Bug 5651 - Error when disconnecting from Web Access on Firefox
: Error when disconnecting from Web Access on Firefox
Status: NEW
: ThinLinc
Web Access
: trunk
: PC Unknown
: P2 Normal
: Next
Assigned To:
  Show dependency treegraph
Reported: 2015-09-23 17:12 by
Modified: 2017-04-21 16:03 (History)
Acceptance Criteria:

Screenshot of the error (54.13 KB, image/png)
2016-10-07 16:58, Samuel Mannehed
Screenshot of the error (68.18 KB, image/png)
2017-04-20 11:23, Samuel Mannehed


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Description From cendio 2015-09-23 17:12:39
Half the time when logging out from a ThinLinc session open in the HTML5 client
we get the following error:


Issue found on Firefox 38 on Fedora 20. It does not happen everytime I log out,
could be some sort of race?
Can not reproduce in Firefox 38 on Windows 10 nor in Google Chrome on Windows
or Linux.

Possibly related to: https://bugzilla.mozilla.org/show_bug.cgi?id=712329
------- Comment #1 From cendio 2015-09-23 17:15:07 -------
I have seen this issue for a long time (it has probably always been here) but
note that since the changes in bug 5603 this bug is now shown to the users.
------- Comment #2 From cendio 2016-02-10 09:06:02 -------
Got it today on Fedora 23 with Firefox 44.
------- Comment #3 From cendio 2016-10-07 16:57:31 -------
Since the implementation of continuous updates and fences done on bug 5814 we
now get this error message a lot more frequently.

Commit r31514 improved the consistency in how we send data on the websocket. It
also added support for receiving Fence messages. A side effect of these changes
is that we are now getting the "NS_ERROR_NOT_CONNECTED"-error more often.

The error message appears since queued-up actions are still trying to use the
websocket even after it is closed.

In ThinLinc 4.6.0 (tested on castro), we see this error quite rarely. This is
due to the fact that the message queue has to contain a message that provokes
an action on the websocket that isn't executed before we have closed the
connection to the socket.

In ThinLinc 4.7.0rc1, this error message ALWAYS pops up when logging out using
a desktop environment that has some sort of graphical effect upon logout.
Examples of such DE's are Gnome 3 and Unity. The new server will be sending
fence messages quite frequently, which in turn triggers a response from the
HTML5 client. Since we are trying to send a response on a closing socket we
trigger the error.

To consistently trigger this error, no matter the desktop environment, or the
type of server-initiated disconnection:

In a terminal within the session -
* run any application that triggers graphical updates (glxgears for example)
* run tl-disconnect
------- Comment #4 From cendio 2016-10-07 16:58:52 -------
Created an attachment (id=751) [details]
Screenshot of the error
------- Comment #5 From cendio 2016-10-07 17:02:28 -------
Moving from Future to '---' milestone for discussion since the error message is
now extremely frequent and very visual. I believe this gives a very bad
impression of the HTML5 client for all Firefox users. We should consider at
least hiding the error message for ThinLinc 4.7.0 to spare headache for
ThinLinc administrators and customers. A proper solution could wait until next
release in my opinion.
------- Comment #6 From cendio 2016-10-07 17:29:11 -------
I cannot provoke the error using the UI disconnect button. Only seen on
server-initated disconnects.
------- Comment #7 From cendio 2017-04-20 11:23:45 -------
Created an attachment (id=802) [details]
Screenshot of the error

After changes done on bug 6132, the error now looks like this.
------- Comment #8 From cendio 2017-04-21 16:03:31 -------
This error message is hidden for now, done on bug 6132. When solving this bug,
revert commit r32426.