Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
RFC 7232
Document | Type |
RFC - Proposed Standard
(June 2014; Errata)
Obsoletes RFC 2616
|
|
---|---|---|---|
Authors | Roy Fielding , Julian Reschke | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Mark Nottingham | ||
Shepherd write-up | Show (last changed 2013-10-07) | ||
IESG | IESG state | RFC 7232 (Proposed Standard) | |
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Barry Leiba | ||
Send notices to | (None) | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) R. Fielding, Ed. Request for Comments: 7232 Adobe Obsoletes: 2616 J. Reschke, Ed. Category: Standards Track greenbytes ISSN: 2070-1721 June 2014 Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests 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. 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). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7232. Fielding & Reschke Standards Track [Page 1] RFC 7232 HTTP/1.1 Conditional Requests June 2014 Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Fielding & Reschke Standards Track [Page 2] RFC 7232 HTTP/1.1 Conditional Requests June 2014 Table of Contents 1. Introduction ....................................................4 1.1. Conformance and Error Handling .............................4 1.2. Syntax Notation ............................................4 2. Validators ......................................................5 2.1. Weak versus Strong .........................................5 2.2. Last-Modified ..............................................7 2.2.1. Generation ..........................................7 2.2.2. Comparison ..........................................8 2.3. ETag .......................................................9 2.3.1. Generation .........................................10 2.3.2. Comparison .........................................10 2.3.3. Example: Entity-Tags Varying on Content-Negotiated Resources .......................11 2.4. When to Use Entity-Tags and Last-Modified Dates ...........12 3. Precondition Header Fields .....................................13 3.1. If-Match ..................................................13 3.2. If-None-Match .............................................14 3.3. If-Modified-Since .........................................16 3.4. If-Unmodified-Since .......................................17 3.5. If-Range ..................................................18 4. Status Code Definitions ........................................18 4.1. 304 Not Modified ..........................................18 4.2. 412 Precondition Failed ...................................19 5. Evaluation .....................................................19 6. Precedence .....................................................20Show full document text