Monitoring keyboard with uinput backend does not work

[RillingDev]

Description Using the uinput backend and running the script as root does never fire any keyboard events, both under wayland and XOrg.

Platform and pynput version

• Arch Linux (Kernel 5.14.2)
• DE: KDE Plasma 5.22.5
• XOrg server: 1.20.13
• Python: 3.9.7
• pynput: 1.7.3

To Reproduce 1) Create a script with the example code from https://pynput.readthedocs.io/en/latest/keyboard.html#monitoring-the-keyboard 2) Start the script with root and the environment variables set to PYNPUT_BACKEND_MOUSE=dummy and PYNPUT_BACKEND_KEYBOARD=uinput 3) Input any keys 4) No logging takes place

Notes

• I was only able to test this on one device.
• I confirmed that the backend was determined correctly, as when starting without root, the error message in regards to having to use root is shown.
• I saw the note on https://pynput.readthedocs.io/en/latest/#forcing-a-specific-backend regarding limitations of the uinput backend, but it seems like listening to keyboard input should be supported?
• When using the default XOrg backend, everything works.
• I also ran the example code for injecting keys, which did send input events.

[moses-palmer]

Thank you for your report.

I have not been able to reproduce your issue, but according to a post on Stackoverflow, this might be caused by X interfering, although the post talks about a Wacom device. It appears that you are running your application under X. I myself use Wayland, which might be the reason I cannot reproduce.

Have you tried running under Wayland?

[RillingDev]

Thank you for the response!

I did try running it under Wayland (KDE Plasma under Wayland), with the same result (no keyboard events being received).

I did however notice that keys on my mouse such as Key.media_play_pause are received and logged by the example script, unlike my keyboards events. I did not find anything in the pyinput docs regarding selectingwhich device to listen to, so I was assuming that pyinput usually should listen to all devices, is this correct?

[moses-palmer]

I apologise for this late reply.

pynput does not listen to all devices; given the type of listener that is requested (well, only keyboard is supported) it will iterate over all input devices and select the first one with the required capabilities (see here).

This suggests that your mouse is found before your keyboard, and since your mouse is capable of keboard events, it will unfortunately be picked.

A workaround is to provide the---for now undocumented---keyword argument uinput_device_paths. It should be a list of paths to input devices such as ['/dev/input/event0'].

[RillingDev]

No worries, thanks for taking the time to assist me with this issue!

I explicitly specified a list of just the keyboard path like you suggested, and it works - events are detected properly!

[Apacelus]

Hey, so I'm having the same issue. How does this

A workaround is to provide the---for now undocumented---keyword argument uinput_device_paths. It should be a list of paths to input devices such as ['/dev/input/event0'].

translate into a command? Like this?:

sudo env PYNPUT_BACKEND_KEYBOARD=uinput PYNPUT_BACKEND_MOUSE=dummy python3 script.py --uinput_device_paths ['/dev/input/event0']

[moses-palmer]

uinput_device_paths should be specified as a keyword argument to the constructor.