Re: [xwiki-devs] XWiki chat

Hi Everybody, as promised here it is a more detailed mail about the work I did on XWiki chat. First of all I committed the code of the current prototype here: https://github.com/xwiki-contrib/xwiki-platform-chat Now some technical details: 1) The system uses an embedded Vysper XMPP server (http://mina.apache.org/vysper/) with the Multi User Chat extension. 2) The communication is done using the BOSH protocol (http://en.wikipedia.org/wiki/BOSH). The BOSH endpoint is in the application context path, which means that the BOSH servlet will receive all the cookies as the other servlets (important for authentication, see after) 3) The whole UI of the chat system is contained in the XWiki.XWikiChatSkin. I've setup some tricky XSL transformations for bundling all the needed resources into this skin (see https://github.com/xwiki-contrib/xwiki-platform-chat/blob/master/xwiki-plat…) The result is that all javascript files, VM overrides, and CSS files are added to the skin as properties. 4) The Javascript, VM overrides and templates are available as separate file in https://github.com/xwiki-contrib/xwiki-platform-chat/tree/master/xwiki-plat…. In order to hack it I use https://github.com/xwiki/xwiki-debug-eclipse and make symbolic links through the Eclipse interface so that those resources are available as if they were on the file system. 5) The current authentication is dummy (see https://github.com/xwiki-contrib/xwiki-platform-chat/blob/master/xwiki-plat…) What is needed to do is to process the data coming from the cookies and use the XWiki authentication subsystem to check the credentials coming at the beginning of an XMPP session. This could be quite tricky and will need some work for modifying the BoshServlet in order to make these credentials available to the code that will need them. 6) When the page is loaded a connection is established and several chat rooms are automatically joined: wiki, space and page. This of course is temporary. The idea is that on page load the user will joing the chatroom for the current wiki, the current space and the current page, depending on what she is looking at. This means that there will potentially be a chat room for every page in the wiki, for every space and, in a multi-wiki environment, for every wiki. The number of users in these chatroom will depend on what the users are actually working on. 7) Chatrooms are left on page unload. This means that looking at the chatrooms population we might be able to understand how many users are currently connected and where. 8) Since XWiki has a feature for defining a social network (i.e., following/followers) this data can be used to show in the chat the users that I am following that are online, so that I might be able to send them private messages. 9) Currently no the XMPP server is not backed by any storage, but it is possible to write a storage system that stores all the discussions in some wiki object (e.g., a page) so that a trace is kept. 10) The XMPP server also supports a Publish/Subscribe module. This could be used to implement a live notification system. But even without using pubsub, a special chatroom can be used to send these messages that will be displayed, for example, using a special UI à la growl (http://growl.info/screenshots) or equivalent. There is currently a limitation with the Vysper BOSH servlet... It seems that it doesn't like too much Tomcat which can be a problem. The thread where the problem is explained is here: http://mail-archives.apache.org/mod_mbox/tomcat-users/201201.mbox/%3C4F1031… I haven't yet investigated the problem, but a possible solution (or a roadmap towards a solution) should be found as soon as possible because if we start to integrate the authorization system and the storage system, it would be difficult to port it to another system [1] I think that's all for the moment. Of course comments are welcome. -Fabio [1] I've looked at other XMPP servers, but I chose Vysper because it is part of a well established Apache project, it's very simple to use, supports all that we need (embeddable server, multi user chat, etc.) and has a quite active community. Other solutions were either GPLv3, or not showing a clear situation wrt the community and the features. On Sat, Mar 31, 2012 at 1:46 AM, Fabio Mancinelli <fabio.mancinelli(a)xwiki.com> wrote: