XMPP Intro - The camp2012

XMPP intro & 101

TheCamp - July 2012
Steffen Larsen (slarsen@braintrust.dk)

Thursday, August 2, 12

This Presentation
I) Intro and presentation of the protocol
What is it?, Usage

Basics and architecture

Examples

II) Advanced Topics and loose talk
Extensions

Plugins and components

III) XMPP 101 - Kick start and play!


About me (blah blah)

Studied Computer Science @ Copenhagen
CEO / Founder of BrainTrust ApS 2010 (Solo Ent.)
Prof. Software Developer for 15+ years
Java (JSE / JEE), C, Erlang, Ruby, Perl.

Open Source developer.. Tigase, Strophe-plugins, XMPPConsole etc.


My XMPP Involvement

Member of XMPP Standard Foundation (XSF)
Developing XMPP since 2007 (Ms.Thesis, pidgin/VOIP)
Done XMPP design and impl. for:
WAOO, Nordija (Set-top-boxes and over-the-top TV and IPTV)

Thrane&Thrane (Maritime Satellite Communication project)

Danske Spil / BetWare (Game software for Bingo etc)


XMPP Intro

What is it?
XMPP - eXtensible Message and Presence
Protocol
Earlier known as Jabber - 1998
Real time messages system for communication
Routes small snipplets of XML - called stanzas


XMPP - What?
Who uses it? Most of you use it every day as chat..
You? Jabber client (pidgin/adium/messenger (m$))
Google (gmail, google hangouts)
Cisco (webex)
Facebook (chat)
Even Micro$oft have XMPP gateways integrated into
their messaging system


XMPP Basics

What can you do with it?
Everything that you can imagine (almost) :-)
More than just chat -- Its about presence, routing
and real-time communication!
Real time web!.. its there - push it!


XMPP Basics
Basic Services and applications
Encryption / Authentication

Presence

Contact / Buddy lists

Messaging (1-1 or group chat)

Push Notiﬁcations (individual or publish/subscribe)

Service discovery and device capability advertisement

Geolocation and notiﬁcations

Voice over IP (VOIP)

Collaborative text editing etc.


XMPP applications
Set-top box and OTT implementation done my self..
Taxi service real-time: http://cabulous.com/
Yammer.com - work in social context (ala facebook)
status.net - DISTRIBUTED twitter (micro blog) - download and federate..
JIVE sbs - big social site for business / whiteboarding
Apple mobile push
stand-alone - adium/pidgin clients etc.
Customer Service - chat and voip - call forwarding/queue
games: tic-tac toe / chess
Energy Trading software


XMPP Basics
Why XMPP? just use normal HTTP (polling), or we
(almost) have websockets and others..)
XMPP is an Open Standard (like HTTP) - XSF and the council does the work
openly.

Proven tech. Almost 15 years of dev.

Secure - Channel encryption and strong auth.

Decentralized. no stand-alone silos (hello twitter and fb..)

Huge community

Extensibility!.. We have above 300 extensions to the XMPP core


XMPP Protocol
Core speciﬁes (RFC 6120 / RFC 6121)
http://xmpp.org/xmpp-protocols/rfcs/
Connect with TCP or other transport protocols (HTTP/
websockets, speciﬁed in extensions)
Opening a Stream tag with with streaming XML stanzas
(<stanza>.. stanza xml .. </stream>)
stanzas


XMPP Architecture

XMPP can consist of many modules:
Servers (many through federation)

Plugins

Components (XEP-0114)

Clients (typically many..)

Proxies

Database, LDAP, SIP and other systems (gateways)


XMPP Architecture


XMPP Addressing & Routing

Standard routing through JID
full JID: <id>@<domain>/<resource>

bare JID: <id>@<domain> (autom. resource)

Domain routing like normal mail (smtp).


XMPP Connection Lifecycle
To illustrate a chat client connecting
• Initiating TCP connection to the XMPP server
• Opening an XML <stream> for session..
• Negotiating stream features and SASL negotiation (Simple Authentiation
and Security Layer)

•Auth mechanisms: PLAIN, DIGETS-MD5, SCRAM, EXTERNAL etc.
• TLS secure layer (authentication towards the server)
• The clients resource gets bound to the session
• The client sends out initial presence
• The client can now communicate (send/receive stanzas)
• The client ends session
• </stream> is send. And TCP connection is closed.


Communication Primitives
Simple, we only have 3 ways:

Stanzas (xml snipplets that ﬂow async.)
Presence
Message
IQ (Information/Query)


Stanzas: Presence
Sets and shows the availability of the entity that is
connected.
chat

away

dnd (do not disturb)

Presence for the system and the subscribers of
the entity (e.g. buddylist)
Specialized Presence extension (PEP) shows what
music you are playing..


Stanzas: Presence
// initial simple presence
<presence/>

// sending away to subscribers
<presence>
<show>away</show>
</presence>

<presence>
<show>dnd</show>
<status>I am working.. </status
</presence>

// before logging off.. more realtime
<presence type='unavailable'/>


Stanzas: Presence
// direct presence

<presence from='juliet@example.com balcony’
to='romeo@example.net'/>

// Capabilities.. version, voip etc.

<presence from='romeo@example.net'>
<c xmlns='http://jabber.org/protocol/caps'
hash='sha-1'
node='http://psi-im.org'
ver='q07IKJEyjvHSyhy//CH0CxmKi8w='/>
</presence>


Stanzas: Message
Using it to communicate with other clients
TO attribute
full JID: direct messaging to speciﬁc entity (e.g. device/computer).

bare JID: will route to one or more of the connected resources - depends of
status, presence, message type etc.

Type attribute (chat, normal, groupchat, headline etc) -
presentation and routing
Body Element - the message


Stanzas: Message
normal message
<message
from='juliet@example.com/balcony'
id='ktx72v49'
to='romeo@example.net'
type='chat'
xml:lang='en'>
<body>Hi romeo where art thou?</body>
</message>

direct message
<message
from='juliet@example.com/balcony'
id='ktx72v50'
to='romeo@example.net/thecastle'
type='chat'
xml:lang='en'>
<body>will you come and visit?</body>
</message>


Stanzas: IQ

A more request / response model. For getting
information and query the server / entities.
Request: GET / SET
Response: RESULT / ERROR
Using it for getting roster, ad-hoc command and
statistics for server (if admin).. etc.


Stanzas: IQ
Example 1: User requests current roster from server

UC: <iq from='romeo@example.net/orchard'
id='hf61v3n7'
type='get'>
<query xmlns='jabber:iq:roster'/>
</iq>

Example 2: User receives roster from server

US: <iq id='hf61v3n7'
to='romeo@example.net/orchard'
type='result'>
<query xmlns='jabber:iq:roster'>
<item jid='juliet@example.com'
name='Juliet'
subscription='both'>
<group>Friends</group>
</item>
<item jid='benvolio@example.org'
name='Benvolio'
subscription='to'/>
<item jid='mercutio@example.org'
name='Mercutio'
subscription='from'/>
</query>
</iq>


Now.. Lets have Coffee!

While having a break and if you want to play with XMPP
later on..
Install java sdk
Install apache


II) Advanced Topics
Extensions:
Pub / Sub (XEP-0060)
BOSH (XMPP over HTTP)
External Database and LDAP
Internal routing and modiﬁcations via. plugins
Components


XMPP Extensions
XSF deﬁnes a set of XMPP Extension Protocols (XEPs).
> 300 at the moment
http://xmpp.org/xmpp-protocols/xmpp-extensions/.

Jingle (Gtalk), MUC (hangouts), ﬁle transfer, etc..
publish/subscribe
We will concentrate on:
publish / subscribe & BOSH (XMPP on the web)


Publish / Subscribe
(XEP-0060)

Pub/Sub embbeds in IQ stanza
Put JIDs into groups and push out messages to many
subscribers!
Let people subscribe/unsubscribe for data on a node
Setup roles and afﬁliates..


Publish / Subscribe
(XEP-0060)
<iq type='set'
from='hamlet@denmark.lit/blogbot'
to='pubsub.shakespeare.lit'
id='pub1'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='princely_musings'>
<item>
<entry xmlns='http://www.w3.org/2005/Atom'>
<title>Soliloquy</title>
<summary>
To be, or not to be: that is the question:
Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,
And by opposing end them?
</summary>
<link rel='alternate' type='text/html'
href='http://denmark.lit/2003/12/13/atom03'/>
<id>tag:denmark.lit,2003:entry-32397</id>
<published>2003-12-13T18:30:02Z</published>
<updated>2003-12-13T18:30:02Z</updated>
</entry>
</item>
</publish>
</pubsub>
</iq>


Publish / Subscribe
(XEP-0060)
Subscribers receives published data
<message from='pubsub.shakespeare.lit' to='francisco@denmark.lit' id='foo'>
<event xmlns='http://jabber.org/protocol/pubsub#event'>
<items node='princely_musings'>
<item id='ae890ac52d0df67ed7cfdf51b644e901'>
[ ... ENTRY ... ]
</item>
</items>
</event>
</message>

<message from='pubsub.shakespeare.lit' to='bernardo@denmark.lit' id='bar'>
<event xmlns='http://jabber.org/protocol/pubsub#event'>
<items node='princely_musings'>
<item id='ae890ac52d0df67ed7cfdf51b644e901'>
[ ... ENTRY ... ]
</item>
</items>
</event>
</message>


BOSH (XEP-0124)
Bidrectional streams Over Synchronous Http
(BOSH)
HTTPs api are great - Polling sucks.
Long Polling. XMPP embedded into HTTP
why? simple, known tech. use compress etc.
Small problem: cross origin policy (diff. ports)
default BOSH port 5280 - HTTP 80


BOSH
HTTP hold the connection until there is something
to send


BOSH - XMPP over HTTP
POST /webclient HTTP/1.1
Host: httpcm.example.com
Accept-Encoding: gzip, deflate
Content-Type: text/xml; charset=utf-8
Content-Length: 188

<body rid='1249243562'
sid='SomeSID'
xmlns='http://jabber.org/protocol/httpbind'>

<message to='contact@example.com'
xmlns='jabber:client'>
<body>Good morning!</body>
</message>

</body>


BOSH - XMPP over HTTP

• No data - empty body tag from server
• Works through header setup and timeouts

HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: 64

<body xmlns='http://jabber.org/protocol/
httpbind'/>


Plugins & Components


Some advanced features
Normal client “bots” easy to do, but have limitations
To incorporate your own business logic you need some
more..
To make advanced features on the server side
Server Plugins
Components
External Auth.. either plain db, ldap or others.


Server Plugins

Located on the server
Change routing strategy
Filter packages / Drop packages
Do statistics etc.
Bound to the server implementation - not portable
Can hog mem/cpu from the server. Its embedded!.
(take care)


Components conn. to the server or vice versa (normal
TCP)
Handshakes and authenticates (trusted by server)
Portable
Can be run externally with code implemented in almost
every language.



Acts almost like a “normal” client. e.g. JID
(comp@braintrust.dk)...
Can act and interact on the whole domain.. not multiple
Can alter the to/from ﬁelds...
Can’t drop/ﬁlter packages for every domain.


Break!! ...
Next developing XMPP 101
Lets have some hands-on experience.
Install Java (version 6 and up is ﬁne)
Install Apache web server
Get XMPP server up and running
Play..


XMPP 101 - playtime!

Install your very own XMPP server!
Setup Apache or other httpd / proxy
Download Strophe and setup examples..
Play!


Developing XMPP
Learned so far:
XMPP can run on every device, on mobile, on the web
on
XMPP makes a bridge and makes the device present
and available to communicate with other entities..
Client frameworks for almost every language
Java, Javascript, C / C++, Erlang, C#, Python, Ruby, Perl etc.

We will focus on the web (client side) and hence do
javascript


XMPP Kick Start!
But ﬁrst! to make it work, we need a server

• Choose your favorite XMPP server!
• The list is long: http://xmpp.org/xmpp-software/servers/

• Be ware of the license. Some are
commercial/gpl/gpl3/apache etc.


XMPP Servers

Administrators would look for monitoring and tools.
Extensions.. E.g. some can pub/sub, some can’t. So
choose from your speciﬁc application.
Clustering or not? What is your demand? 5k users?
500k users?


My recommendations
Ejabberd 2.1.11 (http://www.ejabberd.im/)
cool features dist. out-of-the-box. Thanks
erlang!
high load factor
Tigase 5.1.x (linux, mac etc. *NIX.)
very ﬂexible. Code injection on the ﬂy. Groovy /
Java. Easy to understand
Many extensions available
Good monitoring tools!

Windows users?...

If you can’t run shell scripts etc.
Openﬁre might be easier:
http://goo.gl/9HYeb
Should be easy to setup.. I’ll help later. No worry. :-)


Tigase XMPP server
Install Java if you dont have it!

Install tigase:

download http://goo.gl/jYNFD

run the downloaded jar ﬁle: java -jar tigase...jar

Setup easy. in step 7, choose only base, extras and derby database. in the other
steps just press next!

cd {TIGASE_HOME} (where you installed it)

Start: ./scripts/tigase.sh start etc/tigase.conf

Stop: ./scripts/tigase.sh stop

add a new user to the server (use a client: PSI, Adium , Pidgin etc)


Proxy setup

because of same origin policy.. if you have a
CORS enabled browser, this is not needed
http://httpd.apache.org/download.cgi
proxy_module should be enabled.
in httpd.conf (proxy port 80 to port 5280)
ProxyPass /http-bind/ http://localhost:5280/http-bind/


XMPP libraries..

There a many! http://xmpp.org/xmpp-software/libraries/

Native or BOSH (XMPP over HTTP)
We focus on BOSH.. lets enable real-time push on the
web.
Strophe.js!


Strophe Install
Download here: http://goo.gl/5btM2
unzip / untar the downloaded package into your
Apache web folder (on mac: Library/WebServer/
Documents).
You can change the folder in the httpd.conf if you want.
change in examples/echobot.js :
var BOSH_SERVICE = '/http-bind/';

Ready to run!. if server is running, ﬁre up your browser
and use the user created just before when logging in.


Strophe
Pure javascript XMPP library (integrated with jquery)
Using BOSH as connection type
Simple manipulations with Stanzas
Build everything like DOM
Light and Event driven..
Here is my example: http://localhost/webchat


Strophe

Make connection on the BOSH URL deﬁned in
apache proxy:
var conn = new Strophe.connection(“localhost/http-bind”);

Connect with JID (full/bare) and make cb function:
conn.connect(JID, password, callbackfn);


Strophe

Strophe have static status to check on the connection

function onConnection () {
if (status == Strophe.Status.CONNECTED) {
// do something!
} else if (status ...
..
}


Strophe - Sending /
Receiving
conn.send(xml);....

conn.addHandler(on_message,
null, “message”, “chat”);
on_message(message) {
console.log(“Hi there: “ + message);
return true;
}


Strophe..

1. function onMessage(msg) {
2. $(msg).find("message[type='chat'][from]:has(body)")
3. .each(function () {
4. var body = $(this).find("body:first").text();
5. var from = $(this).attr("from");
6.
7. log('ECHOBOT: I got a message from ' + from + ': ' + body);
8.
9. var reply = $msg({to: from, type: "chat"})
10. .c("body")
11. .t(body);
12. connection.send(reply.tree());
13.
14. log('ECHOBOT: I sent ' + from + ': ' + body);
15. });
16.}


Strophe - Stanzas..

Strophe have convenience methods:
$pres(attributes..);
$msg(attributes..);
$iq(attributes..);


Strophe - Stanzas
Sending initial presence:
$pres();
Building a message stanza:

$msg({to: ‘zooldk@gmail.com’, ‘type’ :
‘chat’}).c(‘body’).t(‘Hello zool!’);


</stream>..the end..
Contact me at
Email/XMPP: slarsen@braintrust.dk / zooldk@gmail.com

LinkedIn: http://dk.linkedin.com/in/zooldk

Illustrations by Adrian Teh (Too lazy to draw my self..)

XMPP standard foundation: http://xmpp.org

Links
Server list: http://xmpp.org/xmpp-software/servers/

Client list: http://xmpp.org/xmpp-software/clients/

Libraries: http://xmpp.org/xmpp-software/libraries/

Strophe:


XMPP Intro - The camp2012

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