draft-ietf-httpbis-p2-semantics-05.txt   draft-ietf-httpbis-p2-semantics-06.txt 
Network Working Group R. Fielding, Ed. HTTPbis Working Group R. Fielding, Ed.
Internet-Draft Day Software Internet-Draft Day Software
Obsoletes: 2616 (if approved) J. Gettys Obsoletes: 2616 (if approved) J. Gettys
Updates: 2817 (if approved) One Laptop per Child Updates: 2817 (if approved) One Laptop per Child
Intended status: Standards Track J. Mogul Intended status: Standards Track J. Mogul
Expires: May 20, 2009 HP Expires: September 10, 2009 HP
H. Frystyk H. Frystyk
Microsoft Microsoft
L. Masinter L. Masinter
Adobe Systems Adobe Systems
P. Leach P. Leach
Microsoft Microsoft
T. Berners-Lee T. Berners-Lee
W3C/MIT W3C/MIT
Y. Lafon, Ed. Y. Lafon, Ed.
W3C W3C
J. Reschke, Ed. J. Reschke, Ed.
greenbytes greenbytes
November 16, 2008 March 9, 2009
HTTP/1.1, part 2: Message Semantics HTTP/1.1, part 2: Message Semantics
draft-ietf-httpbis-p2-semantics-05 draft-ietf-httpbis-p2-semantics-06
Status of this Memo Status of this Memo
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Abstract Abstract
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information protocol for distributed, collaborative, hypermedia information
systems. HTTP has been in use by the World Wide Web global systems. HTTP has been in use by the World Wide Web global
information initiative since 1990. This document is Part 2 of the information initiative since 1990. This document is Part 2 of the
seven-part specification that defines the protocol referred to as seven-part specification that defines the protocol referred to as
"HTTP/1.1" and, taken together, obsoletes RFC 2616. Part 2 defines "HTTP/1.1" and, taken together, obsoletes RFC 2616. Part 2 defines
the semantics of HTTP messages as expressed by request methods, the semantics of HTTP messages as expressed by request methods,
skipping to change at page 2, line 25 skipping to change at page 2, line 43
fields. fields.
Editorial Note (To be removed by RFC Editor) Editorial Note (To be removed by RFC Editor)
Discussion of this draft should take place on the HTTPBIS working Discussion of this draft should take place on the HTTPBIS working
group mailing list (ietf-http-wg@w3.org). The current issues list is group mailing list (ietf-http-wg@w3.org). The current issues list is
at <http://tools.ietf.org/wg/httpbis/trac/report/11> and related at <http://tools.ietf.org/wg/httpbis/trac/report/11> and related
documents (including fancy diffs) can be found at documents (including fancy diffs) can be found at
<http://tools.ietf.org/wg/httpbis/>. <http://tools.ietf.org/wg/httpbis/>.
The changes in this draft are summarized in Appendix B.6. The changes in this draft are summarized in Appendix C.7.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 6 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 6
2. Notational Conventions and Generic Grammar . . . . . . . . . . 6 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 6
3. Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.2.1. Core Rules . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Method Registry . . . . . . . . . . . . . . . . . . . . . 8 1.2.2. ABNF Rules defined in other Parts of the
4. Request Header Fields . . . . . . . . . . . . . . . . . . . . 9 Specification . . . . . . . . . . . . . . . . . . . . 7
5. Status Code and Reason Phrase . . . . . . . . . . . . . . . . 10 2. Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Status Code Registry . . . . . . . . . . . . . . . . . . . 12 2.1. Method Registry . . . . . . . . . . . . . . . . . . . . . 8
6. Response Header Fields . . . . . . . . . . . . . . . . . . . . 12 3. Request Header Fields . . . . . . . . . . . . . . . . . . . . 9
7. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4. Status Code and Reason Phrase . . . . . . . . . . . . . . . . 10
8. Method Definitions . . . . . . . . . . . . . . . . . . . . . . 13 4.1. Status Code Registry . . . . . . . . . . . . . . . . . . . 12
8.1. Safe and Idempotent Methods . . . . . . . . . . . . . . . 13 5. Response Header Fields . . . . . . . . . . . . . . . . . . . . 12
8.1.1. Safe Methods . . . . . . . . . . . . . . . . . . . . . 13 6. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1.2. Idempotent Methods . . . . . . . . . . . . . . . . . . 14 7. Method Definitions . . . . . . . . . . . . . . . . . . . . . . 13
8.2. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1. Safe and Idempotent Methods . . . . . . . . . . . . . . . 13
8.3. GET . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7.1.1. Safe Methods . . . . . . . . . . . . . . . . . . . . . 13
8.4. HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.1.2. Idempotent Methods . . . . . . . . . . . . . . . . . . 14
8.5. POST . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.2. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.6. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.3. GET . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.7. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.4. HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.8. TRACE . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.5. POST . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.9. CONNECT . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.6. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
9. Status Code Definitions . . . . . . . . . . . . . . . . . . . 19 7.7. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Informational 1xx . . . . . . . . . . . . . . . . . . . . 19 7.8. TRACE . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1.1. 100 Continue . . . . . . . . . . . . . . . . . . . . . 19 7.9. CONNECT . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1.2. 101 Switching Protocols . . . . . . . . . . . . . . . 20 8. Status Code Definitions . . . . . . . . . . . . . . . . . . . 19
9.2. Successful 2xx . . . . . . . . . . . . . . . . . . . . . . 20 8.1. Informational 1xx . . . . . . . . . . . . . . . . . . . . 19
9.2.1. 200 OK . . . . . . . . . . . . . . . . . . . . . . . . 20 8.1.1. 100 Continue . . . . . . . . . . . . . . . . . . . . . 20
9.2.2. 201 Created . . . . . . . . . . . . . . . . . . . . . 20 8.1.2. 101 Switching Protocols . . . . . . . . . . . . . . . 20
9.2.3. 202 Accepted . . . . . . . . . . . . . . . . . . . . . 21 8.2. Successful 2xx . . . . . . . . . . . . . . . . . . . . . . 20
9.2.4. 203 Non-Authoritative Information . . . . . . . . . . 21 8.2.1. 200 OK . . . . . . . . . . . . . . . . . . . . . . . . 20
9.2.5. 204 No Content . . . . . . . . . . . . . . . . . . . . 21 8.2.2. 201 Created . . . . . . . . . . . . . . . . . . . . . 21
9.2.6. 205 Reset Content . . . . . . . . . . . . . . . . . . 22 8.2.3. 202 Accepted . . . . . . . . . . . . . . . . . . . . . 21
9.2.7. 206 Partial Content . . . . . . . . . . . . . . . . . 22 8.2.4. 203 Non-Authoritative Information . . . . . . . . . . 21
9.3. Redirection 3xx . . . . . . . . . . . . . . . . . . . . . 22 8.2.5. 204 No Content . . . . . . . . . . . . . . . . . . . . 22
9.3.1. 300 Multiple Choices . . . . . . . . . . . . . . . . . 22 8.2.6. 205 Reset Content . . . . . . . . . . . . . . . . . . 22
9.3.2. 301 Moved Permanently . . . . . . . . . . . . . . . . 23 8.2.7. 206 Partial Content . . . . . . . . . . . . . . . . . 22
9.3.3. 302 Found . . . . . . . . . . . . . . . . . . . . . . 23 8.3. Redirection 3xx . . . . . . . . . . . . . . . . . . . . . 22
9.3.4. 303 See Other . . . . . . . . . . . . . . . . . . . . 24 8.3.1. 300 Multiple Choices . . . . . . . . . . . . . . . . . 23
9.3.5. 304 Not Modified . . . . . . . . . . . . . . . . . . . 25 8.3.2. 301 Moved Permanently . . . . . . . . . . . . . . . . 23
9.3.6. 305 Use Proxy . . . . . . . . . . . . . . . . . . . . 25 8.3.3. 302 Found . . . . . . . . . . . . . . . . . . . . . . 24
9.3.7. 306 (Unused) . . . . . . . . . . . . . . . . . . . . . 25 8.3.4. 303 See Other . . . . . . . . . . . . . . . . . . . . 24
9.3.8. 307 Temporary Redirect . . . . . . . . . . . . . . . . 25 8.3.5. 304 Not Modified . . . . . . . . . . . . . . . . . . . 25
9.4. Client Error 4xx . . . . . . . . . . . . . . . . . . . . . 25 8.3.6. 305 Use Proxy . . . . . . . . . . . . . . . . . . . . 25
9.4.1. 400 Bad Request . . . . . . . . . . . . . . . . . . . 26 8.3.7. 306 (Unused) . . . . . . . . . . . . . . . . . . . . . 25
9.4.2. 401 Unauthorized . . . . . . . . . . . . . . . . . . . 26 8.3.8. 307 Temporary Redirect . . . . . . . . . . . . . . . . 25
9.4.3. 402 Payment Required . . . . . . . . . . . . . . . . . 26 8.4. Client Error 4xx . . . . . . . . . . . . . . . . . . . . . 26
9.4.4. 403 Forbidden . . . . . . . . . . . . . . . . . . . . 26 8.4.1. 400 Bad Request . . . . . . . . . . . . . . . . . . . 26
9.4.5. 404 Not Found . . . . . . . . . . . . . . . . . . . . 26 8.4.2. 401 Unauthorized . . . . . . . . . . . . . . . . . . . 26
9.4.6. 405 Method Not Allowed . . . . . . . . . . . . . . . . 27 8.4.3. 402 Payment Required . . . . . . . . . . . . . . . . . 26
9.4.7. 406 Not Acceptable . . . . . . . . . . . . . . . . . . 27 8.4.4. 403 Forbidden . . . . . . . . . . . . . . . . . . . . 26
9.4.8. 407 Proxy Authentication Required . . . . . . . . . . 27 8.4.5. 404 Not Found . . . . . . . . . . . . . . . . . . . . 27
9.4.9. 408 Request Timeout . . . . . . . . . . . . . . . . . 27 8.4.6. 405 Method Not Allowed . . . . . . . . . . . . . . . . 27
9.4.10. 409 Conflict . . . . . . . . . . . . . . . . . . . . . 27 8.4.7. 406 Not Acceptable . . . . . . . . . . . . . . . . . . 27
9.4.11. 410 Gone . . . . . . . . . . . . . . . . . . . . . . . 28 8.4.8. 407 Proxy Authentication Required . . . . . . . . . . 27
9.4.12. 411 Length Required . . . . . . . . . . . . . . . . . 28 8.4.9. 408 Request Timeout . . . . . . . . . . . . . . . . . 28
9.4.13. 412 Precondition Failed . . . . . . . . . . . . . . . 28 8.4.10. 409 Conflict . . . . . . . . . . . . . . . . . . . . . 28
9.4.14. 413 Request Entity Too Large . . . . . . . . . . . . . 29 8.4.11. 410 Gone . . . . . . . . . . . . . . . . . . . . . . . 28
9.4.15. 414 Request-URI Too Long . . . . . . . . . . . . . . . 29 8.4.12. 411 Length Required . . . . . . . . . . . . . . . . . 29
9.4.16. 415 Unsupported Media Type . . . . . . . . . . . . . . 29 8.4.13. 412 Precondition Failed . . . . . . . . . . . . . . . 29
9.4.17. 416 Requested Range Not Satisfiable . . . . . . . . . 29 8.4.14. 413 Request Entity Too Large . . . . . . . . . . . . . 29
9.4.18. 417 Expectation Failed . . . . . . . . . . . . . . . . 29 8.4.15. 414 URI Too Long . . . . . . . . . . . . . . . . . . . 29
9.5. Server Error 5xx . . . . . . . . . . . . . . . . . . . . . 29 8.4.16. 415 Unsupported Media Type . . . . . . . . . . . . . . 29
9.5.1. 500 Internal Server Error . . . . . . . . . . . . . . 30 8.4.17. 416 Requested Range Not Satisfiable . . . . . . . . . 29
9.5.2. 501 Not Implemented . . . . . . . . . . . . . . . . . 30 8.4.18. 417 Expectation Failed . . . . . . . . . . . . . . . . 30
9.5.3. 502 Bad Gateway . . . . . . . . . . . . . . . . . . . 30 8.5. Server Error 5xx . . . . . . . . . . . . . . . . . . . . . 30
9.5.4. 503 Service Unavailable . . . . . . . . . . . . . . . 30 8.5.1. 500 Internal Server Error . . . . . . . . . . . . . . 30
9.5.5. 504 Gateway Timeout . . . . . . . . . . . . . . . . . 30 8.5.2. 501 Not Implemented . . . . . . . . . . . . . . . . . 30
9.5.6. 505 HTTP Version Not Supported . . . . . . . . . . . . 31 8.5.3. 502 Bad Gateway . . . . . . . . . . . . . . . . . . . 30
10. Header Field Definitions . . . . . . . . . . . . . . . . . . . 31 8.5.4. 503 Service Unavailable . . . . . . . . . . . . . . . 30
10.1. Allow . . . . . . . . . . . . . . . . . . . . . . . . . . 31 8.5.5. 504 Gateway Timeout . . . . . . . . . . . . . . . . . 31
10.2. Expect . . . . . . . . . . . . . . . . . . . . . . . . . . 31 8.5.6. 505 HTTP Version Not Supported . . . . . . . . . . . . 31
10.3. From . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 9. Header Field Definitions . . . . . . . . . . . . . . . . . . . 31
10.4. Location . . . . . . . . . . . . . . . . . . . . . . . . . 33 9.1. Allow . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.5. Max-Forwards . . . . . . . . . . . . . . . . . . . . . . . 34 9.2. Expect . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.6. Referer . . . . . . . . . . . . . . . . . . . . . . . . . 34 9.3. From . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
10.7. Retry-After . . . . . . . . . . . . . . . . . . . . . . . 35 9.4. Location . . . . . . . . . . . . . . . . . . . . . . . . . 33
10.8. Server . . . . . . . . . . . . . . . . . . . . . . . . . . 35 9.5. Max-Forwards . . . . . . . . . . . . . . . . . . . . . . . 34
10.9. User-Agent . . . . . . . . . . . . . . . . . . . . . . . . 36 9.6. Referer . . . . . . . . . . . . . . . . . . . . . . . . . 35
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36 9.7. Retry-After . . . . . . . . . . . . . . . . . . . . . . . 35
11.1. Method Registry . . . . . . . . . . . . . . . . . . . . . 36 9.8. Server . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.2. Status Code Registry . . . . . . . . . . . . . . . . . . . 37 9.9. User-Agent . . . . . . . . . . . . . . . . . . . . . . . . 36
11.3. Message Header Registration . . . . . . . . . . . . . . . 39 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37
12. Security Considerations . . . . . . . . . . . . . . . . . . . 39 10.1. Method Registry . . . . . . . . . . . . . . . . . . . . . 37
12.1. Transfer of Sensitive Information . . . . . . . . . . . . 39 10.2. Status Code Registry . . . . . . . . . . . . . . . . . . . 37
12.2. Encoding Sensitive Information in URIs . . . . . . . . . . 40 10.3. Message Header Registration . . . . . . . . . . . . . . . 39
12.3. Location Headers and Spoofing . . . . . . . . . . . . . . 41 11. Security Considerations . . . . . . . . . . . . . . . . . . . 39
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 41 11.1. Transfer of Sensitive Information . . . . . . . . . . . . 39
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 41 11.2. Encoding Sensitive Information in URIs . . . . . . . . . . 40
14.1. Normative References . . . . . . . . . . . . . . . . . . . 41 11.3. Location Headers and Spoofing . . . . . . . . . . . . . . 41
14.2. Informative References . . . . . . . . . . . . . . . . . . 42 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 41
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 41
13.1. Normative References . . . . . . . . . . . . . . . . . . . 41
13.2. Informative References . . . . . . . . . . . . . . . . . . 42
Appendix A. Compatibility with Previous Versions . . . . . . . . 42 Appendix A. Compatibility with Previous Versions . . . . . . . . 42
A.1. Changes from RFC 2068 . . . . . . . . . . . . . . . . . . 42 A.1. Changes from RFC 2068 . . . . . . . . . . . . . . . . . . 42
A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 43 A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 43
Appendix B. Change Log (to be removed by RFC Editor before Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 44
publication) . . . . . . . . . . . . . . . . . . . . 44 Appendix C. Change Log (to be removed by RFC Editor before
B.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . . 44 publication) . . . . . . . . . . . . . . . . . . . . 47
B.2. Since draft-ietf-httpbis-p2-semantics-00 . . . . . . . . . 44 C.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . . 47
B.3. Since draft-ietf-httpbis-p2-semantics-01 . . . . . . . . . 45 C.2. Since draft-ietf-httpbis-p2-semantics-00 . . . . . . . . . 47
B.4. Since draft-ietf-httpbis-p2-semantics-02 . . . . . . . . . 45 C.3. Since draft-ietf-httpbis-p2-semantics-01 . . . . . . . . . 47
B.5. Since draft-ietf-httpbis-p2-semantics-03 . . . . . . . . . 46 C.4. Since draft-ietf-httpbis-p2-semantics-02 . . . . . . . . . 48
B.6. Since draft-ietf-httpbis-p2-semantics-04 . . . . . . . . . 46 C.5. Since draft-ietf-httpbis-p2-semantics-03 . . . . . . . . . 49
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 C.6. Since draft-ietf-httpbis-p2-semantics-04 . . . . . . . . . 49
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 51 C.7. Since draft-ietf-httpbis-p2-semantics-05 . . . . . . . . . 49
Intellectual Property and Copyright Statements . . . . . . . . . . 54 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 54
1. Introduction 1. Introduction
This document defines HTTP/1.1 request and response semantics. Each This document defines HTTP/1.1 request and response semantics. Each
HTTP message, as defined in [Part1], is in the form of either a HTTP message, as defined in [Part1], is in the form of either a
request or a response. An HTTP server listens on a connection for request or a response. An HTTP server listens on a connection for
HTTP requests and responds to each request, in the order received on HTTP requests and responds to each request, in the order received on
that connection, with one or more HTTP response messages. This that connection, with one or more HTTP response messages. This
document defines the commonly agreed upon semantics of the HTTP document defines the commonly agreed upon semantics of the HTTP
uniform interface, the intentions defined by each request method, and uniform interface, the intentions defined by each request method, and
skipping to change at page 6, line 42 skipping to change at page 6, line 42
An implementation is not compliant if it fails to satisfy one or more An implementation is not compliant if it fails to satisfy one or more
of the MUST or REQUIRED level requirements for the protocols it of the MUST or REQUIRED level requirements for the protocols it
implements. An implementation that satisfies all the MUST or implements. An implementation that satisfies all the MUST or
REQUIRED level and all the SHOULD level requirements for its REQUIRED level and all the SHOULD level requirements for its
protocols is said to be "unconditionally compliant"; one that protocols is said to be "unconditionally compliant"; one that
satisfies all the MUST level requirements but not all the SHOULD satisfies all the MUST level requirements but not all the SHOULD
level requirements for its protocols is said to be "conditionally level requirements for its protocols is said to be "conditionally
compliant." compliant."
2. Notational Conventions and Generic Grammar 1.2. Syntax Notation
This specification uses the ABNF syntax defined in Section 2.1 of This specification uses the ABNF syntax defined in Section 1.2 of
[Part1] and the core rules defined in Section 2.2 of [Part1]: [Part1] (which extends the syntax defined in [RFC5234] with a list
rule). Appendix B shows the collected ABNF, with the list rule
expanded.
DIGIT = <DIGIT, defined in [Part1], Section 2.2> The following core rules are included by reference, as defined in
comment = <comment, defined in [Part1], Section 2.2> [RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF
quoted-string = <quoted-string, defined in [Part1], Section 2.2> (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
token = <token, defined in [Part1], Section 2.2> HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit
OWS = <OWS, defined in [Part1], Section 2.2> sequence of data), SP (space), VCHAR (any visible USASCII character),
RWS = <RWS, defined in [Part1], Section 2.2> and WSP (whitespace).
1.2.1. Core Rules
The core rules below are defined in Section 1.2.2 of [Part1]:
comment = <comment, defined in [Part1], Section 1.2.2>
quoted-string = <quoted-string, defined in [Part1], Section 1.2.2>
token = <token, defined in [Part1], Section 1.2.2>
OWS = <OWS, defined in [Part1], Section 1.2.2>
RWS = <RWS, defined in [Part1], Section 1.2.2>
obs-text = <obs-text, defined in [Part1], Section 1.2.2>
1.2.2. ABNF Rules defined in other Parts of the Specification
The ABNF rules below are defined in other parts: The ABNF rules below are defined in other parts:
absolute-URI = <absolute-URI, defined in [Part1], Section 3.2> absolute-URI = <absolute-URI, defined in [Part1], Section 2.1>
fragment = <fragment, defined in [Part1], Section 3.2> fragment = <fragment, defined in [Part1], Section 2.1>
Host = <Host, defined in [Part1], Section 3.2> Host = <Host, defined in [Part1], Section 2.1>
HTTP-date = <HTTP-date, defined in [Part1], Section 3.3.1> HTTP-date = <HTTP-date, defined in [Part1], Section 3.2.1>
product = <product, defined in [Part1], Section 3.5> partial-URI = <partial-URI, defined in [Part1], Section 2.1>
relativeURI = <relativeURI, defined in [Part1], Section 3.2> product = <product, defined in [Part1], Section 3.4>
TE = <TE, defined in [Part1], Section 8.8> TE = <TE, defined in [Part1], Section 8.8>
Accept = <Accept, defined in [Part3], Section 6.1> Accept = <Accept, defined in [Part3], Section 5.1>
Accept-Charset = Accept-Charset =
<Accept-Charset, defined in [Part3], Section 6.2> <Accept-Charset, defined in [Part3], Section 5.2>
Accept-Encoding = Accept-Encoding =
<Accept-Encoding, defined in [Part3], Section 6.3> <Accept-Encoding, defined in [Part3], Section 5.3>
Accept-Language = Accept-Language =
<Accept-Language, defined in [Part3], Section 6.4> <Accept-Language, defined in [Part3], Section 5.4>
ETag = <ETag, defined in [Part4], Section 7.1> ETag = <ETag, defined in [Part4], Section 6.1>
If-Match = <If-Match, defined in [Part4], Section 7.2> If-Match = <If-Match, defined in [Part4], Section 6.2>
If-Modified-Since = If-Modified-Since =
<If-Modified-Since, defined in [Part4], Section 7.3> <If-Modified-Since, defined in [Part4], Section 6.3>
If-None-Match = <If-None-Match, defined in [Part4], Section 7.4> If-None-Match = <If-None-Match, defined in [Part4], Section 6.4>
If-Unmodified-Since = If-Unmodified-Since =
<If-Unmodified-Since, defined in [Part4], Section 7.5> <If-Unmodified-Since, defined in [Part4], Section 6.5>
Accept-Ranges = <Accept-Ranges, defined in [Part5], Section 6.1> Accept-Ranges = <Accept-Ranges, defined in [Part5], Section 5.1>
If-Range = <If-Range, defined in [Part5], Section 6.3> If-Range = <If-Range, defined in [Part5], Section 5.3>
Range = <Range, defined in [Part5], Section 6.4> Range = <Range, defined in [Part5], Section 5.4>
Age = <Age, defined in [Part6], Section 3.1>
Vary = <Vary, defined in [Part6], Section 3.5>
Age = <Age, defined in [Part6], Section 16.1> Authorization = <Authorization, defined in [Part7], Section 3.1>
Vary = <Vary, defined in [Part6], Section 16.5>
Authorization = <Authorization, defined in [Part7], Section 4.1>
Proxy-Authenticate = Proxy-Authenticate =
<Proxy-Authenticate, defined in [Part7], Section 4.2> <Proxy-Authenticate, defined in [Part7], Section 3.2>
Proxy-Authorization = Proxy-Authorization =
<Proxy-Authorization, defined in [Part7], Section 4.3> <Proxy-Authorization, defined in [Part7], Section 3.3>
WWW-Authenticate = WWW-Authenticate =
<WWW-Authenticate, defined in [Part7], Section 4.4> <WWW-Authenticate, defined in [Part7], Section 3.4>
3. Method 2. Method
The Method token indicates the method to be performed on the resource The Method token indicates the method to be performed on the resource
identified by the Request-URI. The method is case-sensitive. identified by the request-target. The method is case-sensitive.
Method = %x4F.50.54.49.4F.4E.53 ; "OPTIONS", Section 8.2 Method = %x4F.50.54.49.4F.4E.53 ; "OPTIONS", Section 7.2
/ %x47.45.54 ; "GET", Section 8.3 / %x47.45.54 ; "GET", Section 7.3
/ %x48.45.41.44 ; "HEAD", Section 8.4 / %x48.45.41.44 ; "HEAD", Section 7.4
/ %x50.4F.53.54 ; "POST", Section 8.5 / %x50.4F.53.54 ; "POST", Section 7.5
/ %x50.55.54 ; "PUT", Section 8.6 / %x50.55.54 ; "PUT", Section 7.6
/ %x44.45.4C.45.54.45 ; "DELETE", Section 8.7 / %x44.45.4C.45.54.45 ; "DELETE", Section 7.7
/ %x54.52.41.43.45 ; "TRACE", Section 8.8 / %x54.52.41.43.45 ; "TRACE", Section 7.8
/ %x43.4F.4E.4E.45.43.54 ; "CONNECT", Section 8.9 / %x43.4F.4E.4E.45.43.54 ; "CONNECT", Section 7.9
/ extension-method / extension-method
extension-method = token extension-method = token
The list of methods allowed by a resource can be specified in an The list of methods allowed by a resource can be specified in an
Allow header field (Section 10.1). The return code of the response Allow header field (Section 9.1). The return code of the response
always notifies the client whether a method is currently allowed on a always notifies the client whether a method is currently allowed on a
resource, since the set of allowed methods can change dynamically. resource, since the set of allowed methods can change dynamically.
An origin server SHOULD return the status code 405 (Method Not An origin server SHOULD return the status code 405 (Method Not
Allowed) if the method is known by the origin server but not allowed Allowed) if the method is known by the origin server but not allowed
for the requested resource, and 501 (Not Implemented) if the method for the requested resource, and 501 (Not Implemented) if the method
is unrecognized or not implemented by the origin server. The methods is unrecognized or not implemented by the origin server. The methods
GET and HEAD MUST be supported by all general-purpose servers. All GET and HEAD MUST be supported by all general-purpose servers. All
other methods are OPTIONAL; however, if the above methods are other methods are OPTIONAL; however, if the above methods are
implemented, they MUST be implemented with the same semantics as implemented, they MUST be implemented with the same semantics as
those specified in Section 8. those specified in Section 7.
3.1. Method Registry 2.1. Method Registry
The HTTP Method Registry defines the name space for the Method token The HTTP Method Registry defines the name space for the Method token
in the Request line of an HTTP request. in the Request line of an HTTP request.
Registrations MUST include the following fields: Registrations MUST include the following fields:
o Method Name (see Section 3) o Method Name (see Section 2)
o Safe ("yes" or "no", see Section 8.1.1)
o Safe ("yes" or "no", see Section 7.1.1)
o Pointer to specification text o Pointer to specification text
Values to be added to this name space are subject to IETF review Values to be added to this name space are subject to IETF review
([RFC5226], Section 4.1). Any document registering new method names ([RFC5226], Section 4.1). Any document registering new method names
should be traceable through statuses of either 'Obsoletes' or should be traceable through statuses of either 'Obsoletes' or
'Updates' to this document. 'Updates' to this document.
The registry itself is maintained at The registry itself is maintained at
<http://www.iana.org/assignments/http-methods>. <http://www.iana.org/assignments/http-methods>.
4. Request Header Fields 3. Request Header Fields
The request-header fields allow the client to pass additional The request-header fields allow the client to pass additional
information about the request, and about the client itself, to the information about the request, and about the client itself, to the
server. These fields act as request modifiers, with semantics server. These fields act as request modifiers, with semantics
equivalent to the parameters on a programming language method equivalent to the parameters on a programming language method
invocation. invocation.
request-header = Accept ; [Part3], Section 6.1 request-header = Accept ; [Part3], Section 5.1
/ Accept-Charset ; [Part3], Section 6.2 / Accept-Charset ; [Part3], Section 5.2
/ Accept-Encoding ; [Part3], Section 6.3 / Accept-Encoding ; [Part3], Section 5.3
/ Accept-Language ; [Part3], Section 6.4 / Accept-Language ; [Part3], Section 5.4
/ Authorization ; [Part7], Section 4.1 / Authorization ; [Part7], Section 3.1
/ Expect ; Section 10.2 / Expect ; Section 9.2
/ From ; Section 10.3 / From ; Section 9.3
/ Host ; [Part1], Section 8.4 / Host ; [Part1], Section 8.4
/ If-Match ; [Part4], Section 7.2 / If-Match ; [Part4], Section 6.2
/ If-Modified-Since ; [Part4], Section 7.3 / If-Modified-Since ; [Part4], Section 6.3
/ If-None-Match ; [Part4], Section 7.4 / If-None-Match ; [Part4], Section 6.4
/ If-Range ; [Part5], Section 6.3 / If-Range ; [Part5], Section 5.3
/ If-Unmodified-Since ; [Part4], Section 7.5 / If-Unmodified-Since ; [Part4], Section 6.5
/ Max-Forwards ; Section 10.5 / Max-Forwards ; Section 9.5
/ Proxy-Authorization ; [Part7], Section 4.3 / Proxy-Authorization ; [Part7], Section 3.3
/ Range ; [Part5], Section 6.4 / Range ; [Part5], Section 5.4
/ Referer ; Section 10.6 / Referer ; Section 9.6
/ TE ; [Part1], Section 8.8 / TE ; [Part1], Section 8.8
/ User-Agent ; Section 10.9 / User-Agent ; Section 9.9
Request-header field names can be extended reliably only in Request-header field names can be extended reliably only in
combination with a change in the protocol version. However, new or combination with a change in the protocol version. However, new or
experimental header fields MAY be given the semantics of request- experimental header fields MAY be given the semantics of request-
header fields if all parties in the communication recognize them to header fields if all parties in the communication recognize them to
be request-header fields. Unrecognized header fields are treated as be request-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
5. Status Code and Reason Phrase 4. Status Code and Reason Phrase
The Status-Code element is a 3-digit integer result code of the The Status-Code element is a 3-digit integer result code of the
attempt to understand and satisfy the request. The status codes attempt to understand and satisfy the request. The status codes
listed below are defined in Section 9. The Reason-Phrase is intended listed below are defined in Section 8. The Reason-Phrase is intended
to give a short textual description of the Status-Code. The Status- to give a short textual description of the Status-Code. The Status-
Code is intended for use by automata and the Reason-Phrase is Code is intended for use by automata and the Reason-Phrase is
intended for the human user. The client is not required to examine intended for the human user. The client is not required to examine
or display the Reason-Phrase. or display the Reason-Phrase.
The individual values of the numeric status codes defined for The individual values of the numeric status codes defined for
HTTP/1.1, and an example set of corresponding Reason-Phrase's, are HTTP/1.1, and an example set of corresponding Reason-Phrase's, are
presented below. The reason phrases listed here are only presented below. The reason phrases listed here are only
recommendations -- they MAY be replaced by local equivalents without recommendations -- they MAY be replaced by local equivalents without
affecting the protocol. affecting the protocol.
Status-Code = Status-Code =
"100" ; Section 9.1.1: Continue "100" ; Section 8.1.1: Continue
/ "101" ; Section 9.1.2: Switching Protocols / "101" ; Section 8.1.2: Switching Protocols
/ "200" ; Section 9.2.1: OK / "200" ; Section 8.2.1: OK
/ "201" ; Section 9.2.2: Created / "201" ; Section 8.2.2: Created
/ "202" ; Section 9.2.3: Accepted / "202" ; Section 8.2.3: Accepted
/ "203" ; Section 9.2.4: Non-Authoritative Information / "203" ; Section 8.2.4: Non-Authoritative Information
/ "204" ; Section 9.2.5: No Content / "204" ; Section 8.2.5: No Content
/ "205" ; Section 9.2.6: Reset Content / "205" ; Section 8.2.6: Reset Content
/ "206" ; Section 9.2.7: Partial Content / "206" ; Section 8.2.7: Partial Content
/ "300" ; Section 9.3.1: Multiple Choices / "300" ; Section 8.3.1: Multiple Choices
/ "301" ; Section 9.3.2: Moved Permanently / "301" ; Section 8.3.2: Moved Permanently
/ "302" ; Section 9.3.3: Found / "302" ; Section 8.3.3: Found
/ "303" ; Section 9.3.4: See Other / "303" ; Section 8.3.4: See Other
/ "304" ; Section 9.3.5: Not Modified / "304" ; Section 8.3.5: Not Modified
/ "305" ; Section 9.3.6: Use Proxy / "305" ; Section 8.3.6: Use Proxy
/ "307" ; Section 9.3.8: Temporary Redirect / "307" ; Section 8.3.8: Temporary Redirect
/ "400" ; Section 9.4.1: Bad Request / "400" ; Section 8.4.1: Bad Request
/ "401" ; Section 9.4.2: Unauthorized / "401" ; Section 8.4.2: Unauthorized
/ "402" ; Section 9.4.3: Payment Required / "402" ; Section 8.4.3: Payment Required
/ "403" ; Section 9.4.4: Forbidden / "403" ; Section 8.4.4: Forbidden
/ "404" ; Section 9.4.5: Not Found / "404" ; Section 8.4.5: Not Found
/ "405" ; Section 9.4.6: Method Not Allowed / "405" ; Section 8.4.6: Method Not Allowed
/ "406" ; Section 9.4.7: Not Acceptable / "406" ; Section 8.4.7: Not Acceptable
/ "407" ; Section 9.4.8: Proxy Authentication Required / "407" ; Section 8.4.8: Proxy Authentication Required
/ "408" ; Section 9.4.9: Request Time-out / "408" ; Section 8.4.9: Request Time-out
/ "409" ; Section 9.4.10: Conflict / "409" ; Section 8.4.10: Conflict
/ "410" ; Section 9.4.11: Gone / "410" ; Section 8.4.11: Gone
/ "411" ; Section 9.4.12: Length Required / "411" ; Section 8.4.12: Length Required
/ "412" ; Section 9.4.13: Precondition Failed / "412" ; Section 8.4.13: Precondition Failed
/ "413" ; Section 9.4.14: Request Entity Too Large / "413" ; Section 8.4.14: Request Entity Too Large
/ "414" ; Section 9.4.15: Request-URI Too Large / "414" ; Section 8.4.15: URI Too Long
/ "415" ; Section 9.4.16: Unsupported Media Type / "415" ; Section 8.4.16: Unsupported Media Type
/ "416" ; Section 9.4.17: Requested range not satisfiable / "416" ; Section 8.4.17: Requested range not satisfiable
/ "417" ; Section 9.4.18: Expectation Failed / "417" ; Section 8.4.18: Expectation Failed
/ "500" ; Section 9.5.1: Internal Server Error / "500" ; Section 8.5.1: Internal Server Error
/ "501" ; Section 9.5.2: Not Implemented / "501" ; Section 8.5.2: Not Implemented
/ "502" ; Section 9.5.3: Bad Gateway / "502" ; Section 8.5.3: Bad Gateway
/ "503" ; Section 9.5.4: Service Unavailable / "503" ; Section 8.5.4: Service Unavailable
/ "504" ; Section 9.5.5: Gateway Time-out / "504" ; Section 8.5.5: Gateway Time-out
/ "505" ; Section 9.5.6: HTTP Version not supported / "505" ; Section 8.5.6: HTTP Version not supported
/ extension-code / extension-code
extension-code = 3DIGIT extension-code = 3DIGIT
Reason-Phrase = *<TEXT, excluding CR, LF> Reason-Phrase = *( WSP / VCHAR / obs-text )
HTTP status codes are extensible. HTTP applications are not required HTTP status codes are extensible. HTTP applications are not required
to understand the meaning of all registered status codes, though such to understand the meaning of all registered status codes, though such
understanding is obviously desirable. However, applications MUST understanding is obviously desirable. However, applications MUST
understand the class of any status code, as indicated by the first understand the class of any status code, as indicated by the first
digit, and treat any unrecognized response as being equivalent to the digit, and treat any unrecognized response as being equivalent to the
x00 status code of that class, with the exception that an x00 status code of that class, with the exception that an
unrecognized response MUST NOT be cached. For example, if an unrecognized response MUST NOT be cached. For example, if an
unrecognized status code of 431 is received by the client, it can unrecognized status code of 431 is received by the client, it can
safely assume that there was something wrong with its request and safely assume that there was something wrong with its request and
treat the response as if it had received a 400 status code. In such treat the response as if it had received a 400 status code. In such
cases, user agents SHOULD present to the user the entity returned cases, user agents SHOULD present to the user the entity returned
with the response, since that entity is likely to include human- with the response, since that entity is likely to include human-
readable information which will explain the unusual status. readable information which will explain the unusual status.
5.1. Status Code Registry 4.1. Status Code Registry
The HTTP Status Code Registry defines the name space for the Status- The HTTP Status Code Registry defines the name space for the Status-
Code token in the Status line of an HTTP response. Code token in the Status line of an HTTP response.
Values to be added to this name space are subject to IETF review Values to be added to this name space are subject to IETF review
([RFC5226], Section 4.1). Any document registering new status codes ([RFC5226], Section 4.1). Any document registering new status codes
should be traceable through statuses of either 'Obsoletes' or should be traceable through statuses of either 'Obsoletes' or
'Updates' to this document. 'Updates' to this document.
The registry itself is maintained at The registry itself is maintained at
<http://www.iana.org/assignments/http-status-codes>. <http://www.iana.org/assignments/http-status-codes>.
6. Response Header Fields 5. Response Header Fields
The response-header fields allow the server to pass additional The response-header fields allow the server to pass additional
information about the response which cannot be placed in the Status- information about the response which cannot be placed in the Status-
Line. These header fields give information about the server and Line. These header fields give information about the server and
about further access to the resource identified by the Request-URI. about further access to the resource identified by the request-
target.
response-header = Accept-Ranges ; [Part5], Section 6.1 response-header = Accept-Ranges ; [Part5], Section 5.1
/ Age ; [Part6], Section 16.1 / Age ; [Part6], Section 3.1
/ Allow ; Section 10.1 / Allow ; Section 9.1
/ ETag ; [Part4], Section 7.1 / ETag ; [Part4], Section 6.1
/ Location ; Section 10.4 / Location ; Section 9.4
/ Proxy-Authenticate ; [Part7], Section 4.2 / Proxy-Authenticate ; [Part7], Section 3.2
/ Retry-After ; Section 10.7 / Retry-After ; Section 9.7
/ Server ; Section 10.8 / Server ; Section 9.8
/ Vary ; [Part6], Section 16.5 / Vary ; [Part6], Section 3.5
/ WWW-Authenticate ; [Part7], Section 4.4 / WWW-Authenticate ; [Part7], Section 3.4
Response-header field names can be extended reliably only in Response-header field names can be extended reliably only in
combination with a change in the protocol version. However, new or combination with a change in the protocol version. However, new or
experimental header fields MAY be given the semantics of response- experimental header fields MAY be given the semantics of response-
header fields if all parties in the communication recognize them to header fields if all parties in the communication recognize them to
be response-header fields. Unrecognized header fields are treated as be response-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
7. Entity 6. Entity
Request and Response messages MAY transfer an entity if not otherwise Request and Response messages MAY transfer an entity if not otherwise
restricted by the request method or response status code. An entity restricted by the request method or response status code. An entity
consists of entity-header fields and an entity-body, although some consists of entity-header fields and an entity-body, although some
responses will only include the entity-headers. HTTP entity-body and responses will only include the entity-headers. HTTP entity-body and
entity-header fields are defined in [Part3]. entity-header fields are defined in [Part3].
An entity-body is only present in a message when a message-body is An entity-body is only present in a message when a message-body is
present, as described in Section 4.3 of [Part1]. The entity-body is present, as described in Section 4.3 of [Part1]. The entity-body is
obtained from the message-body by decoding any Transfer-Encoding that obtained from the message-body by decoding any Transfer-Encoding that
might have been applied to ensure safe and proper transfer of the might have been applied to ensure safe and proper transfer of the
message. message.
8. Method Definitions 7. Method Definitions
The set of common methods for HTTP/1.1 is defined below. Although The set of common methods for HTTP/1.1 is defined below. Although
this set can be expanded, additional methods cannot be assumed to this set can be expanded, additional methods cannot be assumed to
share the same semantics for separately extended clients and servers. share the same semantics for separately extended clients and servers.
8.1. Safe and Idempotent Methods 7.1. Safe and Idempotent Methods
8.1.1. Safe Methods 7.1.1. Safe Methods
Implementors should be aware that the software represents the user in Implementors should be aware that the software represents the user in
their interactions over the Internet, and should be careful to allow their interactions over the Internet, and should be careful to allow
the user to be aware of any actions they might take which may have an the user to be aware of any actions they might take which may have an
unexpected significance to themselves or others. unexpected significance to themselves or others.
In particular, the convention has been established that the GET and In particular, the convention has been established that the GET and
HEAD methods SHOULD NOT have the significance of taking an action HEAD methods SHOULD NOT have the significance of taking an action
other than retrieval. These methods ought to be considered "safe". other than retrieval. These methods ought to be considered "safe".
This allows user agents to represent other methods, such as POST, PUT This allows user agents to represent other methods, such as POST, PUT
and DELETE, in a special way, so that the user is made aware of the and DELETE, in a special way, so that the user is made aware of the
fact that a possibly unsafe action is being requested. fact that a possibly unsafe action is being requested.
Naturally, it is not possible to ensure that the server does not Naturally, it is not possible to ensure that the server does not
generate side-effects as a result of performing a GET request; in generate side-effects as a result of performing a GET request; in
fact, some dynamic resources consider that a feature. The important fact, some dynamic resources consider that a feature. The important
distinction here is that the user did not request the side-effects, distinction here is that the user did not request the side-effects,
so therefore cannot be held accountable for them. so therefore cannot be held accountable for them.
8.1.2. Idempotent Methods 7.1.2. Idempotent Methods
Methods can also have the property of "idempotence" in that (aside Methods can also have the property of "idempotence" in that (aside
from error or expiration issues) the side-effects of N > 0 identical from error or expiration issues) the side-effects of N > 0 identical
requests is the same as for a single request. The methods GET, HEAD, requests is the same as for a single request. The methods GET, HEAD,
PUT and DELETE share this property. Also, the methods OPTIONS and PUT and DELETE share this property. Also, the methods OPTIONS and
TRACE SHOULD NOT have side effects, and so are inherently idempotent. TRACE SHOULD NOT have side effects, and so are inherently idempotent.
However, it is possible that a sequence of several requests is non- However, it is possible that a sequence of several requests is non-
idempotent, even if all of the methods executed in that sequence are idempotent, even if all of the methods executed in that sequence are
idempotent. (A sequence is idempotent if a single execution of the idempotent. (A sequence is idempotent if a single execution of the
entire sequence always yields a result that is not changed by a entire sequence always yields a result that is not changed by a
reexecution of all, or part, of that sequence.) For example, a reexecution of all, or part, of that sequence.) For example, a
sequence is non-idempotent if its result depends on a value that is sequence is non-idempotent if its result depends on a value that is
later modified in the same sequence. later modified in the same sequence.
A sequence that never has side effects is idempotent, by definition A sequence that never has side effects is idempotent, by definition
(provided that no concurrent operations are being executed on the (provided that no concurrent operations are being executed on the
same set of resources). same set of resources).
8.2. OPTIONS 7.2. OPTIONS
The OPTIONS method represents a request for information about the The OPTIONS method represents a request for information about the
communication options available on the request/response chain communication options available on the request/response chain
identified by the Request-URI. This method allows the client to identified by the request-target. This method allows the client to
determine the options and/or requirements associated with a resource, determine the options and/or requirements associated with a resource,
or the capabilities of a server, without implying a resource action or the capabilities of a server, without implying a resource action
or initiating a resource retrieval. or initiating a resource retrieval.
Responses to this method are not cacheable. Responses to this method are not cacheable.
If the OPTIONS request includes an entity-body (as indicated by the If the OPTIONS request includes an entity-body (as indicated by the
presence of Content-Length or Transfer-Encoding), then the media type presence of Content-Length or Transfer-Encoding), then the media type
MUST be indicated by a Content-Type field. Although this MUST be indicated by a Content-Type field. Although this
specification does not define any use for such a body, future specification does not define any use for such a body, future
extensions to HTTP might use the OPTIONS body to make more detailed extensions to HTTP might use the OPTIONS body to make more detailed
queries on the server. queries on the server.
If the Request-URI is an asterisk ("*"), the OPTIONS request is If the request-target is an asterisk ("*"), the OPTIONS request is
intended to apply to the server in general rather than to a specific intended to apply to the server in general rather than to a specific
resource. Since a server's communication options typically depend on resource. Since a server's communication options typically depend on
the resource, the "*" request is only useful as a "ping" or "no-op" the resource, the "*" request is only useful as a "ping" or "no-op"
type of method; it does nothing beyond allowing the client to test type of method; it does nothing beyond allowing the client to test
the capabilities of the server. For example, this can be used to the capabilities of the server. For example, this can be used to
test a proxy for HTTP/1.1 compliance (or lack thereof). test a proxy for HTTP/1.1 compliance (or lack thereof).
If the Request-URI is not an asterisk, the OPTIONS request applies If the request-target is not an asterisk, the OPTIONS request applies
only to the options that are available when communicating with that only to the options that are available when communicating with that
resource. resource.
A 200 response SHOULD include any header fields that indicate A 200 response SHOULD include any header fields that indicate
optional features implemented by the server and applicable to that optional features implemented by the server and applicable to that
resource (e.g., Allow), possibly including extensions not defined by resource (e.g., Allow), possibly including extensions not defined by
this specification. The response body, if any, SHOULD also include this specification. The response body, if any, SHOULD also include
information about the communication options. The format for such a information about the communication options. The format for such a
body is not defined by this specification, but might be defined by body is not defined by this specification, but might be defined by
future extensions to HTTP. Content negotiation MAY be used to select future extensions to HTTP. Content negotiation MAY be used to select
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OPTIONS request on an absolute-URI for which request forwarding is OPTIONS request on an absolute-URI for which request forwarding is
permitted, the proxy MUST check for a Max-Forwards field. If the permitted, the proxy MUST check for a Max-Forwards field. If the
Max-Forwards field-value is zero ("0"), the proxy MUST NOT forward Max-Forwards field-value is zero ("0"), the proxy MUST NOT forward
the message; instead, the proxy SHOULD respond with its own the message; instead, the proxy SHOULD respond with its own
communication options. If the Max-Forwards field-value is an integer communication options. If the Max-Forwards field-value is an integer
greater than zero, the proxy MUST decrement the field-value when it greater than zero, the proxy MUST decrement the field-value when it
forwards the request. If no Max-Forwards field is present in the forwards the request. If no Max-Forwards field is present in the
request, then the forwarded request MUST NOT include a Max-Forwards request, then the forwarded request MUST NOT include a Max-Forwards
field. field.
8.3. GET 7.3. GET
The GET method means retrieve whatever information (in the form of an The GET method means retrieve whatever information (in the form of an
entity) is identified by the Request-URI. If the Request-URI refers entity) is identified by the request-target. If the request-target
to a data-producing process, it is the produced data which shall be refers to a data-producing process, it is the produced data which
returned as the entity in the response and not the source text of the shall be returned as the entity in the response and not the source
process, unless that text happens to be the output of the process. text of the process, unless that text happens to be the output of the
process.
The semantics of the GET method change to a "conditional GET" if the The semantics of the GET method change to a "conditional GET" if the
request message includes an If-Modified-Since, If-Unmodified-Since, request message includes an If-Modified-Since, If-Unmodified-Since,
If-Match, If-None-Match, or If-Range header field. A conditional GET If-Match, If-None-Match, or If-Range header field. A conditional GET
method requests that the entity be transferred only under the method requests that the entity be transferred only under the
circumstances described by the conditional header field(s). The circumstances described by the conditional header field(s). The
conditional GET method is intended to reduce unnecessary network conditional GET method is intended to reduce unnecessary network
usage by allowing cached entities to be refreshed without requiring usage by allowing cached entities to be refreshed without requiring
multiple requests or transferring data already held by the client. multiple requests or transferring data already held by the client.
The semantics of the GET method change to a "partial GET" if the The semantics of the GET method change to a "partial GET" if the
request message includes a Range header field. A partial GET request message includes a Range header field. A partial GET
requests that only part of the entity be transferred, as described in requests that only part of the entity be transferred, as described in
Section 6.4 of [Part5]. The partial GET method is intended to reduce Section 5.4 of [Part5]. The partial GET method is intended to reduce
unnecessary network usage by allowing partially-retrieved entities to unnecessary network usage by allowing partially-retrieved entities to
be completed without transferring data already held by the client. be completed without transferring data already held by the client.
The response to a GET request is cacheable if and only if it meets The response to a GET request is cacheable if and only if it meets
the requirements for HTTP caching described in [Part6]. the requirements for HTTP caching described in [Part6].
See Section 12.2 for security considerations when used for forms. See Section 11.2 for security considerations when used for forms.
8.4. HEAD 7.4. HEAD
The HEAD method is identical to GET except that the server MUST NOT The HEAD method is identical to GET except that the server MUST NOT
return a message-body in the response. The metainformation contained return a message-body in the response. The metainformation contained
in the HTTP headers in response to a HEAD request SHOULD be identical in the HTTP headers in response to a HEAD request SHOULD be identical
to the information sent in response to a GET request. This method to the information sent in response to a GET request. This method
can be used for obtaining metainformation about the entity implied by can be used for obtaining metainformation about the entity implied by
the request without transferring the entity-body itself. This method the request without transferring the entity-body itself. This method
is often used for testing hypertext links for validity, is often used for testing hypertext links for validity,
accessibility, and recent modification. accessibility, and recent modification.
The response to a HEAD request MAY be cacheable in the sense that the The response to a HEAD request MAY be cacheable in the sense that the
information contained in the response MAY be used to update a information contained in the response MAY be used to update a
previously cached entity from that resource. If the new field values previously cached entity from that resource. If the new field values
indicate that the cached entity differs from the current entity (as indicate that the cached entity differs from the current entity (as
would be indicated by a change in Content-Length, Content-MD5, ETag would be indicated by a change in Content-Length, Content-MD5, ETag
or Last-Modified), then the cache MUST treat the cache entry as or Last-Modified), then the cache MUST treat the cache entry as
stale. stale.
8.5. POST 7.5. POST
The POST method is used to request that the origin server accept the The POST method is used to request that the origin server accept the
entity enclosed in the request as data to be processed by the entity enclosed in the request as data to be processed by the
resource identified by the Request-URI in the Request-Line. POST is resource identified by the request-target in the Request-Line. POST
designed to allow a uniform method to cover the following functions: is designed to allow a uniform method to cover the following
functions:
o Annotation of existing resources; o Annotation of existing resources;
o Posting a message to a bulletin board, newsgroup, mailing list, or o Posting a message to a bulletin board, newsgroup, mailing list, or
similar group of articles; similar group of articles;
o Providing a block of data, such as the result of submitting a o Providing a block of data, such as the result of submitting a
form, to a data-handling process; form, to a data-handling process;
o Extending a database through an append operation. o Extending a database through an append operation.
The actual function performed by the POST method is determined by the The actual function performed by the POST method is determined by the
server and is usually dependent on the Request-URI. server and is usually dependent on the request-target.
The action performed by the POST method might not result in a The action performed by the POST method might not result in a
resource that can be identified by a URI. In this case, either 200 resource that can be identified by a URI. In this case, either 200
(OK) or 204 (No Content) is the appropriate response status, (OK) or 204 (No Content) is the appropriate response status,
depending on whether or not the response includes an entity that depending on whether or not the response includes an entity that
describes the result. describes the result.
If a resource has been created on the origin server, the response If a resource has been created on the origin server, the response
SHOULD be 201 (Created) and contain an entity which describes the SHOULD be 201 (Created) and contain an entity which describes the
status of the request and refers to the new resource, and a Location status of the request and refers to the new resource, and a Location
header (see Section 10.4). header (see Section 9.4).
Responses to this method are not cacheable, unless the response Responses to this method are not cacheable, unless the response
includes appropriate Cache-Control or Expires header fields. includes appropriate Cache-Control or Expires header fields.
However, the 303 (See Other) response can be used to direct the user However, the 303 (See Other) response can be used to direct the user
agent to retrieve a cacheable resource. agent to retrieve a cacheable resource.
8.6. PUT 7.6. PUT
The PUT method requests that the enclosed entity be stored at the The PUT method requests that the enclosed entity be stored at the
supplied Request-URI. If the Request-URI refers to an already supplied request-target. If the request-target refers to an already
existing resource, the enclosed entity SHOULD be considered as a existing resource, the enclosed entity SHOULD be considered as a
modified version of the one residing on the origin server. If the modified version of the one residing on the origin server. If the
Request-URI does not point to an existing resource, and that URI is request-target does not point to an existing resource, and that URI
capable of being defined as a new resource by the requesting user is capable of being defined as a new resource by the requesting user
agent, the origin server can create the resource with that URI. If a agent, the origin server can create the resource with that URI. If a
new resource is created at the Request-URI, the origin server MUST new resource is created at the request-target, the origin server MUST
inform the user agent via the 201 (Created) response. If an existing inform the user agent via the 201 (Created) response. If an existing
resource is modified, either the 200 (OK) or 204 (No Content) resource is modified, either the 200 (OK) or 204 (No Content)
response codes SHOULD be sent to indicate successful completion of response codes SHOULD be sent to indicate successful completion of
the request. If the resource could not be created or modified with the request. If the resource could not be created or modified with
the Request-URI, an appropriate error response SHOULD be given that the request-target, an appropriate error response SHOULD be given
reflects the nature of the problem. The recipient of the entity MUST that reflects the nature of the problem. The recipient of the entity
NOT ignore any Content-* headers (headers starting with the prefix MUST NOT ignore any Content-* headers (headers starting with the
'Content-') that it does not understand or implement and MUST return prefix 'Content-') that it does not understand or implement and MUST
a 501 (Not Implemented) response in such cases. return a 501 (Not Implemented) response in such cases.
If the request passes through a cache and the Request-URI identifies If the request passes through a cache and the request-target
one or more currently cached entities, those entries SHOULD be identifies one or more currently cached entities, those entries
treated as stale. Responses to this method are not cacheable. SHOULD be treated as stale. Responses to this method are not
cacheable.
The fundamental difference between the POST and PUT requests is The fundamental difference between the POST and PUT requests is
reflected in the different meaning of the Request-URI. The URI in a reflected in the different meaning of the request-target. The URI in
POST request identifies the resource that will handle the enclosed a POST request identifies the resource that will handle the enclosed
entity. That resource might be a data-accepting process, a gateway entity. That resource might be a data-accepting process, a gateway
to some other protocol, or a separate entity that accepts to some other protocol, or a separate entity that accepts
annotations. In contrast, the URI in a PUT request identifies the annotations. In contrast, the URI in a PUT request identifies the
entity enclosed with the request -- the user agent knows what URI is entity enclosed with the request -- the user agent knows what URI is
intended and the server MUST NOT attempt to apply the request to some intended and the server MUST NOT attempt to apply the request to some
other resource. If the server desires that the request be applied to other resource. If the server desires that the request be applied to
a different URI, it MUST send a 301 (Moved Permanently) response; the a different URI, it MUST send a 301 (Moved Permanently) response; the
user agent MAY then make its own decision regarding whether or not to user agent MAY then make its own decision regarding whether or not to
redirect the request. redirect the request.
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version. In this case, a PUT request on a general URI might result version. In this case, a PUT request on a general URI might result
in several other URIs being defined by the origin server. in several other URIs being defined by the origin server.
HTTP/1.1 does not define how a PUT method affects the state of an HTTP/1.1 does not define how a PUT method affects the state of an
origin server. origin server.
Unless otherwise specified for a particular entity-header, the Unless otherwise specified for a particular entity-header, the
entity-headers in the PUT request SHOULD be applied to the resource entity-headers in the PUT request SHOULD be applied to the resource
created or modified by the PUT. created or modified by the PUT.
8.7. DELETE 7.7. DELETE
The DELETE method requests that the origin server delete the resource The DELETE method requests that the origin server delete the resource
identified by the Request-URI. This method MAY be overridden by identified by the request-target. This method MAY be overridden by
human intervention (or other means) on the origin server. The client human intervention (or other means) on the origin server. The client
cannot be guaranteed that the operation has been carried out, even if cannot be guaranteed that the operation has been carried out, even if
the status code returned from the origin server indicates that the the status code returned from the origin server indicates that the
action has been completed successfully. However, the server SHOULD action has been completed successfully. However, the server SHOULD
NOT indicate success unless, at the time the response is given, it NOT indicate success unless, at the time the response is given, it
intends to delete the resource or move it to an inaccessible intends to delete the resource or move it to an inaccessible
location. location.
A successful response SHOULD be 200 (OK) if the response includes an A successful response SHOULD be 200 (OK) if the response includes an
entity describing the status, 202 (Accepted) if the action has not entity describing the status, 202 (Accepted) if the action has not
yet been enacted, or 204 (No Content) if the action has been enacted yet been enacted, or 204 (No Content) if the action has been enacted
but the response does not include an entity. but the response does not include an entity.
If the request passes through a cache and the Request-URI identifies If the request passes through a cache and the request-target
one or more currently cached entities, those entries SHOULD be identifies one or more currently cached entities, those entries
treated as stale. Responses to this method are not cacheable. SHOULD be treated as stale. Responses to this method are not
cacheable.
8.8. TRACE 7.8. TRACE
The TRACE method is used to invoke a remote, application-layer loop- The TRACE method is used to invoke a remote, application-layer loop-
back of the request message. The final recipient of the request back of the request message. The final recipient of the request
SHOULD reflect the message received back to the client as the entity- SHOULD reflect the message received back to the client as the entity-
body of a 200 (OK) response. The final recipient is either the body of a 200 (OK) response. The final recipient is either the
origin server or the first proxy or gateway to receive a Max-Forwards origin server or the first proxy or gateway to receive a Max-Forwards
value of zero (0) in the request (see Section 10.5). A TRACE request value of zero (0) in the request (see Section 9.5). A TRACE request
MUST NOT include an entity. MUST NOT include an entity.
TRACE allows the client to see what is being received at the other TRACE allows the client to see what is being received at the other
end of the request chain and use that data for testing or diagnostic end of the request chain and use that data for testing or diagnostic
information. The value of the Via header field (Section 8.9 of information. The value of the Via header field (Section 8.9 of
[Part1]) is of particular interest, since it acts as a trace of the [Part1]) is of particular interest, since it acts as a trace of the
request chain. Use of the Max-Forwards header field allows the request chain. Use of the Max-Forwards header field allows the
client to limit the length of the request chain, which is useful for client to limit the length of the request chain, which is useful for
testing a chain of proxies forwarding messages in an infinite loop. testing a chain of proxies forwarding messages in an infinite loop.
If the request is valid, the response SHOULD contain the entire If the request is valid, the response SHOULD contain the entire
request message in the entity-body, with a Content-Type of "message/ request message in the entity-body, with a Content-Type of "message/
http" (see Section 9.3.1 of [Part1]). Responses to this method MUST http" (see Section 9.3.1 of [Part1]). Responses to this method MUST
NOT be cached. NOT be cached.
8.9. CONNECT 7.9. CONNECT
This specification reserves the method name CONNECT for use with a This specification reserves the method name CONNECT for use with a
proxy that can dynamically switch to being a tunnel (e.g. SSL proxy that can dynamically switch to being a tunnel (e.g. SSL
tunneling [RFC2817]). tunneling [RFC2817]).
9. Status Code Definitions 8. Status Code Definitions
Each Status-Code is described below, including a description of which Each Status-Code is described below, including a description of which
method(s) it can follow and any metainformation required in the method(s) it can follow and any metainformation required in the
response. response.
9.1. Informational 1xx 8.1. Informational 1xx
This class of status code indicates a provisional response, This class of status code indicates a provisional response,
consisting only of the Status-Line and optional headers, and is consisting only of the Status-Line and optional headers, and is
terminated by an empty line. There are no required headers for this terminated by an empty line. There are no required headers for this
class of status code. Since HTTP/1.0 did not define any 1xx status class of status code. Since HTTP/1.0 did not define any 1xx status
codes, servers MUST NOT send a 1xx response to an HTTP/1.0 client codes, servers MUST NOT send a 1xx response to an HTTP/1.0 client
except under experimental conditions. except under experimental conditions.
A client MUST be prepared to accept one or more 1xx status responses A client MUST be prepared to accept one or more 1xx status responses
prior to a regular response, even if the client does not expect a 100 prior to a regular response, even if the client does not expect a 100
(Continue) status message. Unexpected 1xx status responses MAY be (Continue) status message. Unexpected 1xx status responses MAY be
ignored by a user agent. ignored by a user agent.
Proxies MUST forward 1xx responses, unless the connection between the Proxies MUST forward 1xx responses, unless the connection between the
proxy and its client has been closed, or unless the proxy itself proxy and its client has been closed, or unless the proxy itself
requested the generation of the 1xx response. (For example, if a requested the generation of the 1xx response. (For example, if a
proxy adds a "Expect: 100-continue" field when it forwards a request, proxy adds a "Expect: 100-continue" field when it forwards a request,
then it need not forward the corresponding 100 (Continue) then it need not forward the corresponding 100 (Continue)
response(s).) response(s).)
9.1.1. 100 Continue 8.1.1. 100 Continue
The client SHOULD continue with its request. This interim response The client SHOULD continue with its request. This interim response
is used to inform the client that the initial part of the request has is used to inform the client that the initial part of the request has
been received and has not yet been rejected by the server. The been received and has not yet been rejected by the server. The
client SHOULD continue by sending the remainder of the request or, if client SHOULD continue by sending the remainder of the request or, if
the request has already been completed, ignore this response. The the request has already been completed, ignore this response. The
server MUST send a final response after the request has been server MUST send a final response after the request has been
completed. See Section 7.2.3 of [Part1] for detailed discussion of completed. See Section 7.2.3 of [Part1] for detailed discussion of
the use and handling of this status code. the use and handling of this status code.
9.1.2. 101 Switching Protocols 8.1.2. 101 Switching Protocols
The server understands and is willing to comply with the client's The server understands and is willing to comply with the client's
request, via the Upgrade message header field (Section 6.4 of request, via the Upgrade message header field (Section 5.4 of
[Part5]), for a change in the application protocol being used on this [Part5]), for a change in the application protocol being used on this
connection. The server will switch protocols to those defined by the connection. The server will switch protocols to those defined by the
response's Upgrade header field immediately after the empty line response's Upgrade header field immediately after the empty line
which terminates the 101 response. which terminates the 101 response.
The protocol SHOULD be switched only when it is advantageous to do The protocol SHOULD be switched only when it is advantageous to do
so. For example, switching to a newer version of HTTP is so. For example, switching to a newer version of HTTP is
advantageous over older versions, and switching to a real-time, advantageous over older versions, and switching to a real-time,
synchronous protocol might be advantageous when delivering resources synchronous protocol might be advantageous when delivering resources
that use such features. that use such features.
9.2. Successful 2xx 8.2. Successful 2xx
This class of status code indicates that the client's request was This class of status code indicates that the client's request was
successfully received, understood, and accepted. successfully received, understood, and accepted.
9.2.1. 200 OK 8.2.1. 200 OK
The request has succeeded. The information returned with the The request has succeeded. The information returned with the
response is dependent on the method used in the request, for example: response is dependent on the method used in the request, for example:
GET an entity corresponding to the requested resource is sent in the GET an entity corresponding to the requested resource is sent in the
response; response;
HEAD the entity-header fields corresponding to the requested HEAD the entity-header fields corresponding to the requested
resource are sent in the response without any message-body; resource are sent in the response without any message-body;
POST an entity describing or containing the result of the action; POST an entity describing or containing the result of the action;
TRACE an entity containing the request message as received by the TRACE an entity containing the request message as received by the
end server. end server.
9.2.2. 201 Created 8.2.2. 201 Created
The request has been fulfilled and resulted in a new resource being The request has been fulfilled and resulted in a new resource being
created. The newly created resource can be referenced by the URI(s) created. The newly created resource can be referenced by the URI(s)
returned in the entity of the response, with the most specific URI returned in the entity of the response, with the most specific URI
for the resource given by a Location header field. The response for the resource given by a Location header field. The response
SHOULD include an entity containing a list of resource SHOULD include an entity containing a list of resource
characteristics and location(s) from which the user or user agent can characteristics and location(s) from which the user or user agent can
choose the one most appropriate. The entity format is specified by choose the one most appropriate. The entity format is specified by
the media type given in the Content-Type header field. The origin the media type given in the Content-Type header field. The origin
server MUST create the resource before returning the 201 status code. server MUST create the resource before returning the 201 status code.
If the action cannot be carried out immediately, the server SHOULD If the action cannot be carried out immediately, the server SHOULD
respond with 202 (Accepted) response instead. respond with 202 (Accepted) response instead.
A 201 response MAY contain an ETag response header field indicating A 201 response MAY contain an ETag response header field indicating
the current value of the entity tag for the requested variant just the current value of the entity tag for the requested variant just
created, see Section 7.1 of [Part4]. created, see Section 6.1 of [Part4].
9.2.3. 202 Accepted 8.2.3. 202 Accepted
The request has been accepted for processing, but the processing has The request has been accepted for processing, but the processing has
not been completed. The request might or might not eventually be not been completed. The request might or might not eventually be
acted upon, as it might be disallowed when processing actually takes acted upon, as it might be disallowed when processing actually takes
place. There is no facility for re-sending a status code from an place. There is no facility for re-sending a status code from an
asynchronous operation such as this. asynchronous operation such as this.
The 202 response is intentionally non-committal. Its purpose is to The 202 response is intentionally non-committal. Its purpose is to
allow a server to accept a request for some other process (perhaps a allow a server to accept a request for some other process (perhaps a
batch-oriented process that is only run once per day) without batch-oriented process that is only run once per day) without
requiring that the user agent's connection to the server persist requiring that the user agent's connection to the server persist
until the process is completed. The entity returned with this until the process is completed. The entity returned with this
response SHOULD include an indication of the request's current status response SHOULD include an indication of the request's current status
and either a pointer to a status monitor or some estimate of when the and either a pointer to a status monitor or some estimate of when the
user can expect the request to be fulfilled. user can expect the request to be fulfilled.
9.2.4. 203 Non-Authoritative Information 8.2.4. 203 Non-Authoritative Information
The returned metainformation in the entity-header is not the The returned metainformation in the entity-header is not the
definitive set as available from the origin server, but is gathered definitive set as available from the origin server, but is gathered
from a local or a third-party copy. The set presented MAY be a from a local or a third-party copy. The set presented MAY be a
subset or superset of the original version. For example, including subset or superset of the original version. For example, including
local annotation information about the resource might result in a local annotation information about the resource might result in a
superset of the metainformation known by the origin server. Use of superset of the metainformation known by the origin server. Use of
this response code is not required and is only appropriate when the this response code is not required and is only appropriate when the
response would otherwise be 200 (OK). response would otherwise be 200 (OK).
9.2.5. 204 No Content 8.2.5. 204 No Content
The server has fulfilled the request but does not need to return an The server has fulfilled the request but does not need to return an
entity-body, and might want to return updated metainformation. The entity-body, and might want to return updated metainformation. The
response MAY include new or updated metainformation in the form of response MAY include new or updated metainformation in the form of
entity-headers, which if present SHOULD be associated with the entity-headers, which if present SHOULD be associated with the
requested variant. requested variant.
If the client is a user agent, it SHOULD NOT change its document view If the client is a user agent, it SHOULD NOT change its document view
from that which caused the request to be sent. This response is from that which caused the request to be sent. This response is
primarily intended to allow input for actions to take place without primarily intended to allow input for actions to take place without
causing a change to the user agent's active document view, although causing a change to the user agent's active document view, although
any new or updated metainformation SHOULD be applied to the document any new or updated metainformation SHOULD be applied to the document
currently in the user agent's active view. currently in the user agent's active view.
The 204 response MUST NOT include a message-body, and thus is always The 204 response MUST NOT include a message-body, and thus is always
terminated by the first empty line after the header fields. terminated by the first empty line after the header fields.
9.2.6. 205 Reset Content 8.2.6. 205 Reset Content
The server has fulfilled the request and the user agent SHOULD reset The server has fulfilled the request and the user agent SHOULD reset
the document view which caused the request to be sent. This response the document view which caused the request to be sent. This response
is primarily intended to allow input for actions to take place via is primarily intended to allow input for actions to take place via
user input, followed by a clearing of the form in which the input is user input, followed by a clearing of the form in which the input is
given so that the user can easily initiate another input action. The given so that the user can easily initiate another input action. The
response MUST NOT include an entity. response MUST NOT include an entity.
9.2.7. 206 Partial Content 8.2.7. 206 Partial Content
The server has fulfilled the partial GET request for the resource and The server has fulfilled the partial GET request for the resource and
the enclosed entity is a partial representation as defined in the enclosed entity is a partial representation as defined in
[Part5]. [Part5].
9.3. Redirection 3xx 8.3. Redirection 3xx
This class of status code indicates that further action needs to be This class of status code indicates that further action needs to be
taken by the user agent in order to fulfill the request. The action taken by the user agent in order to fulfill the request. The action
required MAY be carried out by the user agent without interaction required MAY be carried out by the user agent without interaction
with the user if and only if the method used in the second request is with the user if and only if the method used in the second request is
GET or HEAD. A client SHOULD detect infinite redirection loops, GET or HEAD. A client SHOULD detect infinite redirection loops,
since such loops generate network traffic for each redirection. since such loops generate network traffic for each redirection.
Note: previous versions of this specification recommended a Note: previous versions of this specification recommended a
maximum of five redirections. Content developers should be aware maximum of five redirections. Content developers should be aware
that there might be clients that implement such a fixed that there might be clients that implement such a fixed
limitation. limitation.
9.3.1. 300 Multiple Choices 8.3.1. 300 Multiple Choices
The requested resource corresponds to any one of a set of The requested resource corresponds to any one of a set of
representations, each with its own specific location, and agent- representations, each with its own specific location, and agent-
driven negotiation information (Section 5 of [Part3]) is being driven negotiation information (Section 4 of [Part3]) is being
provided so that the user (or user agent) can select a preferred provided so that the user (or user agent) can select a preferred
representation and redirect its request to that location. representation and redirect its request to that location.
Unless it was a HEAD request, the response SHOULD include an entity Unless it was a HEAD request, the response SHOULD include an entity
containing a list of resource characteristics and location(s) from containing a list of resource characteristics and location(s) from
which the user or user agent can choose the one most appropriate. which the user or user agent can choose the one most appropriate.
The entity format is specified by the media type given in the The entity format is specified by the media type given in the
Content-Type header field. Depending upon the format and the Content-Type header field. Depending upon the format and the
capabilities of the user agent, selection of the most appropriate capabilities of the user agent, selection of the most appropriate
choice MAY be performed automatically. However, this specification choice MAY be performed automatically. However, this specification
does not define any standard for such automatic selection. does not define any standard for such automatic selection.
If the server has a preferred choice of representation, it SHOULD If the server has a preferred choice of representation, it SHOULD
include the specific URI for that representation in the Location include the specific URI for that representation in the Location
field; user agents MAY use the Location field value for automatic field; user agents MAY use the Location field value for automatic
redirection. This response is cacheable unless indicated otherwise. redirection. This response is cacheable unless indicated otherwise.
9.3.2. 301 Moved Permanently 8.3.2. 301 Moved Permanently
The requested resource has been assigned a new permanent URI and any The requested resource has been assigned a new permanent URI and any
future references to this resource SHOULD use one of the returned future references to this resource SHOULD use one of the returned
URIs. Clients with link editing capabilities ought to automatically URIs. Clients with link editing capabilities ought to automatically
re-link references to the Request-URI to one or more of the new re-link references to the request-target to one or more of the new
references returned by the server, where possible. This response is references returned by the server, where possible. This response is
cacheable unless indicated otherwise. cacheable unless indicated otherwise.
The new permanent URI SHOULD be given by the Location field in the The new permanent URI SHOULD be given by the Location field in the
response. Unless the request method was HEAD, the entity of the response. Unless the request method was HEAD, the entity of the
response SHOULD contain a short hypertext note with a hyperlink to response SHOULD contain a short hypertext note with a hyperlink to
the new URI(s). the new URI(s).
If the 301 status code is received in response to a request method If the 301 status code is received in response to a request method
that is known to be "safe", as defined in Section 8.1.1, then the that is known to be "safe", as defined in Section 7.1.1, then the
request MAY be automatically redirected by the user agent without request MAY be automatically redirected by the user agent without
confirmation. Otherwise, the user agent MUST NOT automatically confirmation. Otherwise, the user agent MUST NOT automatically
redirect the request unless it can be confirmed by the user, since redirect the request unless it can be confirmed by the user, since
this might change the conditions under which the request was issued. this might change the conditions under which the request was issued.
Note: When automatically redirecting a POST request after Note: When automatically redirecting a POST request after
receiving a 301 status code, some existing HTTP/1.0 user agents receiving a 301 status code, some existing HTTP/1.0 user agents
will erroneously change it into a GET request. will erroneously change it into a GET request.
9.3.3. 302 Found 8.3.3. 302 Found
The requested resource resides temporarily under a different URI. The requested resource resides temporarily under a different URI.
Since the redirection might be altered on occasion, the client SHOULD Since the redirection might be altered on occasion, the client SHOULD
continue to use the Request-URI for future requests. This response continue to use the request-target for future requests. This
is only cacheable if indicated by a Cache-Control or Expires header response is only cacheable if indicated by a Cache-Control or Expires
field. header field.
The temporary URI SHOULD be given by the Location field in the The temporary URI SHOULD be given by the Location field in the
response. Unless the request method was HEAD, the entity of the response. Unless the request method was HEAD, the entity of the
response SHOULD contain a short hypertext note with a hyperlink to response SHOULD contain a short hypertext note with a hyperlink to
the new URI(s). the new URI(s).
If the 302 status code is received in response to a request method If the 302 status code is received in response to a request method
that is known to be "safe", as defined in Section 8.1.1, then the that is known to be "safe", as defined in Section 7.1.1, then the
request MAY be automatically redirected by the user agent without request MAY be automatically redirected by the user agent without
confirmation. Otherwise, the user agent MUST NOT automatically confirmation. Otherwise, the user agent MUST NOT automatically
redirect the request unless it can be confirmed by the user, since redirect the request unless it can be confirmed by the user, since
this might change the conditions under which the request was issued. this might change the conditions under which the request was issued.
Note: [RFC1945] and [RFC2068] specify that the client is not Note: [RFC1945] and [RFC2068] specify that the client is not
allowed to change the method on the redirected request. However, allowed to change the method on the redirected request. However,
most existing user agent implementations treat 302 as if it were a most existing user agent implementations treat 302 as if it were a
303 response, performing a GET on the Location field-value 303 response, performing a GET on the Location field-value
regardless of the original request method. The status codes 303 regardless of the original request method. The status codes 303
and 307 have been added for servers that wish to make and 307 have been added for servers that wish to make
unambiguously clear which kind of reaction is expected of the unambiguously clear which kind of reaction is expected of the
client. client.
9.3.4. 303 See Other 8.3.4. 303 See Other
The server directs the user agent to a different resource, indicated The server directs the user agent to a different resource, indicated
by a URI in the Location header field, that provides an indirect by a URI in the Location header field, that provides an indirect
response to the original request. The user agent MAY perform a GET response to the original request. The user agent MAY perform a GET
request on the URI in the Location field in order to obtain a request on the URI in the Location field in order to obtain a
representation corresponding to the response, be redirected again, or representation corresponding to the response, be redirected again, or
end with an error status. The Location URI is not a substitute end with an error status. The Location URI is not a substitute
reference for the originally requested resource. reference for the originally requested resource.
The 303 status is generally applicable to any HTTP method. It is The 303 status is generally applicable to any HTTP method. It is
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represents the previously requested resource. Note that answers to represents the previously requested resource. Note that answers to
the questions of what can be represented, what representations are the questions of what can be represented, what representations are
adequate, and what might be a useful description are outside the adequate, and what might be a useful description are outside the
scope of HTTP and thus entirely determined by the resource owner(s). scope of HTTP and thus entirely determined by the resource owner(s).
A 303 response SHOULD NOT be cached unless it is indicated as A 303 response SHOULD NOT be cached unless it is indicated as
cacheable by Cache-Control or Expires header fields. Except for cacheable by Cache-Control or Expires header fields. Except for
responses to a HEAD request, the entity of a 303 response SHOULD responses to a HEAD request, the entity of a 303 response SHOULD
contain a short hypertext note with a hyperlink to the Location URI. contain a short hypertext note with a hyperlink to the Location URI.
9.3.5. 304 Not Modified 8.3.5. 304 Not Modified
The response to the request has not been modified since the The response to the request has not been modified since the
conditions indicated by the client's conditional GET request, as conditions indicated by the client's conditional GET request, as
defined in [Part4]. defined in [Part4].
9.3.6. 305 Use Proxy 8.3.6. 305 Use Proxy
The 305 status was defined in a previous version of this The 305 status was defined in a previous version of this
specification (see Appendix A.2), and is now deprecated. specification (see Appendix A.2), and is now deprecated.
9.3.7. 306 (Unused) 8.3.7. 306 (Unused)
The 306 status code was used in a previous version of the The 306 status code was used in a previous version of the
specification, is no longer used, and the code is reserved. specification, is no longer used, and the code is reserved.
9.3.8. 307 Temporary Redirect 8.3.8. 307 Temporary Redirect
The requested resource resides temporarily under a different URI. The requested resource resides temporarily under a different URI.
Since the redirection MAY be altered on occasion, the client SHOULD Since the redirection MAY be altered on occasion, the client SHOULD
continue to use the Request-URI for future requests. This response continue to use the request-target for future requests. This
is only cacheable if indicated by a Cache-Control or Expires header response is only cacheable if indicated by a Cache-Control or Expires
field. header field.
The temporary URI SHOULD be given by the Location field in the The temporary URI SHOULD be given by the Location field in the
response. Unless the request method was HEAD, the entity of the response. Unless the request method was HEAD, the entity of the
response SHOULD contain a short hypertext note with a hyperlink to response SHOULD contain a short hypertext note with a hyperlink to
the new URI(s) , since many pre-HTTP/1.1 user agents do not the new URI(s) , since many pre-HTTP/1.1 user agents do not
understand the 307 status. Therefore, the note SHOULD contain the understand the 307 status. Therefore, the note SHOULD contain the
information necessary for a user to repeat the original request on information necessary for a user to repeat the original request on
the new URI. the new URI.
If the 307 status code is received in response to a request method If the 307 status code is received in response to a request method
that is known to be "safe", as defined in Section 8.1.1, then the that is known to be "safe", as defined in Section 7.1.1, then the
request MAY be automatically redirected by the user agent without request MAY be automatically redirected by the user agent without
confirmation. Otherwise, the user agent MUST NOT automatically confirmation. Otherwise, the user agent MUST NOT automatically
redirect the request unless it can be confirmed by the user, since redirect the request unless it can be confirmed by the user, since
this might change the conditions under which the request was issued. this might change the conditions under which the request was issued.
9.4. Client Error 4xx 8.4. Client Error 4xx
The 4xx class of status code is intended for cases in which the The 4xx class of status code is intended for cases in which the
client seems to have erred. Except when responding to a HEAD client seems to have erred. Except when responding to a HEAD
request, the server SHOULD include an entity containing an request, the server SHOULD include an entity containing an
explanation of the error situation, and whether it is a temporary or explanation of the error situation, and whether it is a temporary or
permanent condition. These status codes are applicable to any permanent condition. These status codes are applicable to any
request method. User agents SHOULD display any included entity to request method. User agents SHOULD display any included entity to
the user. the user.
If the client is sending data, a server implementation using TCP If the client is sending data, a server implementation using TCP
SHOULD be careful to ensure that the client acknowledges receipt of SHOULD be careful to ensure that the client acknowledges receipt of
the packet(s) containing the response, before the server closes the the packet(s) containing the response, before the server closes the
input connection. If the client continues sending data to the server input connection. If the client continues sending data to the server
after the close, the server's TCP stack will send a reset packet to after the close, the server's TCP stack will send a reset packet to
the client, which may erase the client's unacknowledged input buffers the client, which may erase the client's unacknowledged input buffers
before they can be read and interpreted by the HTTP application. before they can be read and interpreted by the HTTP application.
9.4.1. 400 Bad Request 8.4.1. 400 Bad Request
The request could not be understood by the server due to malformed The request could not be understood by the server due to malformed
syntax. The client SHOULD NOT repeat the request without syntax. The client SHOULD NOT repeat the request without
modifications. modifications.
9.4.2. 401 Unauthorized 8.4.2. 401 Unauthorized
The request requires user authentication (see [Part7]). The request requires user authentication (see [Part7]).
9.4.3. 402 Payment Required 8.4.3. 402 Payment Required
This code is reserved for future use. This code is reserved for future use.
9.4.4. 403 Forbidden 8.4.4. 403 Forbidden
The server understood the request, but is refusing to fulfill it. The server understood the request, but is refusing to fulfill it.
Authorization will not help and the request SHOULD NOT be repeated. Authorization will not help and the request SHOULD NOT be repeated.
If the request method was not HEAD and the server wishes to make If the request method was not HEAD and the server wishes to make
public why the request has not been fulfilled, it SHOULD describe the public why the request has not been fulfilled, it SHOULD describe the
reason for the refusal in the entity. If the server does not wish to reason for the refusal in the entity. If the server does not wish to
make this information available to the client, the status code 404 make this information available to the client, the status code 404
(Not Found) can be used instead. (Not Found) can be used instead.
9.4.5. 404 Not Found 8.4.5. 404 Not Found
The server has not found anything matching the Request-URI. No The server has not found anything matching the request-target. No
indication is given of whether the condition is temporary or indication is given of whether the condition is temporary or
permanent. The 410 (Gone) status code SHOULD be used if the server permanent. The 410 (Gone) status code SHOULD be used if the server
knows, through some internally configurable mechanism, that an old knows, through some internally configurable mechanism, that an old
resource is permanently unavailable and has no forwarding address. resource is permanently unavailable and has no forwarding address.
This status code is commonly used when the server does not wish to This status code is commonly used when the server does not wish to
reveal exactly why the request has been refused, or when no other reveal exactly why the request has been refused, or when no other
response is applicable. response is applicable.
9.4.6. 405 Method Not Allowed 8.4.6. 405 Method Not Allowed
The method specified in the Request-Line is not allowed for the The method specified in the Request-Line is not allowed for the
resource identified by the Request-URI. The response MUST include an resource identified by the request-target. The response MUST include
Allow header containing a list of valid methods for the requested an Allow header containing a list of valid methods for the requested
resource. resource.
9.4.7. 406 Not Acceptable 8.4.7. 406 Not Acceptable
The resource identified by the request is only capable of generating The resource identified by the request is only capable of generating
response entities which have content characteristics not acceptable response entities which have content characteristics not acceptable
according to the accept headers sent in the request. according to the accept headers sent in the request.
Unless it was a HEAD request, the response SHOULD include an entity Unless it was a HEAD request, the response SHOULD include an entity
containing a list of available entity characteristics and location(s) containing a list of available entity characteristics and location(s)
from which the user or user agent can choose the one most from which the user or user agent can choose the one most
appropriate. The entity format is specified by the media type given appropriate. The entity format is specified by the media type given
in the Content-Type header field. Depending upon the format and the in the Content-Type header field. Depending upon the format and the
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Note: HTTP/1.1 servers are allowed to return responses which are Note: HTTP/1.1 servers are allowed to return responses which are
not acceptable according to the accept headers sent in the not acceptable according to the accept headers sent in the
request. In some cases, this may even be preferable to sending a request. In some cases, this may even be preferable to sending a
406 response. User agents are encouraged to inspect the headers 406 response. User agents are encouraged to inspect the headers
of an incoming response to determine if it is acceptable. of an incoming response to determine if it is acceptable.
If the response could be unacceptable, a user agent SHOULD If the response could be unacceptable, a user agent SHOULD
temporarily stop receipt of more data and query the user for a temporarily stop receipt of more data and query the user for a
decision on further actions. decision on further actions.
9.4.8. 407 Proxy Authentication Required 8.4.8. 407 Proxy Authentication Required
This code is similar to 401 (Unauthorized), but indicates that the This code is similar to 401 (Unauthorized), but indicates that the
client must first authenticate itself with the proxy (see [Part7]). client must first authenticate itself with the proxy (see [Part7]).
9.4.9. 408 Request Timeout 8.4.9. 408 Request Timeout
The client did not produce a request within the time that the server The client did not produce a request within the time that the server
was prepared to wait. The client MAY repeat the request without was prepared to wait. The client MAY repeat the request without
modifications at any later time. modifications at any later time.
9.4.10. 409 Conflict 8.4.10. 409 Conflict
The request could not be completed due to a conflict with the current The request could not be completed due to a conflict with the current
state of the resource. This code is only allowed in situations where state of the resource. This code is only allowed in situations where
it is expected that the user might be able to resolve the conflict it is expected that the user might be able to resolve the conflict
and resubmit the request. The response body SHOULD include enough and resubmit the request. The response body SHOULD include enough
information for the user to recognize the source of the conflict. information for the user to recognize the source of the conflict.
Ideally, the response entity would include enough information for the Ideally, the response entity would include enough information for the
user or user agent to fix the problem; however, that might not be user or user agent to fix the problem; however, that might not be
possible and is not required. possible and is not required.
Conflicts are most likely to occur in response to a PUT request. For Conflicts are most likely to occur in response to a PUT request. For
example, if versioning were being used and the entity being PUT example, if versioning were being used and the entity being PUT
included changes to a resource which conflict with those made by an included changes to a resource which conflict with those made by an
earlier (third-party) request, the server might use the 409 response earlier (third-party) request, the server might use the 409 response
to indicate that it can't complete the request. In this case, the to indicate that it can't complete the request. In this case, the
response entity would likely contain a list of the differences response entity would likely contain a list of the differences
between the two versions in a format defined by the response Content- between the two versions in a format defined by the response Content-
Type. Type.
9.4.11. 410 Gone 8.4.11. 410 Gone
The requested resource is no longer available at the server and no The requested resource is no longer available at the server and no
forwarding address is known. This condition is expected to be forwarding address is known. This condition is expected to be
considered permanent. Clients with link editing capabilities SHOULD considered permanent. Clients with link editing capabilities SHOULD
delete references to the Request-URI after user approval. If the delete references to the request-target after user approval. If the
server does not know, or has no facility to determine, whether or not server does not know, or has no facility to determine, whether or not
the condition is permanent, the status code 404 (Not Found) SHOULD be the condition is permanent, the status code 404 (Not Found) SHOULD be
used instead. This response is cacheable unless indicated otherwise. used instead. This response is cacheable unless indicated otherwise.
The 410 response is primarily intended to assist the task of web The 410 response is primarily intended to assist the task of web
maintenance by notifying the recipient that the resource is maintenance by notifying the recipient that the resource is
intentionally unavailable and that the server owners desire that intentionally unavailable and that the server owners desire that
remote links to that resource be removed. Such an event is common remote links to that resource be removed. Such an event is common
for limited-time, promotional services and for resources belonging to for limited-time, promotional services and for resources belonging to
individuals no longer working at the server's site. It is not individuals no longer working at the server's site. It is not
necessary to mark all permanently unavailable resources as "gone" or necessary to mark all permanently unavailable resources as "gone" or
to keep the mark for any length of time -- that is left to the to keep the mark for any length of time -- that is left to the
discretion of the server owner. discretion of the server owner.
9.4.12. 411 Length Required 8.4.12. 411 Length Required
The server refuses to accept the request without a defined Content- The server refuses to accept the request without a defined Content-
Length. The client MAY repeat the request if it adds a valid Length. The client MAY repeat the request if it adds a valid
Content-Length header field containing the length of the message-body Content-Length header field containing the length of the message-body
in the request message. in the request message.
9.4.13. 412 Precondition Failed 8.4.13. 412 Precondition Failed
The precondition given in one or more of the request-header fields The precondition given in one or more of the request-header fields
evaluated to false when it was tested on the server, as defined in evaluated to false when it was tested on the server, as defined in
[Part4]. [Part4].
9.4.14. 413 Request Entity Too Large 8.4.14. 413 Request Entity Too Large
The server is refusing to process a request because the request The server is refusing to process a request because the request
entity is larger than the server is willing or able to process. The entity is larger than the server is willing or able to process. The
server MAY close the connection to prevent the client from continuing server MAY close the connection to prevent the client from continuing
the request. the request.
If the condition is temporary, the server SHOULD include a Retry- If the condition is temporary, the server SHOULD include a Retry-
After header field to indicate that it is temporary and after what After header field to indicate that it is temporary and after what
time the client MAY try again. time the client MAY try again.
9.4.15. 414 Request-URI Too Long 8.4.15. 414 URI Too Long
The server is refusing to service the request because the Request-URI The server is refusing to service the request because the request-
is longer than the server is willing to interpret. This rare target is longer than the server is willing to interpret. This rare
condition is only likely to occur when a client has improperly condition is only likely to occur when a client has improperly
converted a POST request to a GET request with long query converted a POST request to a GET request with long query
information, when the client has descended into a URI "black hole" of information, when the client has descended into a URI "black hole" of
redirection (e.g., a redirected URI prefix that points to a suffix of redirection (e.g., a redirected URI prefix that points to a suffix of
itself), or when the server is under attack by a client attempting to itself), or when the server is under attack by a client attempting to
exploit security holes present in some servers using fixed-length exploit security holes present in some servers using fixed-length
buffers for reading or manipulating the Request-URI. buffers for reading or manipulating the request-target.
9.4.16. 415 Unsupported Media Type 8.4.16. 415 Unsupported Media Type
The server is refusing to service the request because the entity of The server is refusing to service the request because the entity of
the request is in a format not supported by the requested resource the request is in a format not supported by the requested resource
for the requested method. for the requested method.
9.4.17. 416 Requested Range Not Satisfiable 8.4.17. 416 Requested Range Not Satisfiable
The request included a Range request-header field (Section 6.4 of The request included a Range request-header field (Section 5.4 of
[Part5]) and none of the range-specifier values in this field overlap [Part5]) and none of the range-specifier values in this field overlap
the current extent of the selected resource. the current extent of the selected resource.
9.4.18. 417 Expectation Failed 8.4.18. 417 Expectation Failed
The expectation given in an Expect request-header field (see The expectation given in an Expect request-header field (see
Section 10.2) could not be met by this server, or, if the server is a Section 9.2) could not be met by this server, or, if the server is a
proxy, the server has unambiguous evidence that the request could not proxy, the server has unambiguous evidence that the request could not
be met by the next-hop server. be met by the next-hop server.
9.5. Server Error 5xx 8.5. Server Error 5xx
Response status codes beginning with the digit "5" indicate cases in Response status codes beginning with the digit "5" indicate cases in
which the server is aware that it has erred or is incapable of which the server is aware that it has erred or is incapable of
performing the request. Except when responding to a HEAD request, performing the request. Except when responding to a HEAD request,
the server SHOULD include an entity containing an explanation of the the server SHOULD include an entity containing an explanation of the
error situation, and whether it is a temporary or permanent error situation, and whether it is a temporary or permanent
condition. User agents SHOULD display any included entity to the condition. User agents SHOULD display any included entity to the
user. These response codes are applicable to any request method. user. These response codes are applicable to any request method.
9.5.1. 500 Internal Server Error 8.5.1. 500 Internal Server Error
The server encountered an unexpected condition which prevented it The server encountered an unexpected condition which prevented it
from fulfilling the request. from fulfilling the request.
9.5.2. 501 Not Implemented 8.5.2. 501 Not Implemented
The server does not support the functionality required to fulfill the The server does not support the functionality required to fulfill the
request. This is the appropriate response when the server does not request. This is the appropriate response when the server does not
recognize the request method and is not capable of supporting it for recognize the request method and is not capable of supporting it for
any resource. any resource.
9.5.3. 502 Bad Gateway 8.5.3. 502 Bad Gateway
The server, while acting as a gateway or proxy, received an invalid The server, while acting as a gateway or proxy, received an invalid
response from the upstream server it accessed in attempting to response from the upstream server it accessed in attempting to
fulfill the request. fulfill the request.
9.5.4. 503 Service Unavailable 8.5.4. 503 Service Unavailable
The server is currently unable to handle the request due to a The server is currently unable to handle the request due to a
temporary overloading or maintenance of the server. The implication temporary overloading or maintenance of the server. The implication
is that this is a temporary condition which will be alleviated after is that this is a temporary condition which will be alleviated after
some delay. If known, the length of the delay MAY be indicated in a some delay. If known, the length of the delay MAY be indicated in a
Retry-After header. If no Retry-After is given, the client SHOULD Retry-After header. If no Retry-After is given, the client SHOULD
handle the response as it would for a 500 response. handle the response as it would for a 500 response.
Note: The existence of the 503 status code does not imply that a Note: The existence of the 503 status code does not imply that a
server must use it when becoming overloaded. Some servers may server must use it when becoming overloaded. Some servers may
wish to simply refuse the connection. wish to simply refuse the connection.
9.5.5. 504 Gateway Timeout 8.5.5. 504 Gateway Timeout
The server, while acting as a gateway or proxy, did not receive a The server, while acting as a gateway or proxy, did not receive a
timely response from the upstream server specified by the URI (e.g. timely response from the upstream server specified by the URI (e.g.
HTTP, FTP, LDAP) or some other auxiliary server (e.g. DNS) it needed HTTP, FTP, LDAP) or some other auxiliary server (e.g. DNS) it needed
to access in attempting to complete the request. to access in attempting to complete the request.
Note: Note to implementors: some deployed proxies are known to Note: Note to implementors: some deployed proxies are known to
return 400 or 500 when DNS lookups time out. return 400 or 500 when DNS lookups time out.
9.5.6. 505 HTTP Version Not Supported 8.5.6. 505 HTTP Version Not Supported
The server does not support, or refuses to support, the protocol The server does not support, or refuses to support, the protocol
version that was used in the request message. The server is version that was used in the request message. The server is
indicating that it is unable or unwilling to complete the request indicating that it is unable or unwilling to complete the request
using the same major version as the client, as described in Section using the same major version as the client, as described in Section
3.1 of [Part1], other than with this error message. The response 3.1 of [Part1], other than with this error message. The response
SHOULD contain an entity describing why that version is not supported SHOULD contain an entity describing why that version is not supported
and what other protocols are supported by that server. and what other protocols are supported by that server.
10. Header Field Definitions 9. Header Field Definitions
This section defines the syntax and semantics of HTTP/1.1 header This section defines the syntax and semantics of HTTP/1.1 header
fields related to request and response semantics. fields related to request and response semantics.
For entity-header fields, both sender and recipient refer to either For entity-header fields, both sender and recipient refer to either
the client or the server, depending on who sends and who receives the the client or the server, depending on who sends and who receives the
entity. entity.
10.1. Allow 9.1. Allow
The response-header field "Allow" lists the set of methods advertised The response-header field "Allow" lists the set of methods advertised
as supported by the resource identified by the Request-URI. The as supported by the resource identified by the request-target. The
purpose of this field is strictly to inform the recipient of valid purpose of this field is strictly to inform the recipient of valid
methods associated with the resource. An Allow header field MUST be methods associated with the resource. An Allow header field MUST be
present in a 405 (Method Not Allowed) response. present in a 405 (Method Not Allowed) response.
Allow = "Allow" ":" OWS Allow-v Allow = "Allow" ":" OWS Allow-v
Allow-v = #Method Allow-v = #Method
Example of use: Example of use:
Allow: GET, HEAD, PUT Allow: GET, HEAD, PUT
The actual set of allowed methods is defined by the origin server at The actual set of allowed methods is defined by the origin server at
the time of each request. the time of each request.
A proxy MUST NOT modify the Allow header field even if it does not A proxy MUST NOT modify the Allow header field even if it does not
understand all the methods specified, since the user agent might have understand all the methods specified, since the user agent might have
other means of communicating with the origin server. other means of communicating with the origin server.
10.2. Expect 9.2. Expect
The request-header field "Expect" is used to indicate that particular The request-header field "Expect" is used to indicate that particular
server behaviors are required by the client. server behaviors are required by the client.
Expect = "Expect" ":" OWS Expect-v Expect = "Expect" ":" OWS Expect-v
Expect-v = 1#expectation Expect-v = 1#expectation
expectation = "100-continue" / expectation-extension expectation = "100-continue" / expectation-extension
expectation-extension = token [ "=" ( token / quoted-string ) expectation-extension = token [ "=" ( token / quoted-string )
*expect-params ] *expect-params ]
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with an expectation that it cannot meet. However, the Expect with an expectation that it cannot meet. However, the Expect
request-header itself is end-to-end; it MUST be forwarded if the request-header itself is end-to-end; it MUST be forwarded if the
request is forwarded. request is forwarded.
Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Many older HTTP/1.0 and HTTP/1.1 applications do not understand the
Expect header. Expect header.
See Section 7.2.3 of [Part1] for the use of the 100 (Continue) See Section 7.2.3 of [Part1] for the use of the 100 (Continue)
status. status.
10.3. From 9.3. From
The request-header field "From", if given, SHOULD contain an Internet The request-header field "From", if given, SHOULD contain an Internet
e-mail address for the human user who controls the requesting user e-mail address for the human user who controls the requesting user
agent. The address SHOULD be machine-usable, as defined by "mailbox" agent. The address SHOULD be machine-usable, as defined by "mailbox"
in Section 3.4 of [RFC5322]: in Section 3.4 of [RFC5322]:
From = "From" ":" OWS From-v From = "From" ":" OWS From-v
From-v = mailbox From-v = mailbox
mailbox = <mailbox, defined in [RFC5322], Section 3.4> mailbox = <mailbox, defined in [RFC5322], Section 3.4>
skipping to change at page 33, line 28 skipping to change at page 33, line 41
Internet host which issued the request. For example, when a request Internet host which issued the request. For example, when a request
is passed through a proxy the original issuer's address SHOULD be is passed through a proxy the original issuer's address SHOULD be
used. used.
The client SHOULD NOT send the From header field without the user's The client SHOULD NOT send the From header field without the user's
approval, as it might conflict with the user's privacy interests or approval, as it might conflict with the user's privacy interests or
their site's security policy. It is strongly recommended that the their site's security policy. It is strongly recommended that the
user be able to disable, enable, and modify the value of this field user be able to disable, enable, and modify the value of this field
at any time prior to a request. at any time prior to a request.
10.4. Location 9.4. Location
The response-header field "Location" is used for the identification The response-header field "Location" is used for the identification
of a new resource or to redirect the recipient to a location other of a new resource or to redirect the recipient to a location other
than the Request-URI for completion of the request. For 201 than the request-target for completion of the request. For 201
(Created) responses, the Location is that of the new resource which (Created) responses, the Location is that of the new resource which
was created by the request. For 3xx responses, the location SHOULD was created by the request. For 3xx responses, the location SHOULD
indicate the server's preferred URI for automatic redirection to the indicate the server's preferred URI for automatic redirection to the
resource. The field value consists of a single absolute URI. resource. The field value consists of a single absolute URI.
Location = "Location" ":" OWS Location-v Location = "Location" ":" OWS Location-v
Location-v = absolute-URI [ "#" fragment ] Location-v = absolute-URI [ "#" fragment ]
An example is: An example is:
Location: http://www.example.org/pub/WWW/People.html Location: http://www.example.org/pub/WWW/People.html
Note: The Content-Location header field (Section 6.7 of [Part3]) Note: The Content-Location header field (Section 5.7 of [Part3])
differs from Location in that the Content-Location identifies the differs from Location in that the Content-Location identifies the
original location of the entity enclosed in the response. It is original location of the entity enclosed in the response. It is
therefore possible for a response to contain header fields for therefore possible for a response to contain header fields for
both Location and Content-Location. both Location and Content-Location.
There are circumstances in which a fragment identifier in a Location There are circumstances in which a fragment identifier in a Location
URL would not be appropriate: URL would not be appropriate:
o With a 201 Created response, because in this usage the Location o With a 201 Created response, because in this usage the Location
header specifies the URL for the entire created resource. header specifies the URL for the entire created resource.
o With a 300 Multiple Choices, since the choice decision is intended o With a 300 Multiple Choices, since the choice decision is intended
to be made on resource characteristics and not fragment to be made on resource characteristics and not fragment
characteristics. characteristics.
o With 305 Use Proxy. o With 305 Use Proxy.
10.5. Max-Forwards 9.5. Max-Forwards
The request-header "Max-Forwards" field provides a mechanism with the The request-header "Max-Forwards" field provides a mechanism with the
TRACE (Section 8.8) and OPTIONS (Section 8.2) methods to limit the TRACE (Section 7.8) and OPTIONS (Section 7.2) methods to limit the
number of proxies or gateways that can forward the request to the number of proxies or gateways that can forward the request to the
next inbound server. This can be useful when the client is next inbound server. This can be useful when the client is
attempting to trace a request chain which appears to be failing or attempting to trace a request chain which appears to be failing or
looping in mid-chain. looping in mid-chain.
Max-Forwards = "Max-Forwards" ":" OWS Max-Forwards-v Max-Forwards = "Max-Forwards" ":" OWS Max-Forwards-v
Max-Forwards-v = 1*DIGIT Max-Forwards-v = 1*DIGIT
The Max-Forwards value is a decimal integer indicating the remaining The Max-Forwards value is a decimal integer indicating the remaining
number of times this request message may be forwarded. number of times this request message may be forwarded.
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value prior to forwarding the request. If the received value is zero value prior to forwarding the request. If the received value is zero
(0), the recipient MUST NOT forward the request; instead, it MUST (0), the recipient MUST NOT forward the request; instead, it MUST
respond as the final recipient. If the received Max-Forwards value respond as the final recipient. If the received Max-Forwards value
is greater than zero, then the forwarded message MUST contain an is greater than zero, then the forwarded message MUST contain an
updated Max-Forwards field with a value decremented by one (1). updated Max-Forwards field with a value decremented by one (1).
The Max-Forwards header field MAY be ignored for all other methods The Max-Forwards header field MAY be ignored for all other methods
defined by this specification and for any extension methods for which defined by this specification and for any extension methods for which
it is not explicitly referred to as part of that method definition. it is not explicitly referred to as part of that method definition.
10.6. Referer 9.6. Referer
The request-header field "Referer" [sic] allows the client to The request-header field "Referer" [sic] allows the client to
specify, for the server's benefit, the address (URI) of the resource specify, for the server's benefit, the address (URI) of the resource
from which the Request-URI was obtained (the "referrer", although the from which the request-target was obtained (the "referrer", although
header field is misspelled.) The Referer request-header allows a the header field is misspelled.) The Referer request-header allows a
server to generate lists of back-links to resources for interest, server to generate lists of back-links to resources for interest,
logging, optimized caching, etc. It also allows obsolete or mistyped logging, optimized caching, etc. It also allows obsolete or mistyped
links to be traced for maintenance. The Referer field MUST NOT be links to be traced for maintenance. The Referer field MUST NOT be
sent if the Request-URI was obtained from a source that does not have sent if the request-target was obtained from a source that does not
its own URI, such as input from the user keyboard. have its own URI, such as input from the user keyboard.
Referer = "Referer" ":" OWS Referer-v Referer = "Referer" ":" OWS Referer-v
Referer-v = absolute-URI / relativeURI Referer-v = absolute-URI / partial-URI
Example: Example:
Referer: http://www.example.org/hypertext/Overview.html Referer: http://www.example.org/hypertext/Overview.html
If the field value is a relative URI, it SHOULD be interpreted If the field value is a relative URI, it SHOULD be interpreted
relative to the Request-URI. The URI MUST NOT include a fragment. relative to the request-target. The URI MUST NOT include a fragment.
See Section 12.2 for security considerations. See Section 11.2 for security considerations.
10.7. Retry-After 9.7. Retry-After
The response-header "Retry-After" field can be used with a 503 The response-header "Retry-After" field can be used with a 503
(Service Unavailable) response to indicate how long the service is (Service Unavailable) response to indicate how long the service is
expected to be unavailable to the requesting client. This field MAY expected to be unavailable to the requesting client. This field MAY
also be used with any 3xx (Redirection) response to indicate the also be used with any 3xx (Redirection) response to indicate the
minimum time the user-agent is asked wait before issuing the minimum time the user-agent is asked wait before issuing the
redirected request. The value of this field can be either an HTTP- redirected request. The value of this field can be either an HTTP-
date or an integer number of seconds (in decimal) after the time of date or an integer number of seconds (in decimal) after the time of
the response. the response.
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delta-seconds = 1*DIGIT delta-seconds = 1*DIGIT
Two examples of its use are Two examples of its use are
Retry-After: Fri, 31 Dec 1999 23:59:59 GMT Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
Retry-After: 120 Retry-After: 120
In the latter example, the delay is 2 minutes. In the latter example, the delay is 2 minutes.
10.8. Server 9.8. Server
The response-header field "Server" contains information about the The response-header field "Server" contains information about the
software used by the origin server to handle the request. The field software used by the origin server to handle the request. The field
can contain multiple product tokens (Section 3.5 of [Part1]) and can contain multiple product tokens (Section 3.4 of [Part1]) and
comments identifying the server and any significant subproducts. The comments identifying the server and any significant subproducts. The
product tokens are listed in order of their significance for product tokens are listed in order of their significance for
identifying the application. identifying the application.
Server = "Server" ":" OWS Server-v Server = "Server" ":" OWS Server-v
Server-v = product Server-v = product
*( RWS ( product / comment ) ) *( RWS ( product / comment ) )
Example: Example:
skipping to change at page 36, line 23 skipping to change at page 36, line 32
If the response is being forwarded through a proxy, the proxy If the response is being forwarded through a proxy, the proxy
application MUST NOT modify the Server response-header. Instead, it application MUST NOT modify the Server response-header. Instead, it
MUST include a Via field (as described in Section 8.9 of [Part1]). MUST include a Via field (as described in Section 8.9 of [Part1]).
Note: Revealing the specific software version of the server might Note: Revealing the specific software version of the server might
allow the server machine to become more vulnerable to attacks allow the server machine to become more vulnerable to attacks
against software that is known to contain security holes. Server against software that is known to contain security holes. Server
implementors are encouraged to make this field a configurable implementors are encouraged to make this field a configurable
option. option.
10.9. User-Agent 9.9. User-Agent
The request-header field "User-Agent" contains information about the The request-header field "User-Agent" contains information about the
user agent originating the request. This is for statistical user agent originating the request. This is for statistical
purposes, the tracing of protocol violations, and automated purposes, the tracing of protocol violations, and automated
recognition of user agents for the sake of tailoring responses to recognition of user agents for the sake of tailoring responses to
avoid particular user agent limitations. User agents SHOULD include avoid particular user agent limitations. User agents SHOULD include
this field with requests. The field can contain multiple product this field with requests. The field can contain multiple product
tokens (Section 3.5 of [Part1]) and comments identifying the agent tokens (Section 3.4 of [Part1]) and comments identifying the agent
and any subproducts which form a significant part of the user agent. and any subproducts which form a significant part of the user agent.
By convention, the product tokens are listed in order of their By convention, the product tokens are listed in order of their
significance for identifying the application. significance for identifying the application.
User-Agent = "User-Agent" ":" OWS User-Agent-v User-Agent = "User-Agent" ":" OWS User-Agent-v
User-Agent-v = product User-Agent-v = product
*( RWS ( product / comment ) ) *( RWS ( product / comment ) )
Example: Example:
User-Agent: CERN-LineMode/2.15 libwww/2.17b3 User-Agent: CERN-LineMode/2.15 libwww/2.17b3
11. IANA Considerations 10. IANA Considerations
11.1. Method Registry 10.1. Method Registry
The registration procedure for HTTP Methods is defined by Section 3.1 The registration procedure for HTTP Methods is defined by Section 2.1
of this document. of this document.
The HTTP Method Registry located at The HTTP Method Registry located at
<http://www.iana.org/assignments/http-methods> should be populated <http://www.iana.org/assignments/http-methods> should be populated
with the registrations below: with the registrations below:
+---------+------+-------------+ +---------+------+-------------+
| Method | Safe | Reference | | Method | Safe | Reference |
+---------+------+-------------+ +---------+------+-------------+
| CONNECT | no | Section 8.9 | | CONNECT | no | Section 7.9 |
| DELETE | no | Section 8.7 | | DELETE | no | Section 7.7 |
| GET | yes | Section 8.3 | | GET | yes | Section 7.3 |
| HEAD | yes | Section 8.4 | | HEAD | yes | Section 7.4 |
| OPTIONS | yes | Section 8.2 | | OPTIONS | yes | Section 7.2 |
| POST | no | Section 8.5 | | POST | no | Section 7.5 |
| PUT | no | Section 8.6 | | PUT | no | Section 7.6 |
| TRACE | yes | Section 8.8 | | TRACE | yes | Section 7.8 |
+---------+------+-------------+ +---------+------+-------------+
11.2. Status Code Registry 10.2. Status Code Registry
The registration procedure for HTTP Status Codes -- previously The registration procedure for HTTP Status Codes -- previously
defined in Section 7.1 of [RFC2817] -- is now defined by Section 5.1 defined in Section 7.1 of [RFC2817] -- is now defined by Section 4.1
of this document. of this document.
The HTTP Status Code Registry located at The HTTP Status Code Registry located at
<http://www.iana.org/assignments/http-status-codes> should be updated <http://www.iana.org/assignments/http-status-codes> should be updated
with the registrations below: with the registrations below:
+-------+---------------------------------+----------------+ +-------+---------------------------------+----------------+
| Value | Description | Reference | | Value | Description | Reference |
+-------+---------------------------------+----------------+ +-------+---------------------------------+----------------+
| 100 | Continue | Section 9.1.1 | | 100 | Continue | Section 8.1.1 |
| 101 | Switching Protocols | Section 9.1.2 | | 101 | Switching Protocols | Section 8.1.2 |
| 200 | OK | Section 9.2.1 | | 200 | OK | Section 8.2.1 |
| 201 | Created | Section 9.2.2 | | 201 | Created | Section 8.2.2 |
| 202 | Accepted | Section 9.2.3 | | 202 | Accepted | Section 8.2.3 |
| 203 | Non-Authoritative Information | Section 9.2.4 | | 203 | Non-Authoritative Information | Section 8.2.4 |
| 204 | No Content | Section 9.2.5 | | 204 | No Content | Section 8.2.5 |
| 205 | Reset Content | Section 9.2.6 | | 205 | Reset Content | Section 8.2.6 |
| 206 | Partial Content | Section 9.2.7 | | 206 | Partial Content | Section 8.2.7 |
| 300 | Multiple Choices | Section 9.3.1 | | 300 | Multiple Choices | Section 8.3.1 |
| 301 | Moved Permanently | Section 9.3.2 | | 301 | Moved Permanently | Section 8.3.2 |
| 302 | Found | Section 9.3.3 | | 302 | Found | Section 8.3.3 |
| 303 | See Other | Section 9.3.4 | | 303 | See Other | Section 8.3.4 |
| 304 | Not Modified | Section 9.3.5 | | 304 | Not Modified | Section 8.3.5 |
| 305 | Use Proxy | Section 9.3.6 | | 305 | Use Proxy | Section 8.3.6 |
| 306 | (Unused) | Section 9.3.7 | | 306 | (Unused) | Section 8.3.7 |
| 307 | Temporary Redirect | Section 9.3.8 | | 307 | Temporary Redirect | Section 8.3.8 |
| 400 | Bad Request | Section 9.4.1 | | 400 | Bad Request | Section 8.4.1 |
| 401 | Unauthorized | Section 9.4.2 | | 401 | Unauthorized | Section 8.4.2 |
| 402 | Payment Required | Section 9.4.3 | | 402 | Payment Required | Section 8.4.3 |
| 403 | Forbidden | Section 9.4.4 | | 403 | Forbidden | Section 8.4.4 |
| 404 | Not Found | Section 9.4.5 | | 404 | Not Found | Section 8.4.5 |
| 405 | Method Not Allowed | Section 9.4.6 | | 405 | Method Not Allowed | Section 8.4.6 |
| 406 | Not Acceptable | Section 9.4.7 | | 406 | Not Acceptable | Section 8.4.7 |
| 407 | Proxy Authentication Required | Section 9.4.8 | | 407 | Proxy Authentication Required | Section 8.4.8 |
| 408 | Request Timeout | Section 9.4.9 | | 408 | Request Timeout | Section 8.4.9 |
| 409 | Conflict | Section 9.4.10 | | 409 | Conflict | Section 8.4.10 |
| 410 | Gone | Section 9.4.11 | | 410 | Gone | Section 8.4.11 |
| 411 | Length Required | Section 9.4.12 | | 411 | Length Required | Section 8.4.12 |
| 412 | Precondition Failed | Section 9.4.13 | | 412 | Precondition Failed | Section 8.4.13 |
| 413 | Request Entity Too Large | Section 9.4.14 | | 413 | Request Entity Too Large | Section 8.4.14 |
| 414 | Request-URI Too Long | Section 9.4.15 | | 414 | URI Too Long | Section 8.4.15 |
| 415 | Unsupported Media Type | Section 9.4.16 | | 415 | Unsupported Media Type | Section 8.4.16 |
| 416 | Requested Range Not Satisfiable | Section 9.4.17 | | 416 | Requested Range Not Satisfiable | Section 8.4.17 |
| 417 | Expectation Failed | Section 9.4.18 | | 417 | Expectation Failed | Section 8.4.18 |
| 500 | Internal Server Error | Section 9.5.1 | | 500 | Internal Server Error | Section 8.5.1 |
| 501 | Not Implemented | Section 9.5.2 | | 501 | Not Implemented | Section 8.5.2 |
| 502 | Bad Gateway | Section 9.5.3 | | 502 | Bad Gateway | Section 8.5.3 |
| 503 | Service Unavailable | Section 9.5.4 | | 503 | Service Unavailable | Section 8.5.4 |
| 504 | Gateway Timeout | Section 9.5.5 | | 504 | Gateway Timeout | Section 8.5.5 |
| 505 | HTTP Version Not Supported | Section 9.5.6 | | 505 | HTTP Version Not Supported | Section 8.5.6 |
+-------+---------------------------------+----------------+ +-------+---------------------------------+----------------+
11.3. Message Header Registration 10.3. Message Header Registration
The Message Header Registry located at <http://www.iana.org/ The Message Header Registry located at <http://www.iana.org/
assignments/message-headers/message-header-index.html> should be assignments/message-headers/message-header-index.html> should be
updated with the permanent registrations below (see [RFC3864]): updated with the permanent registrations below (see [RFC3864]):
+-------------------+----------+----------+--------------+ +-------------------+----------+----------+-------------+
| Header Field Name | Protocol | Status | Reference | | Header Field Name | Protocol | Status | Reference |
+-------------------+----------+----------+--------------+ +-------------------+----------+----------+-------------+
| Allow | http | standard | Section 10.1 | | Allow | http | standard | Section 9.1 |
| Expect | http | standard | Section 10.2 | | Expect | http | standard | Section 9.2 |
| From | http | standard | Section 10.3 | | From | http | standard | Section 9.3 |
| Location | http | standard | Section 10.4 | | Location | http | standard | Section 9.4 |
| Max-Forwards | http | standard | Section 10.5 | | Max-Forwards | http | standard | Section 9.5 |
| Referer | http | standard | Section 10.6 | | Referer | http | standard | Section 9.6 |
| Retry-After | http | standard | Section 10.7 | | Retry-After | http | standard | Section 9.7 |
| Server | http | standard | Section 10.8 | | Server | http | standard | Section 9.8 |
| User-Agent | http | standard | Section 10.9 | | User-Agent | http | standard | Section 9.9 |
+-------------------+----------+----------+--------------+ +-------------------+----------+----------+-------------+
The change controller is: "IETF (iesg@ietf.org) - Internet The change controller is: "IETF (iesg@ietf.org) - Internet
Engineering Task Force". Engineering Task Force".
12. Security Considerations 11. Security Considerations
This section is meant to inform application developers, information This section is meant to inform application developers, information
providers, and users of the security limitations in HTTP/1.1 as providers, and users of the security limitations in HTTP/1.1 as
described by this document. The discussion does not include described by this document. The discussion does not include
definitive solutions to the problems revealed, though it does make definitive solutions to the problems revealed, though it does make
some suggestions for reducing security risks. some suggestions for reducing security risks.
12.1. Transfer of Sensitive Information 11.1. Transfer of Sensitive Information
Like any generic data transfer protocol, HTTP cannot regulate the Like any generic data transfer protocol, HTTP cannot regulate the
content of the data that is transferred, nor is there any a priori content of the data that is transferred, nor is there any a priori
method of determining the sensitivity of any particular piece of method of determining the sensitivity of any particular piece of
information within the context of any given request. Therefore, information within the context of any given request. Therefore,
applications SHOULD supply as much control over this information as applications SHOULD supply as much control over this information as
possible to the provider of that information. Four header fields are possible to the provider of that information. Four header fields are
worth special mention in this context: Server, Via, Referer and From. worth special mention in this context: Server, Via, Referer and From.
Revealing the specific software version of the server might allow the Revealing the specific software version of the server might allow the
skipping to change at page 40, line 27 skipping to change at page 40, line 27
privacy interests or their site's security policy, and hence it privacy interests or their site's security policy, and hence it
SHOULD NOT be transmitted without the user being able to disable, SHOULD NOT be transmitted without the user being able to disable,
enable, and modify the contents of the field. The user MUST be able enable, and modify the contents of the field. The user MUST be able
to set the contents of this field within a user preference or to set the contents of this field within a user preference or
application defaults configuration. application defaults configuration.
We suggest, though do not require, that a convenient toggle interface We suggest, though do not require, that a convenient toggle interface
be provided for the user to enable or disable the sending of From and be provided for the user to enable or disable the sending of From and
Referer information. Referer information.
The User-Agent (Section 10.9) or Server (Section 10.8) header fields The User-Agent (Section 9.9) or Server (Section 9.8) header fields
can sometimes be used to determine that a specific client or server can sometimes be used to determine that a specific client or server
have a particular security hole which might be exploited. have a particular security hole which might be exploited.
Unfortunately, this same information is often used for other valuable Unfortunately, this same information is often used for other valuable
purposes for which HTTP currently has no better mechanism. purposes for which HTTP currently has no better mechanism.
12.2. Encoding Sensitive Information in URIs 11.2. Encoding Sensitive Information in URIs
Because the source of a link might be private information or might Because the source of a link might be private information or might
reveal an otherwise private information source, it is strongly reveal an otherwise private information source, it is strongly
recommended that the user be able to select whether or not the recommended that the user be able to select whether or not the
Referer field is sent. For example, a browser client could have a Referer field is sent. For example, a browser client could have a
toggle switch for browsing openly/anonymously, which would toggle switch for browsing openly/anonymously, which would
respectively enable/disable the sending of Referer and From respectively enable/disable the sending of Referer and From
information. information.
Clients SHOULD NOT include a Referer header field in a (non-secure) Clients SHOULD NOT include a Referer header field in a (non-secure)
HTTP request if the referring page was transferred with a secure HTTP request if the referring page was transferred with a secure
protocol. protocol.
Authors of services should not use GET-based forms for the submission Authors of services should not use GET-based forms for the submission
of sensitive data because that data will be encoded in the Request- of sensitive data because that data will be encoded in the Request-
URI. Many existing servers, proxies, and user agents log or display target. Many existing servers, proxies, and user agents log or
the Request-URI in places where it might be visible to third parties. display the Request-target in places where it might be visible to
Such services can use POST-based form submission instead. third parties. Such services can use POST-based form submission
instead.
12.3. Location Headers and Spoofing 11.3. Location Headers and Spoofing
If a single server supports multiple organizations that do not trust If a single server supports multiple organizations that do not trust
one another, then it MUST check the values of Location and Content- one another, then it MUST check the values of Location and Content-
Location headers in responses that are generated under control of Location headers in responses that are generated under control of
said organizations to make sure that they do not attempt to said organizations to make sure that they do not attempt to
invalidate resources over which they have no authority. invalidate resources over which they have no authority.
13. Acknowledgments 12. Acknowledgments
14. References 13. References
14.1. Normative References 13.1. Normative References
[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections, and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections,
and Message Parsing", draft-ietf-httpbis-p1-messaging-05 and Message Parsing", draft-ietf-httpbis-p1-messaging-06
(work in progress), November 2008. (work in progress), March 2009.
[Part3] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part3] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 3: Message Payload and J. Reschke, Ed., "HTTP/1.1, part 3: Message Payload
and Content Negotiation", draft-ietf-httpbis-p3-payload-05 and Content Negotiation", draft-ietf-httpbis-p3-payload-06
(work in progress), November 2008. (work in progress), March 2009.
[Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional
Requests", draft-ietf-httpbis-p4-conditional-05 (work in Requests", draft-ietf-httpbis-p4-conditional-06 (work in
progress), November 2008. progress), March 2009.
[Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and
Partial Responses", draft-ietf-httpbis-p5-range-05 (work Partial Responses", draft-ietf-httpbis-p5-range-06 (work
in progress), November 2008. in progress), March 2009.
[Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 6: Caching", and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",
draft-ietf-httpbis-p6-cache-05 (work in progress), draft-ietf-httpbis-p6-cache-06 (work in progress),
November 2008. March 2009.
[Part7] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part7] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 7: Authentication", and J. Reschke, Ed., "HTTP/1.1, part 7: Authentication",
draft-ietf-httpbis-p7-auth-05 (work in progress), draft-ietf-httpbis-p7-auth-06 (work in progress),
November 2008. March 2009.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
14.2. Informative References [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
13.2. Informative References
[RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext
Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996. Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996.
[RFC2068] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., and T. [RFC2068] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., and T.
Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1",
RFC 2068, January 1997. RFC 2068, January 1997.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
skipping to change at page 42, line 43 skipping to change at page 42, line 49
May 2008. May 2008.
[RFC5322] Resnick, P., "Internet Message Format", RFC 5322, [RFC5322] Resnick, P., "Internet Message Format", RFC 5322,
October 2008. October 2008.
Appendix A. Compatibility with Previous Versions Appendix A. Compatibility with Previous Versions
A.1. Changes from RFC 2068 A.1. Changes from RFC 2068
Clarified which error code should be used for inbound server failures Clarified which error code should be used for inbound server failures
(e.g. DNS failures). (Section 9.5.5). (e.g. DNS failures). (Section 8.5.5).
201 (Created) had a race that required an Etag be sent when a 201 (Created) had a race that required an Etag be sent when a
resource is first created. (Section 9.2.2). resource is first created. (Section 8.2.2).
Rewrite of message transmission requirements to make it much harder Rewrite of message transmission requirements to make it much harder
for implementors to get it wrong, as the consequences of errors here for implementors to get it wrong, as the consequences of errors here
can have significant impact on the Internet, and to deal with the can have significant impact on the Internet, and to deal with the
following problems: following problems:
1. Changing "HTTP/1.1 or later" to "HTTP/1.1", in contexts where 1. Changing "HTTP/1.1 or later" to "HTTP/1.1", in contexts where
this was incorrectly placing a requirement on the behavior of an this was incorrectly placing a requirement on the behavior of an
implementation of a future version of HTTP/1.x implementation of a future version of HTTP/1.x
skipping to change at page 43, line 31 skipping to change at page 43, line 36
before it sends a required 100 (Continue) response. before it sends a required 100 (Continue) response.
6. Allow, rather than require, a server to omit 100 (Continue) if it 6. Allow, rather than require, a server to omit 100 (Continue) if it
has already seen some of the request body. has already seen some of the request body.
7. Allow servers to defend against denial-of-service attacks and 7. Allow servers to defend against denial-of-service attacks and
broken clients. broken clients.
This change adds the Expect header and 417 status code. This change adds the Expect header and 417 status code.
Clean up confusion between 403 and 404 responses. (Section 9.4.4, Clean up confusion between 403 and 404 responses. (Section 8.4.4,
9.4.5, and 9.4.11) 8.4.5, and 8.4.11)
The PATCH, LINK, UNLINK methods were defined but not commonly The PATCH, LINK, UNLINK methods were defined but not commonly
implemented in previous versions of this specification. See Section implemented in previous versions of this specification. See Section
19.6.1 of [RFC2068]. 19.6.1 of [RFC2068].
A.2. Changes from RFC 2616 A.2. Changes from RFC 2616
This document takes over the Status Code Registry, previously defined This document takes over the Status Code Registry, previously defined
in Section 7.1 of [RFC2817]. (Section 5.1) in Section 7.1 of [RFC2817]. (Section 4.1)
Clarify definition of POST. (Section 8.5) Clarify definition of POST. (Section 7.5)
Failed to consider that there are many other request methods that are Failed to consider that there are many other request methods that are
safe to automatically redirect, and further that the user agent is safe to automatically redirect, and further that the user agent is
able to make that determination based on the request method able to make that determination based on the request method
semantics. (Sections 9.3.2, 9.3.3 and 9.3.8) semantics. (Sections 8.3.2, 8.3.3 and 8.3.8)
Deprecate 305 Use Proxy status code, because user agents did not Deprecate 305 Use Proxy status code, because user agents did not
implement it. It used to indicate that the requested resource must implement it. It used to indicate that the requested resource must
be accessed through the proxy given by the Location field. The be accessed through the proxy given by the Location field. The
Location field gave the URI of the proxy. The recipient was expected Location field gave the URI of the proxy. The recipient was expected
to repeat this single request via the proxy. (Section 9.3.6) to repeat this single request via the proxy. (Section 8.3.6)
Reclassify Allow header as response header, removing the option to Reclassify Allow header as response header, removing the option to
specify it in a PUT request. Relax the server requirement on the specify it in a PUT request. Relax the server requirement on the
contents of the Allow header and remove requirement on clients to contents of the Allow header and remove requirement on clients to
always trust the header value. (Section 10.1) always trust the header value. (Section 9.1)
Correct syntax of Location header to allow fragment, as referred Correct syntax of Location header to allow fragment, as referred
symbol wasn't what was expected, and add some clarifications as to symbol wasn't what was expected, and add some clarifications as to
when it would not be appropriate. (Section 10.4) when it would not be appropriate. (Section 9.4)
In the description of the Server header, the Via field was described In the description of the Server header, the Via field was described
as a SHOULD. The requirement was and is stated correctly in the as a SHOULD. The requirement was and is stated correctly in the
description of the Via header in Section 8.9 of [Part1]. description of the Via header in Section 8.9 of [Part1].
(Section 10.8) (Section 9.8)
Appendix B. Change Log (to be removed by RFC Editor before publication) Appendix B. Collected ABNF
B.1. Since RFC2616 Accept = <Accept, defined in [Part3], Section 5.1>
Accept-Charset = <Accept-Charset, defined in [Part3], Section 5.2>
Accept-Encoding = <Accept-Encoding, defined in [Part3], Section 5.3>
Accept-Language = <Accept-Language, defined in [Part3], Section 5.4>
Accept-Ranges = <Accept-Ranges, defined in [Part5], Section 5.1>
Age = <Age, defined in [Part6], Section 3.1>
Allow = "Allow:" OWS Allow-v
Allow-v = [ ( "," / Method ) *( OWS "," [ OWS Method ] ) ]
Authorization = <Authorization, defined in [Part7], Section 3.1>
ETag = <ETag, defined in [Part4], Section 6.1>
Expect = "Expect:" OWS Expect-v
Expect-v = *( "," OWS ) expectation *( OWS "," [ OWS expectation ] )
From = "From:" OWS From-v
From-v = mailbox
HTTP-date = <HTTP-date, defined in [Part1], Section 3.2.1>
Host = <Host, defined in [Part1], Section 2.1>
If-Match = <If-Match, defined in [Part4], Section 6.2>
If-Modified-Since =
<If-Modified-Since, defined in [Part4], Section 6.3>
If-None-Match = <If-None-Match, defined in [Part4], Section 6.4>
If-Range = <If-Range, defined in [Part5], Section 5.3>
If-Unmodified-Since =
<If-Unmodified-Since, defined in [Part4], Section 6.5>
Location = "Location:" OWS Location-v
Location-v = absolute-URI [ "#" fragment ]
Max-Forwards = "Max-Forwards:" OWS Max-Forwards-v
Max-Forwards-v = 1*DIGIT
Method = %x4F.50.54.49.4F.4E.53 / %x47.45.54 / %x48.45.41.44 /
%x50.4F.54 / %x50.55.54 / %x44.45.4C.45.54.45 / %x54.52.41.43.45 /
%x43.4E.4E.45.43.54 / extension-method
OWS = <OWS, defined in [Part1], Section 1.2.2>
Proxy-Authenticate =
<Proxy-Authenticate, defined in [Part7], Section 3.2>
Proxy-Authorization =
<Proxy-Authorization, defined in [Part7], Section 3.3>
RWS = <RWS, defined in [Part1], Section 1.2.2>
Range = <Range, defined in [Part5], Section 5.4>
Reason-Phrase = *( WSP / VCHAR / obs-text )
Referer = "Referer:" OWS Referer-v
Referer-v = absolute-URI / partial-URI
Retry-After = "Retry-After:" OWS Retry-After-v
Retry-After-v = HTTP-date / delta-seconds
Server = "Server:" OWS Server-v
Server-v = product *( RWS ( product / comment ) )
Status-Code = "100" / "101" / "200" / "201" / "202" / "203" / "204" /
"205" / "206" / "300" / "301" / "302" / "303" / "304" / "305" /
"307" / "400" / "401" / "402" / "403" / "404" / "405" / "406" /
"407" / "408" / "409" / "410" / "411" / "412" / "413" / "414" /
"415" / "416" / "417" / "500" / "501" / "502" / "503" / "504" /
"505" / extension-code
TE = <TE, defined in [Part1], Section 8.8>
User-Agent = "User-Agent:" OWS User-Agent-v
User-Agent-v = product *( RWS ( product / comment ) )
Vary = <Vary, defined in [Part6], Section 3.5>
WWW-Authenticate =
<WWW-Authenticate, defined in [Part7], Section 3.4>
absolute-URI = <absolute-URI, defined in [Part1], Section 2.1>
comment = <comment, defined in [Part1], Section 1.2.2>
delta-seconds = 1*DIGIT
expect-params = ";" token [ "=" ( token / quoted-string ) ]
expectation = "100-continue" / expectation-extension
expectation-extension = token [ "=" ( token / quoted-string )
*expect-params ]
extension-code = 3DIGIT
extension-method = token
fragment = <fragment, defined in [Part1], Section 2.1>
mailbox = <mailbox, defined in [RFC5322], Section 3.4>
obs-text = <obs-text, defined in [Part1], Section 1.2.2>
partial-URI = <partial-URI, defined in [Part1], Section 2.1>
product = <product, defined in [Part1], Section 3.4>
quoted-string = <quoted-string, defined in [Part1], Section 1.2.2>
request-header = Accept / Accept-Charset / Accept-Encoding /
Accept-Language / Authorization / Expect / From / Host / If-Match /
If-Modified-Since / If-None-Match / If-Range / If-Unmodified-Since /
Max-Forwards / Proxy-Authorization / Range / Referer / TE /
User-Agent
response-header = Accept-Ranges / Age / Allow / ETag / Location /
Proxy-Authenticate / Retry-After / Server / Vary / WWW-Authenticate
token = <token, defined in [Part1], Section 1.2.2>
ABNF diagnostics:
; Reason-Phrase defined but not used
; Status-Code defined but not used
; request-header defined but not used
; response-header defined but not used
Appendix C. Change Log (to be removed by RFC Editor before publication)
C.1. Since RFC2616
Extracted relevant partitions from [RFC2616]. Extracted relevant partitions from [RFC2616].
B.2. Since draft-ietf-httpbis-p2-semantics-00 C.2. Since draft-ietf-httpbis-p2-semantics-00
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/5>: "Via is a MUST" o <http://tools.ietf.org/wg/httpbis/trac/ticket/5>: "Via is a MUST"
(<http://purl.org/NET/http-errata#via-must>) (<http://purl.org/NET/http-errata#via-must>)
o <http://tools.ietf.org/wg/httpbis/trac/ticket/6>: "Fragments o <http://tools.ietf.org/wg/httpbis/trac/ticket/6>: "Fragments
allowed in Location" allowed in Location"
(<http://purl.org/NET/http-errata#location-fragments>) (<http://purl.org/NET/http-errata#location-fragments>)
skipping to change at page 45, line 14 skipping to change at page 47, line 45
o <http://tools.ietf.org/wg/httpbis/trac/ticket/65>: "Informative o <http://tools.ietf.org/wg/httpbis/trac/ticket/65>: "Informative
references" references"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/84>: "Redundant o <http://tools.ietf.org/wg/httpbis/trac/ticket/84>: "Redundant
cross-references" cross-references"
Other changes: Other changes:
o Move definitions of 304 and 412 condition codes to [Part4] o Move definitions of 304 and 412 condition codes to [Part4]
B.3. Since draft-ietf-httpbis-p2-semantics-01 C.3. Since draft-ietf-httpbis-p2-semantics-01
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/21>: "PUT side o <http://tools.ietf.org/wg/httpbis/trac/ticket/21>: "PUT side
effects" effects"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/91>: "Duplicate Host o <http://tools.ietf.org/wg/httpbis/trac/ticket/91>: "Duplicate Host
header requirements" header requirements"
Ongoing work on ABNF conversion Ongoing work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Move "Product Tokens" section (back) into Part 1, as "token" is o Move "Product Tokens" section (back) into Part 1, as "token" is
used in the definition of the Upgrade header. used in the definition of the Upgrade header.
o Add explicit references to BNF syntax and rules imported from o Add explicit references to BNF syntax and rules imported from
skipping to change at page 45, line 36 skipping to change at page 48, line 19
o Move "Product Tokens" section (back) into Part 1, as "token" is o Move "Product Tokens" section (back) into Part 1, as "token" is
used in the definition of the Upgrade header. used in the definition of the Upgrade header.
o Add explicit references to BNF syntax and rules imported from o Add explicit references to BNF syntax and rules imported from
other parts of the specification. other parts of the specification.
o Copy definition of delta-seconds from Part6 instead of referencing o Copy definition of delta-seconds from Part6 instead of referencing
it. it.
B.4. Since draft-ietf-httpbis-p2-semantics-02 C.4. Since draft-ietf-httpbis-p2-semantics-02
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/24>: "Requiring o <http://tools.ietf.org/wg/httpbis/trac/ticket/24>: "Requiring
Allow in 405 responses" Allow in 405 responses"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/59>: "Status Code o <http://tools.ietf.org/wg/httpbis/trac/ticket/59>: "Status Code
Registry" Registry"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/61>: "Redirection o <http://tools.ietf.org/wg/httpbis/trac/ticket/61>: "Redirection
skipping to change at page 46, line 24 skipping to change at page 49, line 8
o Reference RFC 3984, and update header registrations for headers o Reference RFC 3984, and update header registrations for headers
defined in this document. defined in this document.
Ongoing work on ABNF conversion Ongoing work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Replace string literals when the string really is case-sensitive o Replace string literals when the string really is case-sensitive
(method). (method).
B.5. Since draft-ietf-httpbis-p2-semantics-03 C.5. Since draft-ietf-httpbis-p2-semantics-03
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/98>: "OPTIONS o <http://tools.ietf.org/wg/httpbis/trac/ticket/98>: "OPTIONS
request bodies" request bodies"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/119>: "Description o <http://tools.ietf.org/wg/httpbis/trac/ticket/119>: "Description
of CONNECT should refer to RFC2817" of CONNECT should refer to RFC2817"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/125>: "Location o <http://tools.ietf.org/wg/httpbis/trac/ticket/125>: "Location
Content-Location reference request/response mixup" Content-Location reference request/response mixup"
Ongoing work on Method Registry Ongoing work on Method Registry
(<http://tools.ietf.org/wg/httpbis/trac/ticket/72>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/72>):
o Added initial proposal for registration process, plus initial o Added initial proposal for registration process, plus initial
content (non-HTTP/1.1 methods to be added by a separate content (non-HTTP/1.1 methods to be added by a separate
specification). specification).
B.6. Since draft-ietf-httpbis-p2-semantics-04 C.6. Since draft-ietf-httpbis-p2-semantics-04
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/103>: "Content-*" o <http://tools.ietf.org/wg/httpbis/trac/ticket/103>: "Content-*"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/132>: "RFC 2822 is o <http://tools.ietf.org/wg/httpbis/trac/ticket/132>: "RFC 2822 is
updated by RFC 5322" updated by RFC 5322"
Ongoing work on ABNF conversion Ongoing work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Use "/" instead of "|" for alternatives. o Use "/" instead of "|" for alternatives.
o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
whitespace ("OWS") and required whitespace ("RWS"). whitespace ("OWS") and required whitespace ("RWS").
o Rewrite ABNFs to spell out whitespace rules, factor out header o Rewrite ABNFs to spell out whitespace rules, factor out header
value format definitions. value format definitions.
skipping to change at page 47, line 15 skipping to change at page 49, line 48
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Use "/" instead of "|" for alternatives. o Use "/" instead of "|" for alternatives.
o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
whitespace ("OWS") and required whitespace ("RWS"). whitespace ("OWS") and required whitespace ("RWS").
o Rewrite ABNFs to spell out whitespace rules, factor out header o Rewrite ABNFs to spell out whitespace rules, factor out header
value format definitions. value format definitions.
C.7. Since draft-ietf-httpbis-p2-semantics-05
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/94>: "Reason-Phrase
BNF"
Final work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Add appendix containing collected and expanded ABNF, reorganize
ABNF introduction.
Index Index
1 1
100 Continue (status code) 19 100 Continue (status code) 20
101 Switching Protocols (status code) 20 101 Switching Protocols (status code) 20
2 2
200 OK (status code) 20 200 OK (status code) 20
201 Created (status code) 20 201 Created (status code) 21
202 Accepted (status code) 21 202 Accepted (status code) 21
203 Non-Authoritative Information (status code) 21 203 Non-Authoritative Information (status code) 21
204 No Content (status code) 21 204 No Content (status code) 22
205 Reset Content (status code) 22 205 Reset Content (status code) 22
206 Partial Content (status code) 22 206 Partial Content (status code) 22
3 3
300 Multiple Choices (status code) 22 300 Multiple Choices (status code) 23
301 Moved Permanently (status code) 23 301 Moved Permanently (status code) 23
302 Found (status code) 23 302 Found (status code) 24
303 See Other (status code) 24 303 See Other (status code) 24
304 Not Modified (status code) 25 304 Not Modified (status code) 25
305 Use Proxy (status code) 25 305 Use Proxy (status code) 25
306 (Unused) (status code) 25 306 (Unused) (status code) 25
307 Temporary Redirect (status code) 25 307 Temporary Redirect (status code) 25
4 4
400 Bad Request (status code) 26 400 Bad Request (status code) 26
401 Unauthorized (status code) 26 401 Unauthorized (status code) 26
402 Payment Required (status code) 26 402 Payment Required (status code) 26
403 Forbidden (status code) 26 403 Forbidden (status code) 26
404 Not Found (status code) 26 404 Not Found (status code) 27
405 Method Not Allowed (status code) 27 405 Method Not Allowed (status code) 27
406 Not Acceptable (status code) 27 406 Not Acceptable (status code) 27
407 Proxy Authentication Required (status code) 27 407 Proxy Authentication Required (status code) 27
408 Request Timeout (status code) 27 408 Request Timeout (status code) 28
409 Conflict (status code) 27 409 Conflict (status code) 28
410 Gone (status code) 28 410 Gone (status code) 28
411 Length Required (status code) 28 411 Length Required (status code) 29
412 Precondition Failed (status code) 28 412 Precondition Failed (status code) 29
413 Request Entity Too Large (status code) 29 413 Request Entity Too Large (status code) 29
414 Request-URI Too Long (status code) 29 414 URI Too Long (status code) 29
415 Unsupported Media Type (status code) 29 415 Unsupported Media Type (status code) 29
416 Requested Range Not Satisfiable (status code) 29 416 Requested Range Not Satisfiable (status code) 29
417 Expectation Failed (status code) 29 417 Expectation Failed (status code) 30
5 5
500 Internal Server Error (status code) 30 500 Internal Server Error (status code) 30
501 Not Implemented (status code) 30 501 Not Implemented (status code) 30
502 Bad Gateway (status code) 30 502 Bad Gateway (status code) 30
503 Service Unavailable (status code) 30 503 Service Unavailable (status code) 30
504 Gateway Timeout (status code) 30 504 Gateway Timeout (status code) 31
505 HTTP Version Not Supported (status code) 31 505 HTTP Version Not Supported (status code) 31
A A
Allow header 31 Allow header 31
C C
CONNECT method 19 CONNECT method 19
D D
DELETE method 18 DELETE method 18
E E
Expect header 31 Expect header 32
F F
From header 32 From header 33
G G
GET method 15 GET method 15
Grammar Grammar
Allow 31 Allow 31
Allow-v 31 Allow-v 31
delta-seconds 35 delta-seconds 35
Expect 32 Expect 32
expect-params 32 expect-params 32
Expect-v 32 Expect-v 32
expectation 32 expectation 32
expectation-extension 32 expectation-extension 32
extension-code 11 extension-code 11
extension-method 8 extension-method 8
From 32 From 33
From-v 32 From-v 33
Location 33 Location 33
Location-v 33 Location-v 33
Max-Forwards 34 Max-Forwards 34
Max-Forwards-v 34 Max-Forwards-v 34
Method 8 Method 8
Reason-Phrase 11 Reason-Phrase 11
Referer 35 Referer 35
Referer-v 35 Referer-v 35
request-header 9 request-header 9
response-header 12 response-header 12
skipping to change at page 49, line 25 skipping to change at page 52, line 23
Server 36 Server 36
Server-v 36 Server-v 36
Status-Code 11 Status-Code 11
User-Agent 36 User-Agent 36
User-Agent-v 36 User-Agent-v 36
H H
HEAD method 16 HEAD method 16
Headers Headers
Allow 31 Allow 31
Expect 31 Expect 32
From 32 From 33
Location 33 Location 33
Max-Forwards 34 Max-Forwards 34
Referer 34 Referer 35
Retry-After 35 Retry-After 35
Server 35 Server 36
User-Agent 36 User-Agent 36
I I
Idempotent Methods 14 Idempotent Methods 14
L L
LINK method 43 LINK method 43
Location header 33 Location header 33
M M
skipping to change at page 50, line 17 skipping to change at page 53, line 15
O O
OPTIONS method 14 OPTIONS method 14
P P
PATCH method 43 PATCH method 43
POST method 16 POST method 16
PUT method 17 PUT method 17
R R
Referer header 34 Referer header 35
Retry-After header 35 Retry-After header 35
S S
Safe Methods 13 Safe Methods 13
Server header 35 Server header 36
Status Codes Status Codes
100 Continue 19 100 Continue 20
101 Switching Protocols 20 101 Switching Protocols 20
200 OK 20 200 OK 20
201 Created 20 201 Created 21
202 Accepted 21 202 Accepted 21
203 Non-Authoritative Information 21 203 Non-Authoritative Information 21
204 No Content 21 204 No Content 22
205 Reset Content 22 205 Reset Content 22
206 Partial Content 22 206 Partial Content 22
300 Multiple Choices 22 300 Multiple Choices 23
301 Moved Permanently 23 301 Moved Permanently 23
302 Found 23 302 Found 24
303 See Other 24 303 See Other 24
304 Not Modified 25 304 Not Modified 25
305 Use Proxy 25 305 Use Proxy 25
306 (Unused) 25 306 (Unused) 25
307 Temporary Redirect 25 307 Temporary Redirect 25
400 Bad Request 26 400 Bad Request 26
401 Unauthorized 26 401 Unauthorized 26
402 Payment Required 26 402 Payment Required 26
403 Forbidden 26 403 Forbidden 26
404 Not Found 26 404 Not Found 27
405 Method Not Allowed 27 405 Method Not Allowed 27
406 Not Acceptable 27 406 Not Acceptable 27
407 Proxy Authentication Required 27 407 Proxy Authentication Required 27
408 Request Timeout 27 408 Request Timeout 28
409 Conflict 27 409 Conflict 28
410 Gone 28 410 Gone 28
411 Length Required 28 411 Length Required 29
412 Precondition Failed 28 412 Precondition Failed 29
413 Request Entity Too Large 29 413 Request Entity Too Large 29
414 Request-URI Too Long 29 414 URI Too Long 29
415 Unsupported Media Type 29 415 Unsupported Media Type 29
416 Requested Range Not Satisfiable 29 416 Requested Range Not Satisfiable 29
417 Expectation Failed 29 417 Expectation Failed 30
500 Internal Server Error 30 500 Internal Server Error 30
501 Not Implemented 30 501 Not Implemented 30
502 Bad Gateway 30 502 Bad Gateway 30
503 Service Unavailable 30 503 Service Unavailable 30
504 Gateway Timeout 30 504 Gateway Timeout 31
505 HTTP Version Not Supported 31 505 HTTP Version Not Supported 31
T T
TRACE method 18 TRACE method 18
U U
UNLINK method 43 UNLINK method 43
User-Agent header 36 User-Agent header 36
Authors' Addresses Authors' Addresses
skipping to change at page 54, line 4 skipping to change at line 2528
Julian F. Reschke (editor) Julian F. Reschke (editor)
greenbytes GmbH greenbytes GmbH
Hafenweg 16 Hafenweg 16
Muenster, NW 48155 Muenster, NW 48155
Germany Germany
Phone: +49 251 2807760 Phone: +49 251 2807760
Fax: +49 251 2807761 Fax: +49 251 2807761
Email: julian.reschke@greenbytes.de Email: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/ URI: http://greenbytes.de/tech/webdav/
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contained in BCP 78, and except as set forth therein, the authors
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