RFC 7232 - Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests

Metadata

• RFC Number: 7232
• Title: Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
• Authors: R. Fielding (Ed.), J. Reschke (Ed.)
• Date: June 2014
• Status: Proposed Standard
• Obsoletes: RFC 2616
• Obsoleted by: RFC 9110
• Category: Standards Track

Abstract

The Hypertext Transfer Protocol (HTTP) is a stateless application-level protocol for distributed, collaborative, hypertext information systems. This document defines HTTP/1.1 conditional requests, including metadata header fields for indicating state changes, request header fields for making preconditions on such state, and rules for constructing the responses to a conditional request when one or more preconditions evaluate to false.

Contents

• 1. Introduction
  • 1.1 Conformance and Error Handling
  • 1.2 Syntax Notation
• 2. Validators
  • 2.1 Weak versus Strong
  • 2.2 Last-Modified
  • 2.3 ETag
  • 2.4 When to Use Entity-Tags and Last-Modified Dates
• 3. Precondition Header Fields
  • 3.1 If-Match
  • 3.2 If-None-Match
  • 3.3 If-Modified-Since
  • 3.4 If-Unmodified-Since
  • 3.5 If-Range
• 4. Status Code Definitions
  • 4.1 304 Not Modified
  • 4.2 412 Precondition Failed
• 5. Evaluation
• 6. Precedence
• 7. IANA Considerations
• 8. Security Considerations
• 9. Acknowledgments
• 10. References
• Appendix A. Changes from RFC 2616
• Appendix B. Imported ABNF
• Appendix C. Collected ABNF

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG).

Copyright Notice

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