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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group J. Snell 3 Internet-Draft August 31, 2007 4 Intended status: Standards Track 5 Expires: March 3, 2008 7 Atom Publishing Protocol Features Extension 8 draft-snell-atompub-feature-08.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 March 3, 2008. 35 Copyright Notice 37 Copyright (C) The IETF Trust (2007). 39 Abstract 41 This document introduces extensions to the Atom Publishing Protocol 42 service document format for expressing metadata about the behaviors, 43 functions and capabilities supported by an Atom Publishing Protocol 44 collection. 46 Table of Contents 48 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 49 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 50 3. The f:feature element . . . . . . . . . . . . . . . . . . . . 4 51 3.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 7 52 3.2. Contradictory Features . . . . . . . . . . . . . . . . . . 7 53 4. The f:type element . . . . . . . . . . . . . . . . . . . . . . 8 54 4.1. An example f:feature using the f:type element . . . . . . 9 55 5. Digitally Signing Service Documents . . . . . . . . . . . . . 9 56 6. The "http://purl.org/atompub/features/1.0" Namespace . . . . . 10 57 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 58 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 59 8.1. Registry of Atom Publishing Features . . . . . . . . . . . 10 60 8.1.1. Initial Assignments . . . . . . . . . . . . . . . . . 11 61 9. Normative References . . . . . . . . . . . . . . . . . . . . . 21 62 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 22 63 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 23 64 Intellectual Property and Copyright Statements . . . . . . . . . . 24 66 1. Introduction 68 This document introduces extensions for the Atom Publishing Protocol 69 service document [I-D.ietf-atompub-protocol] format for expressing 70 metadata about the behaviors, functions and capabilities supported by 71 an Atom Publishing Protocol collection. 73 2. Notational Conventions 75 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 76 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 77 document are to be interpreted as described in BCP 14, [RFC2119]. 79 This specification uses XML Namespaces [W3C.REC-xml-names-19990114] 80 to uniquely identify XML element names. It uses the following 81 namespace prefix for the indicated namespace URI; 83 "f": "http://purl.org/atompub/features/1.0" 85 This specification uses terms from the XML Infoset 86 [W3C.REC-xml-infoset-20040204]. However, this specification uses a 87 shorthand; the phrase "Information Item" is omitted when naming 88 Element Information Items. Therefore, when this specification uses 89 the terms "element" and "attribute" it is referring, respectively, to 90 the Element and Attribute Information Items in Infoset terms. 92 This specification uses the terms "atomUri" and 93 "atomCommonAttributes" from the non-normative RELAX NG Compact schema 94 included in [RFC4287]. Where used, these serve the same purpose and 95 have the same meaning as their use in [RFC4287]. 97 Atom allows the use of IRIs [RFC3987]. Every URI [RFC3986] is also 98 an IRI, so a URI may be used wherever below an IRI is named. There 99 are two special considerations: (1) when an IRI that is not also a 100 URI is given for dereferencing, it MUST be mapped to a URI using the 101 steps in Section 3.1 of [RFC3987] and (2) when an IRI is serving as 102 an identifier, it MUST NOT be so mapped. 104 Any element defined by this specification MAY have an xml:base 105 attribute [W3C.REC-xmlbase-20010627]. When xml:base is used, it 106 serves the function described in section 5.1.1 of [RFC3986], 107 establishing the base URI (or IRI) for resolving any relative 108 references found within the effective scope of the xml:base 109 attribute. 111 Any element defined by this specification MAY have an xml:lang 112 attribute, whose content indicates the natural language for the 113 element and its descendents. The language context is only 114 significant for elements and attributes declared to be "Language- 115 Sensitive". Requirements regarding the content and interpretation of 116 xml:lang are specified in XML 1.0 [W3C.REC-xml-20040204], Section 117 2.12. 119 3. The f:feature element 121 A feature is an abstract behavior, function and capability supported 122 by an Atom Publishing Protocol collection. Examples of features that 123 might be supported by an Atom publishing server include support for 124 draft entries, scheduled publication of entries, use of a particular 125 set of Atom format extensions, use of a particular authentication 126 scheme, and so on. The f:feature element can be used in an app: 127 collection element to declare that a collection supports the feature 128 specified and may require that a client use that feature when 129 interacting with the endpoint. Features are identified using 130 permanent, universally unique IRI's. 132 namespace f = "http://purl.org/atompub/features/1.0" 134 feature = element f:feature { 135 atomCommonAttributes, 136 attribute ref { atomUri }, 137 attribute status { 'supported' | 'preferred' | 138 'required' | 'unsupported'}?, 139 attribute href { atomUri }?, 140 attribute label { text }?, 141 (anyElement)* 142 } 144 anyElement = element * - f:feature { 145 (attribute * { text } 146 | text 147 | anyElement)* 148 } 150 The ref attribute specifies a globally unique IRI identifying a 151 feature supported by a collection. The value of the ref attribute 152 MUST be compared on a case-sensitive, character-by-character basis. 153 Relative references MUST NOT be used. 155 The status attribute indicates a collection's level of support for 156 the identified feature. The value of the attribute can be 157 "supported", "preferred", "required" or "unsupported". If not 158 specified, the value is assumed to be "supported". If any value 159 other than those listed in this specification is specified, the 160 attibute MUST be interpreted as being "supported". 162 Support attribute values are case-insenstive. 164 o The value "supported" indicates that the server supports the 165 identified feature. Clients MAY utilize the feature when 166 interacting with the collection. If the client does not support 167 or recognize a "supported" feature, the client can safely ignore 168 it. 169 o The value "preferred" indicates that the server prefers the use of 170 the identified feature. Clients SHOULD utilize the feature when 171 interacting with the collection. 172 o The value "required" indicates that server supports the identified 173 feature and requires that clients utilize it when interacting with 174 a collection. A client that does not support or understand a 175 required feature SHOULD NOT attempt to interact with the 176 collection. 177 o The value "unsupported" indicates that the server explicitly does 178 not support a feature. Clients SHOULD NOT utilize the feature 179 when interacting with the collection. 181 Some features supported by a collection might not require that the 182 client take any specific action when interacting with the server. 183 For such features, the "required" and "preferred" support levels 184 SHOULD be considered to be synonymous with "supported". 186 An optional href attribute MAY be used to specify the URI of a human- 187 readable description of the feature. Relative references MAY be 188 used. 190 The optional label attribute MAY be used to specify a human-readable 191 label for the feature. The value of the label attribute is Language- 192 Sensitive as defined by Section 2 of [RFC4287]. 194 The f:feature element MAY contain any number of child elements and 195 attributes from any XML namespace, with the exception of the 196 f:feature element itself. Such markup is considered to be metadata 197 applicable to the feature identified by the f:feature element. 198 Software agents MUST NOT stop processing or signal an error or change 199 their behavior as a result of encountering such markup. 201 An app:collection element MAY contain zero or more f:feature elements 202 but MUST NOT contain more than one with the same ref attribute value. 203 The order in which f:feature elements appear within the app: 204 collection element is insignificant. 206 The f:feature element MAY contain attributes included as part of the 207 atomCommonAttributes production defined by Section 2 of [RFC4287] or 208 any update thereof. When used on an f:feature element, such 209 attributes serve the same purpose described in [RFC4287] or their 210 corresponding specifications. 212 It is important to point out that implementors who add "required" 213 features to existing collections can cause existing client 214 applications to fail and can limit the ability of client applications 215 to evolve independently of a specific server implementation. A 216 better strategy would be to indicate that new features are 217 "preferred". Doing so can allow existing clients to continue to 218 function while communicating the servers preference that new clients 219 utilize the new feature. 221 Server implementors also need to remember that, as an extension to 222 the Service Document syntax, not all Atom Publishing Protocol client 223 applications will recognize and support the use of the f:feature 224 element. Such clients will be incapable of determining which 225 features are supported, preferred, or required. 227 3.1. Example 229 The following is an example of a collection supporting one 230 hypothetical required feature, one unsupported feature, and a number 231 of supported features. 233 237 238 My Workspace 239 240 My Atom Collection 241 application/atom+xml;type=entry 242 244 247 249 251 253 256 260 261 262 264 3.2. Contradictory Features 266 Some combinations of features can be contradictory when the support 267 level of one or more of those features is "required" and the others 268 are "supported" or "preferred". For instance, a collection that 269 specifies that XHTML values in the atom:title is required and that 270 HTML in an atom:title is supported is contradictory. Such 271 contradictions can cause problems for clients that are attempting to 272 select an appropriate collection based on the support level of 273 various features. A service document MUST NOT specify contradictory 274 features. If a client determines that the features specified in a 275 service document are contradictory, the client SHOULD proceed as if 276 the support level for each of those features is "supported". 278 When multiple, potentially contradictory features are specified such 279 that the support level for one is marked as "preferred" and the 280 others are "supported", clients SHOULD use the "preferred" feature. 281 If more than one potentially contradictory feature is marked as 282 "preferred", the client SHOULD proceed as if the support level for 283 each of those features is "supported". 285 4. The f:type element 287 The content of an f:type element is a media-range as defined in 288 [RFC2616]. 290 type = 291 element f:type { 292 atomCommonAttributes, 293 ( text? ) 294 } 296 Media type parameters are allowed within f:type, but f:type has no 297 notion of preference - "accept-params" or "q" arguments, as specified 298 in Section 14.1 of [RFC2616] are not significant. 300 White space (as defined in [W3C.REC-xml-20040204]) around the f:type 301 element's media-range is insignificant and MUST be ignored. 303 Any number of f:type elements MAY appear as children of an f:feature 304 element. When used with features whose ref attributes identify the 305 "XML Content", "Binary Content" or "Reference Content" features as 306 defined in Section 6.1.1, the f:type elements specify the set of 307 media types that can be specified in the atom:content elements type 308 attribute and thereby the type of content that be included within or 309 referenced by the atom:content. If no f:type elements are specified 310 for these features, clients SHOULD treat this as equivalent to an 311 f:type element with the content "*/*". 313 The order of f:type elements within a f:feature element is 314 insignificant. 316 4.1. An example f:feature using the f:type element 318 320 image/jpg 321 image/png 322 image/gif 323 text/* 324 326 5. Digitally Signing Service Documents 328 Because the mechanisms defined in this specification can be used to 329 compel client applications to implement certain behaviors when 330 interacting with a collection, implementors who specify required 331 features are encouraged to sign Service Documents containing the 332 features extension using an Enveloped Signature, as described by XML- 333 Signature and Syntax Processing [W3C.REC-xmldsig-core-20020212]. 335 Processors of Service Documents MUST NOT reject signed documents 336 because they are not capable of verifying it; they MUST continue 337 processing and MAY inform the user of their failure to validate the 338 signature. In other words, the presence of an element with the 339 namespace URI "http://www.w3.org/2000/09/xmldsig#" and a local name 340 of "Signature" as a child of the document element MUST NOT cause a 341 Processor to fail merely because of its presence. 343 Section 6.5.1 of [W3C.REC-xmldsig-core-20020212] requires support for 344 Canonical XML [W3C.REC-xml-c14n-20010315]. However, many 345 implementers do not use it because signed XML documents enclosed in 346 other XML documents have their signatures broken. Thus, Processors 347 that verify signed Service Documents MUST be able to canonicalize 348 with the exclusive XML canonicalization method identified by the URI 349 "http://www.w3.org/2001/10/xml-exc-c14n#", as specified in Exclusive 350 XML Canonicalization [W3C.REC-xml-exc-c14n-20020718]. 352 Section 4.4.2 of [W3C.REC-xmldsig-core-20020212] requires support for 353 DSA signatures and recommends support for RSA signatures. However, 354 because of the much greater popularity in the market of RSA versus 355 DSA, Processors that verify signed Atom Service Documents MUST be 356 able to verify RSA signatures, but do not need be able to verify DSA 357 signatures. Due to security issues that can arise if the keying 358 material for message authentication code (MAC) authentication is not 359 handled properly, Service Documents SHOULD NOT use MACs for 360 signatures. 362 6. The "http://purl.org/atompub/features/1.0" Namespace 364 The "http://purl.org/atompub/features/1.0" XML namespace is reserved 365 for future forward-compatible revisions of this specification. 366 Future updates to this document can add new elements and attributes 367 to the namespace. Software written to conform to this version of the 368 specification will not be able to process such markup correctly and, 369 in fact, will not be able to distinguish it from markup error. 371 Processors that encounter such markup MUST NOT stop processing or 372 signal an error. It might be the case that the Processor is able to 373 handle such markup correctly, and does so. Otherwise, processors MAY 374 bypass the markup and MUST NOT change their behavior as a result of 375 the markups presence. 377 7. Security Considerations 379 Specific features supported by a collection may introduce security 380 considerations and concerns beyond those discussed by the Atom 381 Publishing Protocol and Atom Syndication Format specifications. 382 Implementors must refer to the specifications and description of each 383 feature to determine the security considerations relevant to each. 385 Service documents can be signed using [W3C.REC-xmldsig-core-20020212] 386 and are subject to the security considerations implied by its use. 388 Digital signatures provide authentication, message integrity, and 389 non-repudiation with proof of origin. 391 8. IANA Considerations 393 8.1. Registry of Atom Publishing Features 395 The Registry of Atom Publishing Features is maintained by IANA and 396 contains information about known features that can be supported by 397 Atom Publishing Protocol implementations. New assignments are 398 subject to IESG approval, as outlined in [RFC2434]. Requests should 399 be made by email to IANA, which will then forward the request to the 400 IESG, requesting approval. The request should use the following 401 template: 403 o Ref: (A globally unique IRI identifying the feature) 404 o Label: (A human-readable label for the feature) 405 o Support Levels: (A description of the relevant support levels for 406 the feature) 408 o Contradictory Features: (A listing of features that are 409 contradictory to this feature when one or more are marked as 410 "required") 411 o Href: (A URI referencing a document containing a detailed 412 definition of the feature) 413 o Security Considerations: 415 8.1.1. Initial Assignments 417 The Registry of Features initially contains the following 418 assignments: 420 8.1.1.1. Drafts 422 o Ref: http://www.w3.org/2007/app/drafts 423 o Label: Drafts 424 o Support Levels: 425 * "supported" indicates that the collection accepts entries that 426 contain the app:draft control element. 427 * "required" indicates that the collection requires all entries 428 to contain the app:draft control element. 429 * "unsupported" indicates that the collection does not accept 430 entries that use the app:draft control element or that the 431 server will ignore the element if present. 432 o Contradictory Features: none 434 8.1.1.2. XHTML Content 436 o Ref: http://www.w3.org/2007/app/xhtml-content 437 o Label: XHTML Content 438 o Support Levels: 439 * "supported" indicates that the collection accepts entries that 440 provide XHTML in the atom:content element. 441 * "required" indicates that the collection requires all entries 442 to provide XHTML in the atom:content element. 443 * "unsupported" indicates that the collection does not accept 444 entries that provide XHTML in the atom:content element. 445 o Contradictory Features: http://www.w3.org/2007/app/html-content, 446 http://www.w3.org/2007/app/text-content, 447 http://www.w3.org/2007/app/xml-content, 448 http://www.w3.org/2007/app/binary-content, 449 http://www.w3.org/2007/app/ref-content 451 8.1.1.3. HTML Content 453 o Ref: http://www.w3.org/2007/app/html-content 454 o Label: HTML Content 455 o Support Levels: 456 * "supported" indicates that the collection accepts entries that 457 provide HTML in the atom:content element. 458 * "required" indicates that the collection requires all entries 459 to provide HTML in the atom:content element. 460 * "unsupported" indicates that the collection does not accept 461 entries that provide HTML in the atom:content element. 462 o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, 463 http://www.w3.org/2007/app/text-content, 464 http://www.w3.org/2007/app/xml-content, 465 http://www.w3.org/2007/app/binary-content, 466 http://www.w3.org/2007/app/ref-content 468 8.1.1.4. Text Content 470 o Ref: http://www.w3.org/2007/app/text-content 471 o Label: Text Content 472 o Support Levels: 473 * "supported" indicates that the collection accepts entries that 474 provide plain text in the atom:content element. 475 * "required" indicates that the collection requires all entries 476 to provide plain text in the atom:content element. 477 * "unsupported" indicates that the collection does not accept 478 entries that provide plain text in the atom:content element. 479 o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, 480 http://www.w3.org/2007/app/html-content, 481 http://www.w3.org/2007/app/xml-content, 482 http://www.w3.org/2007/app/binary-content, 483 http://www.w3.org/2007/app/ref-content 485 8.1.1.5. XML Content 487 o Ref: http://www.w3.org/2007/app/xml-content 488 o Label: XML Content 489 o Support Levels: 490 * "supported" indicates that the collection accepts entries that 491 provide well-formed XML in the atom:content element. 492 * "required" indicates that the collection requires all entries 493 to provide well-formed XML in the atom:content element. 494 * "unsupported" indicates that the collection does not accept 495 entries that provide XML in the atom:content element. The MIME 496 media type of acceptable XML formats is specified using one or 497 more f:type elements within the f:feature. 498 o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, 499 http://www.w3.org/2007/app/html-content, 500 http://www.w3.org/2007/app/text-content, 501 http://www.w3.org/2007/app/binary-content, 502 http://www.w3.org/2007/app/ref-content 504 8.1.1.6. Binary Content 506 o Ref: http://www.w3.org/2007/app/binary-content 507 o Label: Binary Content 508 o Support Levels: 509 * "supported" indicates that the collection accepts entries that 510 provide binary content in the atom:content element. 511 * "required" indicates that the collection requires all entries 512 to provide binary content in the atom:content element. 513 * "unsupported" indicates that the collection does not accept 514 entries that provide binary content in the atom:content 515 element. The MIME media type of acceptable binary formats is 516 specified using one or more f:type elements within the 517 f:feature. 518 o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, 519 http://www.w3.org/2007/app/html-content, 520 http://www.w3.org/2007/app/text-content, 521 http://www.w3.org/2007/app/xml-content, 522 http://www.w3.org/2007/app/ref-content 524 8.1.1.7. Referenced Content 526 o Ref: http://www.w3.org/2007/app/ref-content 527 o Label: XHTML Content 528 o Support Levels: 529 * "supported" indicates that the collection accepts entries that 530 use the atom:content src attribute to reference external 531 content. 532 * "required" indicates that the collection requires all entries 533 to use the atom:content src attribute to reference external 534 content. 535 * "unsupported" indicates that the collection does not accept 536 entries that use the atom:content src attribute. The MIME 537 media type of acceptable referenced resources is specified 538 using one or more f:type elements within the f:feature. 539 o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, 540 http://www.w3.org/2007/app/html-content, 541 http://www.w3.org/2007/app/text-content, 542 http://www.w3.org/2007/app/xml-content, 543 http://www.w3.org/2007/app/binary-content 545 8.1.1.8. XHTML Title 547 o Ref: http://www.w3.org/2007/app/xhtml-title 548 o Label: XHTML Title 549 o Support Levels: 550 * "supported" indicates that the collection accepts entries that 551 provide XHTML in the atom:title element. 552 * "required" indicates that the collectionrequires all entries to 553 provide XHTML in the atom:title element. 554 * "unsupported" indicates that the collection does not accept 555 entries that provide XHTML in the atom:title element. 556 o Contradictory Features: http://www.w3.org/2007/app/html-title, 557 http://www.w3.org/2007/app/text-title 559 8.1.1.9. HTML Title 561 o Ref: http://www.w3.org/2007/app/html-title 562 o Label: HTML Title 563 o Support Levels: 564 * "supported" indicates that the collection accepts entries that 565 provide HTML in the atom:title element. 566 * "required" indicates that the collection requires all entries 567 to provide HTML in the atom:title element. 568 * "unsupported" indicates that the collection does not accept 569 entries that provide HTML in the atom:title element. 570 o Contradictory Features: http://www.w3.org/2007/app/xhtml-title, 571 http://www.w3.org/2007/app/text-title 573 8.1.1.10. Text Title 575 o Ref: http://www.w3.org/2007/app/text-title 576 o Label: Text Title 577 o Support Levels: 578 * "supported" indicates that the collection accepts entries that 579 provide plain text in the atom:title element. 580 * "required" indicates that the collection requires all entries 581 to provide plain text in the atom:title element. 582 * "unsupported" indicates that the collection does not accept 583 entries that provide plain text in the atom:title element. 584 o Contradictory Features: http://www.w3.org/2007/app/xhtml-title, 585 http://www.w3.org/2007/app/html-title 587 8.1.1.11. Summary 589 o Ref: http://www.w3.org/2007/app/summary 590 o Label: Summary 591 o Support Levels: 592 * "supported" indicates that the server will allow the use of the 593 atom:summary element to provide a summary or excerpt that is 594 independent of the atom:content. 596 * "required" indicates that the server requires the presence of 597 an atom:summary element to provide a summary or excerpt that is 598 independent of the atom:content. 599 * "unsupported" indicates that the server does not support the 600 use of the atom:summary element to provide a summary or excerpt 601 independent of the atom:content. When an atom:summary is 602 provided by a client, the server will either reject the request 603 or ignore the element. 604 o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, 605 http://www.w3.org/2007/app/html-summary, 606 http://www.w3.org/2007/app/text-summary 608 8.1.1.12. Auto Summary 610 o Ref: http://www.w3.org/2007/app/auto-summary 611 o Label: Auto Summary 612 o Support Levels: 613 * "supported" indicates that the server will automatically 614 generate an atom:summary element if the entry provided by the 615 client does not already contain one. 616 * For this feature,"required" is synonymous with "supported". 617 * "unsupported" indicates that the server will not automatically 618 generate an atom:summary element. 619 o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, 620 http://www.w3.org/2007/app/html-summary, 621 http://www.w3.org/2007/app/text-summary 623 8.1.1.13. XHTML Summary 625 o Ref: http://www.w3.org/2007/app/xhtml-summary 626 o Label: XHTML Summary 627 o Support Levels: 628 * "supported" indicates that the collection accepts entries that 629 provide XHTML in the atom:summary element. 630 * "required" indicates that the collection requires all entries 631 to provide XHTML in the atom:summary element. 632 * "unsupported" indicates that the collection does not accept 633 entries that provide XHTML in the atom:summary element. 634 o Contradictory Features: http://www.w3.org/2007/app/html-summary, 635 http://www.w3.org/2007/app/text-summary 637 8.1.1.14. HTML Summary 639 o Ref: http://www.w3.org/2007/app/html-summary 640 o Label: HTML Summary 641 o Support Levels: 643 * "supported" indicates that the collection accepts entries that 644 provide HTML in the atom:summary element. 645 * "required" indicates that the collection requires all entries 646 to provide HTML in the atom:summary element. 647 * "unsupported" indicates that the collection does not accept 648 entries that provide HTML in the atom:summary element. 649 o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, 650 http://www.w3.org/2007/app/text-summary 652 8.1.1.15. Text Summary 654 o Ref: http://www.w3.org/2007/app/text-summary 655 o Label: Text Summary 656 o Support Levels: 657 * "supported" indicates that the collection accepts entries that 658 provide plain text in the atom:summary element. 659 * "required" indicates that the collection requires all entries 660 to provide plain text in the atom:summary element. 661 * "unsupported" indicates that the collection does not accept 662 entries that provide plain text in the atom:summary element. 663 o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, 664 http://www.w3.org/2007/app/html-summary 666 8.1.1.16. XHTML Rights 668 o Ref: http://www.w3.org/2007/app/xhtml-rights 669 o Label: XHTML Rights 670 o Support Levels: 671 * "supported" indicates that the collection accepts entries that 672 provide XHTML in the atom:rights element. 673 * "required" indicates that the collection requires all entries 674 to provide XHTML in the atom:rights element. 675 * "unsupported" indicates that the collection does not accept 676 entries that provide XHTML in the atom:rights element. 677 o Contradictory Features: http://www.w3.org/2007/app/html-rights, 678 http://www.w3.org/2007/app/text-rights 680 8.1.1.17. HTML Rights 682 o Ref: http://www.w3.org/2007/app/html-rights 683 o Label: HTML Rights 684 o Support Levels: 685 * "supported" indicates that the collection accepts entries that 686 provide HTML in the atom:rights element. 687 * "required" indicates that the collection requires all entries 688 to provide HTML in the atom:rights element. 690 * "unsupported" indicates that the collection does not accept 691 entries that provide HTML in the atom:rights element. 692 o Contradictory Features: http://www.w3.org/2007/app/xhtml-rights, 693 http://www.w3.org/2007/app/text-rights 695 8.1.1.18. Text Rights 697 o Ref: http://www.w3.org/2007/app/text-rights 698 o Label: Text Rights 699 o Support Levels: 700 * "supported" indicates that the collection accepts entries that 701 provide plain text in the atom:rights element. 702 * "required" indicates that the collection requires all entries 703 to provide plain text in the atom:rights element. 704 * "unsupported" indicates that the collection does not accept 705 entries that provide plain text in the atom:rights element. 706 o Contradictory Features: http://www.w3.org/2007/app/xhtml-rights, 707 http://www.w3.org/2007/app/html-rights 709 8.1.1.19. Authenticated Author 711 o Ref: http://www.w3.org/2007/app/auth-author 712 o Label: Authenticated Author 713 o Support Levels: 714 * "supported" indicates that the server will automatically 715 generate the atom:author element based on the client's 716 authenticated identity. 717 * For this feature,"required" is synonymous with "supported". 718 * "unsupported" indicates that the server will not automatically 719 generate the atom:author for an entry based on the client's 720 authenticated identity. 721 o Contradictory Features: 722 http://www.w3.org/2007/app/multiple-authors 724 8.1.1.20. Slug 726 o Ref: http://www.w3.org/2007/app/slug 727 o Label: Slug 728 o Support Levels: 729 * "supported" indicates that the collection accepts the use of 730 the Slug header in POST requests. 731 * "required" indicates that the collection requires that the Slug 732 header be used for all POST requests. 733 * "unsupported" indicates that the collection will not accept the 734 use of the Slug header in POST requests or that the header will 735 be ignored. 737 o Contradictory Features: none 739 8.1.1.21. Multiple Categories 741 o Ref: http://www.w3.org/2007/app/multiple-categories 742 o Label: Multiple Categories 743 o Support Levels: 744 * "supported" indicates that the collection accepts the use of 745 multiple atom:category elements within an entry. 746 * For this feature, "required" is synonymous with "supported". 747 * "unsupported" indicates that the collection will not accept 748 entries with multiple atom:category elements or that that 749 additional atom:category elements will be ignored. 750 o Contradictory Features: none 752 8.1.1.22. Multiple Authors 754 o Ref: http://www.w3.org/2007/app/multiple-authors 755 o Label: Multiple Authors 756 o Support Levels: 757 * "supported" indicates that the collection accepts the use of 758 multiple atom:author elements within an entry. 759 * For this feature, "required" is synonymous with "supported". 760 * "unsupported" indicates that the collection will not accept 761 entries with multiple atom:author elements or that the 762 additional atom:author elements will be ignored. 763 o Contradictory Features: http://www.w3.org/2007/app/auth-author 765 8.1.1.23. Multiple Contributors 767 o Ref: http://www.w3.org/2007/app/contributors 768 o Label: Multiple Contributors 769 o Support Levels: 770 * "supported" indicates that the collection accepts the use of 771 multiple atom:contributor elements within an entry. 772 * For this feature, "required" is synonymous with "supported". 773 * "unsupported" indicates that the collection will not accept 774 entries with multiple atom:contributor elements or that the 775 additional atom:contributor elements will be ignored. 776 o Contradictory Features: none 778 8.1.1.24. Preserve Infoset 780 o Ref: http://www.w3.org/2007/app/preserve-infoset 781 o Label: Preserve Infoset 782 o Support Levels: 784 * "supported" indicates that the collection will store entries in 785 such a way as to preserve the complete XML infoset of the entry 786 document. 787 * For this feature, "required" is synonymous with "supported". 788 * "unsupported" indicates that the collection will not preserve 789 the complete XML infoset of the entry when storing. 790 o Contradictory Features: none 792 8.1.1.25. Preserve IDs 794 o Ref: http://www.w3.org/2007/app/preserve-id 795 o Label: Preserve IDs 796 o Support Levels: 797 * "supported" indicates that the collection will preserve the 798 value of the atom:id element as provided by the client. 799 * For this feature, "required" is synonymous with "supported". 800 * "unsupported" indicates that the collection will not preserve 801 the value of the atom:id element as provided by the client 802 (e.g. the server will generate it's own value for the atom:id 803 element. 804 o Contradictory Features: none 806 8.1.1.26. Preserve Dates 808 o Ref: http://www.w3.org/2007/app/preserve-updated 809 o Label: Preserve Dates 810 o Support Levels: 811 * "supported" indicates that the collection will preserve the 812 value of all date elements as provided by the client. 813 * For this feature,"required" is synonymous with "supported". 814 * "unsupported" indicates that the collection will not preserve 815 the value of date elements as provided by the client (e.g. the 816 server will generate it's own value for the date elements. 817 o Contradictory Features: none 819 8.1.1.27. Preserve Extensions 821 o Ref: http://www.w3.org/2007/app/preserve-extensions 822 o Label: Preserve Extensions 823 o Support Levels: 824 * "supported" indicates that the collection will preserve all 825 extensions contained within an entry. 826 * For this feature, "required" is synonymous with "supported". 827 * "unsupported" indicates that the collection will not preserve 828 all extensions contained within an entry, however some 829 extensions may be preserved. 831 o Contradictory Features: none 833 8.1.1.28. Preserve Links 835 o Ref: http://www.w3.org/2007/app/preserve-links 836 o Label: Preserve Links 837 o Support Levels: 838 * "supported" indicates that the collection will preserve all 839 atom:link elements contained within an entry. 840 * For this feature, "required" is synonymous with "supported". 841 * "unsupported" indicates that the collection will not preserve 842 all atom:links contained within an entry, however some atom: 843 link elements may be preserved. 844 o Contradictory Features: none 846 8.1.1.29. Preserve Rights 848 o Ref: http://www.w3.org/2007/app/preserve-rights 849 o Label: Preserve Rights 850 o Support Levels: 851 * "supported" indicates that the collection will preserve the 852 value of the atom:rights element as well as all License Links 853 [RFC4946] contained within an entry. 854 * For this feature, "required" is synonymous with "supported". 855 * "unsupported" indicates that the collection may not preserve 856 the value of the atom:rights element or all License Links 857 [RFC4946], however, some rights information may be preserved. 858 o Contradictory Features: none 860 8.1.1.30. Threading 862 o Ref: http://purl.org/syndication/thread/1.0 863 o Label: Threading 864 o Support Levels: 865 * "supported" indicates that the collection accepts entries that 866 contain the in-reply-to element as defined by [RFC4685]. 867 * "required" indicates that the collection requires that all 868 entries contain an in-reply-to element. 869 * "unsupported" indicates that the collection will not accept 870 entries containing the in-reply-to element or that the element 871 will be ignored if present. 872 o Contradictory Features: none 874 8.1.1.31. Scheduled Publishing 876 o Ref: http://www.w3.org/2007/app/scheduled-publishing 877 o Label: Scheduled Publishing 878 o Support Levels: 879 * "supported" indicates that the collection allows clients to 880 specify a future instant in time for the atom:published element 881 when the entry should be made publicly available. 882 * "required" indicates that the collection requires clients to 883 specify a future instant in time for the atom:published 884 element. 885 * "unsupported" indicates that the collection will not allow 886 clients to specify a future instance in time for the atom: 887 published element. 888 o Contradictory Features: none 890 9. Normative References 892 [I-D.ietf-atompub-protocol] 893 Hora, B. and J. Gregorio, "The Atom Publishing Protocol", 894 draft-ietf-atompub-protocol-17 (work in progress), 895 July 2007. 897 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 898 Requirement Levels", BCP 14, RFC 2119, March 1997. 900 [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 901 IANA Considerations Section in RFCs", BCP 26, RFC 2434, 902 October 1998. 904 [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., 905 Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext 906 Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. 908 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 909 Resource Identifier (URI): Generic Syntax", STD 66, 910 RFC 3986, January 2005. 912 [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource 913 Identifiers (IRIs)", RFC 3987, January 2005. 915 [RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom 916 Syndication Format", RFC 4287, December 2005. 918 [RFC4685] Snell, J., "Atom Threading Extensions", RFC 4685, 919 September 2006. 921 [RFC4946] Snell, J., "Atom License Extension", RFC 4946, July 2007. 923 [W3C.REC-xml-20040204] 924 Yergeau, F., Maler, E., Bray, T., Paoli, J., and C. 925 Sperberg-McQueen, "Extensible Markup Language (XML) 1.0 926 (Third Edition)", World Wide Web Consortium 927 FirstEdition REC-xml-20040204, February 2004, 928 . 930 [W3C.REC-xml-c14n-20010315] 931 Boyer, J., "Canonical XML Version 1.0", World Wide Web 932 Consortium Recommendation REC-xml-c14n-20010315, 933 March 2001, 934 . 936 [W3C.REC-xml-exc-c14n-20020718] 937 Boyer, J., 3rd, D., and J. Reagle, "Exclusive XML 938 Canonicalization Version 1.0", World Wide Web Consortium 939 Recommendation REC-xml-exc-c14n-20020718, July 2002, 940 . 942 [W3C.REC-xml-infoset-20040204] 943 Tobin, R. and J. Cowan, "XML Information Set (Second 944 Edition)", World Wide Web Consortium Recommendation REC- 945 xml-infoset-20040204, February 2004, 946 . 948 [W3C.REC-xml-names-19990114] 949 Hollander, D., Bray, T., and A. Layman, "Namespaces in 950 XML", World Wide Web Consortium FirstEdition REC-xml- 951 names-19990114, January 1999, 952 . 954 [W3C.REC-xmlbase-20010627] 955 Marsh, J., "XML Base", World Wide Web Consortium 956 Recommendation REC-xmlbase-20010627, June 2001, 957 . 959 [W3C.REC-xmldsig-core-20020212] 960 Reagle, J., Eastlake, D., and D. Solo, "XML-Signature 961 Syntax and Processing", World Wide Web Consortium 962 Recommendation REC-xmldsig-core-20020212, February 2002, 963 . 965 Appendix A. Acknowledgements 967 The author acknowledges the feedback from the other members of the 968 IETF Atom Publishing working group during the development of this 969 specification. 971 Author's Address 973 James M Snell 975 Phone: 976 Email: jasnell@gmail.com 977 URI: http://snellspace.com 979 Full Copyright Statement 981 Copyright (C) The IETF Trust (2007). 983 This document is subject to the rights, licenses and restrictions 984 contained in BCP 78, and except as set forth therein, the authors 985 retain all their rights. 987 This document and the information contained herein are provided on an 988 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 989 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 990 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 991 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 992 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 993 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 995 Intellectual Property 997 The IETF takes no position regarding the validity or scope of any 998 Intellectual Property Rights or other rights that might be claimed to 999 pertain to the implementation or use of the technology described in 1000 this document or the extent to which any license under such rights 1001 might or might not be available; nor does it represent that it has 1002 made any independent effort to identify any such rights. Information 1003 on the procedures with respect to rights in RFC documents can be 1004 found in BCP 78 and BCP 79. 1006 Copies of IPR disclosures made to the IETF Secretariat and any 1007 assurances of licenses to be made available, or the result of an 1008 attempt made to obtain a general license or permission for the use of 1009 such proprietary rights by implementers or users of this 1010 specification can be obtained from the IETF on-line IPR repository at 1011 http://www.ietf.org/ipr. 1013 The IETF invites any interested party to bring to its attention any 1014 copyrights, patents or patent applications, or other proprietary 1015 rights that may cover technology that may be required to implement 1016 this standard. Please address the information to the IETF at 1017 ietf-ipr@ietf.org. 1019 Acknowledgment 1021 Funding for the RFC Editor function is provided by the IETF 1022 Administrative Support Activity (IASA).