How to check XDG_CACHE_HOME

Hi,

I want to write a cache file to speed up later runs of the appimage. For this I want to check XDG_CACHE_HOME and have a fallback variable for when it is not set.

In bash the check would look like this:

 echo ${XDG_CACHE_HOME:-$HOME/.cache}

Documentation for this is here: https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html

Setting that in the recipe results in wrong path descriptions.

    runtime:
      path_mappings:
        - /dev/:$APPDIR/dev
      env:
        GST_PLUGIN_SYSTEM_PATH_1_0: '${APPDIR}/usr/lib/@CMAKE_SYSTEM_PROCESSOR@-linux-gnu/gstreamer-1.0' 
        GST_REGISTRY: "${XDG_CACHE_HOME:-$HOME/.cache}/application/gstreamer-cache.bin"

That writes to /home/user/-/home/user/.cache/application/. Is there a way to have such a check or is it simply impossible?

[azubieta]

This is now documented at https://appimage-builder.readthedocs.io/en/latest/advanced/helpers.html

Closing the issue, please feel free to reopen if needed.

[azubieta]

Is there any documentation as to what helpers exist and what they do?

Sorry for that, right now the only documentation is the code. It would be great if someone could assist me on documenting them. These are the helpers available: https://github.com/AppImageCrafters/appimage-builder/tree/master/appimagebuilder/modules/setup/helpers