Reliable path for add-on data storage

Question

How can I use the python API to find the most reliable location that an add-on can use to store data like images, assets, etc. automatically?

It's important that this location:

• doesn't change for different versions of blender
• doesn't get deleted on system reboot like some temp folders
• is available on every OS

One option I've found is to use bpy.utils.resource_path('USER') which ends in the version number (on windows C:\Users\blah\AppData\Roaming\Blender Foundation\Blender\2.78), but then do a relative jump to the folder above it. Is there a better way?

Answer 1

Set it once in the addons User Preferences.

Suggest using a property in addon preferences The user chooses the folder. I had deleted this answer, as it is not "automatic", however setting a storage location once, is IMO, not a huge overhead.

Modify the script in link with a folder property

class ExampleAddonPreferences(AddonPreferences):
    # this must match the addon name, use '__package__'
    # when defining this in a submodule of a python package.
    bl_idname = __name__

    assets_folder = StringProperty(
            name="Assets Folder",
            subtype='DIR_PATH',
            )

    def draw(self, context):
        layout = self.layout
        layout.label(text="This is a preferences view for our addon")
        layout.prop(self, "assets_folder")

And then when you need to access it

    preferences = context.preferences
    addon_prefs = preferences.addons[__name__].preferences

    assets_folder = addon_prefs.assets_folder

Answer 2

What about os.path.expanduser('~')?

From what i read on https://docs.python.org/2/library/os.path.html it should work for all UNIX system and Windows. Moreover it is assured that the user have write permission in it.