< draft-ietf-simple-xcap-diff-01.txt   draft-ietf-simple-xcap-diff-02.txt >
SIMPLE J. Rosenberg SIMPLE J. Rosenberg
Internet-Draft Cisco Systems Internet-Draft Cisco Systems
Expires: January 19, 2006 July 18, 2005 Expires: April 25, 2006 October 22, 2005
An Extensible Markup Language (XML) Document Format for Indicating An Extensible Markup Language (XML) Document Format for Indicating A
Changes in XML Configuration Access Protocol (XCAP) Resources Change in XML Configuration Access Protocol (XCAP) Resources
draft-ietf-simple-xcap-diff-01 draft-ietf-simple-xcap-diff-02
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
This specification defines a document format that can be used to This specification defines a document format that can be used to
describe the differences between versions of resources managed by the indicate that a change has occurred in a document managed by the
Extensible Markup Language (XML) Configuration Access Protocol Extensible Markup Language (XML) Configuration Access Protocol
(XCAP). XCAP diff documents can be delivered to clients using a (XCAP). This format indicates the document that has changed and its
number of means, including the Session Initiation Protocol (SIP) former and new entity tags. XCAP diff documents can be delivered to
event package for configuration data. By subscribing to this event clients using a number of means, including the Session Initiation
package, clients can learn about document changes made by other Protocol (SIP) event package for configuration data. By subscribing
clients. to this event package, clients can learn about document changes made
by other clients. The XCAP diff format is extensible, so that
additional information, such as a description of the actual change,
can be included.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Structure of an XCAP Diff Document . . . . . . . . . . . . . 4 3. Structure of an XCAP Diff Document . . . . . . . . . . . . . . 4
4. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Example Document . . . . . . . . . . . . . . . . . . . . . . 7 5. Example Document . . . . . . . . . . . . . . . . . . . . . . . 6
6. Usage with the Config Framework . . . . . . . . . . . . . . 8 6. Usage with the Config Framework . . . . . . . . . . . . . . . 7
7. Constructing a Document from the Change Log . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . 11 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . 11 8.1 application/xcap-diff+xml MIME Type . . . . . . . . . . . 8
9.1 application/xcap-diff+xml MIME Type . . . . . . . . . . . 11 8.2 URN Sub-Namespace Registration for
9.2 URN Sub-Namespace Registration for urn:ietf:params:xml:ns:xcap-diff . . . . . . . . . . . . . 9
urn:ietf:params:xml:ns:xcap-diff . . . . . . . . . . . . . 12 8.3 Schema Registration . . . . . . . . . . . . . . . . . . . 10
9.3 Schema Registration . . . . . . . . . . . . . . . . . . . 13 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1 Normative References . . . . . . . . . . . . . . . . . . . 10
10.1 Normative References . . . . . . . . . . . . . . . . . . 13 9.2 Informative References . . . . . . . . . . . . . . . . . . 11
10.2 Informative References . . . . . . . . . . . . . . . . . 14 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . 15 Intellectual Property and Copyright Statements . . . . . . . . 13
Intellectual Property and Copyright Statements . . . . . . . 16
1. Introduction 1. Introduction
The Extensible Markup Language (XML) Configuration Access Protocol The Extensible Markup Language (XML) Configuration Access Protocol
(XCAP) [8] is a protocol that allows clients to manipulate XML (XCAP) [8] is a protocol that allows clients to manipulate XML
documents stored on a server. These XML documents serve as documents stored on a server. These XML documents serve as
configuration information for application protocols. As an example, configuration information for application protocols. As an example,
resource list [12] subscriptions (also known as presence lists) allow resource list [12] subscriptions (also known as presence lists) allow
a client to have a single SIP subscription to a list of users, where a client to have a single SIP subscription to a list of users, where
the list is maintained on a server. The server will obtain presence the list is maintained on a server. The server will obtain presence
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cached version becomes stale. This modification event must be made cached version becomes stale. This modification event must be made
known to all clients which have cached copies of the document, so known to all clients which have cached copies of the document, so
that they can fetch the most recent one. that they can fetch the most recent one.
To deal with this problem, clients can use the Session Initiation To deal with this problem, clients can use the Session Initiation
Protocol (SIP) [10] event package [11] for subscribing to changes in Protocol (SIP) [10] event package [11] for subscribing to changes in
configuration and profile information [9], including application data configuration and profile information [9], including application data
that resides on an XCAP server. With that package, a user gets that resides on an XCAP server. With that package, a user gets
notified that a particular document has changed. This notification notified that a particular document has changed. This notification
can include the full content of the new document, or it can be a can include the full content of the new document, or it can be a
content indirection [15]. However, in both cases, the transfer of content indirection [15]. Though content indirection can tell a
the entire document is ultimately required. This may require a lot client that a document has changed, it provides it with MIME
of bandwidth, particularly for wireless devices with large documents Content-ID indicating the new version of the document. The MIME
(such as a resource list [12] with hundreds of users listed). Content-ID is not the same as the entity tag, which is used by XCAP
Furthermore, though content indirection can tell a client that a for document versioning. As such, a client cannot easily ascertain
document has changed, it provides it with MIME Content-ID indicating whether an indication of a change in a document is due to a change it
the new version of the document. The MIME Content-ID is not the same just made, or due to a change another client made at around the same
as the entity tag, which is used by XCAP for document versioning. As time.
such, a client cannot easily ascertain whether an indication of a
change in a document is due to a change it just made, or due to a
change another client made at around the same time.
To resolve this problem, this document defines a data format which In addition, when an XCAP client inserts a new element or attribute
can convey changes in XML documents managed by an XCAP server. This into an existing document, the client has no way to know whether the
data format is an XML document format, called an XCAP diff document. insertion was done against its cached version of the document. The
This format can indicate that a document has changed, provide its reasons for this are described in Section 7.10 of XCAP. To help a
previous and new entity tags, and optionally include the xcap client ascertain whether this has occurred after performing the
operation that was performed which resulted in that change. This insertion, the XCAP response needs to contain a document which
specification also explains how this format is used in conjunction indicates the entity tags before and after the document was modified.
with the configuration profile framework.
To resolve these problems, this document defines a data format which
can convey the fact that an XML document has changed. This data
format is an XML document format, called an XCAP diff document. This
format can indicate that a document has changed, and provide its
previous and new entity tags. This specification also explains how
this format is used in conjunction with the configuration profile
framework.
2. Terminology 2. Terminology
In this document, the key words "MUST", "MUST NOT", "REQUIRED", In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in RFC 2119 [7] and and "OPTIONAL" are to be interpreted as described in RFC 2119 [7] and
indicate requirement levels for compliant implementations. indicate requirement levels for compliant implementations.
This specification also defines the following additional terms: This specification also defines the following additional terms:
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selector", and a three optional attributes, "new-etag", "previous- selector", and a three optional attributes, "new-etag", "previous-
etag" and "hash". The "doc-selector" identifies the specific etag" and "hash". The "doc-selector" identifies the specific
document within the XCAP root for which changes are indicated. Its document within the XCAP root for which changes are indicated. Its
content MUST be a relative path reference, with the base URI being content MUST be a relative path reference, with the base URI being
equal to the XCAP root URI. The "new-etag" attribute provides the equal to the XCAP root URI. The "new-etag" attribute provides the
etag for the document after the application of the changes, assuming etag for the document after the application of the changes, assuming
the document exists after those changes. If the change being the document exists after those changes. If the change being
reported is the deletion of the document, the "new-etag" attribute reported is the deletion of the document, the "new-etag" attribute
will not be present. A server MUST include the "new-etag" unless the will not be present. A server MUST include the "new-etag" unless the
document does not exist subsequent to the changes reported in the document does not exist subsequent to the changes reported in the
XCAP diff document. If The "previous-etag" attribute provides an XCAP diff document. The "previous-etag" attribute provides an
identifier for the document instance prior to the change. If the identifier for the document instance prior to the change. If the
document did not exist prior to the change (that is, the change was document did not exist prior to the change (that is, the change was
the creation of the document), the "previous-etag" is not present. the creation of the document), the "previous-etag" is not present.
If the server is reporting a specific set of document changes via the
<change-log> element described below, a server MUST include the The "previous-etag" and "new-etag" need not have been sequentially
"previous-etag" unless the document did not exist prior to changes assigned etags at the server. An XCAP diff document can indicate
reported in the XCAP diff document. If the <change-log> element is changes that have occurred over a series of XCAP operations.
not present, the "previous-etag" SHOULD be present. The "previous-
etag" and "new-etag" need not have been sequentially assigned etags
at the server. An XCAP diff document can describe changes that have
occurred over a series of XCAP operations.
The optional "hash" attribute provides an HMAC of the document The optional "hash" attribute provides an HMAC of the document
instance whose etag is "new-etag", once that document is represented instance whose etag is "new-etag", once that document is represented
in canonical form. See Section 6 for details on how this value is in canonical form. To compute this value, the server MUST apply the
computed. This attribute is optional, and a server MAY elect not to mandatory XML canonicalization defined in the Canonical XML 1.0 [1]
include it. Even if present, a client MAY elect to ignore it. specification, and then computes an HMAC [13] using SHA1 over this
canonical document, with a key whose value is 0x2238a. The result is
Each <document> element contains zero or one <change-log> element, the value of the "hash" attribute. This attribute is optional, and a
followed by any number of elements from another namespace for the server MAY elect not to include it. Even if present, a client MAY
purposes of extensibility. Any such unknown elements MUST be ignored elect to ignore it.
by the client. When present, the <change-log> element tells the
client the specific set of XCAP operations that can be applied to
transform the document from the version whose etag was "previous-
etag" to the version whose etag is "new-etag". If the "previous-
etag" is not present, the <change-log> element tells the client the
specific set of XCAP operations that can be applied to create a
document from nothing, and result in the document whose etag is "new-
etag". The series of operations in the <change-log> do not have to
be the same exact series of operations that occurred at the server.
The only requirement is that, if the server includes the <change-log>
element, the sequence of events, when executed serially, will result
in the transformation of the document with the etag "previous-etag"
to the one whose etag is "new-etag". If the <change-log> element is
not present, it means that the document has changed in some way, but
the XCAP server has elected not to provide the set of changes. In
that case, a client can retrieve the latest document if its cached
etag doesn't match the value of "new-etag".
It is important to note that a <document> element with no <change-
log> child is not equivalent to a <document> element with a <change-
log> child that is itself empty. The latter means that the document
has been assigned a new etag but its content is unchanged. The
former means that it has been assigned a new etag as a result of a
change, but the specific changes are not being reported in the XCAP
diff document.
Each <change-log> element contains zero or more <put-event> or This contents of the <document> element are extensible, and can
<delete-event> elements. It can also contain elements from other include elements from other namespaces. It is anticipated that
namespaces, which allows for extensibility to other events in the extensions would be defined that allow the actual change in the
future. A client MUST ignore any such elements it does not document to be reported.
understand. Each <delete-event> element reports an HTTP DELETE
operation, and each <put-event> element reports an HTTP PUT
operation. Both <put-event> and <delete-event> have a single
optional attribute, "node-selector", which contains the node selector
in the Request URI (after removing any escape coding) of the HTTP PUT
or DELETE request. The server MUST include the "node-selector" when
the PUT or DELETE operation was against an XML element or attribute.
The "node-selector" attribute MUST NOT be present if the PUT or
DELETE operation was against the document itself. The <put-event>
element also has the mandatory attribute "content-type", which
indicates the Content-Type of the HTTP PUT request. The content of
the <put-event> element is text. This text contains the body of the
HTTP PUT request. If that content was an XML type (including
application/xcap-el+xml) that contains angle brackets, it MUST be
represented as CDATA. If the content did not contain angle brackets
(as is the case with application/xcap-att+xml), it MAY be represented
as CDATA.
4. XML Schema 4. XML Schema
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns="urn:ietf:params:xml:ns:xcap-diff" <xs:schema targetNamespace="urn:ietf:params:xml:ns:xcap-diff"
xmlns="urn:ietf:params:xml:ns:xcap-diff"
xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xs="http://www.w3.org/2001/XMLSchema"
targetNamespace="urn:ietf:params:xml:ns:xcap-diff"
elementFormDefault="qualified" attributeFormDefault="unqualified"> elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:element name="document"> <xs:element name="document">
<xs:complexType> <xs:complexType>
<xs:sequence> <xs:sequence>
<xs:element ref="change-log" minOccurs="0"/>
<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/> <xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence> </xs:sequence>
<xs:attribute name="doc-selector" type="xs:anyURI" use="required"/> <xs:attribute name="doc-selector" type="xs:anyURI" use="required"/>
<xs:attribute name="new-etag" type="xs:string" use="optional"/> <xs:attribute name="new-etag" type="xs:string" use="optional"/>
<xs:attribute name="previous-etag" type="xs:string" use="optional"/> <xs:attribute name="previous-etag" type="xs:string" use="optional"/>
<xs:attribute name="hash" type="xs:string" use="optional"/> <xs:attribute name="hash" type="xs:string" use="optional"/>
<xs:anyAttribute namespace="##other" processContents="lax"/> <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType> </xs:complexType>
</xs:element> </xs:element>
<xs:element name="xcap-diff"> <xs:element name="xcap-diff">
<xs:complexType> <xs:complexType>
<xs:sequence> <xs:sequence>
<xs:element ref="document"/> <xs:element ref="document"/>
</xs:sequence> </xs:sequence>
<xs:attribute name="xcap-root" type="xs:anyURI" use="required"/> <xs:attribute name="xcap-root" type="xs:anyURI" use="required"/>
</xs:complexType> </xs:complexType>
</xs:element> </xs:element>
<xs:element name="change-log">
<xs:complexType>
<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:choice>
<xs:element ref="delete-event"/>
<xs:element ref="put-event"/>
<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</xs:choice>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="put-event">
<xs:complexType>
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="node-selector" type="xs:anyURI" use="optional"/>
<xs:attribute name="content-type" type="xs:string" use="required"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:element>
<xs:element name="delete-event">
<xs:complexType>
<xs:attribute name="node-selector" type="xs:anyURI" use="optional"/>
</xs:complexType>
</xs:element>
</xs:schema> </xs:schema>
5. Example Document 5. Example Document
The following is an example of a document compliant to the schema. The following is an example of a document compliant to the schema.
Line wrapping is for readability purposes only:
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<xcap-diff xmlns="urn:ietf:params:xml:ns:xcap-diff" <xcap-diff xmlns="urn:ietf:params:xml:ns:xcap-diff"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:xcap-diff xcap-diff.xsd"
xcap-root="http://xcap.example.com/root"> xcap-root="http://xcap.example.com/root">
<document new-etag="7ahggs" <document new-etag="7ahggs"
doc-selector="resource-lists/users/joe/coworkers" doc-selector="resource-lists/users/joe/coworkers"
previous-etag="8a77f8d"> previous-etag="8a77f8d"/>
<change-log>
<delete-event
node-selector="resouce-lists/list[@name="friends"]/ent
ry[@uri="bill@example.com"]"/>
<put-event
node-selector="resouce-lists/list[@name="friends"]/ent
ry[@uri="jane@example.com"]"
content-type="application/xml"><![CDATA[<entry uri="sip:jane@exa
mple.com"><display-name>Jane Doe</display-name></entry>]]>
</put-event>
</change-log>
</document>
</xcap-diff> </xcap-diff>
This example XCAP diff document will transform the example document This indicates that the document with URI
in Section 3.3 of [14] by removing the entry for Bill Smith and http://xcap.example.com/root/resource-lists/users/joe/coworkers has
adding one for Jane Doe. changed. Its previous entity tag is 8a77f8d and its new one is
7ahggs.
6. Usage with the Config Framework 6. Usage with the Config Framework
The framework for user agent profile delivery [9] defines an event The framework for user agent profile delivery [9] defines an event
package which can be used to subscribe to user, device, application package which can be used to subscribe to user, device, application
or local-network data that defines the configuration of a client. or local-network data that defines the configuration of a client.
This data can be present in an XCAP server. Normally, content This data can be present in an XCAP server. Normally, content
indirection [15] will be used as the NOTIFY body format, to indicate indirection [15] will be used as the NOTIFY body format, to indicate
the specific document that has changed, and should be re-fetched. the specific document that has changed, and should be re-fetched.
However, if the client includes an Accept header field including the However, if the client includes an Accept header field including the
MIME type "application/xcap-diff+xml", the server has the option of MIME type "application/xcap-diff+xml", the server has the option of
returning documents in this format instead. returning documents in this format instead.
When the client performs an initial subscription, the rules in [9] When the client performs an initial subscription, the rules in [9]
are used to select the set of documents which the subscription are used to select the set of documents which the subscription
applies to. Upon initial subscription, the server does not know applies to. Upon initial subscription, the server does not know
which instances of each document (where each instance is identified which instances of each document (where each instance is identified
by an etag) the client currently posessses, if any. Indeed, upon by an etag) the client currently posessses, if any. Indeed, upon
startup, the client will not have any documents. The initial NOTIFY startup, the client will not have any documents. The initial NOTIFY
in this case MUST include a <document> element for each document in this case MUST include a <document> element for each document
associated with the subscription. The <change-log> for each of those associated with the subscription. The "previous-etag" attribute MUST
<document> elements MUST be absent. The "previous-etag" attribute be absent, and the "new-etag" attribute MUST be present and contain
MUST be absent, and the "new-etag" attribute MUST be present and the entity tag for the current version of that document resource. An
contain the entity tag for the current version of that document XCAP diff document structured this way is called a "reference" XCAP
resource. An XCAP diff document structured this way is called a diff document. It establishes the baseline etags and document URIs
"reference" XCAP diff document. It establishes the baseline etags for the documents covered by the subscription.
and document URIs for the documents covered by the subscription.
Upon receipt of this document, the client can determine whether its Upon receipt of this document, the client can determine whether its
local instance documents, if any, match the etags in the XCAP diff local instance documents, if any, match the etags in the XCAP diff
document. If they do not match, the client SHOULD perform a document. If they do not match, the client SHOULD perform a
conditional GET for each document. The document URI is constructed conditional GET for each document. The document URI is constructed
by appending the XCAP root in the "xcap-root" attribute of the <xcap- by appending the XCAP root in the "xcap-root" attribute of the <xcap-
diff> element to the escape coded "doc-selector" from each <document> diff> element to the escape coded "doc-selector" from each <document>
element. The request is made conditional by including an If-Match element. The request is made conditional by including an If-Match
header field, with the value of the etag from each <document> header field, with the value of the etag from each <document>
element. So long as the documents haven't changed between the NOTIFY element. So long as the documents haven't changed between the NOTIFY
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that future extensions to the profile delivery framework will allow a that future extensions to the profile delivery framework will allow a
client to include, in its SUBSCRIBE request, an indicator of the client to include, in its SUBSCRIBE request, an indicator of the
current version of the documents it holds. That would obviate the current version of the documents it holds. That would obviate the
need for a potentially never-ending stream of SUBSCRIBE/GET sequences need for a potentially never-ending stream of SUBSCRIBE/GET sequences
should the documents be rapidly changing, for some reason. should the documents be rapidly changing, for some reason.
Once the client has obtained the versions of the documents identified Once the client has obtained the versions of the documents identified
in the reference XML diff, it can process NOTIFY requests on that in the reference XML diff, it can process NOTIFY requests on that
subscription. To process the NOTIFY requests, it makes sure that its subscription. To process the NOTIFY requests, it makes sure that its
current version matches the version in the "previous-etag" attribute current version matches the version in the "previous-etag" attribute
of the <document> element. It then follows the procedures of of the <document> element. If not, the client can then fetch the
Section 7. updated document from the server. If they do match, the client has
the most current version.
Once the client has finished applying the instructions to the
document, it should end up with the same document the server has. To
verify this, the client MAY apply the mandatory XML canonicalization
defined in the Canonical XML 1.0 [1] specification, and computes an
HMAC [13] using SHA1 over this canonical document, with a key whose
value is 0x2238a. The resulting string is compared with the "hash"
attribute of the <document> element. If they match, the client can
be sure that it has the most up to date version. If they don't
match, the client MUST flush its current version of the document from
memory. It can then obtain a new XCAP diff reference by sending a
SUBSCRIBE refresh request on the dialog.
Of course, this mechanism for computing the most current document
from the hash is optional. A client can elect to ignore the
information on what changed and simply fetch the most recent document
every time it gets a change indication where the new version is not
the same as the one cached by the client. Furthermore, the server
may elect to not send the hash, in which case this check cannot be
made.
7. Constructing a Document from the Change Log
When the XCAP diff document contains a <change-log> element for a
document, and the client possesses the document instance whose etag
matches the "previous-etag" for the document, the client can follow
the procedures defined here to obtain the instance document with the
etag value of "new-etag". This procedure is relatively
straightforward, and is done by having the client emulate XCAP server
behavior as defined in [8]
The client starts with the its version of the document whose etag is
"previous-etag" as the current document. If there was no "previous-
etag", the client starts with no document. The client MUST iterate
through each child of <change-log>, in order. For each element, it
MUST apply processing depending on the name of the element.
If the element is <delete-event>, the client takes the current
document. If the "node-selector" attribute was absent, it deletes
the entire document. If the "node-selector" attribute was present,
it selects the element or attribute using that node selector, as
described in Section 6.3 of [8]. Note that the node selector present
in the "node-selector" attribute is not escape coded, and will follow
the grammar defined in that section. The selected element or
attribute is deleted from the document, and the result becomes the
current document. There is no need for the client to run the
validity checks or idempotency checks normally performed by the
server; a client will always be provided with <delete-event>
operations that succeeded at the server.
If the element is <put-event>, the client takes the current document.
It then computes the Request URI that was seen by the server, by
concatenating the XCAP root with the "doc-selector" attribute of th
<document> element, appending the path separator, and then adding the
"node-selector" attribute of the <put-event> element, if present.
The client then "acts" as if it were the server, having receive an
HTTP PUT request with the Request URI equal to this value prior to
escape coding, with a body of Content-Type equal to the value of the
"content-type" attribute, and whose body equals the value of the
<put-event> element. It follows the logic of Section 8.2 of [8] to
apply the PUT, ignorning all validity checks, resource
interdependency computations, error processing and verification of
document content. The resulting document becomes the current
document. An actual implementation need not literally act as a
server; the behavior is defined in these terms to specify what the
correct output of the processing has to be.
If the element is unknown to the client, it is skipped.
When each child element of <change-log> has been processed, the
current document is equal to the document on the server whose etag
equals "new-etag".
8. Security Considerations 7. Security Considerations
XCAP diff documents contain the same information in the documents XCAP diff documents are not very sensitive; they only contain entity
whose differences they describe. As such, the security tags and the URI for documents. An attacker that is able to examine
considerations associated with those documents apply to XCAP diff such a document cannot access or modify the referenced document
documents. unless it has also managed to attack XCAP itself. Thus, there is no
requirement for message confidentiality. However, an attacker that
can modify XCAP diff documents in transit could fool a client into
thinking that a document hasn't changed, when it has, or vice-a-
versa. Therefore, protocols which transport XCAP Diff documents
SHOULD provide message integrity.
9. IANA Considerations 8. IANA Considerations
There are several IANA considerations associated with this There are several IANA considerations associated with this
specification. specification.
9.1 application/xcap-diff+xml MIME Type 8.1 application/xcap-diff+xml MIME Type
MIME media type name: application MIME media type name: application
MIME subtype name: xcap-diff+xml MIME subtype name: xcap-diff+xml
Mandatory parameters: none Mandatory parameters: none
Optional parameters: Same as charset parameter application/xml as Optional parameters: Same as charset parameter application/xml as
specified in RFC 3023 [4]. specified in RFC 3023 [4].
Encoding considerations: Same as encoding considerations of Encoding considerations: Same as encoding considerations of
application/xml as specified in RFC 3023 [4]. application/xml as specified in RFC 3023 [4].
Security considerations: See Section 10 of RFC 3023 [4] and Security considerations: See Section 10 of RFC 3023 [4] and
Section 8 of RFCXXXX [[NOTE TO RFC-EDITOR/IANA: Please replace Section 7 of RFCXXXX [[NOTE TO RFC-EDITOR/IANA: Please replace
XXXX with the RFC number of this specification.]]. XXXX with the RFC number of this specification.]].
Interoperability considerations: none. Interoperability considerations: none.
Published specification: This document. Published specification: This document.
Applications which use this media type: This document type has Applications which use this media type: This document type has
been used to support manipulation of resource lists [14] using been used to support manipulation of resource lists [14] using
XCAP. XCAP.
skipping to change at page 12, line 24 skipping to change at page 9, line 28
Macintosh file type code: "TEXT" Macintosh file type code: "TEXT"
Personal and email address for further information: Jonathan Personal and email address for further information: Jonathan
Rosenberg, jdrosen@jdrosen.net Rosenberg, jdrosen@jdrosen.net
Intended usage: COMMON Intended usage: COMMON
Author/Change controller: The IETF. Author/Change controller: The IETF.
9.2 URN Sub-Namespace Registration for urn:ietf:params:xml:ns:xcap-diff 8.2 URN Sub-Namespace Registration for urn:ietf:params:xml:ns:xcap-diff
This section registers a new XML namespace, as per the guidelines in This section registers a new XML namespace, as per the guidelines in
[6] [6]
URI: The URI for this namespace is URI: The URI for this namespace is
urn:ietf:params:xml:ns:xcap-diff. urn:ietf:params:xml:ns:xcap-diff.
Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org), Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
Jonathan Rosenberg (jdrosen@jdrosen.net). Jonathan Rosenberg (jdrosen@jdrosen.net).
skipping to change at page 13, line 25 skipping to change at page 10, line 25
<body> <body>
<h1>Namespace for XCAP Diff</h1> <h1>Namespace for XCAP Diff</h1>
<h2>urn:ietf:params:xml:ns:xcap-diff</h2> <h2>urn:ietf:params:xml:ns:xcap-diff</h2>
<p>See <a href="[URL of published RFC]">RFCXXXX[[NOTE <p>See <a href="[URL of published RFC]">RFCXXXX[[NOTE
TO IANA/RFC-EDITOR: Please replace XXXX with the RFC number of this TO IANA/RFC-EDITOR: Please replace XXXX with the RFC number of this
specification.]]</a>.</p> specification.]]</a>.</p>
</body> </body>
</html> </html>
END END
9.3 Schema Registration 8.3 Schema Registration
This section registers a new XML schema per the procedures in [6]. This section registers a new XML schema per the procedures in [6].
URI: urn:ietf:params:xml:schema:xcap-diff URI: urn:ietf:params:xml:schema:xcap-diff
Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org), Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
Jonathan Rosenberg (jdrosen@jdrosen.net). Jonathan Rosenberg (jdrosen@jdrosen.net).
The XML for this schema can be found as the sole content of The XML for this schema can be found as the sole content of
Section 4. Section 4.
10. References 9. References
10.1 Normative References 9.1 Normative References
[1] Boyer, J., "Canonical XML Version 1.0", W3C REC REC-xml-c14n- [1] Boyer, J., "Canonical XML Version 1.0", W3C REC REC-xml-c14n-
20010315, March 2001. 20010315, March 2001.
[2] Bray, T., Paoli, J., Sperberg-McQueen, C., and E. Maler, [2] Bray, T., Paoli, J., Sperberg-McQueen, C., and E. Maler,
"Extensible Markup Language (XML) 1.0 (Second Edition)", W3C "Extensible Markup Language (XML) 1.0 (Second Edition)", W3C
FirstEdition REC-xml-20001006, October 2000. FirstEdition REC-xml-20001006, October 2000.
[3] Moats, R., "URN Syntax", RFC 2141, May 1997. [3] Moats, R., "URN Syntax", RFC 2141, May 1997.
skipping to change at page 14, line 20 skipping to change at page 11, line 20
January 2004. January 2004.
[7] Bradner, S., "Key words for use in RFCs to Indicate Requirement [7] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[8] Rosenberg, J., "The Extensible Markup Language (XML) [8] Rosenberg, J., "The Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)", draft-ietf-simple-xcap-07 Configuration Access Protocol (XCAP)", draft-ietf-simple-xcap-07
(work in progress), June 2005. (work in progress), June 2005.
[9] Petrie, D., "A Framework for Session Initiation Protocol User [9] Petrie, D., "A Framework for Session Initiation Protocol User
Agent Profile Delivery", draft-ietf-sipping-config-framework-06 Agent Profile Delivery", draft-ietf-sipping-config-framework-07
(work in progress), February 2005. (work in progress), July 2005.
10.2 Informative References 9.2 Informative References
[10] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., [10] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002. Session Initiation Protocol", RFC 3261, June 2002.
[11] Roach, A., "Session Initiation Protocol (SIP)-Specific Event [11] Roach, A., "Session Initiation Protocol (SIP)-Specific Event
Notification", RFC 3265, June 2002. Notification", RFC 3265, June 2002.
[12] Roach, A., Rosenberg, J., and B. Campbell, "A Session [12] Roach, A., Rosenberg, J., and B. Campbell, "A Session
Initiation Protocol (SIP) Event Notification Extension for Initiation Protocol (SIP) Event Notification Extension for
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