Support for sound

[MyriaCore]

This stackoverflow post implies that notification managers can actually control sounds. Not 100% sure if many applications use this, or if they just play the sounds themselves, but that's the deal. This is from the hints table:

   +------------------------------------------------------------------------+
   |       Name       | Value Type |              Description               |
   |------------------+------------+----------------------------------------|
   | "urgency"        | byte       |   The urgency level.                   |
   |------------------+------------+----------------------------------------|
   | "category"       | string     |   The type of notification this is.    |
   |------------------+------------+----------------------------------------|
   |                  |            |   This specifies the name of the       |
   |                  |            | desktop filename representing the      |
   |                  |            | calling program. This should be the    |
   |                  |            | same as the prefix used for the        |
   | "desktop-entry"> | string     | application's .desktop file. An        |
   |                  |            | example would be "rhythmbox" from      |
   |                  |            | "rhythmbox.desktop". This can be used  |
   |                  |            | by the daemon to retrieve the correct  |
   |                  |            | icon for the application, for logging  |
   |                  |            | purposes, etc.                         |
   |------------------+------------+----------------------------------------|
   |                  |            |   This is a raw data image format      |
   |                  |            | which describes the width, height,     |
   | "image_data"     | (iiibiiay) | rowstride, has alpha, bits per sample, |
   |                  |            | channels and image data respectively.  |
   |                  |            | We use this value if the icon field is |
   |                  |            | left blank.                            |
   |------------------+------------+----------------------------------------|
   | "sound-file"     | string     |   The path to a sound file to play     |
   |                  |            | when the notification pops up.         |
   |------------------+------------+----------------------------------------|
   |                  |            |   Causes the server to suppress        |
   |                  |            | playing any sounds, if it has that     |
   | "suppress-sound" | boolean    | ability. This is usually set when the  |
   |                  |            | client itself is going to play its own |
   |                  |            | sound.                                 |
   |------------------+------------+----------------------------------------|
   |                  |            |   Specifies the X location on the      |
   | "x"              | int        | screen that the notification should    |
   |                  |            | point to. The "y" hint must also be    |
   |                  |            | specified.                             |
   |------------------+------------+----------------------------------------|
   |                  |            |   Specifies the Y location on the      |
   | "y"              | int        | screen that the notification should    |
   |                  |            | point to. The "x" hint must also be    |
   |                  |            | specified.                             |
   +------------------------------------------------------------------------+

It'd be cool to try to implement this functionality, specifically sound-file and suppress-sound.

[phuhl]

As a general reference (you might have stumbled upon it already), https://developer.gnome.org/notification-spec/ is the official source for the protocol, that we need to implement.

I'd like this feature. But takes some effort.

[S-NA]

The spec hosted on gnome.org 404s now. I used https://specifications.freedesktop.org/notification-spec/latest/ar01s09.html instead.

I have a rough version of sound support (it currently does not respect if do not disturb is set).
You can find it here: https://github.com/S-NA/linux_notification_center/commit/7e204b18991388f6380a773dfe59e1ac3a827a64.patch

I will probably get around to adding do not disturb, eventually. Though I am not sure if the approach of spawning an external player is the correct one. Feedback is appreciated.

[phuhl]

Intresting, this looks pretty good. Would you mind opening a Draft PR?

For playing sound, maybe this could be interesting: https://wiki.haskell.org/SDL