Chat and messaging service infrastructure

The old instant messaging infrastructure based on the external OpenFire Jabber server is causing many severe issue:

• synchronisation problems for users and groups
• per logged in user multiple threads are generated consuming 1MB of RAM per user even when idle
• updating of status messages causes many code roundtrips
• connection problems etc.

The chat just does not work well and causes many problems.

The solution is a new and fully integrated chat and messaging infrastructure:

• chat and messaging service, clustersave
• database persistance for messages
• modular message format that allows to extend a message with other elements than text (e.g. file attachment, canvas drawing commands etc, just an option for the future).

Features:

• chat one-to-tone
• chat in a group (group or course)
• chat anonymous or with real name
• chat log
• download and delete of chat log for administrative users (group and course)
• archive chat log on course delete
• interrupt mode: when in QTI test, SCORM etc.

Status:

• 3 state implemented:
  • available (messages delivered instantly opening the chat window)
  • do-not-disturb (messages indicated in top navigation (as today), delivered when user clicks the icon)
  • unavailable (messages indicated in top navigation (as today), delivered when user clicks the icon)
• not delivered messages (user is offline) are delivered after next login (envelope in top navigation). In addition, a standard notification should be triggered (synthetic notification or something