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Programming and Extending JabberXMPP
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Open XML-based protocol. Exchange messages and presence between any two ... Jabber ICQ gateway (JIT - http://jit.jabberstudio.org/) provides a bidirectional ... – PowerPoint PPT presentation
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Title: Programming and Extending JabberXMPP
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Programming and Extending Jabber/XMPP
- Mrinal Kalakrishnan
- PES Institute of Technology
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Jabber and XMPP
- Open XML-based protocol
- Exchange messages and presence between any two
points on the internet - Instant messaging, and much more
- Decentralized like email
- XMPP eXtensible Messaging and Presence
Protocol, standardized by the IETF
3
Decentralization
C1
C2
S1.com
C7
S2.net
S3.org
C3
S2S
C8
C4
C2S
C5
C9
C6
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JIDs, Resources, Priorities
- JID Jabber ID
- username_at_servername.com
- username2_at_servername.com
- Multiple connections allowed from the same JID
- Each connection has a unique Resource name
- username_at_servername.com/home
- username_at_servername.com/work
- Each connection/resource also has a priority
- Higher priority resource gets all messages
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XML Protocol Basics
- Client to Server connection TCP port 5222
- XML Streams
- One XML document in each direction
- lt?xml version1.0?gt
- ltroottaggt
- ltfragment1/gt
- ltfragment2/gt
- ltfragment3/gt
- lt/roottaggt
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The Building Blocks
- ltmessage/gt
- ltpresence/gt
- ltiq/gt
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ltmessage/gt
- Send messages from one Jabber entity to another
- Example
- ltmessage from'me_at_myserver.com/home'
to'you_at_yourserver.com' type'chat'gt - ltsubjectgtTime to meet?lt/subjectgt
- ltbodygtWhen do you want to meet?lt/bodygt
- lt/messagegt
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ltpresence/gt
- Used to indicate availability (or unavailability)
of a Jabber entity - Example
- ltpresence from'me_at_myserver.com/home'
to'you_at_yourserver.com'gt - ltshowgtawaylt/showgt
- ltstatusgtStepped out for a whilelt/statusgt
- ltprioritygt5lt/prioritygt
- lt/presencegt
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ltiq/gt
- Iq Info/Query
- Any kind of structured (XML) conversation between
two entities - Example (logging on to the server)
- ltiq typesetgt
- ltquery xmlnsjabberiqauthgt
- ltusernamegtmynamelt/usernamegt
- ltresourcegtHomelt/resourcegt
- ltdigestgtb495d84ca048ef01508503dba94elt/digestgt
- lt/querygt
- lt/iqgt
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The Roster and Presence Subscription
- Roster (contact list) is stored on the server
- Retrieved after logging on using an ltiq/gt query
- Adding another Jabber user to the roster is
termed presence subscription - To add a user
- ltpresence to'you_at_yourserver.com'
type'subscribe'gt - Response
- ltpresence from'you_at_yourserver.com'
type'subscribed'gt
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More than just Instant Messaging
- Collaboration tools
- File sharing
- Gaming
- Remote systems monitoring
- Network management
- Content syndication
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Jabber Code Libraries
- C
- C
- Java
- Perl
- Python
- C / .NET
- Tcl
- Objective-C
- PHP
- Ruby
- Flash
- Delphi
http//www.jabber.org/developer/librarylist.php
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Basic Jabber Application Programming
- Connect to port 5222 of the server
- Open XML stream, and authenticate with the server
- Send initial presence, and request roster
- Register callback functions for incoming
ltmessage/gt, ltpresence/gt and ltiq/gt packets - Respond appropriately to the incoming packets in
the callback functions - Send out ltmessage/gt, ltpresence/gt and ltiq/gt
packets when needed
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Example Application Webber
- A Jabber presence indicator for a webpage
- Uses the jabber.py Python library
- Implementation consists of two distinct sections
- A 'bot' program continuously running as a Jabber
client, gathering presence information and
updating a database - The webpage, a PHP script which reads the
database and displays the presence status
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Webberbot
- A daemon program running as a Jabber client
- Processes incoming ltpresence/gt packets
- If presence type is available or unavailable,
update the presence information in a table with
the full JID as the key - If presence type is subscribe or unsubscribe,
send the appropriate reply ltpresence/gt packets. - Ignore ltmessage/gt and ltiq/gt packets.
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Webber The PHP Script
- Read the presence entries from the database
- If there are multiple resources listed for the
same JID, return the status of the highest
priority - Display the status on the page!
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Example 2 SMS Interfacing
- Jabber ICQ gateway (JIT - http//jit.jabberstudio.
org/) provides a bidirectional interface between
Jabber and SMS - Build a client that responds to message events
from the JID of the mobile phone (eg
919845012345_at_sms.myjabberserver.com) and performs
actions based on the message contents - Simple to program, and the possibilities are
endless!
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Resources and URLs
- http//www.jabber.org/ - Home of the Jabber
Software Foundation - http//www.jabberstudio.org/ - Development hub
for the Jabber community - http//mrinal.net/webber/ - The example
application - Contact me at mail_at_mrinal.net
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