Meta Events about wamp-proto HOT 4 CLOSED

I like the idea of presence as I have written that logic in two of my applications on top of the wamp wire. I've also written an application using pub/sub where it wasn't needed and I would not desire the transmission of unneeded data to each client.

+1 to Presence, but optionally on a per-use basis.

from wamp-proto.

When a presence message is generated (with #joined/#left metatopics), in which attribute name of the "metaevent" argument should be encoded the "session ID" of the (un)subscribed client? Maybe "sessionId"? i.e:
[ METAEVENT, "http://awesometopic#1", "http://wamp.ws/sub#joined", { "sessionId" : "v59mbCGDXZ7WTyxB" } ]

And what about adding the "#created" & "#removed" metatopics? (to be used when any topic is created/deleted from the server)

I'm also interested in subscribing only to the presence MetaTopics (for monitoring purposes).

For example, when calling the function "sess.subscribe(topicURI, null, onMetaEventCallback)", it could send a message like:
[ MSG_TYPE_SUBSCRIBE_E, topicURI, { "EVENTS": false, "METAEVENTS": true } ]

In this case, the server should not send "EVENT" messages to the monitoring client, neither send the "#joined"/"#left" METAEVENT messages from the subscribed monitoring client to other subscribers (real clients). But the monitor should receive #joined/#left METAEVENTs from the other clients and #removed/#created" METAEVENTS generated by the server.

On the JavaScript client-side, I think the "sess.subscribe" method should have an optional parameter to request extra subscription features (like: "last", "sinceTime", "identifyEventPublisher", "enableEventId"). i.e:
sess.subscribe("http://awesometopic#1", onEvent1, onMetaEvent1, { sinceTime: 0 } );

from wamp-proto.

I will implement stuff along the outline above now. Rereading after some time, I think it makes sense.

@jmarine :

1. Regarding attribute name .. yeah, probably just session, that is

    [ METAEVENT,
         "http://awesometopic#1",
         "http://wamp.ws/sub#joined",
         { "session" : "v59mbCGDXZ7WTyxB" } ]
   

2. Topic created/removed meta events: topics with AutobahnPython server at least are not created, but registered on a specific session.

3. Meta events only. Not generating presence events for clients that do meta event only subscribes. Mmmh. seems very specific. Need to think/see ..

4. JS API. Yep. I'd only change the order of args:

   sess.subscribe("http://awesometopic#1",
                          onEvent1,
                          {metaevents: ["http://wamp.ws/sub#joined", "http://wamp.ws/sub#left"]},
                          onMetaEvent1);
   

since one needs to specify the meta events to be received anyway, but if no meta events, supplying extra subscribe info like topic matching type (exact, prefix, wildcard) could be present.

from wamp-proto.

WAMPv2 solves the issues discussed above in 2 ways:

1. SUBSCRIBE now is always acknowledged (with a subscription ID). UNSUBSCRIBE is also acknowledged.

2. Nevertheless, for presence and potentially other things in the future, WAMPv2 has METAEVENTs:

     [METAEVENT,           Subscription|id, Metatopic|uri]
     [METAEVENT,           Subscription|id, Metatopic|uri, Details|dict]
   

from wamp-proto.