XMPP Intro 1101 - 2008
- 1. XMPP intro E Extensible Messaging and Presence Protocol Steffen Larsen (slarsen@nordija.com)
- 2. XMPP - what is it? • Extensible Messaging and Presence Protocol • An Open Source Instant Messaging (IM) system. I would also like to refer to it as a session protocol. • Easy integration of extensions • Widely used and many implementations of the core system.
- 3. XMPP clients • Pidgin (formerly known as gaim, all) • Adium (based on pidgin lib.,mac) • GTalk (Google Talk, m$ windoze) • psi (all) • gajim (all), etc... MANY!
- 4. XMPP core • Going from Jabber (1999) to XMPP • XMPP foundation, founded 2003. For standardization. • RFC 3920, RFC 3921 (define XML stream, login and architecture)
- 5. XMPP core • XMPP is a XML streaming standard • XMPP defines a <stream/> to make a stream session. • TLS (authentication) / SASL (Simple Authentication and Security Layer)
- 6. XMPP core core consists of the following: • <stream/> • Addressing standard (JIDs): user@host.domain/resource. This is important for the routing/prioritizing. • stanzas
- 7. XML Streams • <stream/> container for XML elements in a stream. • <stream/> once in a session, send many xml elements! • <stream/> consists of: • negotiation of TLS and SASL • stanzas
- 8. The “layers” • TCP (your socket!) • TLS secure layer • SASL negotiation • XMPP (send/receive stanzas) • Third party channel.. (initiated by XMPP, voice etc)
- 9. Using the language • Logging in <stream>, TLS, SASL.. • SASL for negotiating diff. encryption mechanisms. • Challenge/Response.. • server binds the client resource • fetching the buddy list.. <iq get roster..> • sending stanzas messages, presence etc.
- 10. Language Elements • XMPP have 3 XML stanzas. (well structured children under the <stream/> element): • <presence/> • <message/> • <iq/> (Information, Query: get, set)
- 11. XML Stream example Basic sessions: |--------------------| C: <?xml version='1.0'?> | <stream> | <stream:stream |--------------------| to='example.com' | <presence> | xmlns='jabber:client' | <show/> | xmlns:stream='http://etherx.jabber.org/streams' | </presence> | version='1.0'> |--------------------| S: <?xml version='1.0'?> | <message to='foo'> | <stream:stream | <body/> | from='example.com' | </message> | id='someid' |--------------------| xmlns='jabber:client' | <iq to='bar'> | xmlns:stream='http://etherx.jabber.org/streams' | <query/> | version='1.0'> | </iq> | ... encryption, authentication, and resource binding ... |--------------------| C: <message from='juliet@example.com' | ... | to='romeo@example.net' |--------------------| xml:lang='en'> | </stream> | C: <body>Art thou not Romeo, and a Montague?</body> |--------------------| C: </message> S: <message from='romeo@example.net' to='juliet@example.com' xml:lang='en'> S: <body>Neither, fair saint, if either thee dislike.</body> S: </message> C: </stream:stream> S: </stream:stream>
- 12. XMPP Stanzas <message/> <message from='northumberland@shakespeare.lit/westminster' id='richard2-4.1.247' to='kingrichard@royalty.england.lit/throne'> <body>My lord, dispatch; read o'er these articles.</body> <request xmlns='urn:xmpp:receipts'/> </message> <iq/> Example: Client requests current roster from server: <iq from='juliet@example.com/balcony' type='get' id='roster_1'> <query xmlns='jabber:iq:roster'/> e.g. get roster </iq> Example: Client receives roster from server: at startup <iq to='juliet@example.com/balcony' type='result' id='roster_1'> <query xmlns='jabber:iq:roster'> <item jid='romeo@example.net' name='Romeo' subscription='both'> <group>Friends</group> </item> <item jid='mercutio@example.org' name='Mercutio' subscription='from'> <group>Friends</group> </item> <item jid='benvolio@example.org' name='Benvolio' subscription='both'> <group>Friends</group> </item> </query> </iq>
- 13. XMPP Architecture server - server. xmpp registar with cert. client - client
- 14. XMPP Architecture server- Text Text client-gw- SIP
- 15. XMPP Extensions (XEP) • XMPP defines a set of XEPs • Definition of an extension (XEP-001). XEP relies on namespaces. • XEP-166, XEP-167 (Jingles), XEP-176 important right now • Feature and service discovery important. Can also be done in
- 16. XMPP Platforms • ejabberd (erlang) • xfire (uses smack-lib, java based) • google talk (based on libjingle, c++). Can connect to the base XMPP architecture and vice versa. Some XEPs are NOT the same (voice/video/ ice)!
- 17. XMPP Libraries • Libjingle (google, c++, not compliant to some xmpp extensions) • Perl:XMPP (perl!, dah!) • LibIksmeal (C, very unorganized!) • Smack (Java, JMF!) • My own!... :-) (core in libpurple, plugin lib for xep-166,167,176)
- 18. XMPP in the future? • Will it become a de-facto standard? (xmpp is what http was in the past) • New extensions? • XEP-666 for set top boxes? ;-) • XEP for Conferencing?
- 19. XMPP links: • www.xmpp.org • http://www.xmpp.org/rfcs/rfc3920.htm • http://www.xmpp.org/rfcs/rfc3921.htm • http://www.xmpp.org/extensions/
- 20. Questions? If you don’t have any: • when is xep-166 etc. (jingle) a standard? • where do I start? • ....