idnits 2.17.1
draft-snell-atompub-feed-expires-00.txt:
Checking boilerplate required by RFC 5378 and the IETF Trust (see
https://trustee.ietf.org/license-info):
----------------------------------------------------------------------------
** It looks like you're using RFC 3978 boilerplate. You should update this
to the boilerplate described in the IETF Trust License Policy document
(see https://trustee.ietf.org/license-info), which is required now.
-- Found old boilerplate from RFC 3978, Section 5.1 on line 15.
-- Found old boilerplate from RFC 3978, Section 5.5 on line 317.
-- Found old boilerplate from RFC 3979, Section 5, paragraph 1 on line 294.
-- Found old boilerplate from RFC 3979, Section 5, paragraph 2 on line 301.
-- Found old boilerplate from RFC 3979, Section 5, paragraph 3 on line 307.
** This document has an original RFC 3978 Section 5.4 Copyright Line,
instead of the newer IETF Trust Copyright according to RFC 4748.
** This document has an original RFC 3978 Section 5.5 Disclaimer, instead
of the newer disclaimer which includes the IETF Trust according to RFC
4748.
Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt:
----------------------------------------------------------------------------
== No 'Intended status' indicated for this document; assuming Proposed
Standard
Checking nits according to https://www.ietf.org/id-info/checklist :
----------------------------------------------------------------------------
** The document seems to lack separate sections for Informative/Normative
References. All references will be assumed normative when checking for
downward references.
Miscellaneous warnings:
----------------------------------------------------------------------------
== The copyright year in the RFC 3978 Section 5.4 Copyright Line does not
match the current year
-- The document seems to lack a disclaimer for pre-RFC5378 work, but may
have content which was first submitted before 10 November 2008. If you
have contacted all the original authors and they are all willing to grant
the BCP78 rights to the IETF Trust, then this is fine, and you can ignore
this comment. If not, you may need to add the pre-RFC5378 disclaimer.
(See the Legal Provisions document at
https://trustee.ietf.org/license-info for more information.)
-- The document date (August 16, 2005) is 6827 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)
== Unused Reference: 'I-D.ietf-atompub-format' is defined on line 248, but
no explicit reference was found in the text
Summary: 4 errors (**), 0 flaws (~~), 3 warnings (==), 7 comments (--).
Run idnits with the --verbose option for more detailed information about
the items above.
--------------------------------------------------------------------------------
2 Network Working Group J. Snell
3 Internet-Draft August 16, 2005
4 Expires: February 17, 2006
6 Atom Entry Expiration: Specifying Expiration Timestamps for Atom Entry
7 metadata
8 draft-snell-atompub-feed-expires-00.txt
10 Status of this Memo
12 By submitting this Internet-Draft, each author represents that any
13 applicable patent or other IPR claims of which he or she is aware
14 have been or will be disclosed, and any of which he or she becomes
15 aware will be disclosed, in accordance with Section 6 of BCP 79.
17 Internet-Drafts are working documents of the Internet Engineering
18 Task Force (IETF), its areas, and its working groups. Note that
19 other groups may also distribute working documents as Internet-
20 Drafts.
22 Internet-Drafts are draft documents valid for a maximum of six months
23 and may be updated, replaced, or obsoleted by other documents at any
24 time. It is inappropriate to use Internet-Drafts as reference
25 material or to cite them other than as "work in progress."
27 The list of current Internet-Drafts can be accessed at
28 http://www.ietf.org/ietf/1id-abstracts.txt.
30 The list of Internet-Draft Shadow Directories can be accessed at
31 http://www.ietf.org/shadow.html.
33 This Internet-Draft will expire on February 17, 2006.
35 Copyright Notice
37 Copyright (C) The Internet Society (2005).
39 Abstract
41 This memo presents a mechanism that allows feed publishers to express
42 maximum age and expiration properties for information content within
43 an Atom entry.
45 Table of Contents
47 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
48 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
49 3. The 'expires' extension element . . . . . . . . . . . . . . . 4
50 4. The 'max-age' extension element . . . . . . . . . . . . . . . 5
51 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
52 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
53 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
54 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 7
55 A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
56 Intellectual Property and Copyright Statements . . . . . . . . 8
58 1. Introduction
60 This document specifies a mechanism that allows the expression of
61 expiration timestamps and maximum age properties for information
62 content within the Atom Syndication Format ([I-D.ietf-atompub-
63 format]). The mechanism defines two mutually exclusive extension
64 elements that may be used to specify either an exact instant that the
65 information content of an atom:entry expires, or a maximum age from
66 the moment specified by an entries atom:updated element.
68 When an entry contains an 'expires' or 'max-age' extension element,
69 the information content of that entry is considered to be 'time
70 constrained'. Time constrainted information content is considered to
71 be either 'active' or 'expired'. The default state is 'active'.
72 When the age (calculated in miliseconds from the moment specified by
73 the atom:updated element) exceeds the value specified by the 'max-
74 age' extension, or when the moment specified by the 'expires'
75 extension elements passes, the state of the time constrained
76 information content MUST be considered to be 'expired' and no longer
77 valid. It is strongly recommended that implementations either
78 discard 'expired' entries or otherwise warn users that the
79 information content of the entry has expired.
81 The mechanism defined herein MUST NOT be used mechanism to support
82 caching of Atom documents and MUST NOT be used to schedule when a
83 client should revisit/refresh local copies of Atom documents.
84 Specifically, the 'expires' and 'max-age' extension elements are
85 relevant only to the informational content within an atom:entry and
86 are not relevant to the Atom Feed and Entry Documents in which they
87 happen to appear.
89 2. Notational Conventions
91 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
92 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
93 document are to be interpreted as described in BCP 14, [RFC2119], as
94 scoped to those conformance targets.
96 In this specification, "entry" refers to an atom:entry element.
98 In this specification, "feed" refers to an Atom Feed Document.
100 In this specification, "head section" refers to the children of a
101 feed's document-wide metadata container; e.g., the child elements of
102 the atom:feed element in an Atom Feed Document.
104 In this specification, the term "extension element" refers to a
105 structured extension element as described in [I-D.ietf-atompub-
106 format].
108 In this specification, the term "information content" refers to the
109 collection of metadata relevant to an atom:entry element.
111 This specification uses XML Namespaces [W3C.REC-xml-names-19990114]
112 to uniquely identify XML element names. It uses the following
113 namespace prefix for the indicated namespace URI;
114 "age": "http://purl.org/syndication/age/1.0"
116 This specification uses terms from the XML Infoset [W3C.REC-xml-
117 infoset-20040204]. However, this specification uses a shorthand; the
118 phrase "Information Item" is omitted when naming Element Information
119 Items. Therefore, when this specification uses the term "element,"
120 it is referring to an Element Information Item in Infoset terms.
122 This specification defines the notion of a Non-Negative Integer
123 Construct whose value MUST conform to the canonical representation of
124 the "nonNegativeInteger" construction defined by [W3C.REC-xmlschema-
125 2-20041028]. The value of the Non-Negative Integer Construct MUST
126 NOT contain any leading or trailing whitespace.
127 nonNegativeIntegerConstruct =
128 atomCommonAttributes,
129 xsd:nonNegativeInteger
131 Example Non-Negative Integer Constructs
132 0
133 1000000
135 3. The 'expires' extension element
137 The 'expires' extension element conforms to the Atom Date Construct
138 and is used to indicate a precise moment in time (inclusive) when the
139 information content of an entry expires.
140 expiresElement = element age:expires { atomDateConstruct }
142 o atom:entry elements MAY contain exactly one 'expires' extension
143 element.
144 o atom:feed elements MAY contain exactly one 'expires' extension
145 element.
146 o atom:source elements MAY contain exactly one 'expires' extension
147 element.
148 o If an atom:entry element does not contain an 'expires' extension
149 element, the 'expires' extension element of the contained atom:
150 source is considered to apply
151 o In an Atom Feed Document, if an atom:entry element or a contained
152 atom:source element do not contain an 'expires' extension element,
153 the 'expires' extension element in the feed head section are
154 considered to apply.
155 o An atom:entry that contains an 'expires' extension element MUST
156 NOT contain a 'max-age' extension element.
157 o An atom:source that contains an 'expires' extension element MUST
158 NOT contain a 'max-age' extension element.
159 o An atom:feed that contains an 'expires' extension element MUST NOT
160 contain a 'max-age' extension element.
162 For example
163
165 http://www.example.com/myfeed
166 My Example Feed
167 2005-07-28T12:00:00Z
168
169 James
170
171 tag:entries.com,2005:1
172 An entry with an expiration timestamp
173
174 2005-12-12T12:00:00Z
175 An entry with an expiration
176
177
179 While the 'expires' element MAY appear as a child of the atom:feed
180 and atom:source elements, it's effect is constrained to the
181 information content of atom:entry elements.
183 4. The 'max-age' extension element
185 The 'max-age' extension element is used to indicate the maximum age
186 of the information content in miliseconds from the moment specified
187 by the atom:updated element. The value is specified as a non-
188 negative integer conforming to the nonNegativeIntegerConstruct.
189 maxAgeElement = element age:max-age { nonNegativeIntegerConstruct }
191 o atom:entry elements MAY contain exactly one 'max-age' extension
192 element.
193 o atom:feed elements MAY contain exactly one 'max-age' extension
194 element.
195 o atom:source elements MAY contain exactly one 'max-age' extension
196 element.
197 o If an atom:entry element does not contain an 'max-age' extension
198 element, the 'max-age' extension element of the contained atom:
199 source is considered to apply
201 o In an Atom Feed Document, if an atom:entry element or a contained
202 atom:source element do not contain an 'max-age' extension element,
203 the 'max-age' extension element in the feed head section are
204 considered to apply.
205 o An atom:entry that contains an 'max-age' extension element MUST
206 NOT contain a 'expires' extension element.
207 o An atom:source that contains an 'max-age' extension element MUST
208 NOT contain a 'expires' extension element.
209 o An atom:feed that contains an 'max-age' extension element MUST NOT
210 contain a 'expires' extension element.
212 For example
213
215 http://www.example.com/myfeed
216 My Example Feed
217 2005-07-28T12:00:00Z
218
219 James
220
221 tag:entries.com,2005:1
222 An entry with a maximum age of 20 seconds
223
224 20000
225 expire after a mere 20 seconds
226
227
229 While the 'max-age' element MAY appear as a child of the atom:feed
230 and atom:source elements, it's effect is constrained to the
231 information content of atom:entry elements.
233 5. Security Considerations
235 It is possible for malicious intermediaries to alter the expiration
236 metadata for an entry. This risk can be mitigated by digitally
237 signing the atom:feed or atom:entry in which the 'expires' or 'max-
238 age' extension elements appear. It is strongly recommended that
239 implementations discard expired atom:entry elements or otherwise warn
240 users that the atom:entry has expired.
242 6. IANA Considerations
244 There are no IANA considerations introduced by this specification.
246 7. References
248 [I-D.ietf-atompub-format]
249 Sayre, R. and M. Nottingham, "The Atom Syndication
250 Format", draft-ietf-atompub-format-11 (work in progress),
251 August 2005.
253 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
254 Requirement Levels", BCP 14, RFC 2119, March 1997.
256 [W3C.REC-xml-infoset-20040204]
257 Tobin, R. and J. Cowan, "XML Information Set (Second
258 Edition)", W3C REC REC-xml-infoset-20040204,
259 February 2004.
261 [W3C.REC-xml-names-19990114]
262 Hollander, D., Bray, T., and A. Layman, "Namespaces in
263 XML", W3C REC REC-xml-names-19990114, January 1999.
265 [W3C.REC-xmlschema-2-20041028]
266 Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes
267 Second Edition", W3C REC REC-xmlschema-2-20041028,
268 October 2004.
270 Author's Address
272 James M Snell
274 Phone:
275 Email: jasnell@gmail.com
276 URI: http://snellspace.com
278 Appendix A. Acknowledgements
280 The author gratefully acknowledges the feedback from Eric Scheid,
281 Walter Underwood, Henry Story and the other members of Atom
282 Publishing Format and Protocol working group during the development
283 of this specification.
285 Intellectual Property Statement
287 The IETF takes no position regarding the validity or scope of any
288 Intellectual Property Rights or other rights that might be claimed to
289 pertain to the implementation or use of the technology described in
290 this document or the extent to which any license under such rights
291 might or might not be available; nor does it represent that it has
292 made any independent effort to identify any such rights. Information
293 on the procedures with respect to rights in RFC documents can be
294 found in BCP 78 and BCP 79.
296 Copies of IPR disclosures made to the IETF Secretariat and any
297 assurances of licenses to be made available, or the result of an
298 attempt made to obtain a general license or permission for the use of
299 such proprietary rights by implementers or users of this
300 specification can be obtained from the IETF on-line IPR repository at
301 http://www.ietf.org/ipr.
303 The IETF invites any interested party to bring to its attention any
304 copyrights, patents or patent applications, or other proprietary
305 rights that may cover technology that may be required to implement
306 this standard. Please address the information to the IETF at
307 ietf-ipr@ietf.org.
309 Disclaimer of Validity
311 This document and the information contained herein are provided on an
312 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
313 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
314 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
315 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
316 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
317 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
319 Copyright Statement
321 Copyright (C) The Internet Society (2005). This document is subject
322 to the rights, licenses and restrictions contained in BCP 78, and
323 except as set forth therein, the authors retain all their rights.
325 Acknowledgment
327 Funding for the RFC Editor function is currently provided by the
328 Internet Society.