idnits 2.17.1
draft-ietf-httpbis-cice-02.txt:
Checking boilerplate required by RFC 5378 and the IETF Trust (see
https://trustee.ietf.org/license-info):
----------------------------------------------------------------------------
No issues found here.
Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt:
----------------------------------------------------------------------------
No issues found here.
Checking nits according to https://www.ietf.org/id-info/checklist :
----------------------------------------------------------------------------
No issues found here.
Miscellaneous warnings:
----------------------------------------------------------------------------
== The copyright year in the IETF Trust and authors Copyright Line does not
match the current year
-- The document date (August 13, 2015) is 3184 days in the past. Is this
intentional?
Checking references for intended status: Proposed Standard
----------------------------------------------------------------------------
(See RFCs 3967 and 4897 for information about using normative references
to lower-maturity documents in RFCs)
** Obsolete normative reference: RFC 7230 (Obsoleted by RFC 9110, RFC 9112)
** Obsolete normative reference: RFC 7231 (Obsoleted by RFC 9110)
Summary: 2 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--).
Run idnits with the --verbose option for more detailed information about
the items above.
--------------------------------------------------------------------------------
2 HTTP Working Group J. Reschke
3 Internet-Draft greenbytes
4 Intended status: Standards Track August 13, 2015
5 Expires: February 14, 2016
7 Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding
8 draft-ietf-httpbis-cice-02
10 Abstract
12 In HTTP, content codings allow for payload encodings such as for
13 compression or integrity checks. In particular, the "gzip" content
14 coding is widely used for payload data sent in response messages.
16 Content codings can be used in request messages as well, however
17 discoverability is not on par with response messages. This document
18 extends the HTTP "Accept-Encoding" header field for use in responses,
19 to indicate the content codings that are supported in requests.
21 Editorial Note (To be removed by RFC Editor before publication)
23 Discussion of this draft takes place on the HTTPBIS working group
24 mailing list (ietf-http-wg@w3.org), which is archived at
25 .
27 Working Group information can be found at
28 and ;
29 source code and issues list for this draft can be found at
30 .
32 The changes in this draft are summarized in Appendix A.5.
34 Status of This Memo
36 This Internet-Draft is submitted in full conformance with the
37 provisions of BCP 78 and BCP 79.
39 Internet-Drafts are working documents of the Internet Engineering
40 Task Force (IETF). Note that other groups may also distribute
41 working documents as Internet-Drafts. The list of current Internet-
42 Drafts is at http://datatracker.ietf.org/drafts/current/.
44 Internet-Drafts are draft documents valid for a maximum of six months
45 and may be updated, replaced, or obsoleted by other documents at any
46 time. It is inappropriate to use Internet-Drafts as reference
47 material or to cite them other than as "work in progress."
48 This Internet-Draft will expire on February 14, 2016.
50 Copyright Notice
52 Copyright (c) 2015 IETF Trust and the persons identified as the
53 document authors. All rights reserved.
55 This document is subject to BCP 78 and the IETF Trust's Legal
56 Provisions Relating to IETF Documents
57 (http://trustee.ietf.org/license-info) in effect on the date of
58 publication of this document. Please review these documents
59 carefully, as they describe your rights and restrictions with respect
60 to this document. Code Components extracted from this document must
61 include Simplified BSD License text as described in Section 4.e of
62 the Trust Legal Provisions and are provided without warranty as
63 described in the Simplified BSD License.
65 Table of Contents
67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
68 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
69 3. Using the 'Accept-Encoding' Header Field in Responses . . . . . 3
70 4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
71 5. Deployment Considerations . . . . . . . . . . . . . . . . . . . 5
72 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
73 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
74 7.1. Header Field Registry . . . . . . . . . . . . . . . . . . . 5
75 7.2. Status Code Registry . . . . . . . . . . . . . . . . . . . 6
76 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
77 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6
78 8.2. Informative References . . . . . . . . . . . . . . . . . . 6
79 Appendix A. Change Log (to be removed by RFC Editor before
80 publication) . . . . . . . . . . . . . . . . . . . . . 7
81 A.1. Since draft-reschke-http-cice-00 . . . . . . . . . . . . . 7
82 A.2. Since draft-reschke-http-cice-01 . . . . . . . . . . . . . 7
83 A.3. Since draft-reschke-http-cice-02 . . . . . . . . . . . . . 7
84 A.4. Since draft-ietf-httpbis-cice-00 . . . . . . . . . . . . . 7
85 A.5. Since draft-ietf-httpbis-cice-01 . . . . . . . . . . . . . 7
86 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . . 7
88 1. Introduction
90 In HTTP, content codings allow for payload encodings such as for
91 compression or integrity checks ([RFC7231], Section 3.1.2). In
92 particular, the "gzip" content coding is widely used for payload data
93 sent in response messages.
95 Content codings can be used in request messages as well, however
96 discoverability is not on par with response messages. This document
97 extends the HTTP "Accept-Encoding" header field ([RFC7231], Section
98 5.3.4) for use in responses, to indicate the content codings that are
99 supported in requests. It furthermore updates the definition of
100 status code 415 (Unsupported Media Type) ([RFC7231], Section 6.5.13),
101 recommending to include the "Accept-Encoding" header field when
102 appropriate.
104 2. Notational Conventions
106 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
107 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
108 document are to be interpreted as described in [RFC2119].
110 This document reuses terminology defined in the base HTTP
111 specifications, namely Section 2 of [RFC7230] and Section 3.1.2 of
112 [RFC7231].
114 3. Using the 'Accept-Encoding' Header Field in Responses
116 Section 5.3.4 of [RFC7231] defines "Accept-Encoding" as a request
117 header field only.
119 This specification expands that definition to allow "Accept-Encoding"
120 as a response header field as well. When present in a response, it
121 indicates what content codings the resource was willing to accept in
122 the associated request. A field value that only contains "identity"
123 implies that no content codings were supported.
125 Note that this information is specific to the associated request; the
126 set of supported encodings might be different for other resources on
127 the same server, and could change over time or depend on other
128 aspects of the request (such as the request method).
130 Section 6.5.13 of [RFC7231] defines status code 415 (Unsupported
131 Media Type) to apply to both media type and content coding related
132 problems.
134 Servers that fail a request due to an unsupported content coding
135 SHOULD respond with a 415 status and SHOULD include an "Accept-
136 Encoding" header field in that response, allowing clients to
137 distinguish between content coding related issues and media type
138 related issues. In order to avoid confusion with media type related
139 problems, servers that fail a request with a 415 status for reasons
140 unrelated to content codings SHOULD NOT include the "Accept-Encoding"
141 header field.
143 It is expected that the most common use of "Accept-Encoding" in
144 responses will have the 415 (Unsupported Media Type) status code, in
145 response to optimistic use of a content coding by clients. However,
146 the header field can also be used to indicate to clients that content
147 codings are supported, to optimize future interactions. For example,
148 a resource might include it in a 2xx response when the request
149 payload was big enough to justify use of a compression coding, but
150 the client failed do so.
152 4. Example
154 A client submits a POST request using the "compress" content coding
155 ([RFC7231], Section 3.1.2.1):
157 POST /edit/ HTTP/1.1
158 Host: example.org
159 Content-Type: application/atom+xml;type=entry
160 Content-Encoding: compress
162 ...compressed payload...
164 The server rejects request because it only allows the "gzip" content
165 coding:
167 HTTP/1.1 415 Unsupported Media Type
168 Date: Fri, 09 May 2014 11:43:53 GMT
169 Accept-Encoding: gzip
170 Content-Length: 68
171 Content-Type: text/plain
173 This resource only supports the "gzip" content coding in requests.
175 ...at which point the client can retry the request with the supported
176 "gzip" content coding.
178 Alternatively, a server that does not support any content codings in
179 requests could answer with:
181 HTTP/1.1 415 Unsupported Media Type
182 Date: Fri, 09 May 2014 11:43:53 GMT
183 Accept-Encoding: identity
184 Content-Length: 61
185 Content-Type: text/plain
187 This resource does not support content codings in requests.
189 5. Deployment Considerations
191 Servers that do not support content codings in requests already are
192 required to fail a request that uses a content coding. Section
193 6.5.13 of [RFC7231] defines the status code 415 (Unsupported Media
194 Type) for this purpose, so the only change needed is to include the
195 "Accept-Encoding" header field with value "identity" in that
196 response.
198 Servers that do support some content codings are required to fail
199 requests with unsupported content codings as well. To be compliant
200 with this specification, servers will need to use the status code 415
201 (Unsupported Media Type) to signal the problem, and will have to
202 include an "Accept-Encoding" header field that enumerates the content
203 codings that are supported. As the set of supported content codings
204 is usually static and small, adding the header field ought to be
205 trivial.
207 6. Security Considerations
209 This specification does not introduce any new security considerations
210 beyond those discussed in Section 9 of [RFC7231].
212 7. IANA Considerations
214 7.1. Header Field Registry
216 HTTP header fields are registered within the "Message Headers"
217 registry located at
218 , as defined by
219 [BCP90].
221 This document updates the definition of the "Accept-Encoding" header
222 field, so the "Permanent Message Header Field Names" registry ought
223 to be updated accordingly:
225 +-----------------+----------+----------+---------------------------+
226 | Header Field | Protocol | Status | Reference |
227 | Name | | | |
228 +-----------------+----------+----------+---------------------------+
229 | Accept-Encoding | http | standard | [RFC7231], Section 5.3.4, |
230 | | | | and Section 3 of this |
231 | | | | document |
232 +-----------------+----------+----------+---------------------------+
234 7.2. Status Code Registry
236 HTTP status codes are registered within the "Status Code" registry
237 located at .
239 This document updates the definition of the status code 415
240 (Unsupported Media Type), so the "Status Code" registry ought to be
241 updated accordingly:
243 +-------+------------------+----------------------------------------+
244 | Value | Description | Reference |
245 +-------+------------------+----------------------------------------+
246 | 415 | Unsupported | [RFC7231], Section 6.5.13, and |
247 | | Media Type | Section 3 of this document |
248 +-------+------------------+----------------------------------------+
250 8. References
252 8.1. Normative References
254 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
255 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
256 RFC2119, March 1997,
257 .
259 [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
260 Protocol (HTTP/1.1): Message Syntax and Routing",
261 RFC 7230, DOI 10.17487/RFC7230, June 2014,
262 .
264 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
265 Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
266 DOI 10.17487/RFC7231, June 2014,
267 .
269 8.2. Informative References
271 [BCP90] Klyne, G., Nottingham, M., and J. Mogul, "Registration
272 Procedures for Message Header Fields", BCP 90, RFC 3864,
273 September 2004, .
275 Appendix A. Change Log (to be removed by RFC Editor before publication)
277 A.1. Since draft-reschke-http-cice-00
279 Clarified that the information returned in Accept-Encoding is per
280 resource, not per server.
282 Added some deployment considerations.
284 Updated HTTP/1.1 references.
286 A.2. Since draft-reschke-http-cice-01
288 Restrict the scope of A-E from "future requests" to "at the time of
289 this request".
291 Mention use of A-E in responses other than 415.
293 Recommend not to include A-E in a 415 response unless there was
294 actually a problem related to content coding.
296 A.3. Since draft-reschke-http-cice-02
298 First Working Group draft; updated boilerplate accordingly.
300 A.4. Since draft-ietf-httpbis-cice-00
302 Apply editorial improvements suggested by Mark Nottingham.
304 A.5. Since draft-ietf-httpbis-cice-01
306 Clarify that we're also extending the definition of status code 415
307 (so update that IANA registry entry as well).
309 Appendix B. Acknowledgements
311 Thanks go to the members of the and HTTPbis Working Group, namely
312 Amos Jeffries, Mark Nottingham, Pete Resnick, and Ted Hardie.
314 Author's Address
316 Julian F. Reschke
317 greenbytes GmbH
318 Hafenweg 16
319 Muenster, NW 48155
320 Germany
322 EMail: julian.reschke@greenbytes.de
323 URI: http://greenbytes.de/tech/webdav/