Editing Booru Bulk Downloader (Userscript) (section)

== The Hard Part: Finding The Original ==

The thumbnail <code>&lt;img&gt;</code> is never the original, and every booru hides the original differently. The resolver works in three tiers, cheapest first, cached per post id:

# '''DOM attribute''' — Danbooru puts <code>data-file-url</code> directly on the thumbnail. Zero extra requests.
# '''Site JSON API''' — <code>?page=dapi&amp;s=post&amp;q=index&amp;json=1&amp;id=N</code> (Gelbooru family) or <code>post.json?tags=id:N</code> (Moebooru family), returning <code>file_url</code> plus tags.
# '''Post page HTML''' — fetch the post page and read <code>og:image</code> and the tag links. Universal, and needs no API key. This is the tier that saves you when a site starts demanding credentials.

Site support is a data array — host regex, item selector, id/link/original extractors, tag source, and API shape — so adding a booru is one object plus one <code>@match</code> line. Anything exposing a <code>data-file-url</code>-style attribute is handled by a built-in generic adapter.