mirror of
https://github.com/moparisthebest/xeps
synced 2024-11-21 16:55:07 -05:00
381 lines
20 KiB
XML
381 lines
20 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>Message Archive Management</title>
|
|
<abstract>This document defines a protocol to query and control and archive of messages stored on a server.</abstract>
|
|
&LEGALNOTICE;
|
|
<number>0313</number>
|
|
<status>Experimental</status>
|
|
<type>Standards Track</type>
|
|
<sig>Standards</sig>
|
|
<dependencies>
|
|
<spec>XMPP Core</spec>
|
|
<spec>XEP-0030</spec>
|
|
<spec>XEP-0059</spec>
|
|
<spec>XEP-0297</spec>
|
|
</dependencies>
|
|
<supersedes/>
|
|
<supersededby/>
|
|
<shortname>mam</shortname>
|
|
<schemaloc>
|
|
<url>http://www.xmpp.org/schemas/archive-management.xsd</url>
|
|
</schemaloc>
|
|
<author>
|
|
<firstname>Matthew</firstname>
|
|
<surname>Wild</surname>
|
|
<email>me@matthewwild.co.uk</email>
|
|
<jid>me@matthewwild.co.uk</jid>
|
|
</author>
|
|
<revision>
|
|
<version>0.1</version>
|
|
<date>2012-04-18</date>
|
|
<initials>mw</initials>
|
|
<remark><p>Initial version, to much rejoicing.</p></remark>
|
|
</revision>
|
|
</header>
|
|
|
|
<section1 topic='Introduction' anchor='intro'>
|
|
<p>It is a common desire for a user using XMPP for IM to want to store their messages in a central archive
|
|
on their server. This feature allows them to record conversations that take place on clients that do not
|
|
support local history storage, and also to synchronise their conversation history seamlessly between
|
|
multiple clients.</p>
|
|
</section1>
|
|
|
|
<section1 topic='Requirements'>
|
|
<p>As this extension aims to make things easy for client developers, some research was made into the
|
|
way clients handle history today. The resulting protocol was designed to allow for the following primary
|
|
usage scenarios:</p>
|
|
<ul>
|
|
<li>Automatic history synchronization between multiple clients.</li>
|
|
<li>Calendar-based on-demand display of historic messages in a client that doesn't keep local history.</li>
|
|
<li>So-called 'infinite' scrollback, whereby a client automatically fetches and displays historic messages
|
|
naturally in the message log as the user scrolls back in time.</li>
|
|
</ul>
|
|
<p>Another extension for archiving already exists in XMPP, &xep0136;). However implementation experience has
|
|
shown that the protocol defined therein supports rather more functionality than is typically needed for the
|
|
above uses, and is significantly more effort to implement.</p>
|
|
<p>This specification aims to define a much simpler and modular protocol for working with a server-side
|
|
message store. Through this it is hoped to boost implementation and deployment of archiving in XMPP. It
|
|
should be noted that (although not required) a server is free to implement XEP-0136 alongside this
|
|
protocol if it so chooses, though a mapping between both protocols is beyond the scope of this specification.</p>
|
|
<p>Notable functionality in XEP-0136 that is intentionally not defined by this specification for simplicity:</p>
|
|
<ul>
|
|
<li>Support for 'collections'. Few clients even support this concept for local history storage, and
|
|
it is possible to apply the logic for splitting a stream of messages into conversations on the
|
|
client-side, thus greatly simplifying the protocol.</li>
|
|
<li>Support for uploading to the archive. On the assumption that a server automatically archives
|
|
messages to and from the client, it is typically rare for a client to end up with messages that are
|
|
not already in the archive. Uploading could be useful for bootstrapping an empty archive however, and
|
|
may be defined in a future specification if there is demand for such functionality.</li>
|
|
<li>Support for 'off the record' chats (OTR; not to be confused with the encryption algorithm of
|
|
the same name). This allowed complex negotiation for either the user or contact to command specific
|
|
conversations to bypass the archive. In reality the archiving behaviour of a contact's server cannot
|
|
be enforced (they could ignore the OTR request and archive the messages anyway without your consent)
|
|
so this specification does not try and regulate that. Equivalent functionality can be implemented with
|
|
server logic for not including encrypted or specially-tagged messages in the archive (out of scope for
|
|
this specification).</li>
|
|
<li>Support per-session configuration. This feature was deemed unnecessary for the majority of
|
|
implementations, and hence the configuration protocol in this specification is much simplified,
|
|
which allows for a simple user interface in clients. Advanced configuration however may be performed
|
|
through ad-hoc commands depending on the server implementation.</li>
|
|
</ul>
|
|
</section1>
|
|
|
|
<section1 topic='Message archives'>
|
|
<p>An archive is a collection of messages stored on a user's server. Messages sent to or from a
|
|
user's account are generally automatically added to a user's archive by the server. The collection
|
|
is ordered chronologically by the time each message was sent/received.</p>
|
|
<p>Exactly which messages a server archives is left up to implementation and deployment policy,
|
|
but as a minimum servers SHOULD NOT archive messages that do not have a <body/> child tag.</p>
|
|
<p>At a minimum, a stored message consists of the following pieces of information:</p>
|
|
<ul>
|
|
<li>A timestamp of when the message was sent (for an outgoing message) or received (for
|
|
an incoming message).</li>
|
|
<li>The remote JID that the stanza is to (for an outgoing message) or from (for an
|
|
incoming message).</li>
|
|
<li>A server-assigned UID that MUST be unique within the archive.</li>
|
|
<li>The message stanza itself. The entire original stanza SHOULD be stored, but at a
|
|
minimum only the <body/> tag MUST be preserved (ie. the server might, at its
|
|
discretion, strip certain extensions from messages before storage).</li>
|
|
</ul>
|
|
<p>A server MAY impose limits on the size of a user's archive. For example a server might begin
|
|
to discard old messages once the archive reaches a certain size, or only keep messages until they
|
|
reach a certain age. The UIDs of deleted messages MUST NOT be reused for new messages.</p>
|
|
<p>Finally, there is no restriction on where an archive may be hosted. Servers that archive
|
|
messages on behalf of local users SHOULD expose archives to the user on their bare JID, while a
|
|
MUC service might allow MAM queries to be sent to the room's bare JID.</p>
|
|
</section1>
|
|
|
|
<section1 topic='Querying the archive'>
|
|
<p>A client is able to query the archive for all messages within a certain timespan, optionally
|
|
restricting results to those to/from a particular JID. To allow limiting the results or paging
|
|
through them a client may use &xep0059;, which MUST be supported by servers.</p>
|
|
<p>A query consists of an <iq/> stanza addressed to the account or server entity hosting
|
|
the archive, with a 'query' payload. On receiving the query, the server pushes to the client a
|
|
series of messages from the archive that match the client's given criteria, and finally returns
|
|
the <iq/> result.</p>
|
|
<example caption='Querying the archive for messages'><![CDATA[
|
|
<iq type='get' id='juliet1'>
|
|
<query xmlns='urn:xmpp:mam:tmp' queryid='f27' />
|
|
</iq>
|
|
|
|
[... server sends matching messages ...]
|
|
|
|
<iq type='result' id='juliet1'/>
|
|
]]></example>
|
|
<p>To ensure that the client knows when the results are complete, the server MUST delay the result
|
|
<iq/> until after it has pushed all the results to the client. An optional 'queryid' attribute
|
|
allows the client to match results to a certain query.</p>
|
|
<section2 topic="Filtering results">
|
|
<p>The query can contain any combination of three filtering tags - <with/>, <start/>
|
|
and <end/>. By default all messages match a query, the filters are used to request a subset
|
|
of the archived messages.</p>
|
|
<section3 topic="Filtering by contact">
|
|
<p>If a <with/> element is present in the <query/>, it contains a JID against which
|
|
to match messages. The server MUST only return messages if they match the supplied JID.</p>
|
|
<p>If <with/> is omitted, the server SHOULD return all messages in the selected timespan,
|
|
regardless of the to/from addresses on each message.</p>
|
|
<example caption='Querying for all messages to/from a particular JID'><![CDATA[
|
|
<iq type='get' id='juliet1'>
|
|
<query xmlns='urn:xmpp:mam:tmp'>
|
|
<with>juliet@capulet.com</with>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
<p>If (and only if) the supplied JID is a bare JID (i.e. no resource is present), then
|
|
the server SHOULD return messages if their bare to/from address would match it. For example,
|
|
if the client supplies with='juliet@capulet.com' this filter would also match messages to
|
|
or from "juliet@capulet.com/balcony" and "juliet@capulet.com/chamber".</p>
|
|
</section3>
|
|
<section3 topic="Filtering by time received">
|
|
<p>The <start/> and <end/> elements, if provided, MUST contain timestamps
|
|
formatted according to the DateTime profile defined in &xep0082;</p>
|
|
<p>The <start/> element is used to filter out messages before a certain date/time.
|
|
If specified, a server MUST only return messages whose timestamp is equal to or later
|
|
than the given timestamp.</p>
|
|
<p>If omitted, the server SHOULD assume the value of <start/> to be equal to the
|
|
date/time of the earliest message stored in the archive.</p>
|
|
<p>Conversely, the <end/> element is used to exclude from the results messages
|
|
after a certain point in time. If specified, a server MUST only return messages whose
|
|
timestamp is equal to or earlier than the timestamp given in the <end/> element.</p>
|
|
<p>If omitted, the server SHOULD assume the value of <end/> to be equal to the
|
|
date/time of the most recent message stored in the archive.</p>
|
|
<example caption='Querying the archive for all messages in a certain timespan'><![CDATA[
|
|
<iq type='get' id='juliet1'>
|
|
<query xmlns='urn:xmpp:mam:tmp'>
|
|
<start>2010-06-07T00:00:00Z</start>
|
|
<end>2010-07-07T13:23:54Z</end>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
<example caption='Querying the archive for all messages after a certain time'><![CDATA[
|
|
<iq type='get' id='juliet1'>
|
|
<query xmlns='urn:xmpp:mam:tmp'>
|
|
<start>2010-08-07T00:00:00Z</start>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
</section3>
|
|
<section3 topic='Limiting results'>
|
|
<p>Finally, in order for the client or server to limit the number of results transmitted at
|
|
a time a server MUST support &xep0059; and SHOULD support the paging mechanism defined therein.
|
|
A client MAY include a <set/> element in its query.</p>
|
|
<p>For the purposes of this protocol, the UIDs used by RSM correspond with the UIDs of the
|
|
stanzas stored in the archive.</p>
|
|
<example caption='A query using Result Set Management'><![CDATA[
|
|
<iq type='get' id='q29302'>
|
|
<query xmlns='urn:xmpp:mam:tmp'>
|
|
<start>2010-08-07T00:00:00Z</start>
|
|
<set xmlns='http://jabber.org/protocol/rsm'>
|
|
<limit>10</limit>
|
|
</set>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
<p>To conserve resources, a server MAY place a reasonable limit on how many stanzas may be
|
|
pushed to a client in one request. If a query returns a number of stanzas greater than this
|
|
limit and either the client did not specify a limit using RSM then the server should return
|
|
a policy-violation error to the client. If the query did include a <set/> element then
|
|
the server SHOULD simply return its limited results and adjust the <before/> and <after/>
|
|
in its reply to allow the client to page through them by timestamp.</p>
|
|
<example caption='Client without RSM requests too many results'><![CDATA[
|
|
<iq type='error' id='q29302'>
|
|
<error type='modify'>
|
|
<policy-violation xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
|
|
<text>Too many results</text>
|
|
</error>
|
|
</iq>
|
|
]]></example>
|
|
</section3>
|
|
</section2>
|
|
<section2 topic="Query results">
|
|
<p>The server responds to the archive query by transmitting to the client all the messages
|
|
that match the criteria the client requested. The results are sent as individual stanzas,
|
|
with the original message encapsulated in a <forwarded/> element as described in &xep0297;.
|
|
</p>
|
|
<p>The result messages MUST contain a <result/> element with an 'id' attribute that gives
|
|
the current message's UID. If the client gave a 'queryid' attribute in its initial query, the
|
|
server MUST also include that in this result element.</p>
|
|
<p>The <forwarded/> element SHOULD contain the original message as it was received, and
|
|
SHOULD also contain a <delay/> element qualified by the 'urn:xmpp:delay' namespace
|
|
specified in &xep0203;. The value of the 'stamp' attribute MUST be the time the message was
|
|
originally received by the forwarding entity.
|
|
</p>
|
|
<example caption='Server returns two matching messages'><![CDATA[
|
|
<message id='aeb213' to='juliet@capulet.com/chamber'>
|
|
<result xmlns='urn:xmpp:mam:tmp' queryid='f27' id='28482-98726-73623' />
|
|
<forwarded xmlns='urn:xmpp:forward:0'>
|
|
<delay xmlns='urn:xmpp:delay' stamp='2010-07-10T23:08:25Z'/>
|
|
<message to='juliet@capulet.com/balcony'
|
|
from='romeo@montague.net/orchard'
|
|
type='chat'>
|
|
<body>Call me but love, and I'll be new baptized; Henceforth I never will be Romeo.</body>
|
|
</message>
|
|
</forwarded>
|
|
</message>
|
|
|
|
<message id='aeb214' to='juliet@capulet.com/chamber'>
|
|
<result xmlns='urn:xmpp:mam:tmp' queryid='f27' id='5d398-28273-f7382'/>
|
|
<forwarded xmlns='urn:xmpp:forward:0'>
|
|
<delay xmlns='urn:xmpp:delay' stamp='2010-07-10T23:09:32Z'/>
|
|
<message to='romeo@montague.net/orchard'
|
|
from='juliet@capulet.com/balcony'
|
|
type='chat' id='8a54s'>
|
|
<body>What man art thou that thus bescreen'd in night so stumblest on my counsel?</body>
|
|
</message>
|
|
</forwarded>
|
|
</message>
|
|
]]></example>
|
|
</section2>
|
|
</section1>
|
|
|
|
<section1 topic="Archiving Preferences">
|
|
<p>Depending on implementation and deployment policies, a server MAY allow the user to have control
|
|
over the server's archiving behaviour. This specification defines a basic protocol for this, and
|
|
also allows a server to offer more advanced configuration to a user.</p>
|
|
<section2 topic='Simple configuration'>
|
|
<p>If the server supports and allows configuration then it SHOULD implement the protocol defined
|
|
in this section. This allows the user to configure the following preferences:</p>
|
|
<ul>
|
|
<li>A list of JIDs that should always have messages to/from archived in the user's store.</li>
|
|
<li>A list of JIDs that should never have messages to/from archived in the user's store.</li>
|
|
<li>The default archiving behaviour (for JIDs in neither of the above lists).</li>
|
|
</ul>
|
|
<example caption='Updating archiving preferences'><![CDATA[
|
|
<iq type='set' id='juliet2'>
|
|
<prefs xmlns='urn:xmpp:mam:tmp' default="roster">
|
|
<always>
|
|
<jid>romeo@montague.net</jid>
|
|
</always>
|
|
<never>
|
|
<jid>montague@montague.net</jid>
|
|
</never>
|
|
</prefs>
|
|
</iq>
|
|
]]></example>
|
|
<p>The server then replies with the applied preferences (note that due to server policies these
|
|
MAY be different to the preferences sent by the client):</p>
|
|
<example caption='Server responds with updated preferences'><![CDATA[
|
|
<iq type='result' id='juliet1'>
|
|
<prefs xmlns='urn:xmpp:mam:tmp' default="roster">
|
|
<always>
|
|
<jid>romeo@montague.net</jid>
|
|
</always>
|
|
<never>
|
|
<jid>montague@montague.net</jid>
|
|
</never>
|
|
</prefs>
|
|
</iq>
|
|
]]></example>
|
|
<section3 topic='Default behaviour'>
|
|
<p>If a JID is in neither the 'always archive' nor the 'never archive' list then whether it
|
|
is archived depends on this setting, the default.
|
|
</p>
|
|
<p>The 'default' attribute of the 'prefs' element MUST be one of the following values:</p>
|
|
<ul>
|
|
<li>'always' - all messages are archived by default.</li>
|
|
<li>'never' - messages are never archived by default.</li>
|
|
<li>'roster' - messages are archived only if the contact's bare JID is in the user's roster.</li>
|
|
</ul>
|
|
</section3>
|
|
<section3 topic='Always archive'>
|
|
<p>The <prefs/> element MAY contain an <always/> child element. If present, it
|
|
contains a list of <jid/> elements, each containing a single JID. The server SHOULD
|
|
archive any messages to/from this JID (see 'JID matching').
|
|
</p>
|
|
<p>If missing from the preferences, <always/> SHOULD be assumed by the server to be an
|
|
empty list.
|
|
</p>
|
|
</section3>
|
|
<section3 topic='Never archive'>
|
|
<p>The <prefs/> element MAY contain an <never/> child element. If present, it
|
|
contains a list of <jid/> elements, each containing a single JID. The server SHOULD
|
|
NOT archive any messages to/from this JID (see 'JID matching').
|
|
</p>
|
|
<p>If missing from the preferences, <never/> SHOULD be assumed by the server to be an
|
|
empty list.
|
|
</p>
|
|
</section3>
|
|
</section2>
|
|
<section2 topic='Advanced configuration'>
|
|
<p>In addition to this protocol, a server MAY offer more advanced configuration to the user
|
|
through &xep0050;. Such an interface might, for example, allow the user to configure what
|
|
types of messages to store, or set a limit on how long messages should remain in the
|
|
archive.</p>
|
|
<p>If supported, such a configuration command SHOULD be presented on the well-defined
|
|
command node of "urn:xmpp:mam#configure".</p>
|
|
</section2>
|
|
<section2 topic='JID matching'>
|
|
<section3 topic='General rules'>
|
|
<p>When comparing the message target JID against the user's roster (ie. when the user has
|
|
set default='roster') the comparison MUST use the bare target JID (that is, stripped of
|
|
any resource).
|
|
</p>
|
|
<p>For matching against entries in either the 'allow' or 'never' lists, for each listed
|
|
JID:
|
|
</p>
|
|
<ul>
|
|
<li>If the listed JID contains a resource, compare against the target JID as-is.</li>
|
|
<li>If the listed JID has no resource (it is a bare JID) then first strip any resource
|
|
from the target JID prior to comparison.
|
|
</li>
|
|
</ul>
|
|
</section3>
|
|
<section3 topic='Outgoing messages'>
|
|
<p>For outgoing messages, the server MUST use the value of the 'to' attribute as the target JID.
|
|
</p>
|
|
</section3>
|
|
<section3 topic='Incoming messages'>
|
|
<p>For incoming messages, the server MUST use the value of the 'from' attribute as the target JID.
|
|
</p>
|
|
</section3>
|
|
</section2>
|
|
</section1>
|
|
|
|
<section1 topic='Determining support'>
|
|
<p>If a server or other entity hosts archives and supports MAM queries, it MUST advertise that fact
|
|
by including the feature "urn:xmpp:mam:tmp" in response to a &xep0030; request:</p>
|
|
<example caption='Client queries for server features'><![CDATA[
|
|
<iq type='get' id='disco1' to='capulet.lit' from='juliet@capulet.lit/balcony'>
|
|
<query xmlns='http://jabber.org/protocol/disco#info'/>
|
|
</iq>
|
|
]]></example>
|
|
|
|
<example caption='Server responds with features'><![CDATA[
|
|
<iq type='result' id='disco1' from='capulet.lit' to='juliet@capulet.lit/balcony'>
|
|
<query xmlns='http://jabber.org/protocol/disco#info'>
|
|
...
|
|
<feature var='urn:xmpp:mam:tmp'/>
|
|
...
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
</section1>
|
|
|
|
</xep>
|