Add support for appimage

[jnweiger]

Seen with nemo 5.6.3 on Linux Mint

• User downloads an appimage through e.g. firefox.
• Firefox shows the finished download and the user clicks on it, in order to run the appimage.
• A window named Library (not sure if that is from nautilus or nemo or unrelated) shows
  

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• User launches nemo, and navigates to the Downloads folder.
• nemo also does not offer anything useful:
  

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Expected behaviour:

• appimage is a well known binary format nowadays.
• Instead of "Choose a program", nemo should offer "Make executable" and maybe remind the user about trusted and untrusted sources.
• Once the user clicks on Make executable, the button could change to "Start appimage" and maybe with a reminder to move the appimage to better location.

I understand that nemo's current behaviour is in sync with other file browsers like nautilus.
But I don't understand, why that obvious (and probably simple) enhancement is not discussed more.

[jnweiger]

Further enhancement ideas:

• use the icon embedded in the appimage, instead of a generic gear icon
• capture stdout/stderr, and when an appimage quits immediately, display a popup. A common first time user issue is

dlopen(): error loading libfuse.so.2

AppImages require FUSE to run. 
You might still be able to extract the contents of this AppImage 
if you run it with the --appimage-extract option. 
See https://github.com/AppImage/AppImageKit/wiki/FUSE 
for more information

[mtwebster]

fyi, you can install xapp-appimage-thumbnailer for icons.

[jnweiger]

Thanks for that hint. I found an installable package at https://github.com/mttbernardini/appimage-thumbnailer/releases
Hmm, seems it chooses the lowest possible resolution, but better than nothing:

[mtwebster]

I'm not familiar with that one. Is xapp-appimage-thumbnailer not installable?
On Mint 21,

apt install xapp-appimage-thumbnailer

[jnweiger]

Here is how openSUSE Leap 15.4 (KDE desktop) does it:

[Jeremy7701]

I would not want appimages (or indeed flatpacks) polluting a LMDE installation, either deliberately or as a result of some automatic upgrade process.
It would need to be something that was disabled by default.

[jnweiger]

I am not familiar with the differences between LMDE and "good old" Linux Mint. For me Mint has been a distribution with a good focus on the kind of usability that is needed in my environment. I recommend Mint to students a lot. I would not mind to have helpful usability disabled by default, as long as there is a hint (if that path gets approval).

I don't want to turn this into a political discussion, but I don't see an appimage as pollution these days.
In the past it was a horrible thought to have many copies of (slowly aging) libraries hidden in appimage. But in my experience that is not a big issue any more. Updated appimages are often released quickly (e.g. directly at github).
Upgrade / downgrade / uninstall are so transparent and straightfoward, that as an end-user one can develop a good trust in the reliability of an appimage.

[Jeremy7701]

Personally, I trust software from Debian Stable and Mint (where written for LMDE), but I couldn't have the same degree of trust for some (probably Ubuntu) application enclosed in a app image etc.
Since I'm running a basically Debian system, I'd consider it safe to install Debian packages - but very un-safe to install Ubuntu packages.
But different people are obviously going to have different viewpoints.
Functionally, Mint and LMDE are virtually identical, except that Mint is built on a Ubuntu base whilst LMDE is built on a Debian base.

[edgarogh]

Great suggestion, this has bothered me for a few years!

This should actually be implemented for all ELF executables too really. .run is also a pretty common file extension for programs that are supposed to be chmoded and run as-is. If an ELF header is found, the option to launch as-is should be suggested.

I've never ever contributed to any of Mint's software, but if this sounds like a not-too-unapproachable first issue, I'm willing to give it a try.

[AtomicRobotMan0101]

Came here today to make this EXACT recommendation.

This week Ive migrated one noob off Windows and another off MacOS and both were stuck after downloading an appImage.

By having a trivial launcher which asks the user WHAT they'd like to do, for this very specific thing, seems like a bloody good idea.