[GalleryDLInfo] gallery-dl downloaded metadata scraper

[spaceyuck]

Scraper type(s)

• performerByName
• performerByFragment
• performerByURL
• sceneByName
• sceneByQueryFragment
• sceneByFragment
• sceneByURL
• groupByURL
• galleryByFragment
• galleryByURL
• imageByFragment
• imageByURL

Examples to test

Includes a test suite using example data based on a few different structures encountered in the wild

Short description

gallery-dl has a few interesting options (--write-info-json and --write-metadata), that produce per gallery and per file JSON metadata files while downloading. This scraper implements processing these files.

These could be very helpful, if the source is for whatever reason no longer scrapable with existing scrapers (cloudflare, API ban, content removed by uploader, ...).

There seems to be somewhat of a consensus on the structure, but there are a lot of site-specific differences, so it's once again a best effort approach, which may or may not work well for any of the hundreds of sites supported by gallery-dl.

closes #2240

This scraper includes unit tests and test data, right now these are placed right besides the scraper, I don't know if they should maybe go somewhere else.

[spaceyuck]

OK, reworked some stuff, no more site-specific code paths or references.

But as already said, it's only as generic as far as there is a consensus between implementations on their side. Some fields have a few different guesses of what they might be named, but it remains a bit of whack-a-mole.

[DogmaDragon]

I don't think including test and test data serves any purpose for end users.

[spaceyuck]

I don't think including test and test data serves any purpose for end users.

I have moved the tests and test data into a sub-folder for the scraper under a new top folder scraper-tests, this should keep all tests code and test data away from the actual scrapers while still mirroring the directory structure, so associations remain clear.