CometD

[cpd73]

> Code checked into cometd branch.

Thanks. Played with it, but didn't get it to report anything either. I
do see that it's connecting to the server. But no events.

--

Michael

[cpd73]

CometD

Thinking about using CometD to obtain status updates, rather than polling in Material Skin. I found a Javascript library for this at https://github.com/cometd/cometd-javascript (As an aside, I had to rename this libcometd.js, otherwise LMS would just return some error message instead of the JS file?)

Just quickly adding this to my server.js file, so that I can see how things work, I tried:

        var cometd = new org.cometd.CometD();
        cometd.init({url: lmsServerAddress + '/cometd', logLevel:'debug'});
        cometd.addListener('/meta/handshake', function(message) {
            if (eval(message).successful) {
                console.log("Handshake successful");
                cometd.subscribe('/slim/serverstatus', cometd.getClientId(),
                                function(res) { console.log("serverstatus:"+JSON.stringify(res, null, 2));},
                                {data:{response:'/'+cometd.getClientId()+'/slim/serverstatus', request:['', ['serverstatus', 0, 50, 'subscribe:60']]}});
            }
        });

But I never get any serverstatus messages. CometD does produce some logging, and the handshake is successful. If I edit the libcometd.js file and replace channel: '/meta/subscribe' with channel: '/slim/subscribe' in CometD.subscribe(), then CometD does log what appears to be serverstatus messages. But still my handler above is not called. This is hack anyway, and I'm sure its not a correct change.

Any ideas as to what's wrong? Anybody have experience using cometd.js with LMS?

[mherger]

CometD

> Just quickly adding this to my -server.js- file, so that I can see how
> things work, I tried:

Could you please create a branch on github I could play with this? Would
be easier than finding the right place to put this in...

> Any ideas as to what's wrong? Anybody have experience using cometd.js
> with LMS?

I'll see what I did when I was using it - when I find some time.

--

Michael

[cpd73]

> Just quickly adding this to my -server.js- file, so that I can see how
> things work, I tried:

Could you please create a branch on github I could play with this? Would
be easier than finding the right place to put this in...

Sure, but it'll have to be much later - at work at the moment. But, I literally just copied cometd.js to MaterialSkin/HTML/material/html/lib/libcometd.js (must be renamed), edited desktop.html to include this JS file, and placed the above code in the "mounted" section of server.js

[cpd73]

> Just quickly adding this to my -server.js- file, so that I can see how
> things work, I tried:

Could you please create a branch on github I could play with this? Would
be easier than finding the right place to put this in...

Code checked into cometd branch.

[expectingtofly]

Sorry to resurrect an old thread, I've been wrestling with cometD from a REACT Javascript app I'm building and not having much luck.

I'm handshaking fine, but when I subscribe I get nothing.
I'm using the standard npm package for cometD.

If for example, I use similar code to Craig's code above it sends a message like this :

[
  {
    "data": {
      "response": "/4954119f/slim/serverstatus",
      "request": [
        "",
        [
          "serverstatus",
          0,
          50,
          "subscribe:60"
        ]
      ]
    },
    "id": "3",
    "channel": "/meta/subscribe",
    "subscription": "/slim/subscribe",
    "clientId": "4954119f"
  }
]

Which, if I look at the documentation for CometD, is correct.

However, if I look at the LMS code, it states this :

			# A valid /slim/subscribe message looks like this:
			# {
			#   channel  => '/slim/subscribe',
			#   id       => <unique id>,
			#   data     => {
			#     response => '/slim/serverstatus', # the channel all messages should be sent back on
			#     request  => [ '', [ 'serverstatus', 0, 50, 'subscribe:60' ],
			#     priority => <value>, # optional priority value, is passed-through with the response
			#   }

Note, it says '/slim/subscribe' should be in the 'channel' key (instead of 'meta/subscribe' and there should be no 'subscription' key.

Is it simply that LMS is non-standard and I'm going to have to hand craft my own subscription method?


[EDIT]
Ah, I now realise that is exactly what Craig has done, he is maintaining is own amended version of libcometd.js and put some custom code in to make it work : https://github.com/CDrummond/lms-mat...ometd.js#L2820

[expectingtofly]

I now realise that Craig has been down this journey before, I'll just have to look at his amended libcometd.js.