draft-ietf-httpapi-idempotency-key-header-07.unpg.txt   draft-ietf-httpapi-idempotency-key-header-latest.txt 
Network Working Group J. Jena Network Working Group J. Jena
Internet-Draft Internet-Draft
Intended status: Standards Track S. Dalal Intended status: Standards Track S. Dalal
Expires: April 18, 2026 October 15, 2025 Expires: May 10, 2026 November 06, 2025
The Idempotency-Key HTTP Header Field The Idempotency-Key HTTP Header Field
draft-ietf-httpapi-idempotency-key-header-07 draft-ietf-httpapi-idempotency-key-header-latest
Abstract Abstract
The HTTP Idempotency-Key request header field can be used to make The HTTP Idempotency-Key request header field can be used to make
non-idempotent HTTP methods such as "POST" or "PATCH" fault-tolerant. non-idempotent HTTP methods such as "POST" or "PATCH" fault-tolerant.
About This Document About This Document
This note is to be removed before publishing as an RFC. This note is to be removed before publishing as an RFC.
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Copyright Notice Copyright Notice
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document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
2. The Idempotency-Key HTTP Request Header Field 2. The Idempotency-Key HTTP Request Header Field . . . . . . . . 3
2.1. Syntax 2.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Uniqueness of Idempotency Key 2.2. Uniqueness of Idempotency Key . . . . . . . . . . . . . . 3
2.3. Idempotency Key Validity and Expiry 2.3. Idempotency Key Validity and Expiry . . . . . . . . . . . 4
2.4. Idempotency Fingerprint 2.4. Idempotency Fingerprint . . . . . . . . . . . . . . . . . 4
2.5. Responsibilities 2.5. Responsibilities . . . . . . . . . . . . . . . . . . . . 4
2.5.1. Client 2.5.1. Client . . . . . . . . . . . . . . . . . . . . . . . 4
2.5.2. Resource 2.5.2. Resource . . . . . . . . . . . . . . . . . . . . . . 5
2.6. Idempotency Enforcement 2.6. Idempotency Enforcement . . . . . . . . . . . . . . . . . 5
2.7. Error Handling 2.7. Error Handling . . . . . . . . . . . . . . . . . . . . . 5
3. IANA Considerations 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
3.1. The Idempotency-Key HTTP Request Header Field 3.1. The Idempotency-Key HTTP Request Header Field . . . . . . 7
4. Implementation Status 4. Implementation Status . . . . . . . . . . . . . . . . . . . . 7
4.1. Implementing the Concept 4.1. Implementing the Concept . . . . . . . . . . . . . . . . 9
5. Security Considerations 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. Examples 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7. References 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References 7.1. Normative References . . . . . . . . . . . . . . . . . . 12
7.2. Informative References 7.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Changes from Draft-06 Appendix A. Changes from Draft-05 . . . . . . . . . . . . . . . 13
Acknowledgments Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
In mathematics and computer science, an idempotent operation is one In mathematics and computer science, an idempotent operation is one
that can be applied multiple times without changing the result beyond that can be applied multiple times without changing the result beyond
the initial application. It does not matter if the operation is the initial application. It does not matter if the operation is
called only once or tens of times over. called only once or tens of times over.
Idempotency is important in building fault-tolerant HTTP APIs. An Idempotency is important in building fault-tolerant HTTP APIs. An
HTTP request method is considered "idempotent" if the intended effect HTTP request method is considered "idempotent" if the intended effect
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7.3. URIs 7.3. URIs
[1] https://github.com/paypal/api-standards/blob/master/ [1] https://github.com/paypal/api-standards/blob/master/
patterns.md#idempotency patterns.md#idempotency
[2] https://stripe.com/docs/idempotency [2] https://stripe.com/docs/idempotency
[3] https://tools.ietf.org/html/draft-nottingham-http-poe-00 [3] https://tools.ietf.org/html/draft-nottingham-http-poe-00
Appendix A. Changes from Draft-06 Appendix A. Changes from Draft-05
This revision has made the following changes: * Added change log
starting from previous draft * Correction in introduction * Added an
implementer
Acknowledgments Acknowledgments
The authors would like to thank Mark Nottingham for his support for The authors would like to thank Mark Nottingham for his support for
this Internet Draft. We would like to acknowledge that this draft is this Internet Draft. We would like to acknowledge that this draft is
inspired by Idempotency related patterns described in API inspired by Idempotency related patterns described in API
documentation of PayPal [1] and Stripe [2] as well as Internet Draft documentation of PayPal [1] and Stripe [2] as well as Internet Draft
on POST Once Exactly [3] authored by Mark Nottingham. on POST Once Exactly [3] authored by Mark Nottingham.
The authors take all responsibility for errors and omissions. The authors take all responsibility for errors and omissions.
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