Channel.request_x11() either doesn't work or needs a good demo

[fatboy92]

A number of users report not being able to get Channel.request_x11() to work correctly in situations where ssh -X works fine. We need to figure out whether this functionality is currently broken, or if it simply requires additional non-obvious code in order to work (in which case we need to improve the docs/demos.)

Originally submitted issue from @fatboy92:

Hi all,
first of all: thanks for that module, I feel it gives me more control, than pexpect.

Now, here is my question:
I am trying to use the channel method request_x11 (and yes I looked at the example programs). Just like when you do ssh -X.

When I do, the process is started as expected but no window is displayed. Same behaviour with invoke_shell(), the display variable is set correctly (localhost:10 or similar), but again no window is displayed. I checked with wmctrl, it isn't there, not even outside the visible area of the screen.

Any thoughts?

Many thanks for all answers.
H. Witsch

[bitprophet]

N.B. above "commit reference" is unfortunately for another repo that got merged into this one. It is 100% unrelated.

---

Making this ticket the clearinghouse for "wtf X11?". Other instances of people having problems with this:

• http://stackoverflow.com/questions/12354047/x11-forwarding-with-paramiko?rq=1
• http://stackoverflow.com/questions/4448089/paramiko-x11-mode-with-python-programming
• http://www.mail-archive.com/paramiko@lag.net/msg00490.html
• http://superuser.com/questions/217420/paramiko-ssh-x-option

Unfortunately I haven't used the X11 bits in Paramiko myself so I have no immediate or obvious fix (and I have other higher priorities re: digging in :(). However I'm more than willing to assist anybody who has a clue, or who can at least be available on eg IRC to help test/debug things on their end.

[garyvdm]

I wrote a working example for one of the stackoverflow questions. See http://stackoverflow.com/a/12903844/72911

It still needs some work, for example, I want to make it handle multiple connections. But it is a start....

[dnozay]

As Gary pointed out in the stackoverflow answer, the handler for x11 requests needs to:

• accept the connection
• open a connection to local display.
• add descriptor for both remote end and local display to poll / select() fd list

then while there's data to handle

• forward data back and forth between remote end and local x11 display.

[bitprophet]

Thanks @garyvdm & @dnozay! Still don't have time to dig into this in full, but it sounds like the issue is "no concrete example included in the source" -- not "X11 channel support is actually broken." Yes? no?

Gary's link implies "yes", so I'd definitely merge a pull request adding @garyvdm's example as a new file in demos/, with the notes inlined as comments or as docstrings (module-level or otherwise).

[amrit-poudel]

Tried everything mentioned on this thread, but nothing seems to work on macosx big sur (local machine) with python 3.9 and xquartz installed on the macosx. ssh -X on the terminal works without any issue.. Main issue is echo $DISPLAY on macosx returns /tmp/…./org.xquartz:0 which does not work with xlib_connect.get_display(). Then paramiko’s channel.request_x11() fails. Its been a decade, and a workable solution still doesn’t seem to exist. I would truly appreciate if anyone could offer a workable solution/code to this problem. Thanks!