tumbler for one-shot use / as a component
With the recent support for sh_thumbnails in Thunar there is now good need to create shared thumbnails. For disk-based media, this is well covered in #12.
In other cases, especially for media not written the same way as they are read, this can need bespoke mechanisms -- when building a photo CD (do these still exist?) the burner may create them, or (as is my concrete case) a file server may create shared thumbnails as files come in (say, via web upload or git push), even though they don't look like a removable medium to the server (which makes it hard to go the #12 route), or the files may not even be arranged in the same layout as normally (which is my case; the file server has them in a kind of object store and'd serve sh_thumbnails).
For these cases, it would be convenient to utilize mechanisms already well established in tumbler (the internal thumbnailer, the solib based ones and the .thumbnailer ones) without using the thumbnail management Dbus API.
Is there any existing way to use tumbler like that (as an executable or library)? Would it be within the scope to add one?
In a make-a-wish scenario, the thumbnailer could provide an interface like this: Be a standalone executable, take a file per file name argument (ideally also per open file handler), and produce files in a given sh_thumbnails folder, with parsable output as to which files were created. The input parameters file name and mtime should be overridable, because the input may not necessarily look exactly like it's perceived in the read form of the shared medium.
If this is out of scope for tumbler, I suppose the best alternative is to write custom thumbnailers for these. To avoid duplicate work that would probably use the same .thumbnailer files (which'd be relatively straightforward) and .so plugins (which I think is the only current use for the tumbler library API).