the user indicate the intermediate protocols and recipients between the user
agent and the server on requests, and between the origin server and agent and the server on requests, and between the origin server and
the client on responses. It is analogous to the "Received" field of the client on responses. It is analogous to the "Received" field of
[RFC822] and is intended to be used for tracking message forwards, [RFC2822] and is intended to be used for tracking message forwards,
avoiding request loops, and identifying the protocol capabilities of avoiding request loops, and identifying the protocol capabilities of
all senders along the request/response chain. all senders along the request/response chain.
Via = "Via" ":" 1#( received-protocol received-by [ comment ] ) Via = "Via" ":" 1#( received-protocol received-by [ comment ] )
received-protocol = [ protocol-name "/" ] protocol-version received-protocol = [ protocol-name "/" ] protocol-version
protocol-name = token protocol-name = token
protocol-version = token protocol-version = token
received-by = ( host [ ":" port ] ) | pseudonym received-by = ( host [ ":" port ] ) | pseudonym
pseudonym = token pseudonym = token
The received-protocol indicates the protocol version of the message The received-protocol indicates the protocol version of the message
received by the server or client along each segment of the request/ received by the server or client along each segment of the request/
response chain. The received-protocol version is appended to the Via response chain. The received-protocol version is appended to the Via
field value when the message is forwarded so that information about field value when the message is forwarded so that information about
the protocol capabilities of upstream applications remains visible to the protocol capabilities of upstream applications remains visible to
all recipients. all recipients.
The protocol-name is optional if and only if it would be "HTTP". The The protocol-name is optional if and only if it would be "HTTP". The
received-by field is normally the host and optional port number of a received-by field is normally the host and optional port number of a
skipping to change at page 159, line 19 skipping to change at page 159, line 19
The Warning general-header field is used to carry additional The Warning general-header field is used to carry additional
information about the status or transformation of a message which information about the status or transformation of a message which
might not be reflected in the message. This information is typically might not be reflected in the message. This information is typically
used to warn about a possible lack of semantic transparency from used to warn about a possible lack of semantic transparency from
caching operations or transformations applied to the entity body of caching operations or transformations applied to the entity body of
the message. the message.
Warning headers are sent with responses using: Warning headers are sent with responses using:
Warning = "Warning" ":" 1#warning-value Warning = "Warning" ":" 1#warning-value
warning-value = warn-code SP warn-agent SP warn-text warning-value = warn-code SP warn-agent SP warn-text
[SP warn-date] [SP warn-date]
warn-code = 3DIGIT warn-code = 3DIGIT
warn-agent = ( host [ ":" port ] ) | pseudonym warn-agent = ( host [ ":" port ] ) | pseudonym
; the name or pseudonym of the server adding ; the name or pseudonym of the server adding
; the Warning header, for use in debugging ; the Warning header, for use in debugging
warn-text = quoted-string warn-text = quoted-string
warn-date = <"> HTTP-date <"> warn-date = <"> HTTP-date <">
A response MAY carry more than one Warning header. A response MAY carry more than one Warning header.
The warn-text SHOULD be in a natural language and character set that The warn-text SHOULD be in a natural language and character set that
is most likely to be intelligible to the human user receiving the is most likely to be intelligible to the human user receiving the
response. This decision MAY be based on any available knowledge, response. This decision MAY be based on any available knowledge,
such as the location of the cache or user, the Accept-Language field such as the location of the cache or user, the Accept-Language field
in a request, the Content-Language field in a response, etc. The in a request, the Content-Language field in a response, etc. The
default language is English and the default character set is ISO- default language is English and the default character set is ISO-
8859-1. 8859-1.
skipping to change at page 161, line 43 skipping to change at page 161, line 43
of the warning-values are deleted for this reason, the Warning header of the warning-values are deleted for this reason, the Warning header
MUST be deleted as well. MUST be deleted as well.
14.47. WWW-Authenticate 14.47. WWW-Authenticate
The WWW-Authenticate response-header field MUST be included in 401 The WWW-Authenticate response-header field MUST be included in 401
(Unauthorized) response messages. The field value consists of at (Unauthorized) response messages. The field value consists of at
least one challenge that indicates the authentication scheme(s) and least one challenge that indicates the authentication scheme(s) and
parameters applicable to the Request-URI. parameters applicable to the Request-URI.
WWW-Authenticate = "WWW-Authenticate" ":" 1#challenge WWW-Authenticate = "WWW-Authenticate" ":" 1#challenge
The HTTP access authentication process is described in "HTTP The HTTP access authentication process is described in "HTTP
Authentication: Basic and Digest Access Authentication" [RFC2617]. Authentication: Basic and Digest Access Authentication" [RFC2617].
User agents are advised to take special care in parsing the WWW- User agents are advised to take special care in parsing the WWW-
Authenticate field value as it might contain more than one challenge, Authenticate field value as it might contain more than one challenge,
or if more than one WWW-Authenticate header field is provided, the or if more than one WWW-Authenticate header field is provided, the
contents of a challenge itself can contain a comma-separated list of contents of a challenge itself can contain a comma-separated list of
authentication parameters. authentication parameters.
15. Security Considerations 15. Security Considerations
skipping to change at page 168, line 10 skipping to change at page 168, line 10
15.7.1. Denial of Service Attacks on Proxies 15.7.1. Denial of Service Attacks on Proxies
They exist. They are hard to defend against. Research continues. They exist. They are hard to defend against. Research continues.
Beware. Beware.
16. Acknowledgments 16. Acknowledgments
16.1. (RFC2616) 16.1. (RFC2616)
This specification makes heavy use of the augmented BNF and generic This specification makes heavy use of the augmented BNF and generic
constructs defined by David H. Crocker for [RFC822]. Similarly, it constructs defined by David H. Crocker for [RFC822ABNF]. Similarly,
reuses many of the definitions provided by Nathaniel Borenstein and it reuses many of the definitions provided by Nathaniel Borenstein
Ned Freed for MIME [RFC2045]. We hope that their inclusion in this and Ned Freed for MIME [RFC2045]. We hope that their inclusion in
specification will help reduce past confusion over the relationship this specification will help reduce past confusion over the
between HTTP and Internet mail message formats. relationship between HTTP and Internet mail message formats.
The HTTP protocol has evolved considerably over the years. It has The HTTP protocol has evolved considerably over the years. It has
benefited from a large and active developer community--the many benefited from a large and active developer community--the many
people who have participated on the www-talk mailing list--and it is people who have participated on the www-talk mailing list--and it is
that community which has been most responsible for the success of that community which has been most responsible for the success of
HTTP and of the World-Wide Web in general. Marc Andreessen, Robert HTTP and of the World-Wide Web in general. Marc Andreessen, Robert
Cailliau, Daniel W. Connolly, Bob Denny, John Franks, Jean-Francois Cailliau, Daniel W. Connolly, Bob Denny, John Franks, Jean-Francois
Groff, Phillip M. Hallam-Baker, Hakon W. Lie, Ari Luotonen, Rob Groff, Phillip M. Hallam-Baker, Hakon W. Lie, Ari Luotonen, Rob
McCool, Lou Montulli, Dave Raggett, Tony Sanders, and Marc McCool, Lou Montulli, Dave Raggett, Tony Sanders, and Marc
VanHeyningen deserve special recognition for their efforts in VanHeyningen deserve special recognition for their efforts in
skipping to change at page 169, line 23 skipping to change at page 169, line 23
The Apache Group, Anselm Baird-Smith, author of Jigsaw, and Henrik The Apache Group, Anselm Baird-Smith, author of Jigsaw, and Henrik
Frystyk implemented RFC 2068 early, and we wish to thank them for the Frystyk implemented RFC 2068 early, and we wish to thank them for the
discovery of many of the problems that this document attempts to discovery of many of the problems that this document attempts to
rectify. rectify.
16.2. (This Document) 16.2. (This Document)
This document has benefited greatly from the comments of all those This document has benefited greatly from the comments of all those
participating in the HTTP-WG. In particular, we thank Scott Lawrence participating in the HTTP-WG. In particular, we thank Scott Lawrence
for maintaining the RFC2616 Errata list, and Mark Baker, Roy for maintaining the RFC2616 Errata list, and Mark Baker, David Booth,
Fielding, Bjoern Hoehrmann, Brian Kell, Jamie Lokier, Larry Masinter, Adrien de Croy, Martin Duerst, Roy Fielding, Hugo Haas, Bjoern
Howard Melman, Alexey Melnikov, Jeff Mogul, Henrik Nordstrom, Alex Hoehrmann, Brian Kell, Jamie Lokier, Paul Marquess, Larry Masinter,
Rousskov, Travis Snoozy and Dan Winship for contributions to it. Howard Melman, Alexey Melnikov, Jeff Mogul, Henrik Nordstrom, Joe
Orton, Alex Rousskov, Travis Snoozy and Dan Winship for further
contributions.
17. References 17. References
17.1. References (to be classified) 17.1. References (to be classified)
[RFC1737] Masinter, L. and K. Sollins, "Functional Requirements for
Uniform Resource Names", RFC 1737, December 1994.
[RFC2048] Freed, N., Klensin, J., and J. Postel, "Multipurpose
Internet Mail Extensions (MIME) Part Four: Registration
Procedures", BCP 13, RFC 2048, November 1996.
17.2. Normative References
[ISO-8859-1] [ISO-8859-1]
International Organization for Standardization, International Organization for Standardization,
"Information technology - 8-bit single byte coded graphic "Information technology -- 8-bit single-byte coded graphic
- character sets", 1987-1990. character sets -- Part 1: Latin alphabet No. 1", ISO/
IEC 8859-1:1998, 1998.
Part 1: Latin alphabet No. 1, ISO-8859-1:1987. Part 2: [RFC1766] Alvestrand, H., "Tags for the Identification of
Latin alphabet No. 2, ISO-8859-2, 1987. Part 3: Latin Languages", RFC 1766, March 1995.
alphabet No. 3, ISO-8859-3, 1988. Part 4: Latin alphabet
No. 4, ISO-8859-4, 1988. Part 5: Latin/Cyrillic alphabet, [RFC1864] Myers, J. and M. Rose, "The Content-MD5 Header Field",
ISO-8859-5, 1988. Part 6: Latin/Arabic alphabet, ISO- RFC 1864, October 1995.
8859-6, 1987. Part 7: Latin/Greek alphabet, ISO-8859-7,
1987. Part 8: Latin/Hebrew alphabet, ISO-8859-8, 1988. [RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format
Part 9: Latin alphabet No. 5, ISO-8859-9, 1990. Specification version 3.3", RFC 1950, May 1996.
RFC1950 is an Informational RFC, thus it may be less
stable than this specification. On the other hand, this
downward reference was present since [RFC2068] (published
in 1997), therefore it is unlikely to cause problems in
practice.
[RFC1951] Deutsch, P., "DEFLATE Compressed Data Format Specification
version 1.3", RFC 1951, May 1996.
RFC1951 is an Informational RFC, thus it may be less
stable than this specification. On the other hand, this
downward reference was present since [RFC2068] (published
in 1997), therefore it is unlikely to cause problems in
practice.
[RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and G.
Randers-Pehrson, "GZIP file format specification version
4.3", RFC 1952, May 1996.
RFC1952 is an Informational RFC, thus it may be less
stable than this specification. On the other hand, this
downward reference was present since [RFC2068] (published
in 1997), therefore it is unlikely to cause problems in
practice.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC2822] Resnick, P., "Internet Message Format", RFC 2822,
April 2001.
[RFC822ABNF]
Crocker, D., "Standard for the format of ARPA Internet
text messages", STD 11, RFC 822, August 1982.
[USASCII] American National Standards Institute, "Coded Character
Set -- 7-bit American Standard Code for Information
Interchange", ANSI X3.4, 1986.
17.3. Informative References
[Luo1998] Luotonen, A., "Tunneling TCP based protocols through Web [Luo1998] Luotonen, A., "Tunneling TCP based protocols through Web
proxy servers", Work in Progress. proxy servers", draft-luotonen-web-proxy-tunneling-01
(work in progress), August 1998.
[Nie1997] Nielsen, H., Gettys, J., Prud'hommeaux, E., Lie, H., and [Nie1997] Nielsen, H., Gettys, J., Prud'hommeaux, E., Lie, H., and
C. Lilley, "Network Performance Effects of HTTP/1.1, CSS1, C. Lilley, "Network Performance Effects of HTTP/1.1, CSS1,
and PNG", Proceedings of ACM SIGCOMM '97, Cannes France , and PNG", Proceedings of ACM SIGCOMM '97, Cannes France ,
Sep 1997. Sep 1997.
[Pad1995] Padmanabhan, V. and J. Mogul, "Improving HTTP Latency", [Pad1995] Padmanabhan, V. and J. Mogul, "Improving HTTP Latency",
Computer Networks and ISDN Systems v. 28, pp. 25-35, Computer Networks and ISDN Systems v. 28, pp. 25-35,
Dec 1995. Dec 1995.
Slightly revised version of paper in Proc. 2nd Slightly revised version of paper in Proc. 2nd
International WWW Conference '94: Mosaic and the Web, Oct. International WWW Conference '94: Mosaic and the Web, Oct.
1994, which is available at <http://www.ncsa.uiuc.edu/SDG/ 1994, which is available at <http://www.ncsa.uiuc.edu/SDG/
IT94/Proceedings/DDay/mogul/HTTPLatency.html>. IT94/Proceedings/DDay/mogul/HTTPLatency.html>.
[RFC1036] Horton, M. and R. Adams, "Standard for interchange of
USENET messages", RFC 1036, December 1987.
[RFC1123] Braden, R., "Requirements for Internet Hosts - Application [RFC1123] Braden, R., "Requirements for Internet Hosts - Application
and Support", STD 3, RFC 1123, October 1989. and Support", STD 3, RFC 1123, October 1989.
[RFC1305] Mills, D., "Network Time Protocol (Version 3) [RFC1305] Mills, D., "Network Time Protocol (Version 3)
Specification, Implementation", RFC 1305, March 1992. Specification, Implementation", RFC 1305, March 1992.
[RFC1436] Anklesaria, F., McCahill, M., Lindner, P., Johnson, D., [RFC1436] Anklesaria, F., McCahill, M., Lindner, P., Johnson, D.,
Torrey, D., and B. Alberti, "The Internet Gopher Protocol Torrey, D., and B. Alberti, "The Internet Gopher Protocol
(a distributed document search and retrieval protocol)", (a distributed document search and retrieval protocol)",
RFC 1436, March 1993. RFC 1436, March 1993.
[RFC1590] Postel, J., "Media Type Registration Procedure", RFC 1590,
March 1994.
[RFC1630] Berners-Lee, T., "Universal Resource Identifiers in WWW: A [RFC1630] Berners-Lee, T., "Universal Resource Identifiers in WWW: A
Unifying Syntax for the Expression of Names and Addresses Unifying Syntax for the Expression of Names and Addresses
of Objects on the Network as used in the World-Wide Web", of Objects on the Network as used in the World-Wide Web",
RFC 1630, June 1994. RFC 1630, June 1994.
[RFC1737] Masinter, L. and K. Sollins, "Functional Requirements for
Uniform Resource Names", RFC 1737, December 1994.
[RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform [RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
Resource Locators (URL)", RFC 1738, December 1994. Resource Locators (URL)", RFC 1738, December 1994.
[RFC1766] Alvestrand, H., "Tags for the Identification of
Languages", RFC 1766, March 1995.
[RFC1806] Troost, R. and S. Dorner, "Communicating Presentation [RFC1806] Troost, R. and S. Dorner, "Communicating Presentation
Information in Internet Messages: The Content-Disposition Information in Internet Messages: The Content-Disposition
Header", RFC 1806, June 1995. Header", RFC 1806, June 1995.
[RFC1808] Fielding, R., "Relative Uniform Resource Locators", [RFC1808] Fielding, R., "Relative Uniform Resource Locators",
RFC 1808, June 1995. RFC 1808, June 1995.
[RFC1864] Myers, J. and M. Rose, "The Content-MD5 Header Field",
RFC 1864, October 1995.
[RFC1866] Berners-Lee, T. and D. Connolly, "Hypertext Markup
Language - 2.0", RFC 1866, November 1995.
[RFC1867] Masinter, L. and E. Nebel, "Form-based File Upload in
HTML", RFC 1867, November 1995.
[RFC1900] Carpenter, B. and Y. Rekhter, "Renumbering Needs Work", [RFC1900] Carpenter, B. and Y. Rekhter, "Renumbering Needs Work",
RFC 1900, February 1996. RFC 1900, February 1996.
[RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext
Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996. Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996.
[RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format
Specification version 3.3", RFC 1950, May 1996.
[RFC1951] Deutsch, P., "DEFLATE Compressed Data Format Specification
version 1.3", RFC 1951, May 1996.
[RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and G.
Randers-Pehrson, "GZIP file format specification version
4.3", RFC 1952, May 1996.
[RFC2026] Bradner, S., "The Internet Standards Process -- Revision [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996. 3", BCP 9, RFC 2026, October 1996.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996.
[RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Five: Conformance Criteria and Extensions (MIME) Part Five: Conformance Criteria and
Examples", RFC 2049, November 1996. Examples", RFC 2049, November 1996.
[RFC2068] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., and T. [RFC2068] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., and T.
Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1",
RFC 2068, January 1997. RFC 2068, January 1997.
[RFC2069] Franks, J., Hallam-Baker, P., Hostetler, J., Leach, P.,
Luotonen, A., Sink, E., and L. Stewart, "An Extension to
HTTP : Digest Access Authentication", RFC 2069,
January 1997.
[RFC2076] Palme, J., "Common Internet Message Headers", RFC 2076, [RFC2076] Palme, J., "Common Internet Message Headers", RFC 2076,
February 1997. February 1997.
[RFC2110] Palme, J. and A. Hopmann, "MIME E-mail Encapsulation of
Aggregate Documents, such as HTML (MHTML)", RFC 2110,
March 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2145] Mogul, J., Fielding, R., Gettys, J., and H. Nielsen, "Use [RFC2145] Mogul, J., Fielding, R., Gettys, J., and H. Nielsen, "Use
and Interpretation of HTTP Version Numbers", RFC 2145, and Interpretation of HTTP Version Numbers", RFC 2145,
May 1997. May 1997.
[RFC2183] Troost, R., Dorner, S., and K. Moore, "Communicating [RFC2183] Troost, R., Dorner, S., and K. Moore, "Communicating
Presentation Information in Internet Messages: The Presentation Information in Internet Messages: The
Content-Disposition Header Field", RFC 2183, August 1997. Content-Disposition Header Field", RFC 2183, August 1997.
[RFC2277] Alvestrand, H., "IETF Policy on Character Sets and [RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
Languages", BCP 18, RFC 2277, January 1998. Languages", BCP 18, RFC 2277, January 1998.
[RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 2279, January 1998.
[RFC2324] Masinter, L., "Hyper Text Coffee Pot Control Protocol [RFC2324] Masinter, L., "Hyper Text Coffee Pot Control Protocol
(HTCPCP/1.0)", RFC 2324, April 1998. (HTCPCP/1.0)", RFC 2324, April 1998.
[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC2388] Masinter, L., "Returning Values from Forms: multipart/
Resource Identifiers (URI): Generic Syntax", RFC 2396, form-data", RFC 2388, August 1998.
August 1998.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., [RFC2557] Palme, F., Hopmann, A., Shelness, N., and E. Stefferud,
Leach, P., Luotonen, A., and L. Stewart, "HTTP "MIME Encapsulation of Aggregate Documents, such as HTML
Authentication: Basic and Digest Access Authentication", (MHTML)", RFC 2557, March 1999.
RFC 2617, June 1999.
[RFC821] Postel, J., "Simple Mail Transfer Protocol", STD 10, [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
RFC 821, August 1982. Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2821] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821,
April 2001.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 3629, STD 63, November 2003.
[RFC3977] Feather, C., "Network News Transfer Protocol (NNTP)",
RFC 3977, October 2006.
[RFC822] Crocker, D., "Standard for the format of ARPA Internet [RFC822] Crocker, D., "Standard for the format of ARPA Internet
text messages", STD 11, RFC 822, August 1982. text messages", STD 11, RFC 822, August 1982.
[RFC959] Postel, J. and J. Reynolds, "File Transfer Protocol", [RFC959] Postel, J. and J. Reynolds, "File Transfer Protocol",
STD 9, RFC 959, October 1985. STD 9, RFC 959, October 1985.
[Spero] Spero, S., "Analysis of HTTP Performance Problems", [Spero] Spero, S., "Analysis of HTTP Performance Problems",
<http://sunsite.unc.edu/mdma-release/http-prob.html>. <http://sunsite.unc.edu/mdma-release/http-prob.html>.
[Tou1998] Touch, J., Heidemann, J., and K. Obraczka, "Analysis of [Tou1998] Touch, J., Heidemann, J., and K. Obraczka, "Analysis of
HTTP Performance", ISI Research Report ISI/RR-98-463 HTTP Performance", USC/ISI ISI/RR-98-463, Dec 1998,
(original report dated Aug.1996), Aug 1998,
<http://www.isi.edu/touch/pubs/http-perf96/>. <http://www.isi.edu/touch/pubs/http-perf96/>.
[USASCII] American National Standards Institute, "Coded Character (Original report dated Aug. 1996)
Set -- 7-bit American Standard Code for Information
Interchange", ANSI X3.4, 1986.
[WAIS] Davis, F., Kahle, B., Morris, H., Salem, J., Shen, T., [WAIS] Davis, F., Kahle, B., Morris, H., Salem, J., Shen, T.,
Wang, R., Sui, J., and M. Grinbaum, "WAIS Interface Wang, R., Sui, J., and M. Grinbaum, "WAIS Interface
Protocol Prototype Functional Specification (v1.5)", Protocol Prototype Functional Specification (v1.5)",
Thinking Machines Corporation , April 1990. Thinking Machines Corporation , April 1990.
17.2. Informative References
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC3977] Feather, C., "Network News Transfer Protocol (NNTP)",
RFC 3977, October 2006.
URIs URIs
[1] <mailto:ietf-http-wg@w3.org> [1] <mailto:ietf-http-wg@w3.org>
[2] <mailto:ietf-http-wg-request@w3.org?subject=subscribe> [2] <mailto:ietf-http-wg-request@w3.org?subject=subscribe>
[3] <http://tools.ietf.org/html/draft-lafon-rfc2616bis-01> [3] <http://tools.ietf.org/html/draft-lafon-rfc2616bis-01>
Appendix A. Internet Media Type message/http and application/http Appendix A. Internet Media Type message/http and application/http
In addition to defining the HTTP/1.1 protocol, this document serves In addition to defining the HTTP/1.1 protocol, this document serves
as the specification for the Internet media type "message/http" and as the specification for the Internet media type "message/http" and
"application/http". The message/http type can be used to enclose a "application/http". The message/http type can be used to enclose a
single HTTP request or response message, provided that it obeys the single HTTP request or response message, provided that it obeys the
MIME restrictions for all "message" types regarding line length and MIME restrictions for all "message" types regarding line length and
encodings. The application/http type can be used to enclose a encodings. The application/http type can be used to enclose a
pipeline of one or more HTTP request or response messages (not pipeline of one or more HTTP request or response messages (not
intermixed). The following is to be registered with IANA [RFC1590]. intermixed). The following is to be registered with IANA [RFC2048].
Media Type name: message Media Type name: message
Media subtype name: http Media subtype name: http
Required parameters: none Required parameters: none
Optional parameters: version, msgtype Optional parameters: version, msgtype
version: The HTTP-Version number of the enclosed message (e.g., version: The HTTP-Version number of the enclosed message (e.g.,
skipping to change at page 181, line 8 skipping to change at page 181, line 8
local time zone MUST NOT influence the calculation or comparison local time zone MUST NOT influence the calculation or comparison
of an age or expiration time. of an age or expiration time.
o If an HTTP header incorrectly carries a date value with a time o If an HTTP header incorrectly carries a date value with a time
zone other than GMT, it MUST be converted into GMT using the most zone other than GMT, it MUST be converted into GMT using the most
conservative possible conversion. conservative possible conversion.
Appendix D. Differences Between HTTP Entities and RFC 2045 Entities Appendix D. Differences Between HTTP Entities and RFC 2045 Entities
HTTP/1.1 uses many of the constructs defined for Internet Mail HTTP/1.1 uses many of the constructs defined for Internet Mail
([RFC822]) and the Multipurpose Internet Mail Extensions (MIME ([RFC2822]) and the Multipurpose Internet Mail Extensions (MIME
[RFC2045]) to allow entities to be transmitted in an open variety of [RFC2045]) to allow entities to be transmitted in an open variety of
representations and with extensible mechanisms. However, RFC 2045 representations and with extensible mechanisms. However, RFC 2045
discusses mail, and HTTP has a few features that are different from discusses mail, and HTTP has a few features that are different from
those described in RFC 2045. These differences were carefully chosen those described in RFC 2045. These differences were carefully chosen
to optimize performance over binary connections, to allow greater to optimize performance over binary connections, to allow greater
freedom in the use of new media types, to make date comparisons freedom in the use of new media types, to make date comparisons
easier, and to acknowledge the practice of some early HTTP servers easier, and to acknowledge the practice of some early HTTP servers
and clients. and clients.
This appendix describes specific areas where HTTP differs from RFC This appendix describes specific areas where HTTP differs from RFC
skipping to change at page 181, line 35 skipping to change at page 181, line 35
D.1. MIME-Version D.1. MIME-Version
HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages
MAY include a single MIME-Version general-header field to indicate MAY include a single MIME-Version general-header field to indicate
what version of the MIME protocol was used to construct the message. what version of the MIME protocol was used to construct the message.
Use of the MIME-Version header field indicates that the message is in Use of the MIME-Version header field indicates that the message is in
full compliance with the MIME protocol (as defined in [RFC2045]). full compliance with the MIME protocol (as defined in [RFC2045]).
Proxies/gateways are responsible for ensuring full compliance (where Proxies/gateways are responsible for ensuring full compliance (where
possible) when exporting HTTP messages to strict MIME environments. possible) when exporting HTTP messages to strict MIME environments.
MIME-Version = "MIME-Version" ":" 1*DIGIT "." 1*DIGIT MIME-Version = "MIME-Version" ":" 1*DIGIT "." 1*DIGIT
MIME version "1.0" is the default for use in HTTP/1.1. However, MIME version "1.0" is the default for use in HTTP/1.1. However,
HTTP/1.1 message parsing and semantics are defined by this document HTTP/1.1 message parsing and semantics are defined by this document
and not the MIME specification. and not the MIME specification.
D.2. Conversion to Canonical Form D.2. Conversion to Canonical Form
[RFC2045] requires that an Internet mail entity be converted to [RFC2045] requires that an Internet mail entity be converted to
canonical form prior to being transferred, as described in Section 4 canonical form prior to being transferred, as described in Section 4
of [RFC2049]. Section 3.7.1 of this document describes the forms of [RFC2049]. Section 3.7.1 of this document describes the forms
skipping to change at page 182, line 41 skipping to change at page 182, line 41
media type, proxies and gateways from HTTP to MIME-compliant media type, proxies and gateways from HTTP to MIME-compliant
protocols MUST either change the value of the Content-Type header protocols MUST either change the value of the Content-Type header
field or decode the entity-body before forwarding the message. (Some field or decode the entity-body before forwarding the message. (Some
experimental applications of Content-Type for Internet mail have used experimental applications of Content-Type for Internet mail have used
a media-type parameter of ";conversions=<content-coding>" to perform a media-type parameter of ";conversions=<content-coding>" to perform
a function equivalent to Content-Encoding. However, this parameter a function equivalent to Content-Encoding. However, this parameter
is not part of RFC 2045). is not part of RFC 2045).
D.5. No Content-Transfer-Encoding D.5. No Content-Transfer-Encoding
HTTP does not use the Content-Transfer-Encoding (CTE) field of RFC HTTP does not use the Content-Transfer-Encoding field of RFC 2045.
2045. Proxies and gateways from MIME-compliant protocols to HTTP Proxies and gateways from MIME-compliant protocols to HTTP MUST
MUST remove any CTE encoding prior to delivering the response message remove any Content-Transfer-Encoding prior to delivering the response
to an HTTP client. message to an HTTP client.
Proxies and gateways from HTTP to MIME-compliant protocols are Proxies and gateways from HTTP to MIME-compliant protocols are
responsible for ensuring that the message is in the correct format responsible for ensuring that the message is in the correct format
and encoding for safe transport on that protocol, where "safe and encoding for safe transport on that protocol, where "safe
transport" is defined by the limitations of the protocol being used. transport" is defined by the limitations of the protocol being used.
Such a proxy or gateway SHOULD label the data with an appropriate Such a proxy or gateway SHOULD label the data with an appropriate
Content-Transfer-Encoding if doing so will improve the likelihood of Content-Transfer-Encoding if doing so will improve the likelihood of
safe transport over the destination protocol. safe transport over the destination protocol.
D.6. Introduction of Transfer-Encoding D.6. Introduction of Transfer-Encoding
skipping to change at page 183, line 32 skipping to change at page 183, line 32
read entity-header read entity-header
while (entity-header not empty) { while (entity-header not empty) {
append entity-header to existing header fields append entity-header to existing header fields
read entity-header read entity-header
} }
Content-Length := length Content-Length := length
Remove "chunked" from Transfer-Encoding Remove "chunked" from Transfer-Encoding
D.7. MHTML and Line Length Limitations D.7. MHTML and Line Length Limitations
HTTP implementations which share code with MHTML [RFC2110] HTTP implementations which share code with MHTML [RFC2557]
implementations need to be aware of MIME line length limitations. implementations need to be aware of MIME line length limitations.
Since HTTP does not have this limitation, HTTP does not fold long Since HTTP does not have this limitation, HTTP does not fold long
lines. MHTML messages being transported by HTTP follow all lines. MHTML messages being transported by HTTP follow all
conventions of MHTML, including line length limitations and folding, conventions of MHTML, including line length limitations and folding,
canonicalization, etc., since HTTP transports all message-bodies as canonicalization, etc., since HTTP transports all message-bodies as
payload (see Section 3.7.2) and does not interpret the content or any payload (see Section 3.7.2) and does not interpret the content or any
MIME header lines that might be contained therein. MIME header lines that might be contained therein.
Appendix E. Additional Features Appendix E. Additional Features
skipping to change at page 184, line 26 skipping to change at page 184, line 26
A number of other headers, such as Content-Disposition and Title, A number of other headers, such as Content-Disposition and Title,
from SMTP and MIME are also often implemented (see [RFC2076]). from SMTP and MIME are also often implemented (see [RFC2076]).
E.1. Content-Disposition E.1. Content-Disposition
The Content-Disposition response-header field has been proposed as a The Content-Disposition response-header field has been proposed as a
means for the origin server to suggest a default filename if the user means for the origin server to suggest a default filename if the user
requests that the content is saved to a file. This usage is derived requests that the content is saved to a file. This usage is derived
from the definition of Content-Disposition in [RFC1806]. from the definition of Content-Disposition in [RFC1806].
content-disposition = "Content-Disposition" ":" content-disposition = "Content-Disposition" ":"
disposition-type *( ";" disposition-parm ) disposition-type *( ";" disposition-parm )
disposition-type = "attachment" | disp-extension-token disposition-type = "attachment" | disp-extension-token
disposition-parm = filename-parm | disp-extension-parm disposition-parm = filename-parm | disp-extension-parm
filename-parm = "filename" "=" quoted-string filename-parm = "filename" "=" quoted-string
disp-extension-token = token disp-extension-token = token
disp-extension-parm = token "=" ( token | quoted-string ) disp-extension-parm = token "=" ( token | quoted-string )
An example is An example is
Content-Disposition: attachment; filename="fname.ext" Content-Disposition: attachment; filename="fname.ext"
The receiving user agent SHOULD NOT respect any directory path The receiving user agent SHOULD NOT respect any directory path
information present in the filename-parm parameter, which is the only information present in the filename-parm parameter, which is the only
parameter believed to apply to HTTP implementations at this time. parameter believed to apply to HTTP implementations at this time.
The filename SHOULD be treated as a terminal component only. The filename SHOULD be treated as a terminal component only.
skipping to change at page 187, line 20 skipping to change at page 187, line 20
Clarified which error code should be used for inbound server failures Clarified which error code should be used for inbound server failures
(e.g. DNS failures). (Section 10.5.5). (e.g. DNS failures). (Section 10.5.5).
CREATE had a race that required an Etag be sent when a resource is CREATE had a race that required an Etag be sent when a resource is
first created. (Section 10.2.2). first created. (Section 10.2.2).
Content-Base was deleted from the specification: it was not Content-Base was deleted from the specification: it was not
implemented widely, and there is no simple, safe way to introduce it implemented widely, and there is no simple, safe way to introduce it
without a robust extension mechanism. In addition, it is used in a without a robust extension mechanism. In addition, it is used in a
similar, but not identical fashion in MHTML [RFC2110]. similar, but not identical fashion in MHTML [RFC2557].
Transfer-coding and message lengths all interact in ways that Transfer-coding and message lengths all interact in ways that
required fixing exactly when chunked encoding is used (to allow for required fixing exactly when chunked encoding is used (to allow for
transfer encoding that may not be self delimiting); it was important transfer encoding that may not be self delimiting); it was important
to straighten out exactly how message lengths are computed. to straighten out exactly how message lengths are computed.
(Sections 3.6, 4.4, 7.2.2, 13.5.2, 14.13, 14.16) (Sections 3.6, 4.4, 7.2.2, 13.5.2, 14.13, 14.16)
A content-coding of "identity" was introduced, to solve problems A content-coding of "identity" was introduced, to solve problems
discovered in caching. (Section 3.5) discovered in caching. (Section 3.5)
skipping to change at page 189, line 33 skipping to change at page 189, line 33
The PATCH, LINK, UNLINK methods were defined but not commonly The PATCH, LINK, UNLINK methods were defined but not commonly
implemented in previous versions of this specification. See implemented in previous versions of this specification. See
[RFC2068]. [RFC2068].
The Alternates, Content-Version, Derived-From, Link, URI, Public and The Alternates, Content-Version, Derived-From, Link, URI, Public and
Content-Base header fields were defined in previous versions of this Content-Base header fields were defined in previous versions of this
specification, but not commonly implemented. See [RFC2068]. specification, but not commonly implemented. See [RFC2068].
F.4. Changes from RFC 2616 F.4. Changes from RFC 2616
Fix bug in BNF allowing backslash characters in qdtext production.
(Section 2.2)
Clarify that HTTP-Version is case sensitive. (Section 3.1) Clarify that HTTP-Version is case sensitive. (Section 3.1)
Eliminate overlooked reference to "unsafe" characters. Eliminate overlooked reference to "unsafe" characters.
(Section 3.2.3) (Section 3.2.3)
Clarify contexts that charset is used in. (Section 3.4) Clarify contexts that charset is used in. (Section 3.4)
Remove reference to non-existant identity transfer-coding value Remove reference to non-existant identity transfer-coding value
tokens. (Sections 3.6, 4.4 and D.5) tokens. (Sections 3.6, 4.4 and D.5)
skipping to change at page 190, line 17 skipping to change at page 190, line 20
safe to automatically redirect, and further that the user agent is safe to automatically redirect, and further that the user agent is
able to make that determination based on the request method able to make that determination based on the request method
semantics. (Sections 10.3.2, 10.3.3 and 10.3.8 ) semantics. (Sections 10.3.2, 10.3.3 and 10.3.8 )
Fix misspelled header and clarify requirements for hop-by-hop headers Fix misspelled header and clarify requirements for hop-by-hop headers
introduced in future specifications. (Section 13.5.1) introduced in future specifications. (Section 13.5.1)
Clarify denial of service attack avoidance requirement. Clarify denial of service attack avoidance requirement.
(Section 13.10) (Section 13.10)
Fix bug in BNF disallowing empty Accept-Encoding headers.
(Section 14.3)
Clarify exactly when close connection options must be sent. Clarify exactly when close connection options must be sent.
(Section 14.10) (Section 14.10)
Correct syntax of Location header to allow fragment, as referred Correct syntax of Location header to allow fragment, as referred
symbol wasn't what was expected, and add some clarifications as to symbol wasn't what was expected, and add some clarifications as to
when it would not be appropriate. (Section 14.30) when it would not be appropriate. (Section 14.30)
In the description of the Server header, the Via field was described In the description of the Server header, the Via field was described
as a SHOULD. The requirement was and is stated correctly in the as a SHOULD. The requirement was and is stated correctly in the
description of the Via header, Section 14.45. (Section 14.38) description of the Via header, Section 14.45. (Section 14.38)
skipping to change at page 193, line 5 skipping to change at page 192, line 18
13.5.1-and-13.5.2", "i61-redirection-vs-location", "i62-whitespace- 13.5.1-and-13.5.2", "i61-redirection-vs-location", "i62-whitespace-
in-quoted-pair", "i63-header-length-limit-with-encoded-words" and in-quoted-pair", "i63-header-length-limit-with-encoded-words" and
"i67-quoting-charsets". "i67-quoting-charsets".
Add and resolve issues "i45-rfc977-reference", "i46-rfc1700_remove", Add and resolve issues "i45-rfc977-reference", "i46-rfc1700_remove",
"i47-inconsistency-in-date-format-explanation", "i48-date-reference- "i47-inconsistency-in-date-format-explanation", "i48-date-reference-
typo" and "i49-connection-header-text". typo" and "i49-connection-header-text".
Rename "References" to "References (to be classified)". Rename "References" to "References (to be classified)".
G.5. Since draft-lafon-rfc2616bis-03
Add issues "i19-bodies-on-GET", "i20-default-charsets-for-text-media-
types", "i22-etag-and-other-metadata-in-status-messages", "i23-no-
store-invalidation", "i24-requiring-allow-in-405-responses", "i27-
put-idempotency", "i28-connection-closing", "i29-age-calculation",
"i30-header-lws", "i32-options-asterisk", "i33-trace-security-
considerations", "i35-split-normative-and-informative-references",
"i37-vary-and-non-existant-headers", "i38-mismatched-vary", "i39-
etag-uniqueness", "i40-header-registration", "i41-security-
considerations", "i64-ws-in-quoted-pair", "i69-clarify-requested-
variant", "i70-cacheability-of-303", "i71-examples-for-etag-
matching", "i72-request-method-registry", "i73-clarification-of-the-
term-deflate", "i74-character-encodings-for-headers", "i75-rfc2145-
normative", "i76-deprecate-305-use-proxy", "i77-line-folding", "i78-
relationship-between-401-authorization-and-www-authenticate", "i79-
content-headers-vs-put", "i80-content-location-is-not-special", "i81-
content-negotiation-for-media-types", "i82-rel_path-not-used" and
"i83-options-asterisk-and-proxies" and "i85-custom-ranges".
Reopen and close issue "i47-inconsistency-in-date-format-
explanation".
Resolve issues "unneeded_references" and "i62-whitespace-in-quoted-
pair" (as duplicate of "i64-ws-in-quoted-pair").
Add and resolve issues "abnf-edit", "consistent-reason-phrases",
"i25-accept-encoding-bnf", "i26-import-query-bnf", "i31-qdtext-bnf",
"i65-informative-references", "i66-iso8859-1-reference", "i68-
encoding-references-normative", "i84-redundant-cross-references",
"i86-normative-up-to-date-references", "i87-typo-in-13.2.2", "media-
reg" (which wasn't resolved by drafts -02 and -03, after all),
"remove-CTE-abbrev", "rfc1766_normative", "rfc2396_normative" and
"usascii_normative".
Add new section "Normative References" (the old "References (to be
classified)" section will be removed once all references are re-
classified).
Update contact information for Jim Gettys.
Appendix H. Resolved issues (to be removed by RFC Editor before Appendix H. Resolved issues (to be removed by RFC Editor before
publication) publication)
Issues that were either rejected or resolved in this version of this Issues that were either rejected or resolved in this version of this
document. document.
H.1. i45-rfc977-reference H.1. unneeded_references
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i45> <http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0054>,
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i44>
julian.reschke@greenbytes.de (2006-10-26): Classify RFC977 (NNTP) as julian.reschke@greenbytes.de (2006-10-19): The reference entries for
informative, and update the reference to RFC3977. RFC1866, RFC2069 and RFC2026 are unused. Remove them?
Resolution (2006-10-26): Done. julian.reschke@greenbytes.de (2006-11-02): See also
<http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0118>.
H.2. i46-rfc1700_remove Resolution (2006-10-24): Remove references to RFC1866 and RFC2069 for
now. Keep RFC2026 for now; it's referenced from Editorial note.
H.2. consistent-reason-phrases
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i46> <http://www.w3.org/mid/472E16C5.8000703@gmx.de>
julian.reschke@greenbytes.de (2006-11-12): RFC1700 ("ASSIGNED julian.reschke@greenbytes.de (2007-11-04): Use consistent status
NUMBERS") has been obsoleted by RFC3232 ("Assigned Numbers: RFC 1700 reason phrases.
is Replaced by an On-line Database").
draft-gettys-http-v11-spec-rev-00 just updates the reference, which I
think is a bug.
In fact, RFC2616 refers to RCF1700
(1) for the definition of the default TCP port (Section 1.4),
(2) for a reference to the character set registry (Section 3.4) and
(3) for a reference to the media type registry (Section 3.7).
I propose to remove the reference, and to make the following changes:
(1) Replace reference with in-lined URL of the IANA port registry,
(2) Replace the first reference with the in-lined URL of the IANA
character set registry, and drop the second one, and
(3) Drop the reference, as the next sentence refers to the Media Type
Registration Process anyway.
(see also <http://lists.w3.org/Archives/Public/ietf-http-wg/
2006OctDec/0181.html>
Resolution (2007-03-18): Accepted during the Prague meeting, see Resolution (2007-11-15): Done.
http://www.w3.org/2007/03/18-rfc2616-minutes.html#action21.
H.3. i47-inconsistency-in-date-format-explanation H.3. i66-iso8859-1-reference
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i66>
julian.reschke@greenbytes.de (2006-10-28): Classify ISO8859 as
normative, and simplify reference to only refer to ISO8859 Part 1
(because that's the only part needed here), and update to the 1998
version.
Resolution (2006-10-28): Done.
H.4. abnf-edit
Type: edit
<http://www.w3.org/mid/4739C417.2040203@gmx.de>
julian.reschke@greenbytes.de (2007-11-13): Fix minor editorial issues
with BNF causing problems with ABNF parsers, such as (1) inconsistent
indentation and (2) missing whitespace.
Resolution (2007-11-15): Done.
H.5. rfc1766_normative
Type: edit
julian.reschke@greenbytes.de (2006-11-15): Classify RFC1766 ("Tags
for the Identification of Languages") as normative (update to RFC4646
in a separate step, see issue languagetag).
Resolution (2006-11-15): Done.
H.6. i86-normative-up-to-date-references
Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i86>
julian.reschke@greenbytes.de (2006-11-12): Classify RFC1864 ("The
Content-MD5 Header Field") as normative. Note that note this
disagrees with draft-gettys-http-v11-spec-rev-00 which made it
informative.
julian.reschke@greenbytes.de (2006-11-14): Classify RFC2045
("Multipurpose Internet Mail Extensions (MIME) Part One: Format of
Internet Message Bodies") as normative.
julian.reschke@greenbytes.de (2006-11-12): Classify RFC2046
("Multipurpose Internet Mail Extensions (MIME) Part Two: Media
Types") as normative.
julian.reschke@greenbytes.de (2006-11-12): Classify RFC2047 ("MIME
(Multipurpose Internet Mail Extensions) Part Three: Message Header
Extensions for Non-ASCII Text") as normative.
julian.reschke@greenbytes.de (2006-10-27): Classify RFC2119 (Key
words for use in RFCs to Indicate Requirement Levels) as normative.
julian.reschke@greenbytes.de (2006-10-27): Classify RFC2617 (HTTP
Authentication) as normative.
Resolution (2007-10-12): Done.
H.7. i68-encoding-references-normative
Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i68>
julian.reschke@greenbytes.de (2007-05-28): Classify RFC1950 (ZLIB),
RFC1951 (DEFLATE) and RFC1952 (GZIP) as normative (note this
disagrees with draft-gettys-http-v11-spec-rev-00 which made it
informative).
julian.reschke@greenbytes.de (2007-06-16): RFC4897 requires us to add
notes to the references explaining why the downref was made (see
<http://tools.ietf.org/html/rfc4897#section-3.1>).
Resolution (2007-06-18): Done.
H.8. rfc2396_normative
Type: edit
julian.reschke@greenbytes.de (2006-11-13): Classify RFC2396 ("Uniform
Resource Identifiers (URI): Generic Syntax") as normative (update to
RFC3986 in a separate step, see i34-updated-reference-for-uris).
Resolution (2006-11-13): Done.
H.9. usascii_normative
Type: edit
julian.reschke@greenbytes.de (2006-10-27): Classify USASCII as
normative.
Resolution (2006-10-27): Done.
H.10. i65-informative-references
Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i65>
julian.reschke@greenbytes.de (2007-05-28): The following references
are informative: Luo1998 ("Tunneling TCP based protocols through Web
proxy servers", also update reference to quote the expired Internet
Draft properly). Nie1997 ("Network Performance Effects of HTTP/1.1,
CSS1, and PNG"). Pad1995 ("Improving HTTP Latency"). RFC821 (SMTP),
also update the reference to RFC2821. RFC822 ("STANDARD FOR THE
FORMAT OF ARPA INTERNET TEXT MESSAGES") -- but add another instance
as RFC822ABNF for the cases where the reference if for the ABNF part
(these references will later be replaced by references to RFC4234
(see issue abnf)). RFC959 (FTP). RFC1036 ("Standard for Interchange
of USENET Messages"). RFC1123 ("Requirements for Internet Hosts --
Application and Support") -- it is only used as a background
reference for rfc1123-date, which this spec defines itself (note this
disagrees with draft-gettys-http-v11-spec-rev-00 which made it
normative). RFC1305 ("Network Time Protocol (Version 3)"). RFC1436
(Gopher). RFC1630 (URI Syntax) -- there'll be a normative reference
to a newer spec. RFC1738 (URL) -- there'll be a normative reference
to a newer spec. RFC1806 ("Communicating Presentation Information in
Internet Messages: The Content-Disposition Header"). RFC1808
(Relative Uniform Resource Locators). RFC1867 ("Form-based File
Upload in HTML"), also update the reference to RFC2388 ("Returning
Values from Forms: multipart/form-data"). RFC1900 ("Renumbering
Needs Work"). RFC1945 (HTTP/1.0). RFC2026 ("The Internet Standards
Process -- Revision 3"). RFC2049 ("Multipurpose Internet Mail
Extensions (MIME) Part Five: Conformance Criteria and Examples").
RFC2068 (HTTP/1.1). RFC2076 ("Common Internet Message Headers").
RFC2110 (MHTML), also update the reference to RFC2557. RFC2145 ("Use
and Interpretation of HTTP Version Numbers"). RFC2183
("Communicating Presentation Information in Internet Messages: The
Content-Disposition Header Field"). RFC2277 ("IETF Policy on
Character Sets and Languages"). RFC2279 (UTF8), also update the
reference to RFC3629. RFC2324 (HTCPCP/1.0). Spero ("Analysis of
HTTP Performance Problems"). Tou1998 ("Analysis of HTTP
Performance"). WAIS ("WAIS Interface Protocol Prototype Functional
Specification (v1.5)").
derhoermi@gmx.net (2007-05-28): _On RFC1950-1952:_ Understanding
these documents is required in order to understand the coding values
defined for the coding registry established and used by the document;
why would it be appropriate to cite them as informative?
Resolution (2007-06-12): Done (with the exceptions noted by Bjoern
Hoehrmann).
H.11. i31-qdtext-bnf
In Section 2.2:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i31>
jamie@shareable.org (2004-03-15): ...I wrote a regular expression
based on the RFC 2616 definition, and that allows "foo\" as a quoted-
string. That's not intended, is it?
Resolution (2007-06-18): Resolved as per
http://www.w3.org/2007/03/18-rfc2616-minutes.html#action13.
H.12. i62-whitespace-in-quoted-pair
In Section 2.2:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i62>
dan.winship@gmail.com (2007-04-20): (...) RFC 2822 updates RFC 822's
quoted-pair rule to disallow CR, LF, and NUL. We should probably
make the same change.
Resolution (2007-10-07): Closed as duplicate of i64-ws-in-quoted-
pair.
H.13. i26-import-query-bnf
In Section 3.2.2:
Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i26>
abodeman@yahoo.com (2005-05-23):
In section 3.2.2, http_URL is defined as follows:
"http_URL = "http:" "//" host [ ":" port ] [ abs_path [ "?" query
]]" -- http://tools.ietf.org/html/rfc2616.html#section-3.2.2
However, RFC 2616 does not contain a rule called "query". I assume
this is meant to be the same "query" that is defined in RFC 2396,
since section 3.2.1 incorporates "URI-reference", "absoluteURI",
"relativeURI", "port", "host", "abs_path", "rel_path", and
"authority" from that specification (but "query" is missing from this
list).
Resolution (2007-10-06): Add "query" to the list of definitions
adopted from RCF2396 (note that RFC2396 has been obsoleted by
RFC3986, but this is a separate issue).
H.14. i47-inconsistency-in-date-format-explanation
In Section 3.3.1: In Section 3.3.1:
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i47> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i47>
julian.reschke@greenbytes.de (2006-11-20): Should say "...obsolete julian.reschke@greenbytes.de (2006-11-20): Should say "...obsolete
RFC1036 date format [...]..." instead of "...obsolete RFC 850 [12] RFC1036 date format [...]..." instead of "...obsolete RFC 850 [12]
date format...". date format...".
See also <http://lists.w3.org/Archives/Public/ietf-http-wg/ See also <http://lists.w3.org/Archives/Public/ietf-http-wg/
2006OctDec/0187.html>. 2006OctDec/0187.html>.
Resolution (2006-11-20): Done. fielding@gbiv.com (2007-11-02):
H.4. i49-connection-header-text The proposed resolution to this issue (in draft 03) is incorrect
because RFC1036 doesn't define the date format in question. This was
an error introduced in the 2616 editing cycle. It should be fixed by
removing reference to 1036, as described below:
In Section 13.5.1: <del>RFC 850, obsoleted by RFC 1036</del><ins>obsolete RFC 850
format</ins>
<del>The second format is in common use, but is based on the obsolete
RFC 850 [RFC1036] date format and lacks a four-digit year.</del><ins>
The other formats are described here only for compatibility with
obsolete implementations.</ins>
Resolution (2007-11-03): Resolved as proposed by Roy.
H.15. media-reg
In Section 3.7:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i49> <http://purl.org/NET/http-errata#media-reg>,
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i8>
julian.reschke@greenbytes.de (2006-12-12): "Other hop-by-hop headers derhoermi@gmx.net (2000-09-10): See <http://lists.w3.org/Archives/
MUST be listed in a Connection header, (section 14.10) to be Public/ietf-http-wg-old/2000SepDec/0013>.
introduced into HTTP/1.1 (or later)." doesn't really make sense.
(See <http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/
0264.html>)
Jeff.Mogul@hp.com (2006-12-12): Proposed rewrite: " Other hop-by-hop Resolution (2006-11-14): Done (note that RFC2048 has been obsoleted
headers, if they are introduced either in HTTP/1.1 or later versions now as well; see separate issue rfc2048_informative_and_obsolete).
of HTTP/1.x, MUST be listed in a Connection header (Section 14.10)." Note that the prosed resolution in
(See <http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/ http://purl.org/NET/http-errata#media-reg contains typos both in the
0265.html>) original text ("4288" rather than "1590") and in the proposed
resolution ("Mulitpurpose").
Resolution (2006-12-15): Resolve as proposed by Jeff Mogul in <http:/ H.16. i84-redundant-cross-references
/lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0265.html>.
H.5. i48-date-reference-typo In Section 9.5:
In Section 14.18: Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i84>
fielding@gbiv.com (2007-09-28):
RFC 2616 sections 9.5 (POST) and 9.6 (PUT) have the following useless
waste of bits
"POST requests MUST obey the message transmission requirements set
out in section 8.2.
See section 15.1.3 for security considerations." --
http://tools.ietf.org/html/rfc2616#section-9.5
and
"PUT requests MUST obey the message transmission requirements set
out in section 8.2." --
http://tools.ietf.org/html/rfc2616#section-9.6
respectively. They can be safely deleted without changing HTTP.
Section 8.2 is not specific to PUT and POST. Likewise, a content-
free forward pointer to just one of the many subsections on security
consideration is a total waste of brain cells.
Those are just two examples of what can only be described as a
spaghetti style of content-free cross-references within the spec that
make it very hard to read. They should be removed in general at the
editors' discretion.
Resolution (2007-09-29): Remove text as proposed.
H.17. i87-typo-in-13.2.2
In Section 13.2.2:
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i48> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i87>
fielding@gbiv.com (2007-09-07):
julian.reschke@greenbytes.de (2006-11-20): Should say "rfc1123-date This typo is still in the current draft.
format [...]" instead of "[...]-date format".
See also <http://lists.w3.org/Archives/Public/ietf-http-wg/
2006OctDec/0186.html>
hno@squid-cache.org (2006-11-29): Better without the [8], making it
an internal reference to the grammar. The rfc1123-date is not a copy
of RFC1123, only a subset thereof.
The relation to RFC 1123 is already well established elsewhere in
3.3.1, including the MUST level requirement on sending the RFC 1123
derived format.
A similar RFC 1123 reference which is better replaced by a rfc1123-
date grammar reference is also seen in 14.21 Last-Modified.
Resolution (2006-11-30): Done. s/ought to used/ought to be used/;
Resolution (2007-09-08): Fixed.
H.18. i25-accept-encoding-bnf
In Section 14.3:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i25>
abodeman@yahoo.com (2005-06-02):
In section 14.3, the definition of Accept-Encoding is given as
follows:
Accept-Encoding = "Accept-Encoding" ":"
1#( codings [ ";" "q" "=" qvalue ] )
This definition implies that there must be at least one non-null
codings. However, just below this definition, one of the examples
given has an empty Accept-Encoding field-value:
Accept-Encoding: compress, gzip
Accept-Encoding:
Accept-Encoding: *
Accept-Encoding: compress;q=0.5, gzip;q=1.0
Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
Furthermore, the fourth rule for testing whether a content-coding is
acceptable mentions the possibility that the field-value may be
empty.
It seems, then, that the definition for Accept-Encoding should be
revised:
Accept-Encoding = "Accept-Encoding" ":"
#( codings [ ";" "q" "=" qvalue ] )
Resolution (2007-03-18): Accepted during the Prague meeting, see
http://www.w3.org/2007/03/18-rfc2616-minutes.html#action09.
H.19. remove-CTE-abbrev
In Section D.5:
Type: edit
<file:///C:/projects/w3c/WWW/Protocols/HTTP/1.1/rfc2616bis/issues/
index.html#i16>
fielding@gbiv.com (2007-11-02): ...there is absolutely no reason to
abbreviate the field name when it is only used twice in the entire
document...
Resolution (2007-11-15): Done.
Appendix I. Open issues (to be removed by RFC Editor prior to Appendix I. Open issues (to be removed by RFC Editor prior to
publication) publication)
I.1. rfc2616bis I.1. rfc2616bis
Type: edit Type: edit
julian.reschke@greenbytes.de (2006-10-10): Umbrella issue for changes julian.reschke@greenbytes.de (2006-10-10): Umbrella issue for changes
with respect to the revision process itself. with respect to the revision process itself.
I.2. unneeded_references I.2. i35-split-normative-and-informative-references
Type: edit Type: change
<http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0054> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i35>
julian.reschke@greenbytes.de (2006-10-19): The reference entries for References are now required to be split into "Normative" and
RFC1866, RFC2069 and RFC2026 are unused. Remove them? "Informative".
julian.reschke@greenbytes.de (2006-11-02): See also julian.reschke@gmx.de (2007-10-12): See related issues: i65-
http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0118 and informative-references, i68-encoding-references-normative, i75-
http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i44. rfc2145-normative, rfc1737_informative_and_obsolete,
rfc1766_normative, i86-normative-up-to-date-references,
rfc2048_informative_and_obsolete, rfc2396_normative, rfc2616bis,
rfc2822_normative, unneeded_references, uri_vs_request_uri and
usascii_normative.
I.3. edit I.3. i40-header-registration
Type: edit Type: change
julian.reschke@greenbytes.de (2006-10-08): Umbrella issue for <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i40>
editorial fixes/enhancements.
I.4. i66-iso8859-1-reference A revision of RFC2616 should mention BCP 90 (Registration Procedures
for Message Header Fields) and should take over as the authoritative
reference for the headers it contains.
Type: change I.4. edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i66> Type: edit
julian.reschke@greenbytes.de (2006-10-28): Classify ISO8859 as julian.reschke@greenbytes.de (2006-10-08): Umbrella issue for
normative, and simplify reference to only refer to ISO8859 Part 1 editorial fixes/enhancements.
(because that's the only part needed here), and update to the 1998
version.
I.5. abnf I.5. abnf
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i36> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i36>
julian.reschke@greenbytes.de (2006-12-03): Update BNF to RFC4234 julian.reschke@greenbytes.de (2006-12-03): Update BNF to RFC4234
(plan to be added). (plan to be added).
julian.reschke@greenbytes.de (2007-07-24): See
<http://www.w3.org/mid/45FBAB8C.6010809@gmx.de> for a to-do list.
julian.reschke@greenbytes.de (2007-11-13): See
<http://www.w3.org/mid/4739C417.2040203@gmx.de> for a summary of
issues with the current ABNF.
I.6. rfc2048_informative_and_obsolete I.6. rfc2048_informative_and_obsolete
Type: edit Type: edit
julian.reschke@greenbytes.de (2006-11-15): Classify RFC2048 julian.reschke@greenbytes.de (2006-11-15): Classify RFC2048
("Multipurpose Internet Mail Extensions (MIME) Part Four: ("Multipurpose Internet Mail Extensions (MIME) Part Four:
Registration Procedures") as informative, update to RFC4288, Registration Procedures") as informative, update to RFC4288,
potentially update the application/http and multipart/byteranges MIME potentially update the application/http and multipart/byteranges MIME
type registration. Also, in Section 3.7 fix first reference to refer type registration. Also, in Section 3.7 fix first reference to refer
to RFC2046 (it's about media types in general, not the registration to RFC2046 (it's about media types in general, not the registration
skipping to change at page 197, line 36 skipping to change at page 204, line 46
julian.reschke@greenbytes.de (2006-11-14): Update RFC2396 ("Uniform julian.reschke@greenbytes.de (2006-11-14): Update RFC2396 ("Uniform
Resource Identifiers (URI): Generic Syntax") to RFC3986. Resource Identifiers (URI): Generic Syntax") to RFC3986.
I.8. i50-misc-typos I.8. i50-misc-typos
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i50> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i50>
a-travis@microsoft.com (2006-12-18): (See http://lists.w3.org/ a-travis@microsoft.com (2006-12-18): (See <http://lists.w3.org/
Archives/Public/ietf-http-wg/2006OctDec/0275.html). Archives/Public/ietf-http-wg/2006OctDec/0275.html>).
julian.reschke@greenbytes.de (2007-06-29): Some of the strictly julian.reschke@greenbytes.de (2007-06-29): Some of the strictly
editorial issues have been resolves as part of issue "edit". editorial issues have been resolves as part of issue "edit".
I.9. i65-informative-references I.9. i52-sort-1.3-terminology
Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i65>
julian.reschke@greenbytes.de (2007-05-28): The following references
are informative: Luo1998 ("Tunneling TCP based protocols through Web
proxy servers", also update reference to quote the expired Internet
Draft properly). Nie1997 ("Network Performance Effects of HTTP/1.1,
CSS1, and PNG"). Pad1995 ("Improving HTTP Latency"). RFC821 (SMTP),
also update the reference to RFC2821. RFC822 ("STANDARD FOR THE
FORMAT OF ARPA INTERNET TEXT MESSAGES") -- but add another instance
as RFC822ABNF for the cases where the reference if for the ABNF part
(these references will later be replaced by references to RFC4234
(see issue abnf)). RFC959 (FTP). RFC1036 ("Standard for Interchange
of USENET Messages"). RFC1123 ("Requirements for Internet Hosts --
Application and Support") -- it is only used as a background
reference for rfc1123-date, which this spec defines itself (note this
disagrees with draft-gettys-http-v11-spec-rev-00 which made it
normative). RFC1305 ("Network Time Protocol (Version 3)"). RFC1436
(Gopher). RFC1630 (URI Syntax) -- there'll be a normative reference
to a newer spec. RFC1738 (URL) -- there'll be a normative reference
to a newer spec. RFC1806 ("Communicating Presentation Information in
Internet Messages: The Content-Disposition Header"). RFC1808
(Relative Uniform Resource Locators). RFC1867 ("Form-based File
Upload in HTML"), also update the reference to RFC2388 ("Returning
Values from Forms: multipart/form-data"). RFC1900 ("Renumbering
Needs Work"). RFC1945 (HTTP/1.0). RFC2026 ("The Internet Standards
Process -- Revision 3"). RFC2049 ("Multipurpose Internet Mail
Extensions (MIME) Part Five: Conformance Criteria and Examples").
RFC2068 (HTTP/1.1). RFC2076 ("Common Internet Message Headers").
RFC2110 (MHTML), also update the reference to RFC2557. RFC2145 ("Use
and Interpretation of HTTP Version Numbers"). RFC2183
("Communicating Presentation Information in Internet Messages: The
Content-Disposition Header Field"). RFC2277 ("IETF Policy on
Character Sets and Languages"). RFC2279 (UTF8), also update the
reference to RFC3629. RFC2324 (HTCPCP/1.0). Spero ("Analysis of
HTTP Performance Problems"). Tou1998 ("Analysis of HTTP
Performance"). WAIS ("WAIS Interface Protocol Prototype Functional
Specification (v1.5)").
derhoermi@gmx.net (2007-05-28): _On RFC1950-1952:_ Understanding
these documents is required in order to understand the coding values
defined for the coding registry established and used by the document;
why would it be appropriate to cite them as informative?
I.10. i52-sort-1.3-terminology
In Section 1.3: In Section 1.3:
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i52> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i52>
a-travis@microsoft.com (2006-12-21): It's irritating to try and look a-travis@microsoft.com (2006-12-21): It's irritating to try and look
up definitions in section 1.3. IMHO, the entries really should be up definitions in section 1.3. IMHO, the entries really should be
sorted alphabetically, despite the fact that the terms have sorted alphabetically, despite the fact that the terms have
dependencies on one another. dependencies on one another.
julian.reschke@greenytes.de (2006-06-15): See action item julian.reschke@greenytes.de (2006-06-15): See action item
http://www.w3.org/2007/03/18-rfc2616-minutes.html#action23 and <http://www.w3.org/2007/03/18-rfc2616-minutes.html#action23> and
proposal in http://lists.w3.org/Archives/Public/ietf-http-wg/ proposal in <http://lists.w3.org/Archives/Public/ietf-http-wg/
2007AprJun/0350.html. 2007AprJun/0350.html>.
julian.reschke@greenytes.de (2006-06-15):
I personally think we should not do this change:
julian.reschke@greenytes.de (2006-06-15): I personally think we
should not do this change:
(1) Sorting paragraphs makes it very hard to verify the changes; in (1) Sorting paragraphs makes it very hard to verify the changes; in
essence, a reviewer would either need to trust us, or re-do the essence, a reviewer would either need to trust us, or re-do the
shuffling to control whether it's correct (nothing lost, no change in shuffling to control whether it's correct (nothing lost, no change in
the definitions). the definitions).
(2) In the RFC2616 ordering, things that belong together (such as (2) In the RFC2616 ordering, things that belong together (such as
"client", "user agent", "server" ...) are close to each other. "client", "user agent", "server" ...) are close to each other.
(3) Contrary to RFC2616, the text version of new spec will contain an (3) Contrary to RFC2616, the text version of new spec will contain an
alphabetical index section anyway (unless it's removed upon alphabetical index section anyway (unless it's removed upon
publication :-). publication :-).
I.11. i63-header-length-limit-with-encoded-words I.10. i63-header-length-limit-with-encoded-words
In Section 2.2: In Section 2.2:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i63> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i63>
derhoermi@gmx.net (2007-05-14): (See http://lists.w3.org/Archives/ derhoermi@gmx.net (2007-05-14): (See <http://lists.w3.org/Archives/
Public/ietf-http-wg/2007AprJun/0050.html). Public/ietf-http-wg/2007AprJun/0050.html>).
I.12. i31-qdtext-bnf I.11. i74-character-encodings-for-headers
In Section 2.2: In Section 2.2:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i31> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i74>
jamie@shareable.org (2004-03-15): ...I wrote a regular expression duerst@it.aoyama.ac.jp (2007-07-10): RFC 2616 prescribes that headers
based on the RFC 2616 definition, and that allows "foo\" as a quoted- containing non-ASCII have to use either iso-8859-1 or RFC 2047. This
string. That's not intended, is it? is unnecessarily complex and not necessarily followed. At the least,
new extensions should be allowed to specify that UTF-8 is used.
I.13. i62-whitespace-in-quoted-pair I.12. i64-ws-in-quoted-pair
In Section 2.2: In Section 2.2:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i62>
dan.winship@gmail.com (2007-04-20): (...) RFC 2822 updates RFC 822's <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i64>
quoted-pair rule to disallow CR, LF, and NUL. We should probably
make the same change.
I.14. i58-what-identifies-an-http-resource dan.winship@gmail.com (2007-04-20):
I think quoted-pair is broken too. Merging your fix into RFC2616
gives:
quoted-string = ( <"> *(qdtext | quoted-pair ) <"> )
qdtext = <any TEXT excluding '"' and '\'>
quoted-pair = "\" CHAR
CHAR = <any US-ASCII character (octets 0 - 127)>
but that means you can do this:
HTTP/1.1 200 OK
Warning: "Don't misparse \
this: it's really a single header!"
(if the receiving implementation follows the recommendations in 19.3
you need to escape the LF instead of the CR, but it's otherwise the
same.)
RFC 2822 updates RFC 822's quoted-pair rule to disallow CR, LF, and
NUL. We should probably make the same change.
I.13. i75-rfc2145-normative
In Section 3.1:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i75>
Jeff.Mogul@hp.com (2007-06-07): http://www.ietf.org/rfc/rfc2145.txt:
There are references from RFC2616, section 3.1, to this document.
Perhaps these should be marked as normative; certainly, a proxy
implemention that violates RFC2145 is non-compliant in any reasonable
sense of the word.
I.14. i82-rel_path-not-used
In Section 3.2.1:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i82>
julian.reschke@gmx.de (2007-10-07):
RFC2616 changed the ABNF for http_URL so that it doesn't use rel_path
(as defined in RFC2396) anymore.
However, that definition is still "adopted" in:
"URIs in HTTP can be represented in absolute form or relative to
some known base URI [11], depending upon the context of their use.
The two forms are differentiated by the fact that absolute URIs
always begin with a scheme name followed by a colon. For
definitive information on URL syntax and semantics, see "Uniform
Resource Identifiers (URI): Generic Syntax and Semantics," RFC
2396 [42] (which replaces RFCs 1738 [4] and RFC 1808 [11]). This
specification adopts the definitions of "URI-reference",
"absoluteURI", "relativeURI", "port", "host","abs_path",
"rel_path", and "authority" from that specification." --
http://tools.ietf.org/html/rfc2616#section-3.2.1
...and used in:
"We note one exception to this rule: since some applications have
traditionally used GETs and HEADs with query URLs (those
containing a "?" in the rel_path part) to perform operations with
significant side effects, caches MUST NOT treat responses to such
URIs as fresh unless the server provides an explicit expiration
time. This specifically means that responses from HTTP/1.0
servers for such URIs SHOULD NOT be taken from a cache. See
Section 9.1.1 for related information." --
http://tools.ietf.org/html/rfc2616#section-13.9
Proposal:
1) get rid of the mention in 3.2.1, and
2) in 13.9 paragraph 2, replace "...query URLs (those containing a
"?" in the rel_path part)..." by "...URLs containing a query part..."
I.15. i58-what-identifies-an-http-resource
In Section 3.2.2: In Section 3.2.2:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i58> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i58>
julian.reschke@gmx.de (2007-01-23): 3.2.2 really doesn't say what julian.reschke@gmx.de (2007-01-23):
identifies the resource:
"If the port is empty or not given, port 80 is assumed. The 3.2.2 really doesn't say what identifies the resource:
semantics are that the identified resource is located at the server
listening for TCP connections on that port of that host, and the "If the port is empty or not given, port 80 is assumed. The
Request-URI for the resource is abs_path (Section 5.1.2)." semantics are that the identified resource is located at the
But it *does* say what part of the HTTP URL becomes the Request-URI, server listening for TCP connections on that port of that host,
and the Request-URI for the resource is abs_path (Section 5.1.2)."
-- http://tools.ietf.org/html/rfc2616#section-3.2.2
But it _does_ say what part of the HTTP URL becomes the Request-URI,
and that definitively needs to be fixed. and that definitively needs to be fixed.
I.15. i51-http-date-vs-rfc1123-date I.16. i51-http-date-vs-rfc1123-date
In Section 3.3.1: In Section 3.3.1:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i51> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i51>
a-travis@microsoft.com (2006-12-18): On closer inspection, shouldn't a-travis@microsoft.com (2006-12-18): On closer inspection, shouldn't
the BNF for that section (14.18) be "rfc1123-date" and not "HTTP- the BNF for that section (14.18) be "rfc1123-date" and not "HTTP-
date"? I mean, why say it's an HTTP-date, but only RFC 1123 form is date"? I mean, why say it's an HTTP-date, but only RFC 1123 form is
allowed (conflicting with the definition of HTTP-date)*? Likewise, allowed (conflicting with the definition of HTTP-date)*? Likewise,
shouldn't we just use the rfc1123-date moniker throughout the shouldn't we just use the rfc1123-date moniker throughout the
document whenever explicitly referring to only dates in RFC 1123 document whenever explicitly referring to only dates in RFC 1123
format? format?
I.16. i67-quoting-charsets I.17. i73-clarification-of-the-term-deflate
In Section 3.5:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i73>
paul_marquess@yahoo.co.uk (2007-08-07):
There is ambiguity in that definition because of the inconsistent use
of the term "deflate". This has resulted in a long standing
confusion about how to implement "deflate" encoding.
There was a time a few years back when most of the high profile
browser and some http server implementations incorrectly implemented
http "deflate" encoding using RFC 1951 without the RFC 1950 wrapper.
Admittedly most, if not all, of the incorrect implementations have
now been fixed, but the fix applied recognises the reality that there
are incorrect implementations of "deflate" out in the wild. All
browsers now seem to be able to cope with "deflate" in both its
RFC1950 or RFC1951 incarnations.
So I suggest there are two issues that need to be addressed
1. The definition of "deflate" needs to be rewritten to remove the
ambiguity.
2. Document the reality that there are incorrect implementations,
and recommend that anyone writing a "deflate" decoder should cope
with both forms.
I.18. i67-quoting-charsets
In Section 3.7: In Section 3.7:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i67> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i67>
maiera@de.ibm.com (2007-05-23): (See http://lists.w3.org/Archives/ maiera@de.ibm.com (2007-05-23): (See <http://lists.w3.org/Archives/
Public/ietf-http-wg/2007AprJun/0065.html). Public/ietf-http-wg/2007AprJun/0065.html>).
I.17. media-reg I.19. i20-default-charsets-for-text-media-types
In Section 3.7: In Section 3.7.1:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i20>
<http://purl.org/NET/http-errata#media-reg> mnot@yahoo-inc.com (2006-05-01):
derhoermi@gmx.net (2000-09-10): See 2616 Section 3.7.1 states;
http://lists.w3.org/Archives/Public/ietf-http-wg-old/2000SepDec/0013.
julian.reschke@greenbytes.de (2007-04-20): See also "When no explicit charset parameter is provided by the sender,
http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i8. media subtypes of the "text" type are defined to have a default
charset value of "ISO-8859-1" when received via HTTP." --
http://tools.ietf.org/html/rfc2616#section-3.7.1
I.18. languagetag However, many, if not all, of the text/* media types define their own
defaults; text/plain (RFC2046), for example, defaults to ASCII, as
does text/xml (RFC3023).
How do these format-specific defaults interact with HTTP's default?
Is HTTP really overriding them?
I'm far from the first to be confused by this text, and I'm sure it's
been asked before, but I haven't been able to find a definitive
answer. If errata are still being considered, perhaps removing/
modifying this line would be a good start...
duerst@it.aoyama.ac.jp (2007-10-05):
Here is another issue that apparently hasn't yet been listed. The
HTTP spec, in section 3.7.1, currently claims that for subtypes of
the media type "text", there is a default of iso-8859-1.
In actual practice, this is, at best, wishful thinking. It may also
pretty much look like it's actually true if you are in Western Europe
or in the Americas, but it doesn't apply world-wide. There are tons
of Web sites in Asia (and Asia is home to more than half of the
World's population) that have no charset, and that are not in iso-
8859-1. And browsers in these regions don't expect pages to be iso-
8859-1.
...
So the text below should be changed to say that data in all character
sets SHOULD be labeled, and move the default to historic. Some
adequate adjustments should also be made to Section 3.4.1. I'll
gladly help with word-smithing.
I.20. languagetag
In Section 3: In Section 3:
Type: change Type: change
<http://purl.org/NET/http-errata#languagetag> <http://purl.org/NET/http-errata#languagetag>,
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i13>
julian.reschke@greenbytes.de (2006-10-14): See julian.reschke@greenbytes.de (2006-10-14): See
http://purl.org/NET/http-errata#languagetag. <http://purl.org/NET/http-errata#languagetag>.
julian.reschke@greenbytes.de (2006-10-14): In the meantime RFC3066 julian.reschke@greenbytes.de (2006-10-14): In the meantime RFC3066
has been obsoleted by RFC4646. See also has been obsoleted by RFC4646. See also
http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0001. <http://lists.w3.org/Archives/Public/ietf-http-wg/2006OctDec/0001>.
julian.reschke@greenbytes.de (2006-11-15): See also I.21. i85-custom-ranges
http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i13.
I.19. i56-6.1.1-can-be-misread-as-a-complete-list In Section 3.12:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i85>
kornel@geekhood.net (2007-08-25):
The RFC 2616 seems to suggest such possibility in 3.12 Range Units:
there's a "other-range-unit" defined.
However definition of Content-Range uses "ranges-specifier" and Range
uses "content-range-spec", which both seem to allow only byte ranges.
In such case, is there any use for "other-range-unit" in Accept-
Ranges?
LMM@acm.org (2007-08-31):
What I remember was that I pushed for custom ranges and that there
was a lot of push-back from people who thought it was too much
complexity.
I think the idea 'sort of' got into the spec, but not fully fleshed
out.
I agree that it belongs in the issue list, to either clarify how to
use custom ranges (with a range unit registry, for example) or else
to remove the feature.
I.22. i30-header-lws
In Section 4.2:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i30>
jamie@shareable.org (2004-03-15): _See
<http://www.w3.org/mid/20040315183116.GC9731@mail.shareable.org>_.
I.23. i77-line-folding
In Section 4.2:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i77>
fielding@gbiv.com (2007-01-19):
...I think the spec should reflect the standard, not be artificially
restricted by adherence to past revisions of itself. By standard, I
mean the measure expected by all of the implementations that are
exchanging legitimate communication via HTTP. AFAIK, there are no
servers or clients that send legitimate messages with anything other
than
Field-name: field-value
so it is time for the spec to reflect that fact. My only caveat is
that there should be an exception for the message/http media type,
such that messages received via SMTP shall allow line folding.
...
...MUST NOT send such LWS is fine, including when a message is
forwarded, but forbidding a server from processing such a message is
not going to happen because it would make all implementations non-
compliant.
Servers should be configurable in regards to robust or restricted
parsing behavior, and nothing we say can improve the "security" of
broken software that was deployed years ago. Software that correctly
parses according to the RFC is not subject to those perceived
security issues.
I.24. i19-bodies-on-GET
In Section 4.3:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i19>
Jeff.Mogul@hp.com (2006-06-22): (See <http://www.w3.org/mid/
200606221739.k5MHd3PA013395@pobox-pa.hpl.hp.com>).
I.25. i28-connection-closing
In Section 4.4:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i28>
joe@manyfish.co.uk (2005-02-26): The phrase "unless the message is
terminated by closing the connection" in Section 4.4 is unnecessary.
Section 3.6 uses the same phrase; it is a little confusing. In 4.4
you could almost read it to mean that presence of "Connection: close"
would mean that a T-E header should be ignored, which is presumably
not the intent (and certainly not the practice).
julian.reschke@gmx.de (2007-10-06): Discussed during the Prague
meeting, see
<http://www.w3.org/2007/03/18-rfc2616-minutes.html#action01>.
I.26. i32-options-asterisk
In Section 5.1.2:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i32>
julian.reschke@gmx.de (2003-11-24): I'd like to see a clarification
about what clients can expect upon OPTIONS *. In particular, can
they expect to find out about *any* method name supported on that
server? I'm asking because this doesn't seem to be the case for at
least two major server bases, being:
- Apache (for instance, additional method names supported by mod_dav
aren't listed) and
- generic Java servlet engines (servlet API does not support
delegation of requests against "*" to all installed web
applications).
julian.reschke@gmx.de (2007-10-08):
Quote Roy Fielding:
"...Allow only applies to URIs, not *..." -- http://
mail-archives.apache.org/mod_mbox/httpd-dev/
200710.mbox/%3c24EE5E9D-9FBB-4530-9735-33BD768FC633@gbiv.com%3e
I.27. i83-options-asterisk-and-proxies
In Section 5.1.2:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i83>
hno@squid-cache.org (2007-10-01): _Text about proxying OPTIONS *
contained in RFC2068 was lost in RCF2616._
julian.reschke@gmx.de (2007-10-03):
The lost text says:
"If a proxy receives a request without any path in the Request-URI
and the method specified is capable of supporting the asterisk
form of request, then the last proxy on the request chain MUST
forward the request with "*" as the final Request-URI. For
example, the request
OPTIONS http://www.ics.uci.edu:8001 HTTP/1.1
would be forwarded by the proxy as
OPTIONS * HTTP/1.1
Host: www.ics.uci.edu:8001
after connecting to port 8001 of host "www.ics.uci.edu"." --
http://tools.ietf.org/html/rfc2068#section-5.1.2
hno@squid-cache.org (2007-10-04):
...
There is one slight problem with the above and it's " and the method
specified is capable of supporting the asterisk form of request".
This requires the proxy to know about each such method, and with HTTP
being extensible it's not fully possible. In RFC2616 only OPTIONS
meets this criteria.
Is there a possibility for other methods than OPTIONS which may make
sense on a global resource-less context? I think not. If this is
complemented with a restriction that the special request-URI "*" may
only be used in OPTIONS requests then it's fine. Interoperability of
extension methods using "*" will be tricky at best..
...
I.28. i56-6.1.1-can-be-misread-as-a-complete-list
In Section 6.1.1: In Section 6.1.1:
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i56> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i56>
henrik@henriknordstrom.net (2007-01-11): The second sentence in the henrik@henriknordstrom.net (2007-01-11): The second sentence in the
first paragraph can on a quick reading be misread as section 10 first paragraph can on a quick reading be misread as section 10
contains a complete definiton of all possible status codes, where it contains a complete definiton of all possible status codes, where it
in reality only has the status codes defined by this RFC. in reality only has the status codes defined by this RFC.
I.20. i57-status-code-and-reason-phrase I.29. i57-status-code-and-reason-phrase
In Section 6.1.1: In Section 6.1.1:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i57> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i57>
henrik@henriknordstrom.net (2007-01-11): 6.1.1 is apparently a bit henrik@henriknordstrom.net (2007-01-11):
too vague about how applications should parse and process the
information, making some implementations parse the reason phrase 6.1.1 is apparently a bit too vague about how applications should
(probably exact matches on the complete status line, not just status parse and process the information, making some implementations parse
code) to determine the outcome. the reason phrase (probably exact matches on the complete status
line, not just status code) to determine the outcome.
There should be a SHOULD requirement or equivalent that applications There should be a SHOULD requirement or equivalent that applications
use the status code to determine the status of the response and only use the status code to determine the status of the response and only
process the Reason Phrase as a comment intended for humans. process the Reason Phrase as a comment intended for humans.
It's true that later in the same section there is a reverse MAY It's true that later in the same section there is a reverse MAY
requirement implying this by saying that the phrases in the rfc is requirement implying this by saying that the phrases in the rfc is
just an example and may be replaced without affecting the protocol, just an example and may be replaced without affecting the protocol,
but apparently it's not sufficient for implementers to understand but apparently it's not sufficient for implementers to understand
that applications should not decide the outcome based on the reason that applications should not decide the outcome based on the reason
phrase. phrase.
I.21. i59-status-code-registry I.30. i59-status-code-registry
In Section 6.1.1: In Section 6.1.1:
Type: edit Type: edit
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i59> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i59>
henrik@henriknordstrom.net (2007-02-18): The IANA status code henrik@henriknordstrom.net (2007-02-18): The IANA status code
registry should be referred to. registry should be referred to.
I.22. i21-put-side-effects I.31. i72-request-method-registry
In Section 9:
Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i72>
henrik@henriknordstrom.net (2007-08-06): I see a need for an official
HTTP request method registry to be established, preferably maintained
by IANA.
I.32. i21-put-side-effects
In Section 9.6: In Section 9.6:
Type: change Type: change
<http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i21> <http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i21>
mnot@yahoo-inc.com (2006-04-03): (See http://lists.w3.org/Archives/ mnot@yahoo-inc.com (2006-04-03):
Public/ietf-http-wg/2006AprJun/0002.html).
I.23. i54-definition-of-1xx-warn-codes 2616 specifically allows PUT to have side effects;
"A single resource MAY be identified by many different URIs. For
example, an article might have a URI for identifying "the current
version" which is separate from the URI identifying each
particular version. In this case, a PUT request on a general URI
might result in several other URIs being defined by the origin
server.
HTTP/1.1 does not define how a PUT method affects the state of an
origin server." --
http://tools.ietf.org/html/rfc2616.html#section-9.6
and it also says (in the context of PUT)
"If a new resource is created, the origin server MUST inform the
user agent via the 201 (Created) response." --
http://tools.ietf.org/html/rfc2616.html#section-9.6
So, if I PUT something to /foo, and it has the side effect if
creating /foo;2006-04-03, is the response required to be a 201
Created?
I.e., read literally, the above requirement requires a 201 Created
when PUT results in *any* resource being created -- even as a side
effect.
This is IMO unnecessarily constraining, and should be relaxed; e.g.,
changed to something like
_"If a new resource is created at the Request-URI, the origin server
MUST inform the user agent via the 201 (Created) response."_
julian.reschke@gmx.de (2007-10-06): Discussed during the Prague
meeting, see
<http://www.w3.org/2007/03/18-rfc2616-minutes.html#action06>:
_Combine to make second sentence dependent upon the first: "If the
Request-URI does not point to an existing resource, and that URI is
capable of being defined as a new resource by the requesting user
agent, the origin server can create the resource with that URI. If a
new resource is created, the origin server MUST inform the user agent
via the 201 (Created) response."_