HTTP Working Group                              R. Fielding, UC Irvine
INTERNET-DRAFT                                      J. Gettys, Digital
<draft-ietf-http-v11-spec-rev-01>                 J. C. Mogul, Digital
                                                    L. Masinter, Xerox
                                                   P. Leach, Microsoft
                                                   H. Frystyk, MIT/LCS
                                               T. Berners-Lee, MIT/LCS
Expires May 21, 1998                                 November 21, 1997

                Hypertext Transfer Protocol -- HTTP/1.1

Status of this Memo

This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups. Note that other groups may also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or made obsolete by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress".

To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).

Distribution of this document is unlimited. Please send comments to the
HTTP working group at <http-wg@cuckoo.hpl.hp.com>. Discussions of the
working group are archived at
<URL:http://www.ics.uci.edu/pub/ietf/http/>. General discussions about
HTTP and the applications which use HTTP should take place on the <www-
talk@w3.org> mailing list.

Abstract

The Hypertext Transfer Protocol (HTTP) is an application-level protocol
for distributed, collaborative, hypermedia information systems. It is a
generic, stateless, object-oriented protocol which can be used for many
tasks, such as name servers and distributed object management systems,
through extension of its request methods. A feature of HTTP is the
typing and negotiation of data representation, allowing systems to be
built independently of the data being transferred.

HTTP has been in use by the World-Wide Web global information initiative
since 1990. This specification defines the protocol referred to as
"HTTP/1.1".

The issues list for HTTP/1.1 can be found at:
http://www.w3.org/Protocols/HTTP/Issues/.

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This draft does not resolve all open issues in the HTTP/1.1
specification requiring closure before HTTP/1.1 goes to draft standard.
It does, however, close most of them, and note where in the document
there are still significant issues under discussion.  The best way to
view this document is to get a copy of the Word 97 document found at:
http://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-rev-
01.doc; all issues are noted as comments in the source document, with
hyperlinks to the Issues list.

This document has had the basic ambiguity problems with OPTIONS
resolved; but does not solve the underlying issue of identifying
extensions to HTTP. The issue OPTIONS is therefore still open; at
Munich, there was strong sentiment to some sort of OPTIONS facility, but
we've not been able to converge; it is on the agenda for Washington.
See draft-ietf-http-options-02.txt for details.

Summary Of Issues since Rev-01 (Rev-01 and Auth-00 under preparation)

4 Open Technical issues: RE-AUTHENTICATION-REQUESTED, PROXY-REDIRECT,
CONTENT-ENCODING, OPTIONS.

Minimal OPTIONS is in Rev-01, PROXY-REDIRECT proposal that was in Rev-00
draft (which interacts with OPTIONS) was removed from rev-01.

8 Open Editorial issues: XREFS,  REQUEST_TARGET, UPDATE_ACKS,
DISPOSITION, REQUIREMENTS, CLEAN_INDEXES, CODE_REGISTRY,
IANA_DIRECTIONS.

4 Ready for Last Call: PUT-RANGE, RE-AUTHENTICATION-REQUESTED,
TRAILER_FIELDS, RANGE_WITH_CONTENTCODING.

12 Last call issues (all edited into Rev-01): DIGEST_SYNTAX,
PROTECTION_SPACE, CONTRADICTION, IMS_INM_MISMATCH, CONNECTION_METHOD,
BYTERANGE_SYNTAX,  RE-VERSION, HOST, AUTH-CHUNKED, REQUIRE-DIGEST,
DOCKDIGEST, GENERIC_MESSAGE.

9 Technical Issues closed since Rev-00 (all edited into Rev-01): 301-
302, REDIRECTS, CACHING-CGI, WARNINGS, DATE-IF-MODIFIED, 403VS404, AGE-
CALCULATION (Yeah!), VARY, RANGE-ERROR.

12 Editorial issues closed since Rev-00 (all edited into Rev-01):
REMOVE_19.6, GENERIC_MESSAGE, RANGE_OPTIONAL, EBNF, CODES, UTF-8,
DOCKDIGEST, URL-SYNTAX, 1310_CACHE, MESSAGE-BODY, LENGTH_WORDING,
CLEANUP.








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Table of Contents



HYPERTEXT TRANSFER PROTOCOL -- HTTP/1.1....................1

Status of this Memo........................................1

Abstract...................................................1

Table of Contents..........................................3

1   Introduction ..........................................8
 1.1  Purpose .............................................8
 1.2  Requirements ........................................9
 1.3  Terminology ........................................10
 1.4  Overall Operation ..................................13

2   Notational Conventions and Generic Grammar ...........14
 2.1  Augmented BNF ......................................14
 2.2  Basic Rules ........................................16

3   Protocol Parameters ..................................17
 3.1  HTTP Version .......................................17
 3.2  Uniform Resource Identifiers .......................19
  3.2.1  General Syntax ..................................19
  3.2.2  http URL ........................................19
  3.2.3  URI Comparison ..................................20
 1.3  Date/Time Formats ..................................20
  1.3.1  Full Date .......................................20
  1.3.2  Delta Seconds ...................................21
 1.4  Character Sets .....................................21
 1.5  Content Codings ....................................22
 1.6  Transfer Codings ...................................23
  1.6.1  Chunked Transfer Coding .........................24
  1.6.2  Identity Transfer Coding ........................25
 1.7  Media Types ........................................25
  1.7.1  Canonicalization and Text Defaults ..............26
  1.7.2  Multipart Types .................................26
 1.8  Product Tokens .....................................27
 1.9  Quality Values .....................................27
 1.10 Language Tags ......................................28
 1.11 Entity Tags ........................................28
 1.12 Range Units ........................................29

4   HTTP Message .........................................29
 4.1  Message Types ......................................29
 4.2  Message Headers ....................................30
 4.3  Message Body .......................................30
 4.4  Message Length .....................................31
 4.5  General Header Fields ..............................32

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5   Request ..............................................33
 5.1  Request-Line .......................................33
  5.1.1  Method ..........................................33
  5.1.2  Request-URI .....................................34
 5.2  The Resource Identified by a Request ...............35
 5.3  Request Header Fields ..............................35

6   Response .............................................36
 6.1  Status-Line ........................................36
  6.1.1  Status Code and Reason Phrase ...................36
 1.2  Response Header Fields .............................38

7   Entity ...............................................39
 7.1  Entity Header Fields ...............................39
 7.2  Entity Body ........................................39
  7.2.1  Type ............................................40
  7.2.2  Length ..........................................40

8   Connections ..........................................40
 8.1  Persistent Connections .............................40
  8.1.1  Purpose .........................................40
  1.1.2  Overall Operation ...............................41
  1.1.3  Proxy Servers ...................................42
  1.1.4  Practical Considerations ........................43
 1.2  Message Transmission Requirements ..................44
  1.2.1  Persistent connections and flow control .........44
  1.2.2  Monitoring connections for error status messages 44
  1.2.3  Automatic retrying of requests ..................44
  1.2.4  Use of the 100 (Continue) status ................44
  1.2.5  Client behavior if server prematurely closes connection
         .................................................46

9   Method Definitions ...................................47
 9.1  Safe and Idempotent Methods ........................47
  9.1.1  Safe Methods ....................................47
  9.1.2  Idempotent Methods ..............................48
 9.2  OPTIONS ............................................48
 9.3  GET ................................................49
 9.4  HEAD ...............................................50
 9.5  POST ...............................................50
 1.6  PUT ................................................51
  1.6.1  Partial PUT (PUT with Content-Range) ............52
 1.7  DELETE .............................................53
 1.8  TRACE ..............................................53
 1.9  CONNECT ............................................54

10   Status Code Definitions .............................54
 10.1 Informational 1xx ..................................54
  10.1.1 100 Continue ....................................54
  10.1.2 101 Switching Protocols .........................54
 10.2 Successful 2xx .....................................55

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  10.2.1 200 OK ..........................................55
  10.2.2 201 Created .....................................55
  10.2.3 202 Accepted ....................................55
  10.2.4 203 Non-Authoritative Information ...............56
  10.2.5 204 No Content ..................................56
  10.2.6 205 Reset Content ...............................56
  10.2.7 206 Partial Content .............................57
  10.2.8 207 Partial Update OK ...........................57
 10.3 Redirection 3xx ....................................58
  10.3.1 300 Multiple Choices ............................58
  10.3.2 301 Moved Permanently ...........................58
  10.3.3 302 Found .......................................59
  10.3.4 303 See Other ...................................59
  10.3.5 304 Not Modified ................................60
  10.3.6 305 Use Proxy ...................................61
  10.3.7 307 Temporary Redirect ..........................61
 10.4 Client Error 4xx ...................................61
  10.4.1 400 Bad Request .................................62
  10.4.2 401 Unauthorized ................................62
  10.4.3 402 Payment Required ............................62
  10.4.4 403 Forbidden ...................................62
  10.4.5 404 Not Found ...................................62
  10.4.6 405 Method Not Allowed ..........................63
  10.4.7 406 Not Acceptable ..............................63
  10.4.8 407 Proxy Authentication Required ...............63
  10.4.9 408 Request Timeout .............................63
  10.4.10 ......................................409 Conflict    64
  10.4.11 ..........................................410 Gone    64
  10.4.12 ...............................411 Length Required    64
  10.4.13 ...........................412 Precondition Failed    65
  10.4.14 ......................413 Request Entity Too Large    65
  10.4.15 ..........................414 Request-URI Too Long    65
  10.4.16 ........................415 Unsupported Media Type    65
  10.4.17 ...............416 Requested range not satisfiable    65
  10.4.18 ............................417 Expectation Failed    66
  10.4.19 .....................418 Reauthentication Required    66
  10.4.20 ...............419 Proxy Reauthentication Required    66
 10.5 Server Error 5xx ...................................67
  10.5.1 500 Internal Server Error .......................67
  10.5.2 501 Not Implemented .............................67
  10.5.3 502 Bad Gateway .................................67
  10.5.4 503 Service Unavailable .........................67
  10.5.5 504 Gateway Timeout .............................67
  10.5.6 505 HTTP Version Not Supported ..................68
  10.5.7 506 Partial Update Not Implemented ..............68

11   Access Authentication ...............................68
 11.1 Digest Authentication ..............................68

12   Content Negotiation .................................68
 12.1 Server-driven Negotiation ..........................69

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 12.2 Agent-driven Negotiation ...........................70
 12.3 Transparent Negotiation ............................70

13   Caching in HTTP .....................................71
  1.1.1  Cache Correctness ...............................72
  1.1.2  Warnings ........................................73
  1.1.3  Cac