Social Networking plaftorms are often built around the concept of feeds. XMPP offers, through Publish-Subscribe (XEP-0060) [1], a really generic way of Publishing and Subscribing elements on XMPP nodes. This extension defines a way to publish social content on PubSub nodes using RFC 4287 [2]
Social features in XMPP were historically built on the Microblogging Over XMPP (XEP-0277) [3] specifications. However in practice Microblogging was not applicable in more common cases and some related features were not used. The current XEP defines a more generic way of handling Social Feeds on XMPP by keeping the existing Microblogging features as a subset of it.
A PubSub Social Feed can be located on any PubSub node on the XMPP network. Some specific use cases, such as the personal eventing (PEP) node Microblog is defined in the Profiles section.
The publication of a Post consist of a valid RFC 4287 [2] entry embeded in a Publish-Subscribe (XEP-0060) [1] item.
The post content itself can be either text (content element without "type" attribute or with "type" attribute with "text" value) or XHTML ("content" element "type" attribute with "xhtml" value). If Romeo publishes XHTML content, his client MUST publish two "content" elements: a text one, and a XHTML one. For XHTML publishing, see Publish-Subscribe (XEP-0060) [1].
<iq from='romeo@montague.lit/pda'
id='pub1'
to='new.montague.lit'
type='set'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='montague-family'>
<item id='1cb57d9c-1c46-11dd-838c-001143d5d5db'>
<entry xmlns='http://www.w3.org/2005/Atom'>
<title type='text'>hanging out at the Caf&#233; Napolitano</title>
<id>tag:montague.lit,2008-05-08:posts-1cb57d9c-1c46-11dd-838c-001143d5d5db</id>
<published>2008-05-08T18:30:02Z</published>
<updated>2008-05-08T18:30:02Z</updated>
</entry>
</item>
</publish>
</pubsub>
</iq>
Note: The "title" element is required to be included in an "atom:entry" element according to RFC 4287 [2]. An implementation MAY provide also "atom:summary" and/or "atom:content" elements too if it needs.
It's possible to insert some rich content in the post or comment. It can be some text formatting, images, etc. Only "xhtml" content type is supported for the moment by this document but possibly it will be extended later. Also, it is RECOMMENDED for the client to restrict XHTML content to the XHTML-IM subset (XHTML-IM (XEP-0071) [4]).
<iq from='romeo@montague.lit/pda'
id='pub2'
to='news.montague.lit'
type='set'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='montague-family'>
<item id='1cb57d9c-1c46-11dd-838c-001143d5d5db'>
<entry xmlns='http://www.w3.org/2005/Atom'>
<title type='xhtml'>
<div xmlns="http://www.w3.org/1999/xhtml">
<p>hanging out at the <strong>Caf&#233; Napolitano</strong></p>
</div>
</title>
<id>tag:montague.lit,2008-05-08:posts-1cb57d9c-1c46-11dd-838c-001143d5d5db</id>
<published>2008-05-08T18:30:02Z</published>
<updated>2008-05-08T18:30:02Z</updated>
<generator uri='https://capu.chat' version='42'>CapuChat</generator>
</entry>
</item>
</publish>
</pubsub>
</iq>
Because Juliet is subscribed to some Romeo's family PubSub service nodes. Romeo's XMPP server will send a PubSub notification to Juliet. The notification can include an XMPP message body for backwards-compatibility with Jabber clients that are not pubsub-capable (see Message Body ).
<message from='news.montague.lit'
to='juliet@capulet.lit'
type='headline'>
<body>hanging out at the Caf&#233; Napolitano</body>
<event xmlns='http://jabber.org/protocol/pubsub#event'>
<items node='montague-family'>
<item id='1cb57d9c-1c46-11dd-838c-001143d5d5db' publisher='romeo@montague.lit'>
<entry xmlns='http://www.w3.org/2005/Atom'>
<title type='text'>hanging out at the Caf&#233; Napolitano</title>
<link rel='alternate'
type='text/html'
href='http://montague.lit/romeo/posts/1cb57d9c-1c46-11dd-838c-001143d5d5db'/>
<link rel='alternate'
href='xmpp:news.montague.lit?;node=montague-family;item=1cb57d9c-1c46-11dd-838c-001143d5d5db'/>
<id>tag:montague.lit,2008-05-08:posts-1cb57d9c-1c46-11dd-838c-001143d5d5db</id>
<published>2008-05-08T18:30:02Z</published>
<updated>2008-05-08T18:30:02Z</updated>
<generator uri='https://capu.chat' version='42'>CapuChat</generator>
</entry>
</item>
</items>
</event>
</message>
Note: these alternate links were not posted by the original client because some clients can't compute them themselves. These things SHOULD be inserted at server side though.
Anyone can publish a post in reply to Romeo's post. Here we assume that a reply comes from Benvolio.
Note: Inclusion of the "thr:in-reply-to" element defined in RFC 4685 [5] indicates the post to which the user is replying. This reply includes two such elements (one pointing to the HTTP URL for the post and the other pointing to the XMPP URI for the post.
Note: The post can be a reply to more than the only one another.
<iq from='benvolio@montague.lit/mobile'
id='uv2x37s5'
to='news.montague.lit'
type='set'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='montague-family'>
<item id='c4145006-1c53-11dd-b2d5-000bcd82471e'>
<entry xmlns='http://www.w3.org/2005/Atom'
xmlns:thr='http://purl.org/syndication/thread/1.0'>
<author>
<name>Benvolio Montague</name>
<uri>xmpp:romeo@montague.lit</uri>
</author>
<title type='text'>@romeo cappuccino this late in the day?</title>
<link rel='alternate'
type='text/html'
href='http://montague.lit/benvolio/posts/c4145006-1c53-11dd-b2d5-000bcd82471e'/>
<link rel='alternate'
href='xmpp:news.montague.lit?;
node=montague-family;
item=c4145006-1c53-11dd-b2d5-000bcd82471e'/>
<id>tag:montague.lit,2008-05-08:posts-c4145006-1c53-11dd-b2d5-000bcd82471e</id>
<published>2008-05-08T18:31:21Z</published>
<updated>2008-05-08T18:31:21Z</updated>
<thr:in-reply-to
ref='tag:montague.lit,2008-05-08:posts-1cb57d9c-1c46-11dd-838c-001143d5d5db'
type='application/xhtml+xml'
href='http://montague.lit/romeo/posts/1cb57d9c-1c46-11dd-838c-001143d5d5db'/>
<thr:in-reply-to
ref='tag:montague.lit,2008-05-08:posts-1cb57d9c-1c46-11dd-838c-001143d5d5db'
href='xmpp:news.montague.lit?;node=montague-family;item=1cb57d9c-1c46-11dd-838c-001143d5d5db'/>
</entry>
</item>
</publish>
</pubsub>
</iq>
Assuming that Romeo has also subscribed to the same node he will receive the reply that Benvolio sent.
When Benvolio wants to repeat a Romeo's post, his client publishes the same post under a different name. But to be able to track the repeated post original author, Benvolio's client MAY use specific "atom:author" child node, "atom:name" and "atom:uri", containing, respectively, the name of the original post author, and his XMPP URI (JID).
The client SHOULD also put an "atom:link" element with "rel" attribute set to "via" and point it to the original post.
<iq from='benvolio@montague.lit/mobile'
id='pub2'
to='news.montague.lit'
type='set'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='montague-family'>
<item id='1re57d3c-1q46-11dd-748r-024943d2d5rt'>
<entry xmlns='http://www.w3.org/2005/Atom'>
<author>
<name>Romeo Montague</name>
<uri>xmpp:romeo@montague.lit</uri>
</author>
<title type='text'>hanging out at the Caf&#233; Napolitano</title>
<link rel='alternate'
type='text/html'
href='http://montague.lit/benvolio/posts/1re57d3c-1q46-11dd-748r-024943d2d5rt'/>
<link rel='alternate'
href='xmpp:news.montague.lit?;node=montague-family;item=1re57d3c-1q46-11dd-748r-024943d2d5rt'/>
<link rel='via'
href='xmpp:rnews.montague.lit?;node=montague-family;item=1cb57d9c-1c46-11dd-838c-001143d5d5db'
ref='tag:montague.lit,2008-05-08:posts-1cb57d9c-1c46-11dd-838c-001143d5d5db'/>
<id>tag:montague.lit,2008-05-08:posts-1re57d3c-1q46-11dd-748r-024943d2d5rt</id>
<published>2008-05-08T18:30:02Z</published>
<updated>2008-05-08T18:32:02Z</updated>
</entry>
</item>
</publish>
</pubsub>
</iq>
Thus, a different author JID value lets the client know the item has been repeated from another one.
It's also possible for Benvolio to add his own thougths to the repost. To do this he SHOULD wrap the original content in the "xhtml:blockquote" element and after it add his own content. Also, the client MAY post reply without quotation to the original thread to inform users about the repost.
There are two different things that carry a similar sense: the XMPP Pubsub Item ID and the "atom:id" element. This section is devoted to make a separation between them.
The pubsub Item ID MUST be used when linking to an entry with an XMPP channel (i.e. by including it in the URI with the "xmpp" schema). the Atom entry ID MUST be built according to RFC 4287 [2] and used in aggregators with the aim of revealing of post duplicates, reposts, mentions, syndications, etc.
Note that the rules of comparing, building and security notes for "atom:id" are listed in the RFC 4287 [2].
Depending on service policies and the value of the "pubsub#include_body" node configuration option, PubSub Social Feed notifications SHOULD include a message "body" element for backwards-compatibility with Jabber clients that are not pubsub-capable. It is RECOMMENDED for the XML character value of the "body" element to be the same as that of the "atom:title" child of the "atom:entry".
Juliet may want to know which places are Romeo's notices related to. That's why Romeo's client MAY geotag microblog entries, using the User Geolocation (XEP-0080) [6] protocol for storing geolocation information.
Romeo's client MUST create a "geoloc" element, with the User Geolocation (XEP-0080) [6] reference namespace: "http://jabber.org/protocol/geoloc".
<iq from='romeo@montague.lit/mobile'
id='pub7'
to='romeo@montague.lit'
type='set'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='urn:xmpp:microblog:0'>
<item id='1zr23z8a-3g12-34fh-750b-120867gjc1sqh'>
<entry xmlns='http://www.w3.org/2005/Atom'>
<author>
<name>Romeo Montague</name>
<uri>xmpp:romeo@montague.lit</uri>
</author>
<title type='text'>Is lost in the forest. Need help!</title>
<link rel='replies'
title='comments'
href='xmpp:pubsub.montague.lit?;node=urn%3Axmpp%3Amicroblog%3A0%3Acomments%2F36ec6dfe61e52b1e2cdb248823520233'/>
<id>tag:montague.lit,2008-05-08:posts-1zr23z8a-3g12-34fh-750b-120867gjc1sqh</id>
<published>2008-05-08T18:43:01Z</published>
<updated>2008-05-08T18:43:01Z</updated>
<geoloc xmlns="http://jabber.org/protocol/geoloc">
<lat>48.171761</lat>
<lon>-3.3667986</lon>
<country>France</country>
<countrycode>FR</countrycode>
<region>Brittany</region>
</geoloc>
</entry>
</item>
</publish>
</pubsub>
</iq>
PubSub Social feeds are specified under profiles. Those profiles are constraints applied to nodes and defined by a specific PubSub type (see Publish-Subscribe (XEP-0060) [1]#registrar-formtypes-metadata)
All the profiles MUST base their default configuration on the Base profile .
This profile is specified by the PubSub type `urn:xmpp:social:0` and define a generic PubSub Social Feed that can be hosted on any PubSub service node or Personal Eventing Protocol (XEP-0163) [7] node.
Those restrictions MUST be used by all the other profiles defined bellow and in other XEPs based on Pubsub Social Feed.
This profile is defined by the PubSub type `urn:xmpp:microblog:0` as defined in Microblogging Over XMPP (XEP-0277) [3] and MUST be created and configured under the PEP `urn:xmpp:microblog:0` node.
On top of the Base profile Pubsub Node Configuration the following node configuration is applied:
This profile is defined by the PubSub type `urn:xmpp:gallery:0` and can be hosted on any PubSub service.
All the items published in a gallery node MUST only have at least one attached picture. This picture MUST be of type `enclosure` as specified in RFC 4287 [2].
<link rel='enclosure' href='https://capulet.lit/upload/romeo.jpg' type='image/jpeg' title='Romeo Portrait'/>
The client SHOULD check that the comment author information (provided in the "author" element) is valid, by checking that the "publisher" item attribute value matches the "uri" element value. If there is a difference or the check can not be performed because there was not a "publisher" attribute included, the comment can be displayed, but it is RECOMMENDED to specify there is a security problem.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [8].
The XMPP Registrar [9] is requested to issue an initial namespace of "urn:xmpp:social:0" and "urn:xmpp:gallery:0".
This specification re-uses the schema for the Atom content format, i.e., the 'http://www.w3.org/2005/Atom' namespace (see RFC 4287 ).
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This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).
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The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.
The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.
Discussion on other xmpp.org discussion lists might also be appropriate; see <https://xmpp.org/community/> for a complete list.
Given that this XMPP Extension Protocol normatively references IETF technologies, discussion on the <xsf-ietf@xmpp.org> list might also be appropriate.
Errata can be sent to <editor@xmpp.org>.
The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".
1. XEP-0060: Publish-Subscribe <https://xmpp.org/extensions/xep-0060.html>.
2. RFC 4287: The Atom Syndication Format <http://tools.ietf.org/html/rfc4287>.
3. XEP-0277: Microblogging over XMPP <https://xmpp.org/extensions/xep-0277.html>.
4. XEP-0071: XHTML-IM <https://xmpp.org/extensions/xep-0071.html>.
5. RFC 4685: Atom Threading Extensions <http://tools.ietf.org/html/rfc4685>.
6. XEP-0080: User Geolocation <https://xmpp.org/extensions/xep-0080.html>.
7. XEP-0163: Personal Eventing Protocol <https://xmpp.org/extensions/xep-0163.html>.
8. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.
9. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.
Note: Older versions of this specification might be available at https://xmpp.org/extensions/attic/
@report{jaussoin2022psf,
title = {PubSub Social Feed},
author = {Jaussoin, Timothée},
type = {XEP},
number = {xxxx},
version = {0.0.1},
institution = {XMPP Standards Foundation},
url = {https://xmpp.org/extensions/xep-xxxx.html},
date = {2022-09-26/2022-09-26},
}END