Support Wayland clipboard

[maximbaz]

Hello, thanks for this awesome app!

I am trying to get clipbard integration working, and having several issues.

I'm running on Wayland, so I have clipboard-get-command = wl-paste -n in my config.

If the clipboard contains absolute path to a file, it works well 👍

If clipboard contains raw image data of type image/jpeg it crashes:

Details...

```sh $ wl-copy < Downloads/whackamole-900px.jpg $ wl-paste -l image/jpeg $ scli (and paste with :c) ..... File "/usr/bin/scli", line 2935, in keypress return self._keypress_cmd_mode(key, key_orig, txt) File "/usr/bin/scli", line 2892, in _keypress_cmd_mode self._cmds.exec(cmd, *args) File "/usr/bin/scli", line 3965, in exec return fn(*args) File "/usr/bin/scli", line 4103, in attach_clip files = clip.files() File "/usr/bin/scli", line 450, in files return callf(cmd, capture_output=True).stdout.split('\n') File "/usr/bin/scli", line 102, in callf proc = subprocess.run(cmd, **subprocess_kwargs) File "/usr/lib/python3.10/subprocess.py", line 503, in run stdout, stderr = process.communicate(input, timeout=timeout) File "/usr/lib/python3.10/subprocess.py", line 1149, in communicate stdout, stderr = self._communicate(input, endtime, timeout) File "/usr/lib/python3.10/subprocess.py", line 2038, in _communicate stdout = self._translate_newlines(stdout, File "/usr/lib/python3.10/subprocess.py", line 1026, in _translate_newlines data = data.decode(encoding, errors) UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte ```

If I copy an image from browser (right click - copy image), nothing happens.

Clipboard contents depend on a browser....

In Chromium:

```sh $ wl-paste -l text/x-moz-url text/html image/png $ wl-paste -n https://media.istockphoto.com/illustrations/mole-illustration-id1152565170?k=20&m=1152565170&s=612x612&w=0&h=INx4ZYSeEJBeT5-4pN_zRAoDnEDyU6pT-s9o94Xwuzo= 27 Whack A Mole Game Illustrations & Clip Art - iStock ```

In qutebrowser (QtWebEngine):

```sh $ wl-paste -l application/x-qt-image text/html text/x-moz-url image/png image/bmp image/cur image/icns image/ico image/jp2 image/jpeg image/jpg image/pbm image/pgm image/ppm image/tif image/tiff image/wbmp image/webp image/xbm image/xpm $ wl-paste -n ```

In Firefox:

```sh $ wl-paste -l text/html text/_moz_htmlinfo text/_moz_htmlcontext image/png image/bmp image/x-bmp image/x-MS-bmp image/x-icon image/x-ico image/x-win-bitmap image/vnd.microsoft.icon application/ico image/ico image/icon text/ico image/jpeg image/tiff image/avif SAVE_TARGETS $ wl-paste -n ```

--debug shows that in all those cases scli tries to parse those as file paths:

DEBUG:root:callf: `['wl-paste', '-n']`
DEBUG:root:callf: <img src="https://media.istockphoto.com/illustrations/game-to-hit-the-mole-illustration-id1153033854?k=20&amp;m=1153033854&amp;s=612x612&amp;w=0&amp;h=qJ-V8PXl9n8w5351vniVy1b9cLdqFHXMhxI5O2vQ44s=" alt="27 Whack A Mole Game Illustrations &amp;amp; Clip Art - iStock"/>
WARNING:root:send_message: Attached file(s) does not exist.
DEBUG:root:callf: `['wl-paste', '-n']`
DEBUG:root:callf: <meta http-equiv="content-type" content="text/html; charset=utf-8"><img src="https://media.istockphoto.com/illustrations/game-to-hit-the-mole-illustration-id1153033854?k=20&amp;m=1153033854&amp;s=612x612&amp;w=0&amp;h=qJ-V8PXl9n8w5351vniVy1b9cLdqFHXMhxI5O2vQ44s=" alt="27 Whack A Mole Illustrations &amp;amp; Clip Art - iStock" jsaction="load:XAeZkd;" jsname="HiaYvf" class="n3VNCb" data-noaft="1" style="width: 612px; height: 437px; margin: 0px;">
WARNING:root:send_message: Attached file(s) does not exist.

So it doesn't pick the right MIME-type from clipboard (obviously, as it just runs wl-paste -n as I told it to....)

For the last issue, do you think it's possible to teach scli to ask for the proper MIME type? On wayland, we can use wl-paste -l to list all available types, and select the type using -t like wl-paste -t image/jpg. Passing invalid type (jpg for a plaintext contents) will return an error. It works in Signal-Desktop, but they may be using some more native integration with clipboard.

Thanks for your help!

[exquo]

Thanks for the detailed tests! Related question about the Wayland clipboard: #150.

By default, scli tries to get the clipboard contents from xclip. As you note, when CLIPBOAND_GET_COMMAND is specified, its output is processed as one filepath per line. To adhere to this, a wrapper script around wl-clipboard is needed.

On scli's side, we can:

• Expand what scli expects from the output of CLIPBOAND_GET_COMMAND to check for: URLs, URLs embedded into HTML, etc. But the range of possible outputs is probably large.

• Add Wayland-specific code to treat it as another "special case" along with xclip. Wayland is becoming more widespread.

• Use a python library that can handle clipboard for multiple display managers. Better than rolling our own solution (further). In general we try to have minimal dependencies, but a library will be more reliable.

Signal-desktop probably has it easy, with Electron taking care of it for them :)

[maximbaz]

The first does sound complicated indeed, I cannot easily find all possible formats that we should be prepare to parse...

Having code specific for wl-clipboard is probably what I had initially in mind - not great in some ways, but simple in a sense that we can experiment with it, and request necessary MIME types and so forth.

If there is a good library we could use to abstract away this complexity, it's something also worth considering!

[exquo]

Implemented in #198