Support AppImage

[probonopd]

More and more upstream projects are already distributing upstream-provided, official AppImages.

Supporting AppImage in Liri OS App Center would have, among others, these advantages:

• Immediate availability of a growing number of applications, directly from their upstream application authors, on the day the software is released
• No unpacking or installation necessary
• No root needed
• No system libraries changed
• Works out of the box, no installation of runtimes needed (unlike Snap and Flatpak)
• Optional desktop integration with appimaged
• Optional binary delta updates, e.g., for continuous builds (only download the binary diff) using AppImageUpdate
• Can optionally GPG2-sign your AppImages (inside the file)
• Works on Live ISOs (unlike Flatpak)
• Can use the same AppImages when dual-booting multiple distributions

[plfiorini]

I have a few questions @probonopd:

1. Can you elaborate on why Flatpak won't work on live images?
2. Is there a library with an API to install, update, uninstall and list installed AppImages?

[probonopd]

Can you elaborate on why Flatpak won't work on live images?

It's just an observation. I have been trying to test Flatpak since years, but since all I run is Live ISOs, I have not succeeded. Tried Ubuntu 17.10 a couple of days and it gave me an error about xattrs.

Is there a library with an API to install, update, uninstall and list installed AppImages?

AppImages do not need to be "installed". They are managed by drag-and-drop in the file manager. So, the file manager really is the way to "install, update, uninstall and list" AppImages. Especially since you can put them anywhere - including network shares, USB thumbdrives, etc.

That being said, there are software center applications like NX Software Center and OCS-Store that integrate the download and update of AppImages. They are using libappimage and libappimageupdate for that.

Then there is the optional appimaged daemon which monitors certain directories and integrates AppImages with the system (e.g., menus) if placed there.