First steps

I'm providing a summary of my progress in the first six days of GSoC coding. Throughout the coding period, I plan to publish a blog post every weekend to document my journey.

My project focuses on expanding the functionality of the Gajim jabber client. To begin, I delved into understanding the existing code responsible for XMPP communication. Gajim utilizes a modified version of the xmpppy library, which includes non-blocking transports with callbacks and message queues to notify connected objects at regular intervals. The Gajim architecture involves three relevant layers: the Connection class, acting as the interface between the UI and xmpppy (one instance per jabber account); the Client class, responsible for establishing the connection to the XMPP server and handling authentication; and the transport classes that format data for different protocols (SSL, TLS, TCP, HTTP proxy, SOCKS5 proxy). The transports themselves are not aware of XMPP stanzas.

In the case of BOSH (Bidirectional-streams Over Synchronous HTTP) messages, XMPP messages are wrapped within a body tag containing BOSH-related attributes. These messages are sent to an HTTP server or proxy known as the Connection Manager, instead of directly to the XMPP server. The communication scheme differs slightly to allow for server-initiated requests in HTTP (refer to XEP-0124). Based on this understanding, I determined the starting point for my coding efforts. Considering the variation in stream initiation between XMPP over BOSH and plain XMPP, I decided to create a BOSHClient class derived from NBCommonClient. In the existing code, the Connection object holds an instance of NonBlockingClient, also derived from NBCommonClient, as shown in the class diagram.

The plan is to utilize the BOSHClient instead of NonBlockingClient for accounts connecting to the BOSH Connection Manager. Currently, I have successfully built and sent the initial request, received and parsed the response, albeit with limited error checking. My next steps involve integrating the Gajim module for SASL authentication and subsequently sending the first message via BOSH.