Editing Booru Bulk Downloader (Userscript)

'''Booru Bulk Downloader''' is a browser userscript written by [[August Casso]] that puts download controls directly onto booru gallery pages, so full-resolution originals can be pulled in bulk without ever opening a post page.

This is the one piece of software in the archive written for a general audience rather than for August's own work: it exists because scraping a gallery one post at a time is a waste of an evening.

== The Script ==

* '''Version:''' 1.0.1
* '''License:''' MIT
* '''Size:''' ~44 KB / 1,122 lines
* '''Runs on:''' Tampermonkey, Greasemonkey, Violentmonkey

=== Install ===

* '''Greasy Fork:''' [https://greasyfork.org/en/scripts/599354-booru-bulk-downloader greasyfork.org/en/scripts/599354-booru-bulk-downloader]
* '''GitHub (canonical source):''' [https://github.com/Reduxed/booru-bulk-downloader github.com/Reduxed/booru-bulk-downloader]
* '''OpenUserJS:''' [https://openuserjs.org/scripts/reductedharmgmail.com/Booru_Bulk_Downloader openuserjs.org/scripts/reductedharmgmail.com/Booru_Bulk_Downloader]

== What It Does ==

A '''checkbox''' and a '''download arrow''' land on every thumbnail in a gallery. The checkbox adds an image to the batch — shift-click takes a range. The arrow grabs that one image's full-resolution original immediately. A draggable panel in the bottom-right corner holds the running count, '''Download selected''', '''Save as .zip''', Select all / Clear / Retry failed, and the filename options. '''Alt+D''' downloads the selection; '''Alt+A''' selects everything.

== 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.

== Filenames Built From Tags ==

Template tokens: <code><nowiki>{{tags}}</nowiki></code> <code><nowiki>{{id}}</nowiki></code> <code><nowiki>{{rating}}</nowiki></code> <code><nowiki>{{site}}</nowiki></code> <code><nowiki>{{user}}</nowiki></code> <code><nowiki>{{md5}}</nowiki></code> <code><nowiki>{{ext}}</nowiki></code> — default <code><nowiki>{{tags}}</nowiki>__<nowiki>{{id}}</nowiki></code>. The extension comes from the real file URL, not the thumbnail. The sanitizer strips <code>\ / : * ? " &lt; &gt; |</code> and control characters, collapses whitespace, trims trailing dots, guards Windows reserved names (<code>CON</code>, <code>LPT1</code>), truncates on a tag boundary at roughly 170 characters, and suffixes <code>_2</code> on collisions inside a batch.

== Download Engine ==

<code>GM_download</code> first, for a real download-manager entry with the exact filename requested; then <code>GM_xmlhttpRequest</code> → blob → object URL → <code>&lt;a download&gt;</code>. A bare <code>&lt;a download&gt;</code> is deliberately never used on its own, because the attribute is ignored cross-origin and would simply navigate the tab. Concurrency is a limited pool (default 3), with per-item success/error state and a retry action.

== What Was Verified, And What Was Not ==

Markup and APIs were checked against live sites rather than assumed:

* '''safebooru.org''' — <code>span.thumb &gt; a &gt; img.preview</code>, tags already present in <code>img[title]</code>; dapi JSON fields confirmed.
* '''konachan.net''' — <code>ul#post-list-posts &gt; li#p&lt;id&gt;</code>, <code>post.json?tags=id:N</code> answered 200. This one exposed a real trap: the true original is <code>a.original-file-unchanged</code> → <code>/image/…</code>, while <code>a#highres</code> is only the converted <code>/jpeg/</code> "larger version" and <code>og:image</code> is the <code>/sample/</code>. The selector list prefers <code>/image/</code> accordingly.
* '''Not verified live:''' Danbooru, Gelbooru.com and e621 — written from their published conventions, and they degrade to the HTML tier if the faster tiers miss.

Building it also caught a junk <code>?</code> pseudo-tag from the tag-link scraper, an operator-precedence bug in the e621 id resolver, and a dead generic fallback.

== Known Gotchas ==

* '''Chrome blocks the second automatic download''' unless ''Automatic downloads'' is allowed for the booru host in site settings. <code>GM_download</code> dodges most of this, not all of it.
* '''Gelbooru.com and rule34.xxx now require an API key''' for the dapi. Paste your <code>api_key</code> and <code>user_id</code> into the script's options, or let it fall through to the slower, key-free HTML tier.

== Publication ==

Published in October 2026 to three hosts, each independently verified rather than assumed:

* '''Greasy Fork''' — listing live, served file matches the release apart from the two <code>@updateURL</code> / <code>@downloadURL</code> lines Greasy Fork injects.
* '''GitHub''' — <code>Reduxed/booru-bulk-downloader</code>, public, the canonical source.
* '''OpenUserJS''' — served source confirmed byte-identical to the release, 44,970 bytes and 1,122 lines.

The OpenUserJS upload initially failed with <code>400 Selected file is not JavaScript.</code> despite the correct filename and byte count. The cause was the multipart part type: the attached File reported <code>text/plain</code> because the staged resource used the default MIME. Staging it with a JavaScript MIME made the File report <code>text/javascript</code> and the upload went straight through. The bytes were never the problem.

== See Also ==
* [[All Billing LLC]]
* [[August Casso]]

[[Category:Augwiki]]