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Anonymous, 02/29/2012 12:33 pm


= XMPP library candidates analysis =

<acronym title="DesignXMPP_analysis, depth=2">TOC</acronym>

In this phase the existing XMPP libraries will be analyzed and one will be chosen to be used throughout the project.

Library requirements * Written in Python (C/C++ could also be used, but a wrapper would need to be written) * Support for XMPP server (or component, details later) * Ability to use it with the current model used by SylkServer * Green threads * Callback based IO XMPP server vs XMPP component

The XMPP protocol was designed to be extended by entities called "components" which sit on the side of the server. A component is addressed with a DNS subdomain in the following form:

{{{
component.domain.tld
}}}

This mechanism is defined in [http://xmpp.org/extensions/xep-0114.html XEP-0114].

With this architecture in place deployment of additional features to an existing XMPP server doesn't require to modify it. The SIP-XMPP gateway can potentially be implemented as either a XMPP component or an standalone XMPP server.

Library evaluation

The following aspects were considered when evaluating a given library:

  • Met requirements stated above
  • Is it actively maintained?
  • Example use cases
  • Deployments in real-world scenarios
  • Perceived complexity to integrate it with SylkServer architecture
= SleekXMPP=== * Plugin architecture, each XEP as a plugin * Client and server component support * Threaded model (thread based scheduler) * Active development

=== Wokkel ===

  • Plugin architecture, 'subprotocols' implementing different XEPs
  • Client and server component support
  • XMPP server-to-server support (s2s)
  • Designed to be used with Twisted (reactor model)
  • Active development
Selected XMPP library

After analyzing candidate libraries '''Wokkel''' was the chosen one. Reasons:

  • Implemented on top of Twisted, which makes integration with SylkServer straightforward
  • Support for both component and XMPP server models, allowing for flexibility in implementation