mangobot

A Discord bot that watches manga series for new chapters and posts them to a channel, pinging whoever subscribed.

How it works

A node-schedule job runs every 30 minutes, fetches the latest chapter for every series in the database, and announces anything newer than what is stored. Members subscribe by reacting to a numbered catalog message.

Every source is a plain HTTP call — there is no browser:

Source	How it is read
WeebCentral	the per-series RSS feed at /series/<id>/rss
AsuraScans	the server-rendered chapter list in the page's Astro island props
MangaDex	the public JSON API

Adding a source means adding an entry to SCRAPERS in src/fetch-manga.ts. That table is satisfies Record<SeriesSource, Scraper>, so a new value in the Prisma enum will not compile until it is routed.

Both scraped sources sit behind Cloudflare and enforce a burst quota, so requests are paced (see REQUEST_GAP_MS in each scraper) and WeebCentral retries on 429.

Web UI

The same process serves a catalog manager on port 3000 (PORT to change): view, add, and remove series. It is a React SPA bundled by Bun at runtime — no build step — sharing src/series-service.ts with the Discord commands, so both surfaces behave identically. No auth.

For local frontend work, leave DISCORD_TOKEN empty (web-only mode) and run bun run scripts/seed-dev.ts once to create a guild for the API to manage.

Running it

Requires Bun (the runtime) and Node (the Prisma CLI). pnpm is pinned via the packageManager field — use corepack, or install it yourself at the same version.

cp .env.template .env      # then fill in DATABASE_URL and DISCORD_TOKEN
pnpm install
pnpm generate              # emits the Prisma client into src/generated (not committed)
pnpm migrate               # applies migrations
pnpm start

pnpm typecheck and pnpm format:check are what CI runs, alongside a Docker build.

Deployment

docker compose up --build, or build the image and point it at an external Postgres. start.sh applies migrations and then execs the bot; it exits non-zero if migrations fail rather than starting against an unmigrated database.

The image exposes port 3000 for the web UI; compose publishes it.

Layout

src/
  index.ts            entrypoint: bot, web server, scheduled update loop, event handlers
  series-service.ts   add/remove/list series — the one implementation behind commands and API
  fetch-manga.ts      routes each series to its scraper
  scrapers/           one module per source, all returning ScraperResult
  commands/           !add, !delete, !setcatalog, !setupdates, !subscriptions, !updatecatalog
  web/                the web UI: server.ts (Bun.serve routes), api-types.ts (wire contract), React SPA
  catalog-line.ts     renders and parses the catalog message (both halves, one file)
  db.ts               re-exports the generated Prisma client
  prisma.ts           the configured client — the only place the driver adapter is wired
scripts/              one-off maintenance scripts, safe by default, --apply to write

Gotchas worth knowing

• Chapter labels are not uniform. WeebCentral publishes Chapter 51, No. 107, Episode 267 and Mag Version 236. Only the trailing number is reliable; reading a fixed token position froze One-Punch Man on the literal string "Version".
• Scraped titles drift. Series are joined back to database rows by URL, never by title — an upstream re-romanisation silently froze two series for months.
• latestChapter only advances once a message is actually delivered, otherwise a failed send would skip that chapter permanently.