[winswitch] Update for Xpra running Wireshark in Docker container

Antoine Martin antoine at nagafix.co.uk
Mon Oct 14 13:07:42 BST 2019

On 14/10/2019 18:36, Florian Feldhaus wrote:
> Thanks a lot for your input, very helpful. I have a few follow up
> questions inline, but first let me ask 2 new questions:
> Is there a way to donate to XPRA? I’d be glad to donate myself and refer
> users of my Docker container to donate to the XPRA project as it
> wouldn’t be possible without the great job you are doing. I couldn’t
> find anything on the XPRA or Winswitch sites.
That's good idea, I'll try to set something up after I inquire about the
legal constraints of it.

> When using the HTML5 client, I have consistently problems with multiple
> OS (checked Linux and Mac OS) regardless of resolution with Firefox and
> Chrome when maximizing Wireshark and then trying to use the scrollbar on
> the right side. It seems that the cursor is generally off to the left in
> this situation. If I make the Wireshark window a bit smaller than
> maximized, everything is still fine. I couldn’t find any ticket on this.
> Is this a known issue? Otherwise I’ll open a ticket.
Please do.
Sounds like the browser window is slightly too small.


>> Am 12.10.2019 | KW 41 um 05:26 schrieb Antoine Martin via
>> shifter-users <shifter-users at lists.devloop.org.uk
>> <mailto:shifter-users at lists.devloop.org.uk>>:
>> On 11/10/2019 22:04, Florian Feldhaus via shifter-users wrote:
>>> 2019-10-11 13:54:10,301 started command 'wireshark' with pid 45
>>> 2019-10-11 13:54:10,303 Warning: cannot watch for application menu
>>> changes without pyinotify:
>>> 2019-10-11 13:54:10,303  No module named 'pyinotify'
>> Not needed unless you want the client to be able to start new commands
>> using a menu GUI.
>> Be aware than since v3, users can start new commands when connected to
>> the server. Use "start-new-commands=no" to disable this capability.
> Is there a way to completely disable the XPRA menu in the HTML5 client?
> It is not needed in my case and could be confusing for users.
>>> 2019-10-11 13:54:10,497 xpra is ready.
>>> 2019-10-11 13:54:10,499 xpra GTK3 X11 version 3.0-r24095 64-bit
>>> 2019-10-11 13:54:10,550 2.0GB of system memory
>>> 2019-10-11 13:54:11,327  uid=1000 (wireshark), gid=1000 (wireshark)
>>> 2019-10-11 13:54:11,328  running with pid 1 on Linux Debian testing
>>> bullseye
>>> 2019-10-11 13:54:11,330  connected to X11 display :0 with 24 bit colors
>>> 2019-10-11 13:54:29,256 Error: wss request failure
>>> 2019-10-11 13:54:29,256  for client
>>> 2019-10-11 13:54:29,256  request:
>>> 'ü1ÿD5a>Gä•®Ç(’ñÑŠ3èÀ–lݐYCEò Dԩ̸ôþñÿÆŸ˜ó{}÷3Œ'o—
>>> Åšð"ššÀ+À/À,À0̨̩ÀÀœ/5'
>>> 2019-10-11 13:54:29,256  [SSL: SSLV3_ALERT_CERTIFICATE_UNKNOWN] sslv3
>>> alert certificate unknown (_ssl.c:2508)
>> SSL client misconfiguration?
> I followed the exact steps in
> https://xpra.org/trac/wiki/Encryption/SSL and still have the issue. I
> have lots of these log entries, but will retry with a trusted
> certificate. One thing I found out is, that when I open the HTML5 client
> in a Browser it is asking for a client certificate. I do have client
> certificates installed, but don’t want to use them and click on cancel.
> Could it be, that client certificates are causing this error?
>>> When I use this on a large display (5K), I often get very blurred
>>> output when a lot of Network packages are analyzed. That is probably
>>> expected, but the blurry images sometimes stay for several seconds
>>> and sometimes are not refreshed at all with a clear picture.
>> Some applications are known to refresh their windows regularly, even
>> when nothing has actually changed on screen, this causes problems with
>> xpra's builtin heuristics which then keep the picture quality lower
>> than desired to try to keep up with the updates.
>> Otherwise, the picture is always eventually refreshed with a lossless
>> one pretty quickly.
>> Also, be aware that I don't have a 5K display so this has never been
>> tested with windows that big - so some things may need tweaking to
>> improve the experience.
>> For a start, we there is a known issue with the html5 client on macos
>> hi-dpi displays:
>> https://xpra.org/trac/ticket/2410
>>> I tested this on a local computer with more or less unlimited
>>> bandwidth. I tried to modify the encoding settings via xpra.conf, but
>>> it seems they had no effect. I checked the information at
>>> https://xpra.org/trac/wiki/Encodings/Debugging
>>> <https://xpra.org/trac/wiki/Encodings/Debugging> but I wasn’t able to
>>> fix this myself. Are there any hints for high quality encoding?
>> The best way would be to just add a new hint so we map wireshark to a
>> "text" mode:
>> https://xpra.org/trac/browser/xpra/trunk/src/content-type
>> https://xpra.org/trac/browser/xpra/trunk/src/content-type/50_class.conf
>> Alternatively, you should be able to get pixel perfect screen updates
>> just by increasing the "min-quality" parameter.
> I added a hint for Wireshark to be mapped to text mode and the quality
> is perfect now. Even if a lot of packages are analyzed, only approx.
> 500KB/s of bandwidth are used to deliver the updates to the client! Can
> we add Wireshark to the official 50_class.conf or should I just do it
> for my docker deployment?
> I still get a lot of DPI errors, even when connecting with devices with
> lower resolutions on Linux:
> 2019-10-14 08:30:02,461 DPI set to 20 x 21 (wanted 96 x 96)
> 2019-10-14 08:30:02,463  you may experience scaling problems, such as
> huge or small fonts, etc
> 2019-10-14 08:30:02,463  to fix this issue, try the dpi switch, or use a
> patched Xorg dummy driver
> 2019-10-14 08:30:02,485 sent updated screen size to 1 client: 1664x896
> (max 8192x4096)
> I tried to manually set dpi=96 in the xpra.conf but that didn’t seem to
> have an effect. I checked the information about Xdummy
> here https://xpra.org/trac/wiki/Xdummy but it seems that is already used
> by default. Output of "cat /usr/local/etc/xpra/conf.d/55_server_x11.conf
> | tail -n1“:
> # Selecting virtual X server:
> xvfb = /usr/lib/xorg/Xorg -noreset -novtswitch -nolisten tcp +extension
> GLX +extension RANDR +extension RENDER -auth $XAUTHORITY -logfile
> ${XPRA_LOG_DIR}/Xorg.${DISPLAY}.log -configdir
> ${XDG_RUNTIME_DIR}/xpra/xorg.conf.d/$PID -config /etc/xpra/xorg.conf
> How can I verify if all required packages are installed and how do I
> solve the DPI issues?
> Thanks again for your great support
> Florian

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