Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
RFC 7232
| Document | Type |
RFC - Proposed Standard
(June 2014; No errata)
Obsoletes RFC 2616
|
|
|---|---|---|---|
| Last updated | 2017-03-08 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication (wg milestone: Sep 2013 - Submit HTTP/1.1 Revi... ) | |
| 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
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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
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