[winswitch] [xpra] HTML5 client bugs

Antoine Martin antoine at nagafix.co.uk
Thu Jul 5 05:31:25 BST 2018

On 05/07/18 05:32, Matteo Ipri via shifter-users wrote:
> Hi all,
> I wrote a couple of Dockerfiles to test the latest stable (xpra X11 version
> 2.3.2-r19729 64-bit as of this writing) and the latest beta version (xpra
> X11 version 2.4-r19803 64-bit as of this writing) and I found some bugs
> when comparing the HTML5 client to the Xpra desktop client I use on my Arch
> Linux running PC.
> The Docker images are based on Ubuntu 17.10 artful and I attach the
> Dockerfiles so that my experiments can be reproduced.
Without the docker files, this cannot be reproduced by others.
Can you share them?

> To build the images, I run the following commands:
> sudo docker build -t xpra -f path/to/xpra/Dockerfile path/to/xpra/
> sudo docker build -t xpra:beta -f path/to/xpra/Dockerfile-beta
> path/to/xpra/
> To run the containers, I enter the following:
> sudo docker run --interactive --tty --rm -p 8080:8080 xpra
> sudo docker run --interactive --tty --rm -p 8080:8080 xpra:beta
> Once a container is running, I open my web browser (Firefox or Chormium)
> and navigate to http://localhost:8080.
> Once xpra is loaded I have an xterm window in my browser.
> So far, so good.
> Once I am in xterm I run the command "xdg-open https://xpra.org".
> With the stable version of xpra I only get a message in my local terminal
> (the one in which I launched the docker container) that says (as expected):
> "2018-07-04 21:04:57,471 New unix-domain connection received on
> /home/matteo/.xpra/62b2edcf1139-0
> 2018-07-04 21:04:57,473 Warning: remote end does not accept URLs"
> If I connect to the container with the desktop client, I get the pop-up
> asking me where to open the link.
> With the beta version, using the HTML5 client, Firefox in the container is
> launched.
> It seems like the xdg-open-forwarding for URLs is broken in the current
> beta.
> If I connect to xpra beta with the desktop client, I get the pop-up as with
> the stable version of xpra.
The current beta version should forward "xdg-open" to the html5 client,
which will display the link in the top bar, as per:
I've just tried it again and it worked fine here.

> I can add that xdg-open-forwarding for URLs was working in version
> v2.4-r19581 I installed as beta in a container some week ago.
> There are two more bugs, that are present in both version of xpra and only
> in HTML5 client.
> If I run "firefox https://xpra.org" in the remote xterm terminal window,
> Firefox launches regularly and the web page loads fine.
> If I ctrl+click on a link, for example on About, the link is opened in the
> same tab instead of a new one.
> If I use the desktop client, the ctrl+click opens the link in a new tab as
> expected.
Looks like a bug with keyboard modifiers (control, shift, etc) not being
synchronized correctly during pointer events.

> The second bug I found is about some keyboard keys.
> If I try to type the "less than" character (<) pressing "shift+," when
> using the HTML5 client, I get the "greater than" character (>).
> This happens on both stable and beta HTML5 clients, but not with the
> desktop client. My keyboard has the US layout and has 104 keys. In the logs
> I see that the "us" layout is chosen by xpra and that the ctrl key press is
> recognized by xpra.
> Other keys with issues are the 4 in the top right corner of the keyboard
> (top right corner of the numpad): /, *, - and +. These four are mapped to
> the similar keys in the main part of the keyboard, thus when I press "*" I
> get "8" and I have to press "shift+*" to get the "*".
Keyboard event support in Javascript is challenging: it isn't always
possible to distinguish the numpad keys from other keys with the same label.
At least not with all the different combinations of browsers, OS and
input language settings.

> Please, let me know if I can help any further in debugging these issues.
Please file tickets here:

> Thank you very for your attention,
> Matteo Ipri

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