Misfire of the polling request

[lyi2012]

I am using Atmosphere 1.0.15. I build my application on top of the Jersey pub-sub sample using long-polling.
I noticed a tricky issue of miss fire of the polling request. I did some troubleshooting and noticed that from "jquery.atmosphere.js", the
function _reconnect(ajaxRequest, request, reconnectInterval);
has the following logic,

request.id = setTimeout(function() {
    _executeRequest(request);
}, reconnectInterval);

Under some conditions, it can be cancelled by clearTimeout() call unexpectedly, which cause the client stop polling.

[lyi2012]

The clearTimeout() is from function _timeout().

[lyi2012]

Hey, Jeanfrancois,

From my observation, I guess the root cause might be as the following.

When the polling request returns, it schedules the next poll using

setTimeout(function() {
_executeRequest(request);
}, 0);

Which is to fire the next polling request immediately after this polling returns. More specifically, after the current thread returns, since JS is single threaded by nature.
However, if the response of the sending request gets in before the next polling request is fired, it calls _timeout() and kills the next polling request.

This happens if incoming message interlays with the sending message. I guess the scheduling of the thread is not guaranteed even if we specifies it to timeout in 0 ms.

Let me know what you think.

Thanks!

[lyi2012]

Hi, Jeanfrancois,

I setup a small application in which the client sends a message to itself.
The following is a copy of logs from my Chrome console, after I put some log lines into jquery.atmosphere.js. On the 4th last line, the clearTimeout kills the next polling request.

// My request
var ch = messagingAgent.subscribe('1');

ch.onMessage = function(message) {
console.log(message);
};

// Console outputs

readyState: 2 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 3 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 4 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
isAllowedToReconnect: true jquery.atmosphere.js:1606
rq.executeCallbackBeforeReconnect: false jquery.atmosphere.js:1607
reconnecting ... jquery.atmosphere.js:1610
before setTimeout for _executeRequest jquery.atmosphere.js:1712
before _executeRequest jquery.atmosphere.js:1714

// My request
ch.send(1, "1");

readyState: 2 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 4 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 2 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 3 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 4 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
isAllowedToReconnect: true jquery.atmosphere.js:1606
rq.executeCallbackBeforeReconnect: false jquery.atmosphere.js:1607
reconnecting ... jquery.atmosphere.js:1610
before setTimeout for _executeRequest jquery.atmosphere.js:1712
1
before _executeRequest jquery.atmosphere.js:1714

// My request
ch.send(1, "1");

// Console outputs
readyState: 2 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 3 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
readyState: 4 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
isAllowedToReconnect: true jquery.atmosphere.js:1606
rq.executeCallbackBeforeReconnect: false jquery.atmosphere.js:1607
reconnecting ... jquery.atmosphere.js:1610
before setTimeout for _executeRequest jquery.atmosphere.js:1712
1
readyState: 2 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222   // RECONNECT REQUEST IS KILLED HERE!
readyState: 4 jquery.atmosphere.js:1504
clearing timeout in _timeout() jquery.atmosphere.js:1222
clearing timeout in _clearState() jquery.atmosphere.js:2403

[jfarcand]

Hey, you need to try 1.0,16. I think this has been fixed. Pull the latest version from here and let me know.

[jfarcand]

OK I was never able to reproduce the issue, but pushed a fix here. Try this version it should now works.