Danish Fapcache

A native Windows (WPF, .NET 8) client for e621: log in with your API key, search by tags, skip posts with unwanted tags, and batch-download in your chosen order.

Screenshots

Features

• Login via a Log in/Log out button and dialog — get an API key at https://e621.net/api_keys (also linked in the dialog). The key is stored encrypted with Windows DPAPI under %APPDATA%\DanishFapcache; logging out deletes it.
• Tag pills: hitting space commits a typed tag into a removable pill; skip-tag pills are tinted red. An optional date range narrows results (API metatags; local created_at filter in export mode).
• Result actions: hover for full metadata, double-click for a resizable preview window, right-click to download one post or open it on e621.
• Gallery mode: browse downloaded folders with thumbnails — paged 500 at a time so 100k-file libraries stay fast — with filename filtering, type filtering (images/animations), sorting (newest/oldest/recently downloaded/natural A–Z), a fullscreen WebView2 viewer (webm/mp4/gif included, with remembered volume), and a slideshow over the whole filtered set, not just the visible page.
• Slideshow niceties: controls and cursor stay out of the way while it runs, images change with a subtle dip-to-black (manual browsing stays instant), + / − adjust the speed on the fly, and with play-through (⇥) on, videos advance when they finish and animated gifs finish their loop first — short loops repeat until your delay is filled.
• Installer & updates: make-installer.sh builds a per-user MSI (Start-menu shortcut, Add/Remove entry, no elevation) and stages it with a version.json manifest in the repo, which doubles as the update channel — the app checks it on startup and offers one-click updates.
• Artist blacklist in Options: their posts never appear, from either source.
• Search with include tags and skip tags; order by latest, oldest, most popular (order:score), or most favourited (order:favcount).
• Two sources: live API queries, or e621's daily DB export — a ~2 GB posts.csv.gz dump downloaded once and imported into a local indexed database (a couple of minutes, once per dump), after which even huge searches answer in milliseconds and cost the site nothing.
• Downloads panel showing each file's thumbnail, name, size, resolution, score, favourites, rating, and live status/progress.
• Options: User-Agent template, API request interval (clamped to e621's 2 req/s hard limit), delay between downloads, download folder, and filename template ({id} {artist} {md5} {score} {rating} {ext}).
• Files land in Downloads\DanishFapcache\<tag-slug>\ by default; already downloaded files are skipped.

Building from WSL

The app is cross-built from Linux with EnableWindowsTargeting and run on the Windows side (needs the .NET 8 Windows Desktop runtime there):

./deploy.sh            # publish, copy to %LOCALAPPDATA%\DanishFapcache, launch
./deploy.sh --no-launch

Being a good API citizen

The client sends a descriptive User-Agent identifying the app (your username is included only if you add {username} to the template yourself), paces API calls at ~1/sec by default, and never exceeds the 2 req/s hard limit — the Options dialog clamps whatever you enter.