Network Working Group J. Gregorio, Ed. Internet-Draft BitWorking, Inc Expires:September 19,November 10, 2005 R. Sayre, Ed.Boswijck Memex Consulting March 18,May 9, 2005 The Atom Publishing Protocoldraft-ietf-atompub-protocol-03.txtdraft-ietf-atompub-protocol-04.txt Status of this MemoThis document is an Internet-Draft and is subject to all provisions of Section 3 of RFC 3667.By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or shebecomebecomes aware will be disclosed, in accordance withRFC 3668.Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents asInternet-Drafts.Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire onSeptember 19,November 10, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This memo presents a protocol for using XML (Extensible Markup Language) and HTTP (HyperText Transport Protocol) to edit content. The Atom Publishing Protocol is an application-level protocol for publishing and editing Web resources belonging to periodically updated websites. The protocol at its core is the HTTP transport of Atom-formatted representations. The Atom format is documented in the Atom Syndication Format (draft-ietf-atompub-format-06.txt). Editorial Note To provide feedback on this Internet-Draft, join theatom-syntaxatom-protocol mailing list(http://www.imc.org/atom-syntax/index.html)(http://www.imc.org/atom-protocol/index.html) [1]. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .4 1.1. 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 41.23. Terminology . . . . . . . . . . . . . . . . . . . . . . .4 2.. . 5 4. The Atom Publishing Protocol Model . . . . . . . . . . . . .4 2.1 Atom Collections . . . . .. 6 4.1 Collections . . . . . . . . . . . . . . .4 2.1.1 Usage. . . . . . . . 6 4.2 Discovery . . . . . . . . . . . . . . . .5 2.1.2 Client and Server Interaction. . . . . . . . 6 4.3 Listing . . . .5 3. Functional Specification. . . . . . . . . . . . . . . . . .5 3.1 Collections. . . 7 4.4 Authoring . . . . . . . . . . . . . . . . . . . .6 3.1.1 Collection Document. . . . 7 4.4.1 Create . . . . . . . . . . . . .6 3.1.2 Elements in a Collection Document. . . . . . . . . .6 3.1.3 Collection Requests. 7 4.4.2 Read . . . . . . . . . . . . . . . .7 3.2 Introspection. . . . . . . . . 8 4.4.3 Update . . . . . . . . . . . . .8 3.2.1 Service Document. . . . . . . . . . . 8 4.4.4 Delete . . . . . . . .8 3.3 Entry Collection. . . . . . . . . . . . . . . . 8 4.5 Success and Failure . . . . .9 3.3.1 Locating. . . . . . . . . . . . . . 9 5. Collections . . . . . . . . .10 3.4 Simple Resource Collection. . . . . . . . . . . . . . . . 103.4.1 Locating . . . .5.1 Collection Documents . . . . . . . . . . . . . . . . . . . 103.4.2 Request . . . . . .5.1.1 Element Definitions . . . . . . . . . . . . . . . . . 103.5 Atom Request and Response Body Constraints . . . . . . . . 11 3.5.1 id . . .5.2 Collection Resource . . . . . . . . . . . . . . . . . . . 12 5.2.2 POST . . . .11 3.5.2 link. . . . . . . . . . . . . . . . . . . . . 14 5.2.3 Usage Scenarios . . . .11 3.5.3 title. . . . . . . . . . . . . . . 15 5.2.4 Range: Header . . . . . . . . .11 3.5.4 summary. . . . . . . . . . . 16 5.2.5 Accept-Ranges: Header . . . . . . . . . . . .11 3.5.5 content. . . . 16 5.2.6 Name: Header . . . . . . . . . . . . . . . . . . .12 3.5.6 issued. . 17 6. Entry Collection . . . . . . . . . . . . . . . . . . . . . .12 3.5.7 modified. 18 6.1 Editing Entry Resources . . . . . . . . . . . . . . . . . 18 6.2 Role of Atom Entry Elements During Editing . . . . .12 3.5.8 created. . . 18 7. Generic Collection . . . . . . . . . . . . . . . . . . . .12 3.5.9 author. . 20 7.1 Editing Generic Resources . . . . . . . . . . . . . . . . 20 8. Introspection . . . . . .13 3.5.10 contributor. . . . . . . . . . . . . . . . . . 21 8.1 Introspection Document . .13 3.5.11 generator. . . . . . . . . . . . . . . . 21 8.1.1 Element Definitions . . . . .13 3.6 Securing the Atom Protocol. . . . . . . . . . . . 21 8.2 Introspection Resource . . . .13 3.6.1 [@@TBD@@ CGI Authentication]. . . . . . . . . . . . .14 4. Security Considerations. 23 8.2.1 Discovery . . . . . . . . . . . . . . . . .14 5. IANA Considerations. . . . . 24 9. Securing the Atom Protocol . . . . . . . . . . . . . . .14 6. Appendix A - SOAP Enabling. . . 25 10. Security Considerations . . . . . . . . . . . . . .15 6.1 Servers. . . . 26 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . 27 12. References .15 6.2 Clients. . . . . . . . . . . . . . . . . . . . . . . . 30 12.1 Normative References .15 7. Appendix B - Examples. . . . . . . . . . . . . . . . . . 30 12.2 Informative References .15 7.1 Example for a weblog. . . . . . . . . . . . . . . . . 31 Authors' Addresses . .15 7.2 Example for a wiki. . . . . . . . . . . . . . . . . . . .15 8.32 A. Revision History . . . . . . . . . . . . . . . . . . . . . .15 9. Normative References . . . . . . . . . . .. 33 Intellectual Property and Copyright Statements . . . . . . . .17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 18 Intellectual Property and Copyright Statements . . . . . . . 1935 1. Introduction The Atom Publishing Protocol is an application-level protocol for publishing and editing Web resources using HTTP [RFC2616] andXML. 1.1XML 1.0 [W3C.REC-xml-20040204]. 2. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].1.23. TerminologyAtom Entry: An Atom Entry is a fragment of a full Atom feed. In this case,URI/IRI - A Uniform Resource Identifier and Internationalized Resource Identifier, respectively. These terms (and thefragment is a single 'entry' elementdistinction between them) are defined in [RFC3986] andall its child elements. Each Atom Entry describes[RFC3987]. Resource - an item identified by asingle Web resource, providing metadata and optionallyURI [W3C.REC-webarch-20041215]. Collection Resource - A resource that contains atextual representationlisting ofthat resource. 2.Member Resources and meets the requirements in Section 5 of this specification. Member Resource - A resource whose URI is listed by a Collection Resource. 4. The Atom Publishing Protocol Model The Atom Publishing Protocolis an application-level protocol for publishing and editing Web resources. The primary way of interaction in the Atom Publishing Protocol is by managing collectionoperates on collections of Web resources. All collections support the same basicmethods of interaction. In addition,interactions, as do the resourcesbelonging to collections also sharewithin thesamecollections. The patterns of interactionpatterns. Usingare based on the common HTTPverbs provides a pattern for working with all such Web resources:verbs. o GET is used to retrieve a representation of a resource or perform a read-only query. oPUTPOST is used toupdatecreate aknownnew, dynamically-named resource. oPOSTPUT is used tocreateupdate anew dynamically-namedknown resource. o DELETE is used to remove a resource.2.1 Atom4.1 CollectionsAn Atom collection is a set of items all of the same type ("members" of the collection), where the "type" may be, for example: Atom entry, category, template, "simple resource", or any other classification of web resource. Each collection has a URIThe APP groups resources into "Collections", whichis given in the introspection file. A GET onare analogous to thecollection URI MUST produce a collection document as defined"folders" or "directories" found in"3.X.1 Collection Document." That document describes PART OFmany file systems. 4.2 Discovery To discover thestatelocation of thecollection. All the members of a collection havecollections exposed by an"updated" property, andAPP service, thecollection is consideredclient must locate and request an Introspection Document (Section 8). Client Server | | | 1.) GET Introspection | |------------------------------->| | | | 2.) Introspection Doc | |<-------------------------------| | | 1. The client sends a GET request tobe ordered by this property. A single collection document may not contain allthe Service Description Resource. 2. The server responds with an Introspection Document containing the locations of collections provided by themembersservice. The content ofa collection. If a collectionthis documentis the responsecan vary based on aspects ofa non-partial GETthe client request,and doesincluding, but notcontain all oflimited to, authentication credentials. 4.3 Listing Once themembersclient has discovered the location of a collection,thenitwill contain the URI of the next collection document which will contain morecan request a listing of thecollection members. By traversing thiscollection's membership. However, collections might be extremely large, so servers are likely to listof collection documentsaclient can obtain all of the memberssmall subset ofa collection. The 'next' attribute will not be present intheresponsecollection by default. Client Server | | | 1.) GET to Collection URI | |------------------------------->| | | | 2.) 200 OK, Atom Feed Doc | |<-------------------------------| | | 1. The client sends apartialGETrequest. 2.1.1 Usage Below two usages are outlined for Atom Collections. They are hererequest tohighlight common idioms for interactingthe Collection's URI. 2. The server responds with an Atom Feed Document containing aCollection Resource and notfull or partial listing of the collection's membership. 4.4 Authoring After locating anormative interaction pattern. The Atom Collectioncollection, a client canbe usedadd entries byclients in two ways. In the first casesending a request to theclient has attachedcollection; other changes are accomplished by sending HTTP requests to its member resources. 4.4.1 Create Client Server | | | 1.) POST to Collection URI | |------------------------------->| | | | 2.) 201 Created @ Location | |<-------------------------------| | | 1. The client sends asite forrepresentation of a member to thefirst time andserver via HTTP POST. The Request URI isdoing an initial syncronization,thatis, retrieving a listofallthemembersCollection. 2. The server responds with a response ofthe collections"201 Created" andpossibly retrieving alla "Location" header containing themembersURI of thecollection also.newly-created resource. 4.4.2 Read Client Server | | | 1.) GET or HEAD to Member URI | |------------------------------->| | | | 2.) 200 OK | |<-------------------------------| | | 1. The clientcan performsends anon-partialGETon the collection resource and it will receive a collection document that either contains all the member of the collection, or the collection document root element 'collection' will contain a 'next' attribute pointing(or HEAD) request to thenext collection document. By repeatedly following the 'next' attribute from documentmember's URI. 2. The server responds with an appropriate representation. 4.4.3 Update Client Server | | | 1.) PUT todocument the client can find all the members of the collection. In the second case theMember URI | |------------------------------->| | | | 2.) 200 OK | |<-------------------------------| 1. The clienthas already donePUTs aninitial sync, and now needsupdated representation tore-sync, becausetheclient was just restarted, or some time has passed since a re-sync, etc.member's URI. 2. Theclient does a partial GET on the collection document, supplyingserver responds with aRange header that begins from the last timerepresentation of the member's new state. 4.4.4 Delete Client Server | | | 1.) DELETE to Member URI | |------------------------------->| | | | 2.) 204 No Content | |<-------------------------------| | | 1. The clientsync'dsends a DELETE request to thecurrent time.member's URI. 2. Thecollection document returned will contain only those members of the collection that have changed since the last time the client syncronized. 2.1.2 Clientserver responds with successful status code. 4.5 Success andServer Interaction [[anchor5: ...]] This document does not specify the formFailure HTTP defines classes ofthe URIs that are used. The URI spaceresponse. HTTP status codes ofeach server is controlled, as defined by HTTP, bytheserver alone. What this document does specify are the formatsform 2xx signal that a request was successful. HTTP status codes of thefilesform 4xx or 5xx signal thatare exchangedan error has occurred, and theactions that can be performed onrequest has failed. Consult theURIs embedded in those files. 3. Functional Specification 3.1HTTP specification for more detailed definitions of each status code. 5. Collections3.1.1 Collection Document AAn Atom Collection is a set of related resources. All members of a collection have an "updated" property, and the collectiondocumentisrootedconsidered to be ordered bya <collection> element.this property. 5.1 Collection Documents An example Collection Document. <?xml version="1.0" encoding='utf-8'?> <collection xmlns="http://purl.org/atom/app#"> <member href="http://example.org/1" hrefreadonly="http://example.com/1/bar" title="Sample 1" updated="2003-12-13T18:30:02Z" /> <member href="http://example.org/2" hrefreadonly="http://example.com/2/bar" title="Sample 2" updated="2003-12-13T18:30:02Z" /> <member href="http://example.org/3" hrefreadonly="http://example.com/3/bar" title="Sample 3" updated="2003-12-13T18:30:02Z" /> <member href="http://example.org/4" title="Sample 4" updated="2003-12-13T18:30:02Z" /> </collection> Atom Collection Documents have the media-type 'application/ atomcoll+xml', see Section 11. 5.1.1 Element Definitions 5.1.1.1 The 'app:collection' Element The 'app:collection' element represents an Atom Collection. A collection document does not necessarily list every member of the collection. appCollection elementmay haveapp:collection { attribute next { text } ?, appMember* } o 'app:collection' elements MAY contain any number of<member>'app:member' elements. o 'app:collection' elementsas children; each such element identifiesMAY contain amember of the collection. In some situations,'next' attribute which identifies a collection documentmay not contain everycontaining memberof the collection itself. Whether complete or partial, theelements updated earlier in time. The members listed in a collection document MUST constitute a consecutive sequence of the collection's members, ordered by their "updated" properties. That is, a collection document MUST contain a contiguous subset of the members of the collection ordered by their 'updated' property.3.1.2 Elements in5.1.1.2 The 'app:member' Element The 'app:member' represents aCollection Document A collection document MAY contain zero or more 'member' elements. Each 'member'single member resource. appMember element app:member { attribute title { text }, attribute href { text }, attribute hrefreadonly { text } ?, attribute updated { text } } o 'app:member' elements MUST include an 'href'attribute identifying a URL ofattribute, whose value conveys themember resource. The 'href'URIof aused to edit the memberresourcesource o 'app:member' elements MAY include an "hrefreadonly (Section 5.1.1.3)" attribute. o 'app:member' elements MUST include a 'title' attribute, whose value is a human-readable name or description for the item. o 'app:member' elements MUST include an"EditURI" under'updated' attribute, whose value is theterms'updated' property ofsection 2, andthe collection member. Its format MUSTrespondconform to thesame HTTP methods as such an EditURI. Each 'member' element MAY include an "hrefreadonly" attribute.date-time production in [RFC3339]. 5.1.1.3 The 'hrefreadonly' Attribute This optional attribute identifies a URI which, on a GET request, responds equivalently to how the "href" URI would respond to the same request. Clients SHOULD NOT apply to this URI any HTTP methods that would be expected to modify the state of the resource (e.g. PUT, POST or DELETE). A PUT or POST request to this URI MAY NOT affect the underlying resource. If the "hrefreadonly" attribute is not given, its value defaults to the "href" value. If the "hrefreadonly" attribute is present, and its value is an empty string, then there is no URI that can be treated in the way such a value would be treated. Clients SHOULD use the "href" value to manipulate the resource within the context of the APP itself. Clients SHOULD prefer the "hrefreadonly" value in any other context. For example, if the resource is an image, a client may replace the image data using a PUT on the "href" value, and may even display a preview of the image by fetching the "href" URI. But when creating a public, read-only reference to the same image resource, the client should use the "hrefreadonly" value. If the "hrefreadonly" value is an empty string, the client SHOULD NOT make public reference to the "href" value.Each 'member' element MUST include a 'title' attribute, whose value is a human-readable name or description[[anchor10: Define extensibility forthe item. The valuesCollection Documents.]] 5.2 Collection Resource This specification defines two HTTP methods for use with collection resources: GET and POST. 5.2.1 GET Collections can contain extremely large numbers of'title' attributes are not required toresources. A naive client such as a web spider or web browser would beunique across all members ofoverwhelmed if the response to acollection. Each 'member' element MUST include an 'updated' attribute, whose value isGET reflected the'updated' propertyfull membership of thecollection member whose format MUST conformcollection, and the server would waste large amounts of bandwidth and processing time on clients unable to handle thedate-time BNF rule in [RFC3339]. 3.1.3 Collection Requests 3.1.3.1 Range: Header HTTP/1.1 allowsresponse. As aclientresult, responses to a simple GET requestthat only part (a range of)represent a server- determined subset of thecollection to be included withincollection's membership. In addition, theresponse. HTTP/1.1 usesclient MAY send a 'Range' header with a rangeunits intype of 'udpated', indicating the subset of theRange header field. Acollectioncan be broken down into subranges accordingtothe members 'updated' property. If a Range:be returned. The 'Range' header ispresentdescribed inthe request, its value explictly identifies theSection 5.2.4. This specification defines two serializations for Atom Collections. Servers MUST provide both, but MAY also provide additional serializations. 1. Atom Collection Documents (application/atomcoll+xml), Section 5.1. 2. Atom Collection Documents wrapped by atime interval interval in which allSOAP envelope (application/soap+xml), . Clients use themembers 'updated' property must fallHTTP 'Accept' request header tobe included inindicate their preference. Example Request, with Accept header GET /collection HTTP/1.1 Host: example.org User-Agent: Agent/1.0 Accept: application/atomcoll+xml Here, theresponse. Range = "Range" ":" ranges-specifier The valueserver could return any subset of theRange:collection as an Atom Collection Document. Example Response, Atom Collection Document HTTP/1.1 200 OK Date: Fri, 25 Mar 2005 17:15:33 GMT Last-Modified: Mon, 04 Oct 2004 18:31:45 GMT ETag: "2b3f6-a4-5b572640" Accept-Ranges: updated Content-Length: nnnn Content-Type: application/atomcoll+xml; charset="utf-8" <?xml version="1.0" encoding="utf-8"?> <collection xmlns="http://purl.org/atom/app#"> ... <member href="http://example.org/1" hrefreadonly="http://example.com/1/bar" title="Example 1" updated="2003-12-13T18:30:02Z" /> ... </collection> Example Request, with SOAP Accept headershould be a pairGET /collection HTTP/1.1 Host: example.org User-Agent: Cosimo/1.0 Accept: application/soap+xml Here, the server could return any subset ofISO 8601 dates, separatedthe collection as an Atom Feed Document wrapped by aslash character; either date may be optionally omitted, in which caseSOAP envelope. Example Response, Atom Feed Document wrapped by a SOAP envelope HTTP/1.1 200 OK Date: Fri, 25 Mar 2005 17:15:33 GMT Last-Modified: Mon, 04 Oct 2004 18:31:45 GMT ETag: "2b3f6-a4-5b572640-89" Accept-Ranges: bytes Content-Length: nnnn Content-Type: application/soap+xml; charset="utf-8" <?xml version="1.0" encoding="utf-8"?> <env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope"> <env:Header /> <env:Body> <collection xmlns="http://purl.org/atom/app#"> ... <member href="http://example.org/1" hrefreadonly="http://example.com/1/bar" title="Example 1" updated="2003-12-13T18:30:02Z" /> ... </collection> </env:Body> </env:Envelope> 5.2.2 POST In addition to GET, a Collection Resource also accepts POST requests. The client POSTs a representation of therange is understood as stretchingdesired resource toinfinity onthe Collection Resource. Note thatend. ranges-specifier = updated-ranges-specifier updated-ranges-specifier = updated-unit "=" updated-range updated-unit = "updated" updated-range = [iso-date] "/" [iso-date] Thesome collections only allow members of a specific media-type and a POST MAY generate a responsetowith acollection requeststatus code of 415 ("Unsupported Media Type"). In the case of a successful creation, the status code MUST be 201 ("Created"). Example Request, Create acollection document, all of whose 'member' elements fall within the requested range. If no members fallresource in a collection. POST /collection HTTP/1.1 Host: example.org User-Agent: Cosimo/1.0 Accept: application/atomcoll+xml Content-Type: image/png Content-Length: nnnn Name: trip-to-beach.png ...binary data... Here, therequested range, the server MUST respond withclient is adding acollection document containing no 'member' elements. 3.1.3.2 Accept-Ranges: Header The responsenew image resource to anon-partial GET request MUST include an Accept-Rangescollection. The Name: headerthatindicatesthattheserver accepts 'updated' range requests. Accept-Ranges = "Accept-Ranges" ":" acceptable-ranges acceptable-ranges = updated-unit ( 1#range-unit ) 3.2 Introspection There are many different kinds of resources thatclient's desired name for the resource, see Section 5.2.6. Example Response, resource created successfully. HTTP/1.1 201 Created Date: Fri, 25 Mar 2005 17:17:11 GMT Content-Length: nnnn Content-Type: application/atomcoll+xml; charset="utf-8" Location: http://example.org/images/trip-to-the-beach-01.png <?xml version="1.0" encoding="UTF-8"?> <collection xmlns="http://purl.org/atom/app#"> <member href="http://example.org/images/trip-to-beach.png" hrefreadonly="http://example.com/ed/im/trip-01.png" title="trip-to-beach.png" updated="2005-03-25T17:17:09Z" /> </collection> 5.2.3 Usage Scenarios These scenarios illustrate common idioms for interactin with Collections. The Atom Collection can bemanaged throughused by clients in two ways. In the first case theAPP,client encounters a Collection forexample, entries, templates, users, etc. The Service Documentthe first time and isa single documentdoing an initial syncronization, thatlistsis, retrieving a list of all thefacetsmembers of theAPP that a site supportscollections andalso containspossibly retrieving all theURIsmembers ofall those resources. 3.2.1 Service Document The Service Document liststheresources that each site makes available.collection also. TheService Resource returns an Service Document in response toclient can perform a non-partial GETrequest. Here is an example of an Service Document. <?xml version="1.0" encoding='utf-8'?> <service version="0.3" xmlns="http://purl.org/atom/ns#"> <workspace title="Main Site" > <collection rel="entries" name="Entries" href="http://example.org/reilly/feed" /> <collection rel="categories" name="Categories" href="http://example.org/reilly/cat" /> <collection rel="templates" name="Templates" href="http://example.org/reilly/tmpl" /> <collection rel="users" name="Users" href="http://example.org/reilly/users" /> <collection rel="resource" name="Pictures" href="http://example.org/reilly/pic" /> </workspace> <workspace title="b-links"> <collection rel="entries" name="Entries" href="http://example.org/reilly/feed" /> <collection rel="http://example.net/booklist" name="Books" href="http://example.org/reilly/books" /> </workspace> </service> o entries o resource o categories o templates o users The default for the rel attribute is 'resource'. Extensibility for 'rel' values is handled inon thesame manner as PaceFieldingLinks. Each 'collection' element in 'workspace' representscollection resource and it will receive asingle facetcollection document that either contains all the members of theAPP. While a site must fully support each facet they list in their Service Document,collection, or the collection document root element 'collection' will contain asite does not need'next' attribute pointing tosupport allthefacets in this RFC. Additionally, new facets may be added either through vendor extension or follow-on RFCs. 3.2.1.1 Service Documet Elements The "service" element isnext collection document. By repeatedly following the 'next' attribute from documentelementto document the client can find all the members ofa Service Document, acting as a container for service data associated with possibly multiple workspaces. Its only child elements MUST be onethe collection. In the second case the client has already done an initial sync, and now needs to re-sync, because the client was just restarted, ormore 'workspace' elements.some time has passed since a re-sync, etc. The'service' element MUST haveclient does asingle attribute 'version' whose content indicates the version ofpartial GET on theAtom specificationcollection document, supplying a Range header that begins from thedocument conforms to. The content of this attribute is unstructured text. The version identifier for this specification is "1.0". The 'workspace' element element contains information elements aboutlast time thecollections of resources available for editing. The only children of 'workspace' MUST be one or more "collection" elements. The 'workspace' element MUST have a single attribute 'title' whose content MUST NOT be empty and which is a human-readable name forclient sync'd to theworkspace.current time. The'collection' element describes various typed groups of resources available for editing or adding to. 3.3 Entry Collection Entries are managed through collections and as such entrycollectionand entries that aredocument returned will contain only those members ofa collection must support alltheoperations enumerated above. An Edit Resource is used to edit a single entry. Each entrycollection thatis editable MUSThavea unique URI. This URI supports both GET and PUT and they are used in tandem for an editing cycle. The client GETschanged since the last time therepresentation which is formatted as an Atom entry. Theclientmay then updatesyncronized. 5.2.4 Range: Header HTTP/1.1 allows a client to request that only part (a range of) theentry and then PUT it backcollection to be included within thesame URI. The PUT will cause allresponse. HTTP/1.1 uses range units in therelated resources toRange header field. A collection can beupdated, for example,broken down into subranges according to theHTML representation. Note thatmembers 'updated' property. If a Range: header is present in the request, its valueofexplictly identifies thecontent elementa time interval interval in which all theAtom entry does not havemembers 'updated' property must fall toexactly matchbe included in thecontent element forresponse. Range = "Range" ":" ranges-specifier The value of thesame entry when it is represented in an Atom feed. For example,Range: header should be aserver may allow the client to post entries whose content is formatted as WikiML, yet the serverpair of ISO 8601 dates, separated by a slash character; either date mayclean up such markup and transform it into well-formed XHTML before placing itbe optionally omitted, in which case thepublicly available Atom feed. Another scenario is summaries--the EditURIrange isfor editing the full content of an entry, but the server may only present excerpts when it produces an Atom feed. A client will send a DELETEunderstood as stretching tothe EditURIinfinity on that end. ranges-specifier = updated-ranges-specifier updated-ranges-specifier = updated-unit "=" updated-range updated-unit = "updated" updated-range = [iso-date] "/" [iso-date] The response todelete an entry. 3.3.1 Locating For editingasite Entry,collection request MUST be a collection document, all of whose 'member' elements fall within thelink tagrequested range. The request range isused. Noteconsidered a closed set, that is, if alink tag is used in both HTML and in the Atom format. A link tag'member' element matches one end of thefollowing format points to the EditURI for a site. In HTML, the link tags for editing are always foundrange exactly it MUST be included in thehead element, whileresponse. If no members fall inAtom they may appear as children oftheentry elements. <link rel="service.edit" type="application/atom+xml" href="URI for Editing goes here" title="Readable desc ofrequested range, theentry." /> Note:server MUST respond with a collection document containing no 'member' elements. Thecritical characteristic of this link tag is the @rel of 'service.edit' and the @type of 'application/atom+xml'. 3.4 Simple Resource Collection Simple Resources are managed through collections and as such simple reource collections and simple resources that are membersinclusion of thecollection must support all the operations enumerated above. Simple Resources can be images, templates, and any other non-entry resources. 3.4.1 Locating For creatingRange: header in anew non-entry resource,request changes thelink tag is used. Note thatrequest to alink tag is used in both HTML and in the Atom format. A link tag of the following format points"partial GET" [RFC2616]. 5.2.5 Accept-Ranges: Header The response tothe ResourcePostURI forasite. In HTML the link tags are always found in the head element, while in Atom they may appear as children of the Feed and entry elements. <link rel="resource.post" href="URI for Resource Posting goes here" title="The name ofnon-partial GET request MUST include an Accept- Ranges header that indicates that thesite."> 3.4.2 Requestserver accepts 'updated' range requests. Accept-Ranges = "Accept-Ranges" ":" acceptable-ranges acceptable-ranges = updated-unit ( 1#range-unit ) 5.2.6 Name: Header [[anchor13: this is new...]] Therequest containsPOST to aresource, sent throughCollection Resource MAY contain astandard HTTP POST, e.g.: POST /_do/exampleblog/post_resource HTTP/1.1 Host: www.example.com Content-Type: image/jpeg Content-Length: nnn ...raw bytes of image go here... 3.5 Atom Request and Response Body ConstraintsName: header that indicates the clients suggested name for the resource. TheAtom format is used asserver MAY ignore therepresentation of allName: header or modify theresources in this specification. As itrequested name to suit local conventions. Name = "Name" ":" relative-part The relative-part production isuseddefined indiffering contexts, there[RFC3986]. 6. Entry Collection Entry Collections aredifferent constraints of which elements may be present, and howCollections that restrict theirvalues should be interpreted. 3.5.1 id PostURI MUST NOT be present. FeedURI MUST be present. EditURI GET MUST be present. PUT MUST be present. 3.5.2 link PostURI MAY be present.membership to Atom entries. This specification defines two serializations for Atom entries. ServersMAYMUST provide both serializations. 1. Atom Entry Documents (application/atom+xml), [AtomFormat]. 2. Atom Entry Documents wrapped by a SOAP envelope (application/ soap+xml), . Clients use theinformationHTTP 'Accept' request header todetermineindicate their preference [RFC2616]. If no 'Accept' header is present in theURI ofrequest, thecreated resource. Relative URLs are to be interpreted relativeserver is free toxml:base. FeedURI MUST be present. EditURI GET MUST be present. PUTchoose any serialization. When an HTTP request contains a body, clients MUSTbe present. 3.5.3 title PostURIinclude a 'Content-Type' header, and servers MUSTbe present. The element may be empty, to explicitly indicate "no title". Servers SHOULD NOT tryaccept both application/atom+xml and application/soap+xml message bodies. 6.1 Editing Entry Resources Atom entries are edited by sending HTTP requests togeneratean individual entry's URI. Servers can determine the processing necessary to interpret atitle if one is not provided. The type attribute MAY be present,request by examining the request's HTTP method andif not it defaults to "text/plain".'Content-Type' header. Ifpresent, itthe request method is POST and the 'Content-Type' is application/ soap+xml, the SOAP document MUSTrepresentcontain aMIME typeWeb-Method property . This specifcation defines two values for thatthe server supports. The mode attribute MAY be present. If not present, it defaults to "xml". If present, it MUST be "xml", "base64", or "escaped". FeedURI MUST be present. EditURIproperty, PUT and DELETE. Processing Client Requests +----------------------------------+------+--------+--------+--------+ | | GETMUST be present.| PUTMUST be present.| DELETE | POST | +----------------------------------+------+--------+--------+--------+ | No Body | Read | x | Delete | x | | | | | | | | Atom Body | x | Update | x | x | | | | | | | | SOAP Body with Web-Method PUT | x | x | x | Update | | | | | | | | SOAP Body with Web-Method DELETE | x | x | x | Delete | +----------------------------------+------+--------+--------+--------+ 6.2 Role of Atom Entry Elements During Editing Theelement may be empty, to explicitly indicate "no title". Servers SHOULD NOT try to generateelements of an Atom Entry Document are either atitle if one'Writable Element' or a 'Round Trip Element'. Writable Element - An element of an Atom Entry whose value is editable by the client and notprovided. 3.5.4 summary PostURI MAY be present. If not present,enforced by theserverserver. Round Trip Element - An element of an Atom Entry whose value iswelcome to produce its own summary. If present but empty,enforced by the serverSHOULD NOT generate a summaryand not editable by the client. That categorization will determine the elements' disposition during editing. +--------------------+------------+ | Atom Entry Element | Property | +--------------------+------------+ | atom:author | Writable | | | | | atom:category | Writable | | | | | atom:content | Writable | | | | | atom:contributor | Writable | | | | | atom:id | Round Trip | | | | | atom:link | Writable | | | | | atom:published | Writable | | | | | atom:source | Writable | | | | | atom:summary | Writable | | | | | atom:title | Writable | | | | | atom:updated | Round Trip | +--------------------+------------+ Table 2 7. Generic Collection Generic Collections are Collections that do not have uniform restrictions on the representations ofits own. The type attribute MAY be present. If not, it defaultsthe member resources. 7.1 Editing Generic Resources Member resources are edited by sending HTTP requests to"text/plain". If present, it must representan individual resource's URI. Servers can determine the processing necessary to interpret aMIME type thatrequest by examining theserver supports. The mode attribute MAY be presentrequest's HTTP method anddefaults to "xml". If present, it must be "xml","base64", or "escaped". FeedURI MAY be present. EditURI'Content-Type' header. Processing Client Requests +----------+------+--------+--------+------+ | | GETMAY be present.| PUTMAY be present. The element may be empty, to explicitly indicate "no summary". Servers SHOULD NOT try| DELETE | POST | +----------+------+--------+--------+------+ | No Body | Read | x | Delete | x | | | | | | | | Any Body | x | Update | x | x | +----------+------+--------+--------+------+ 8. Introspection In order for authoring togeneratecommence, atitle if oneclient must first discover the capabilities and locations of collections offered. 8.1 Introspection Document The Introspection Document describes "workspaces", which are server- defined groupings of collections. There isnot provided. 3.5.5 content PostURI MAY be present butno requirement that servers support multiple workspaces, and a collection maybe empty, to explicitly indicate "no content".appear in more than one workspace. Thetype attribute MAY be present, but defaults to "text/plain" if not present. It must represent a MIME type thatIntrospection Document has theserver supports.media-type 'application/ atomserv+xml', see Section 11 <?xml version="1.0" encoding='utf-8'?> <service xmlns="http://purl.org/atom/app#"> <workspace title="Main Site" > <collection contents="entries" title="My Blog Entries" href="http://example.org/reilly/feed" /> <collection contents="generic" title="Documents" href="http://example.org/reilly/pic" /> </workspace> <workspace title="Side Bar Blog"> <collection contents="entries" title="Entries" href="http://example.org/reilly/feed" /> <collection contents="http://example.net/booklist" title="Books" href="http://example.org/reilly/books" /> </workspace> </service> 8.1.1 Element Definitions 8.1.1.1 TheMODE attribute may be present and defaults to "xml" if not present. It must be "xml","base64", or "escaped". FeedURI MAY be present. EditURI GET MAY be present. PUT MAY be present.'app:service' Element The "service" elementmay be empty, to explicitly indicate "no content". 3.5.6 issued PostURI MUST be present, but may be empty, in which case it signifies "now" inis thetime zonedocument element ofthe server. FeedURI MUST be present. EditURI GET MUST be present. PUT MUST be present. Server policy determines if an updated time is accepted. 3.5.7 modified PostURI MUST NOT be present. FeedURI MAY be present. EditURI GET MAY be present. PUTa Service Document, acting as a container for service data associated with one or more workspaces. appService element app:service { ( appWorkspace* & anyElement* ) } The following child elements are defined by this specification: o app:service elements MAYbe present.contain any number of app:workspace elements. 8.1.1.2 The 'app:workspace' Element The 'workspace' elementmay be empty, to explicitly indicate that 'now' onelement contains information elements about theserver time is to be used. 3.5.8 created PostURI MAY be present. FeedURI MAY be present. EditURI GET MAY be present. PUT MAY be present.collections of resources available for editing. appWorkspace element app:workspace { attribute title { text }, ( appCollection* & anyElement* ) } Theserver may or may not accept an updated value. If the server does not allow updatingfollowing attributes and child elements are defined by this specification: o app:workspace elements MUST contain a 'title' attribute, which conveys a human-readable name for theissued time thenworkspace o app:workspace elements MAY contain anyPUT request withnumber of app:collection elements. 8.1.1.3 The 'app:collection' Element The 'app:collection' element describes collections and their member resources. [[anchor19: We have a collection element that's differentissued valuethan the root element of the collection document. Messy. --R. Sayre]] appCollection element app:collection { attribute title { text }, attribute contents { text }, attribute href { text }, anyElement* } The following attributes are defined by this specification: o app:collection elements MUSTbe rejected. 3.5.9 author PostURIcontain a 'title' attribute, whose value conveys a human-readable name for the workspace o app:collection elements MAYbe present.contain a 'contents' attribute (Section 8.1.1.3.1). If it is not present,the server determines the author. If present, and conflicting with valid values as determined by the server, then the server may change theit's valueof author. FeedURI MAY be present. EditURI GET MAY be present. PUT MAY be present. 3.5.10 contributor PostURI MAY be present. FeedURI MAY be present. EditURI GET MAY be present. PUT MAYis considered to bepresent. 3.5.11 generator PostURI'generic'. o app:collection elements MUSTbe present andcontaina URI.an 'href' attribute, whose value conveys the URI of the collection. 8.1.1.3.1 The 'contents' Attribute The 'contents' attribute conveys the nature of a collection's member resources. This specification defines two initial values for the 'contents' attribute: o entry o generic Extensibility for 'content' values is handled [[anchor20: Same as atom:link]]. 8.1.1.3.1.1 entry A value of 'entry' for theelementcontents attribute indicates that thecode base used to create this request. MUST also haveCollection is an Entry Collection (Section 6). 8.1.1.3.1.2 generic A value of 'generic' for the contents attribute'version' withindicates that the Collection is a Generic Collection (Section 7). 8.2 Introspection Resource To retrieve an Introspection Document, the client sends aversion number. FeedURI MUST NOT be present. EditURIGETMUST NOT be present. PUT MUST NOT be present. 3.6request to its URI. GET /service-desc HTTP/1.1 Host: example.org User-Agent: Cosimo/1.0 Accept: application/atomserv+xml The server responds to a GET request by returning an Introspection Document in the message body. HTTP/1.1 200 OK Date: Mon, 21 Mar 2005 19:20:19 GMT Server: CountBasic/2.0 Last-Modified: Mon, 21 Mar 2005 19:17:26 GMT ETag: "4c083-268-423f1dc6" Content-Length: nnnn Content-Type: application/atomserv+xml <?xml version="1.0" encoding='utf-8'?> <service xmlns="http://purl.org/atom/app#"> ... </service> 8.2.1 Discovery [[anchor24: Add in desc of an HTML link element that points to the Introspection Resource, or add it to the autodisco draft]] 9. Securing the Atom Protocol All instances of publishing Atom entries SHOULD be protected by authentication to prevent posting or editing by unknown sources. Atom servers and clients MUST support one of the following authentication mechanisms, and SHOULD support both. o HTTP Digest Authentication [RFC2617] o [@@TBD@@ CGI Authentication ref] Atom servers and clients MAY support encryption of the Atom session using TLS [RFC2246]. There are cases where an authentication mechanism may not be required, such as a publicly editable Wiki, or when using the PostURI to post comments to a site that does not require authentication to create comments.3.6.19.1 [@@TBD@@ CGI Authentication] This authentication method is included as part of the protocol to allow Atom servers and clients that cannot use HTTP Digest Authentication but where the user can both insert its own HTTP headers and create a CGI program to authenticate entries to the server. This scenario is common in environments where the user cannot control what services the server employs, but the user can write their own HTTP services.4.10. Security Considerations Because Atom is a publishing protocol, it is important that only authorized users can create and edit entries. The security of Atom is based on HTTP Digest Authentication and/or [@@TBD@@ CGI Authentication]. Any weaknesses in either of these authentication schemes will obviously affect the security of the Atom Publishing Protocol. Both HTTP Digest Authentication and [@@TBD@@ CGI Authentication] are susceptible to dictionary-based attacks on the shared secret. If the shared secret is a password (instead of a random string with sufficient entropy), an attacker can determine the secret by exhaustively comparing the authenticating string with hashed results of the public string and dictionary entries. See RFC 2617 for more detailed description of the security properties of HTTP Digest Authentication. @@TBD@@ Talk here about using HTTP basic and digest authentication. @@TBD@@ Talk here about denial of service attacks using large XML files, or the billion laughs DTD attack.5.11. IANA ConsiderationsThis document has no actions for IANA. 6. AppendixA- SOAP Enabling All servers SHOULD supportAtom Collection Document, when serialized as XML 1.0, can be identified with the followingalternate interface mechanismsmedia type: MIME media type name: application MIME subtype name: atomcoll+xml Mandatory parameters: None. Optional parameters: "charset": This parameter has identical semantics toenable a wider varietythe charset parameter ofclients to interact with Atom Publishing Protocol servers. The following requirements arethe "application/xml" media type as specified inaddition[RFC3023]. Encoding considerations: Identical tothe ones listedthose of "application/xml" as described in [RFC3023], section 3.2. Security considerations: As defined in this specification. [[anchor28: update upon publication]] In addition, as this media type uses theFunctional Specification Section. If a server supports SOAP Enabling then"+xml" convention, itMUST support all ofshares thefollowing. 6.1 Servers 1. All servers MUST supportsame security considerations as described in [RFC3023], section 10. Interoperability considerations: There are no known interoperability issues. Published specification: This specification. [[anchor29: update upon publication]] Applications that use this media type: No known applications currently use this media type. Additional information: Magic number(s): As specified for "application/xml" in [RFC3023], section 3.2. File extension: .atomcoll Fragment identifiers: As specified for "application/xml" in [RFC3023], section 5. Base URI: As specified in [RFC3023], section 6. Macintosh File Type code: TEXT Person and email address to contact for further information: Joe Gregorio <joe@bitworking.org> Intended usage: COMMON Author/Change controller: IESG An Atom Introspection Document, when serialized as XML 1.0, can be identified with the following media type: MIME media type name: application MIME subtype name: atomserv+xml Mandatory parameters: None. Optional parameters: "charset": This parameter has identical semantics to thelimited usecharset parameter of theSOAPAction HTTP Header"application/xml" media type asdescribed belowspecified inthe Client section. 2. All servers MUST be able to process well formed XML. Servers need not be able[RFC3023]. Encoding considerations: Identical tohandle processing instructions or DTDs. 3. Servers MUST accept content in a SOAP Envelope, and if they receive a request that is wrappedthose of "application/xml" as described ina SOAP Envelope then they MUST wrap their responses[RFC3023], section 3.2. Security considerations: As defined inSOAP envelopes or produce a SOAP Fault. 6.2 Clients 1. Clients SHOULD use the appropriate HTTP Method when possible. When not possible, they should use POST and include a SOAPAction HTTP header which is constrainedthis specification. [[anchor30: update upon publication]] In addition, asfollows: 2. SOAPAction: "http://schemas.xmlsoap.org/wsdl/http/[METHOD]" 3. Where [METHOD] is replaced bythis media type uses thedesired HTTP Method. 4. Clients MAY wrap their XML payload in a SOAP Envelope. If so, they must also wrap"+xml" convention, itin an element which exactly matchesshares theHTTP Method. 7. Appendix B - Examples 7.1 Example for a weblog Fillsame security considerations as described in [RFC3023], section 10. Interoperability considerations: There are no known interoperability issues. Published specification: This specification. [[anchor31: update upon publication]] Applications that use this media type: No known applications currently use this media type. Additional information: Magic number(s): As specified for "application/xml" inwith an example[RFC3023], section 3.2. File extension: .atomsrv Fragment identifiers: As specified forhow all the above is used"application/xml" in [RFC3023], section 5. Base URI: As specified in [RFC3023], section 6. Macintosh File Type code: TEXT Person and email address to contact fora weblog. Start with main HTML page, link tag of type service.feedfurther information: Joe Gregorio <joe@bitworking.org> Intended usage: COMMON Author/Change controller: This specification's author(s). [[anchor32: update upon publication]] 12. References 12.1 Normative References [AtomFormat] Nottingham, M. and R. Sayre, "The Atom Syndication Format", work-in-progress, April 2005. [RFC2119] Bradner, S., "Key words for use in RFCs tothe 'introspection' file. 1. Creating a new entry 2. Finding an old entry 3. editing an old entry 4. commentingIndicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999. [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, P., Luotonen, A., and L. Stewart, "HTTP Authentication: Basic and Digest Access Authentication", RFC 2617, June 1999. [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media Types", RFC 3023, January 2001. [RFC3339] Klyne, G. and C. Newman, "Date and Time ona entry (via HTMLthe Internet: Timestamps", RFC 3339, July 2002. [RFC3986] Berners-Lee, T., Fielding, R., andAtom) 7.2 Example for a wiki Fill this in like above but for a wiki. 8.L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource Identifiers (IRIs)", RFC 3987, January 2005. [W3C.REC-soap12-part1-20030624] Nielsen, H., Mendelsohn, N., Gudgin, M., Hadley, M., and J. Moreau, "SOAP Version 1.2 Part 1: Messaging Framework", W3C REC REC-soap12-part1-20030624, June 2003. [W3C.REC-soap12-part2-20030624] Nielsen, H., Hadley, M., Moreau, J., Mendelsohn, N., and M. Gudgin, "SOAP Version 1.2 Part 2: Adjuncts", W3C REC REC-soap12-part2-20030624, June 2003. [W3C.REC-xml-20040204] Yergeau, F., Paoli, J., Sperberg-McQueen, C., Bray, T., and E. Maler, "Extensible Markup Language (XML) 1.0 (Third Edition)", W3C REC REC-xml-20040204, February 2004. 12.2 Informative References [W3C.REC-webarch-20041215] Walsh, N. and I. Jacobs, "Architecture of the World Wide Web, Volume One", W3C REC REC-webarch-20041215, December 2004. URIs [1] <http://www.imc.org/atom-protocol/index.html> Authors' Addresses Joe Gregorio (editor) BitWorking, Inc 1002 Heathwood Dairy Rd. Apex, NC 27502 US Phone: +1 919 272 3764 Email: joe@bitworking.com URI: http://bitworking.com/ Robert Sayre (editor) Email: rfsayre@boswijck.com URI: http://boswijck.com Appendix A. Revision History draft-ietf-atompub-protocol-04 - Add ladder diagrams, reorganize, add SOAP interactions draft-ietf-atompub-protocol-03 - Incorporates PaceSliceAndDice3 and PaceIntrospection. draft-ietf-atompub-protocol-02 - Incorporates Pace409Response, PacePostLocationMust, and PaceSimpleResourcePosting. draft-ietf-atompub-protocol-01 - Added in sections on Responses for the EditURI. Allow 2xx for response to EditURI PUTs. Elided all mentions of WSSE. Started adding in some normative references. Added the section "Securing the Atom Protocol". Clarified that it is possible that the PostURI and FeedURI could be the same URI. Cleaned up descriptions for Response codes 400 and 500. Rev draft-ietf-atompub-protocol-00 - 5Jul2004 - Renamed the file and re-titled the document to conform to IETF submission guidelines. Changed MIME type to match the one selected for the Atom format. Numerous typographical fixes. We used to have two 'Introduction' sections. One of them was moved into the Abstract the other absorbed the Scope section. IPR and copyright notifications were added. Rev 09 - 10Dec2003 - Added the section on SOAP enabled clients and servers. Rev 08 - 01Dec2003 - Refactored the specification, merging the Introspection file into the feed format. Also dropped the distinction between the type of URI used to create new entries and the kind used to create comments. Dropped user preferences. Rev 07 - 06Aug2003 - Removed the use of the RSD file forauto-discovery.auto- discovery. Changed copyright until a final standards body is chosen. Changed query parameters for the search facet to all begin with atom- to avoid name collisions. Updated all the Entries to follow the 0.2 version. Changed the format of the search results and template file to a pure element based syntax. Rev 06 - 24Jul2003 - Moved to PUT for updating Entries. Changed all the mime-types to application/x.atom+xml. Added template editing. Changed 'edit-entry' to 'create-entry' in the Introspection file to more accurately reflect it's purpose. Rev 05 - 17Jul2003 - Renamed everything Echo into Atom. Added version numbers in the Revision history. Changed all the mime-types to application/atom+xml. Rev 04 - 15Jul2003 - Updated the RSD version used from 0.7 to 1.0. Change the method of deleting an Entry from POSTing <delete/> to using the HTTP DELETE verb. Also changed the query interface to GET instead of POST. Moved Introspection Discovery to be up under Introspection. Introduced the term 'facet' for the services listed in the Introspection file. Rev 03 - 10Jul2003 - Added a link to the Wiki near the front of the document. Added a section on finding an Entry. Retrieving an Entry now broken out into it's own section. Changed the HTTP status code for a successful editing of an Entry to 205. Rev 02 - 7Jul2003 - Entries are no longer returned from POSTs, instead they are retrieved via GET. Cleaned up figure titles, as they are rendered poorly in HTML. All content-types have been changed to application/atom+xml. Rev 01 - 5Jul2003 - Renamed from EchoAPI.html to follow the more commonly used format: draft-gregorio-NN.html. Renamed all references to URL to URI. Broke out introspection into it's own section. Added the Revision History section. Added more to the warning that the example URIs are not normative.9. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999. [RFC2396] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, P., Luotonen, A. and L. Stewart, "HTTP Authentication: Basic and Digest Access Authentication", RFC 2617, June 1999. [1] <http://www.imc.org/atom-syntax/index.html> Authors' Addresses Joe Gregorio (editor) BitWorking, Inc 1002 Heathwood Dairy Rd. Apex, NC 27502 US Phone: +1 919 272 3764 Email: joe@bitworking.com URI: http://bitworking.com/ Robert Sayre (editor) Boswijck Memex Consulting 148 N 9th St. 4R Brooklyn, NY 11211 US Email: rfsayre@boswijck.com URI: http://boswijck.comIntellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society.