chat.pl -- The SWISH collaboration backbone

We have three levels of identity as enumerated below. Note that these form a hierarchy: a particular user may be logged on using multiple browsers which in turn may have multiple SWISH windows opened.

1. Any open SWISH window has an associated websocket, represented by the identifier returned by hub_add/3.
2. Any browser, possibly having multiple open SWISH windows, is identified by a session cookie.
3. The user may be logged in, either based on the cookie or on HTTP authentication.

 chat_broadcast(+Message) is det

 chat_broadcast(+Message, +Channel) is det

Send Message to all known SWISH clients. Message is a valid JSON object, i.e., a dict or option list. When using Redis we send the message to the swish:chat pubsub channel and listening for swish:chat calls chat_broadcast_local/1,2 in each instance.

Arguments:

Channel

- is either an atom or a term Channel/SubChannel, where both Channel and SubChannel are atoms.

 chat_about(+DocID, +Message) is det

Distribute a chat message about DocID.

 chat_to_profile(ProfileID, :HTML) is det

Send a HTML notification to users logged in using ProfileID.

 notifications(+Options)//

The chat element is added to the navbar and managed by web/js/chat.js

 broadcast_bell(+Options)//

Adds a bell to indicate central chat messages