XMPP, TV and the Semantic Web

XMPP, TV and the Semantic Web
Or ‘how I got to work on something that wasn’t entirely about RDF for a change…’
“This will be a very informal and very short talk tointroduce
The XMPP (Jabber) internet protocol and some potentialimpact
it has for TV and Semantic Web applications."
Dan Brickley – VU WAI talk, Feb 1st 2010

Extensible Messaging and Presence Protocol (XMPP)
Open standard for Instant Messaging (IM) chat
Alternative to vendor-specific closed networks
Built opensource-style, then ratified at IETF
How it works:
userid@my.example.com ‘JIDs’
Neverending 2-way conversation via servers
XML ‘stanzas’ – e.g. chat or info/query messages
Servers can be federated (eg. Google Talk) or standalone (eg. Hyves.nl)

XMPP in a nutshell…
Developed and deployed for 10+ years
XML-based protocol for IM (chat, buddylists, real time messaging)
Almost entirely unlike SOAP and IRC (but a bit like both)
Used in products from Google, Apple and tools like GAIM/Pidgin
Healthy range of toolkits – servers, clients and libraries
All Google accounts; all Hyves accounts, …
Bewildering and impressive range of extensions (XEPs), e.g.
XEP-0166: Jingle, ‘peer-to-peer media sessions’ (e.g. Google Talk)
XEP-0060: Publish-Subscribe
XEP-0174: Local LAN dns-based discovery and point-to-point links
XEP-0059: Result Set management
XEP-0235: OAuth Over XMPP
XEP-0045: Multi-User Chat
XEP-0275: ‘Entity reputation’
many more…

Why care?
XMPP can go where HTTP doesn’t
bots, scripts and services can act for their human users
XMPP’s ‘social graph’ interconnect sites (like email and FOAF, and unlike closed and proprietary ‘social networks’)
Friendly and energetic developer community
Save your time for inventing new things

What does it look like?
Two experimental uses:
JqbusSPARQL experiments (FOAF project)
‘NoTube Network’ ideas for TV remotes (NoTube EU)
Jqbus showed an experimental binding of RDF query (SPARQL) to XMPP
How else can you send queries into home or laptop?
Or filter them based on buddylist rules (colleagues, family)?
Or allow for query results to arrive hours later?
(if you don’t know SPARQL, think of it as
SQL-ish query over linked RDF databases)

Jqbus: sending a query
<iq id="S3IG2-4" to="alice.notube@example.com/sparqlserver" type="get">
<query xmlns='http://www.w3.org/2005/09/xmpp-sparql-binding'>
PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT DISTINCT ?o WHERE {?s foaf:name ?o.} </query>
</iq>
(from bandri@livejournal.com )

Jqbus: a query arrives
<iq id="40z5D-4" to="alice.notube@example.com/sparqlserver" from="bandri@livejournal.com/sparqlclient" type="get">
<query xmlns="http://www.w3.org/2005/09/xmpp-sparql-binding">
PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT DISTINCT ?o WHERE {?s foaf:name ?o.}
</query>
</iq>

A response is sent…
<iq id="40z5D-4" to="bandri@livejournal.com/sparqlclient" from="alice.notube@example.com/sparqlserver" type="result">
<query-result xmlns="http://www.w3.org/2005/09/xmpp-sparql-binding">
<sparql xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xs="http://www.w3.org/2001/XMLSchema#" xmlns="http://www.w3.org/2005/sparql-results#">
<head><variable name="o"/> </head>
<results>
<result> <binding name="o"> <literal>Libby Miller</literal> </binding> </result>
<result> <binding name="o"> <literal>Tim Berners-Lee</literal> </binding> </result> 
</results> </sparql> </query-result> </iq>

…and is received.
Messages can be directed or general
Eg: to danbrickley@gmail.com or to
danbrickley@gmail.com/photo_database
Can be real-time or delayed
Have practical limits on message size
These SPARQL bindings should be redone
Jingle specs help with bulky data and direct links

Eg. 2: “Buttons” (NoTube Network)
Work-in-progress ‘smart remote control’ protocol
XMPP as controlled route thru NAT/firewall
Attached to desktop ‘media centre’ software:
Boxee / XBMC / Plex (TV-like full screen media)
MythTV (linux-based PVR, uses DVB-T USB for TV)
EyeTV (applescript-able OSX tool, also DVB-T)
MediaPortal (Opensource C# software)
Windows Media Centre (with .NET SDK)
Itunes (applescript-able on OSX)

What do these all have in common?
A lot but not enough: chaos of different media-centre APIs and schemas
Remotes tend to be dumb: sending clicks not commands, and no return-path for data…
APIs allow basic navigation, play/pause, screenshot, EPG access, but via local PC or LAN
Can diverse media centres share an API?
Can we expose it over XMPP?
Use it from smartphones? Multi-touch tables?

A remote control with a buddylist?
<iq to="alice.notube@gmail.com/0AEDD375" type="result">
<query xmlns="jabber:iq:roster">
<item jid="bob.notube@gmail.com" subscription="both”>
<item jid="buttons@foaf.tv" subscription="both"/>
<item jid="danbrickley@gmail.com" subscription="both”>
<item jid="libby.miller@gmail.com" subscription="both"/>
<item jid="yves.example @gmail.com" subscription="both"/>
</query>
</iq>

Maybe.
Prototyped at the play/pause/ffwd level
With Strophe.js and BOSH, can do HTML5 too!
Can control Boxee and MythTV via XMPP
Sample client running on iphone
Server attached to xmpp:buttons@foaf.tv
Remote attached to xmpp:bob.notube@gmail.com
Very often super-fast; sometimes awkwardly slow
Can we drop down from server-mediated comms?

Maybe.
XEP-0174 defines local network discovery
And point-to-point XMPP comms (ie. not via gtalk!)
As used in Apple’s Bonjour iChat local chat
The Jingle specs also relevant here
Other tricks for faster UI?
Iphone motion sensor – if it’s moving, send a ping
Design a protocol that sends commands not clicks
But beware downloading megabytes of EPG TV data

Service Discovery
Web service discovery for real?
Which of my buddys have VOIP support? Video?
Which have RDF databases online?
Or a TV / media centre connected?
Which are on same LAN as me?
How do we manage permissions for all this?

Presence and capabilities
<presence from=”example.buddy@gmail.com/BitlBee82551989" to="alice.notube@gmail.com/0AEDD375">
[…] </presence>
<caps:c node="http://mail.google.com/xmpp/client/caps" ver="1.1" ext="pmuc-v1 sms-v1" xmlns:caps="http://jabber.org/protocol/caps"/>

Summary
XMPP – the basics just work
Lots of libraries / tools
Helpful, friendly community
Focal point for problem-sharing
Tread carefully
Navigating the maze of interesting extensions
Guessing which toolkit to bet on for your needs
Learning the landscape and what to rely on

Questions?
Or to danbri@few.vu.nl
MythTV / iChat demo: Libby Miller
Draft iPhone graphics: Vicky Buser
NoTube project: www.notube.tv

XMPP, TV and the Semantic Web

by Dan Brickley

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