mirror of
https://github.com/moparisthebest/xeps
synced 2024-11-24 02:02:16 -05:00
223 lines
8.6 KiB
XML
223 lines
8.6 KiB
XML
<?xml version='1.0' encoding='UTF-8'?>
|
|
<!DOCTYPE xep SYSTEM 'xep.dtd' [
|
|
<!ENTITY % ents SYSTEM 'xep.ent'>
|
|
%ents;
|
|
]>
|
|
<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
|
|
<xep>
|
|
<header>
|
|
<title>File Transfer Thumbnails</title>
|
|
<abstract>This specification defines a way for a client supply a preview image for a file transfer.</abstract>
|
|
&LEGALNOTICE;
|
|
<number>0264</number>
|
|
<status>Deferred</status>
|
|
<type>Standards Track</type>
|
|
<sig>Standards</sig>
|
|
<approver>Council</approver>
|
|
<dependencies>
|
|
<spec>XMPP Core</spec>
|
|
<spec>XEP-0096</spec>
|
|
<spec>XEP-0231</spec>
|
|
</dependencies>
|
|
<supersedes/>
|
|
<supersededby/>
|
|
<shortname>thumbs</shortname>
|
|
<author>
|
|
<firstname>Marcus</firstname>
|
|
<surname>Lundblad</surname>
|
|
<email>ml@update.uu.se</email>
|
|
<jid>mlundblad@jabber.org</jid>
|
|
</author>
|
|
<revision>
|
|
<version>0.3</version>
|
|
<date>2009-04-27</date>
|
|
<initials>ml</initials>
|
|
<remark><p>Fixed typo in author's name :).</p></remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.2</version>
|
|
<date>2009-04-06</date>
|
|
<initials>ml</initials>
|
|
<remark><p>Add paragraph in security section about protecting against malicious thumbnail dimensions in offer. Fixed a typo.</p></remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.1</version>
|
|
<date>2009-04-02</date>
|
|
<initials>psa</initials>
|
|
<remark><p>Initial published version.</p></remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.0.3</version>
|
|
<date>2009-03-10</date>
|
|
<initials>ml</initials>
|
|
<remark><p>Split use-case section into "Introduction", "Requirements", and "Use case".</p>
|
|
</remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.0.2</version>
|
|
<date>2009-02-25</date>
|
|
<initials>ml</initials>
|
|
<remark><p>Removed service disovery.
|
|
Added missing namespace on thumnail elements.</p>
|
|
</remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.0.1</version>
|
|
<date>2009-02-23</date>
|
|
<initials>ml</initials>
|
|
<remark><p>First draft.</p></remark>
|
|
</revision>
|
|
</header>
|
|
<section1 topic='Introduction' anchor='introduction'>
|
|
<p>The current methods for file transfers include basic meta data about the
|
|
file being offered (name, size, and date). There currently is no way to provide an image thumbnail for files such as photos.</p>
|
|
</section1>
|
|
<section1 topic='Requirements' anchor='requirements'>
|
|
<p>This documents defines a way to include a thumbnail image as an additional metadata in a file transfer.</p>
|
|
</section1>
|
|
<section1 topic='Use Case' anchor='usecase'>
|
|
<p>When a client wishes to supply a thumbnail in a transfer offer, it can do so by including an extra <![CDATA[<thumbnail/>]]> element as shown in the following exaples.</p>
|
|
<example caption='Inclusion of a thumbnail in SI file transfer offer'><![CDATA[
|
|
<iq type='set' id='offer1' to='receiver@jabber.org/resource'>
|
|
<si xmlns='http://jabber.org/protocol/si'
|
|
id='a0'
|
|
mime-type='image/jpeg'
|
|
profile='http://jabber.org/protocol/si/profile/file-transfer'>
|
|
<file xmlns='http://jabber.org/protocol/si/profile/file-transfer'
|
|
name='image.jpg'
|
|
size='3032449'>
|
|
<thumbnail xmlns='urn:xmpp:thumbs:0'
|
|
cid='sha1+ffd7c8d28e9c5e82afea41f97108c6b4@bob.xmpp.org'
|
|
mime-type='image/png'
|
|
width='128'
|
|
height='96'/>
|
|
</file>
|
|
<feature xmlns='http://jabber.org/protocol/feature-neg'>
|
|
<x xmlns='jabber:x:data' type='form'>
|
|
<field var='stream-method' type='list-single'>
|
|
<option><value>http://jabber.org/protocol/bytestreams</value></option>
|
|
<option><value>http://jabber.org/protocol/ibb</value></option>
|
|
</field>
|
|
</x>
|
|
</feature>
|
|
</si>
|
|
</iq>
|
|
]]>
|
|
</example>
|
|
<p>The receiver MAY now request the data using the protocol defined in &xep0231;.</p>
|
|
<example caption='Inclusion of a thumbnail in a Jingle file transfer offer'><![CDATA[
|
|
<iq from='romeo@montague.lit/orchard'
|
|
id='nzu25s8'
|
|
to='juliet@capulet.lit/balcony'
|
|
type='set'>
|
|
<jingle xmlns='urn:xmpp:jingle:0'
|
|
action='session-initiate'
|
|
initiator='romeo@montague.lit/orchard'
|
|
sid='851ba2'>
|
|
<content creator='initiator' name='a-file-offer'>
|
|
<description xmlns='urn:xmpp:jingle:apps:file-transfer:1'>
|
|
<offer>
|
|
<file xmlns='http://jabber.org/protocol/si/profile/file-transfer'
|
|
name='image.jpg'
|
|
size='3032449'
|
|
hash='552da749930852c69ae5d2141d3766b1'
|
|
date='1969-07-21T02:56:15Z'>
|
|
<desc>This is a test. If this were a real file...</desc>
|
|
<thumbnail xmlns='urn:xmpp:thumbs:0'
|
|
cid='sha1+ffd7c8d28e9c5e82afea41f97108c6b4@bob.xmpp.org'
|
|
mime-type='image/png'
|
|
width='128'
|
|
height='96'/>
|
|
</file>
|
|
</offer>
|
|
</description>
|
|
...
|
|
</content>
|
|
</jingle>
|
|
</iq>
|
|
]]>
|
|
</example>
|
|
<section2 topic='Definition of the thumbnail Element'
|
|
anchor='thumbnail_element'>
|
|
<p>The following attributes are defined for the <thumbnail/> element.</p>
|
|
<table caption='Attributes of the thumbnail Element'>
|
|
<tr>
|
|
<th>Attribute</th>
|
|
<th>Description</th>
|
|
<th>Inclusion</th>
|
|
</tr>
|
|
<tr>
|
|
<td>cid</td>
|
|
<td>A Content-ID that can be mapped to a cid: URL as specified in &rfc2111;. The 'cid' value SHOULD be of the form algo+hash@bob.xmpp.org, where the "algo" is the hashing algorithm used (e.g., "sha1" for the SHA-1 algorithm as specified in &rfc3174;) and the "hash" is the hex output of the algorithm applied to the binary data itself.</td>
|
|
<td>REQUIRED</td>
|
|
</tr>
|
|
<tr>
|
|
<td>mime-type</td>
|
|
<td>The value of the 'mime-type' attribute MUST match the syntax specified in &rfc2045;. That is, the value MUST include a top-level media type, the "/" character, and a subtype; in addition, it MAY include one or more optional parameters (e.g., the "audio/ogg" MIME type in the example shown below includes a "codecs" parameter as specified in &rfc4281;). The "type/subtype" string SHOULD be registered in the &ianamedia;, but MAY be an unregistered or yet-to-be-registered value.</td>
|
|
<td>RECOMMENDED</td>
|
|
</tr>
|
|
<tr>
|
|
<td>width</td>
|
|
<td>The intended display width of the thumbnail image. Used as a hint for the receiving client to prepare i.e. a dialog window.</td>
|
|
<td>OPTIONAL</td>
|
|
</tr>
|
|
<tr>
|
|
<td>height</td>
|
|
<td>The intended display height of the thumbnail image. Used as a hint for the receiving client to prepare i.e. a dialog window.</td>
|
|
<td>OPTIONAL</td>
|
|
</tr>
|
|
</table>
|
|
|
|
</section2>
|
|
</section1>
|
|
<section1 topic='Security Considerations' anchor='security'>
|
|
<p>The inclusion of an image thumbnail may leak information about a transfer
|
|
otherwise taking place on an e2e encrypted file transfer stream. A client MAY
|
|
wish to not include a thumbnail.</p>
|
|
<p>A client MUST NOT rely on the values specified for the width and height of a thumbnail to allocate a bitmap data buffer for the thumbnail, to prevent possible DoS attacks. Also a client SHOULD apply implementation-specific limits on the thumbnails, if using these values to pepare a UI element for the thumbnail image, of f.ex. 128x128 pixels, values exceeding these would then be truncated and the thumbnail image scaled down when received.</p>
|
|
</section1>
|
|
<section1 topic='IANA Considerations' anchor='iana'>
|
|
<p>This document requires no interaction with &IANA;.</p>
|
|
</section1>
|
|
<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
|
|
<section2 topic='Protocol Namespaces' anchor='registrar-ns'>
|
|
<p>This specification defines the following XML namespace:</p>
|
|
<ul>
|
|
<li>urn:xmpp:thumbs:0</li>
|
|
</ul>
|
|
<p>The ®ISTRAR; includes this namespace in the registry located at &NAMESPACES;, as described in Section 4 of &xep0053;.</p>
|
|
</section2>
|
|
<section2 topic='Protocol Versioning' anchor='registrar-versioning'>
|
|
&NSVER;
|
|
</section2>
|
|
</section1>
|
|
<section1 topic='XML Schema' anchor='schema'>
|
|
<code><![CDATA[
|
|
<?xml version='1.0' encoding='UTF-8'?>
|
|
|
|
<xs:schema
|
|
xmlns:xs='http://www.w3.org/2001/XMLSchema'
|
|
targetNamespace='urn:xmpp:thumbs:0'
|
|
xmlns='urn:xmpp:thumbs:0'
|
|
elementFormDefault='qualified'>
|
|
|
|
<xs:annotation>
|
|
<xs:documentation>
|
|
The protocol documented by this schema is defined in
|
|
xxx
|
|
</xs:documentation>
|
|
</xs:annotation>
|
|
|
|
<xs:element name='thumbnail'>
|
|
<xs:complexType>
|
|
<xs:attribute name='cid' type='xs:string' use='required'/>
|
|
<xs:attribute name='mime-type' type='xs:string' use='optional'/>
|
|
<xs:attribute name='width' type='xs:integer' use='optional'/>
|
|
<xs:attribute name='height' type='xs:integer' use='optional'/>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
</xs:schema>
|
|
]]></code>
|
|
</section1>
|
|
</xep>
|