Files
mangaBookmark/backend/AGENTS.md
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sulthan 13e8e73da7 feat(backend): Discord OAuth login with DB-backed sessions (#23)
The browser UI signs in with a Discord authorization code grant
(identify + guilds.members.read) instead of a shared password. Guild
membership is the gate; the owner's Discord ID is the only identity
allowed in while registration is closed. Sessions become rows in a
sessions table with opaque random ids — the cookie carries only the id,
looked up and expiry-checked per request — so deleting a row revokes a
session. HMAC cookie signing, its derived key, and WEB_PASSWORD are
gone, and no replacement signing secret is introduced (ADR-0002).

Discord's API base is configurable (DISCORD_API_BASE); the full flow is
tested through the real router against a local stub, including the
form-encoded token exchange Discord rejects if sent as JSON.
2026-08-08 08:31:46 +07:00

120 lines
8.5 KiB
Markdown

Guidance for OpenCode (and Claude Code) working under `backend/`. See root `AGENTS.md` for the project-wide architecture diagram, hard constraints, and design system.
- **Backend** (`backend/`): stdlib `net/http` (handful routes, no framework) + Postgres over `jackc/pgx/v5` (pure Go, `CGO_ENABLED=0` -> static binary -> distroless/scratch image). Reverse proxy terminates TLS; Go service listens plain `:8080`.
Single binary, split into packages under `backend/internal/`: `store`
(Bookmark type, Postgres persistence, migration runner), `latest` (background
poller, site parsers, TLS fetcher), `session` (cookie signing, login
rate limiter), `httpmw` (Auth/Gzip/CORS middleware), `api` (JSON
bookmark handlers), `userscript` (userscript-serving handler), `web`
(browser UI handler + `templates/` + `static/`, `go:embed`-ed).
`backend/main.go` is the composition root — the only place that wires
packages together into `newRouter`. Root-level `*_test.go` hold
integration tests that exercise the full router; unit tests for a
package live beside it under `internal/`.
- **Schema is migration-owned.** `internal/store/migrations/*.sql` is
`go:embed`-ed and applied on every start by `store.migrate`: one numbered
file per change, one transaction each, versions recorded in
`schema_migrations`. Files are **append-only** — editing an applied one
changes nothing on a database that already ran it. No column probing, no
data-fixup migrations: both were SQLite-era machinery and are gone.
- **Tests need Docker.** `internal/pgtest` starts one `postgres:17-alpine`
container per test binary (`TestMain` -> `pgtest.Main`) and hands each test
its own database (`pgtest.URL(t)`). A package whose tests touch the store
must have that `TestMain`.
- **Single-owner store, three tables.** `readers` is keyed by Discord user ID
and carries the SHA-256 of the owner's userscript token (the global
`API_TOKEN` today; issue #22). The seed creates exactly one row at startup.
`series` keyed `(site, series_id)`
(`asura`|`demonic`|`comix`|`kagane`|`novelfull`|`lightnovelworld`) owns the
shared facts — title, cover, canonical URL, `kind` (`manga`|`novel`),
Latest Chapter, `latest_checked_at` — and `bookmarks` holds only what
differs between readers: progress, favourite, lifecycle bucket,
`updated_at`. A bookmark is keyed `(reader_id, site, series_id)` — no
surrogate id; the wire `key` is derived as `site:series_id` on read — and
every store read/write is scoped to the reader it names. `Store.OwnerID()`
is the seeded owner, which every handler passes while the global token is
still the only credential. Sync **last-write-wins**; the wire format stays
flat (ADR-0004). `Store.Upsert` decomposes one flat body across two tables
and enforces the ownership rule: client `title`/`series_url`/`cover` are
written only when the series row is new (ADR-0003).
- **Endpoints:** `GET /bookmarks`, `PUT /bookmarks/{key}` (upsert; see `updated_at` rule below), `DELETE /bookmarks/{key}`, `GET /healthz` (no auth).
- **Web UI:** same binary serve the browser UI on a second
hostname — `GET /` (list, or login page when no session),
`GET /auth/discord` + `GET /auth/discord/callback` (Discord OAuth,
ADR-0002), `POST /logout`, `GET /static/*`, htmx fragment endpoints
under `/ui/*`. Templates + assets `go:embed`-ed under
`backend/internal/web/`, so `backend/Dockerfile` must copy the whole
`internal/` tree, not just `*.go`. Sessions are rows in the `sessions`
table: the cookie carries only an opaque id, looked up (and expiry-
checked) on every request, and deleting the row revokes the session.
The owner's Discord ID is the only identity that can sign in while
registration is closed. UI mutations read-modify-write
through `Store.Get` + `Store.Upsert` so `updated_at` rule stays one
place. See `docs/superpowers/specs/2026-07-25-web-ui-design.md`.
**Design-tool caveat:** templates link `/static/style.css` root-absolutely
(correct — served from `/`), but impeccable detector resolves
stylesheet href with `path.resolve(fileDir, href)`, drops directory
on leading `/` and silently skip file. Relative href don't help
either: template's directory isn't its served path. So
`detect.mjs backend/internal/web/templates` reports **false clean** —
always pass `backend/internal/web/static` too. One finding there,
`overused-font` on "Instrument Serif", deliberate identity choice, not debt.
- **Every action that moves series out of list is confirm-gated.**
Archive, finish, remove each open own `.confirm-row` disclosure
(`toggleConfirmRow(key, kind)` in `filter.js`, `kind` ∈
`archive|finish|remove`); restore fire instantly since it's the reversal.
Remove's row wear ember wash, two reversible ones wear `.calm` grey.
`--ember` stay reserved for new-chapter signal: busy bar and inline
error use `--mute`.
- **Latest-chapter poller:** ticker goroutine in same binary re-check
each bookmarked series' newest published chapter from backend's own
network access, so `latest_chapter` stay fresh when user not
browsing. Second, parallel signal — userscript keep own
`maybeCaptureLatestOnSeriesPage`/`backgroundRefreshLatest` logic unchanged.
Two independent clocks: per-series cooldown (`series.latest_checked_at`,
enforced by `Store.DueForLatestCheck`'s WHERE clause) and wake interval.
The poller walks **Series, not Bookmarks** — a series referenced by several
bookmarks is fetched once per cycle, and the due queue orders
`reader_count DESC, latest_checked_at ASC` (ADR-0003). Series row stamped
*before* fetch so broken series wait out full cooldown instead of retrying
every tick; found chapter written straight to the series row via
`Store.SetLatestChapter`, so a bookmark's `updated_at` — and the list
order — is never touched.
Fetches use `bogdanfinn/tls-client` with Chrome profile as defence in depth
against fingerprint-based blocking; any failure log and skip. kagane and
novelfull sit behind Cloudflare JavaScript challenges the TLS client can't
clear, so they are browser-only: fetched over CDP via `BROWSER_WS_URL`, and
simply not polled when that's unset. See
`docs/superpowers/specs/2026-07-26-server-latest-chapter-polling-design.md`.
The poller's series write is a single-column UPDATE
(`Store.SetLatestChapter`), not a read-modify-write of the whole bookmark:
it cannot revert read progress or move `updated_at`, so the old
stale-re-read race is gone with the Get+Upsert flow.
- **`updated_at` drives list order, so moves only on real reading progress:** server apply its timestamp when row new or `last_chapter_num` changes, else keep stored value — favouriting series or recording newly published chapter must not reorder list. `PUT` therefore returns row **as stored**, clients must adopt that response rather than own payload. See `plans/2026-07-25-bookmark-list-favorites-design.md` §4.
- **Lifecycle buckets:** `status` on each bookmark is `reading` | `archived` |
`finished`, orthogonal to `favorite`. Archived and finished appear only in
own tab — not in All, Updated, Favourites, or recent strip. Poller keeps
checking archived series and skip finished ones. `finished` settable
only from web UI; `PUT /bookmarks/{key}` reject it with 400.
**Empty incoming status means "keep stored one"** — resolved on the
`VALUES` side of `Store.Upsert`, not conflict clause, since
`excluded.*` is post-evaluation row and default applied there would
wipe bucket on every PUT from client that predates column. See
`docs/superpowers/specs/2026-07-27-status-buckets-design.md`.
- **Config via env:** `API_TOKEN`, `OWNER_DISCORD_ID` (seeds the owner Reader;
required), `ALLOWED_ORIGINS` (comma list),
`DATABASE_URL` (Postgres connection URL, required — no default),
`PORT` (default `8080`), `DISCORD_CLIENT_ID`/`_CLIENT_SECRET`/`_GUILD_ID`/
`_REDIRECT_URI` (required; Discord OAuth for the browser UI),
`DISCORD_REQUIRED_ROLE` (optional role gate, empty by default),
`DISCORD_API_BASE` (default `https://discord.com/api/v10`),
`LATEST_CHAPTER_POLL_ENABLED`/`_COOLDOWN`/`_INTERVAL`/`_BATCH`/`_STAGGER`
(background latest-chapter poller; defaults on, `1h`/`10m`/`14`/`20s`).
`USERSCRIPT_PATH` and `NOVEL_USERSCRIPT_PATH` (files served at
`/u/{token}/manga-bookmark.user.js` and `/u/{token}/novel-bookmark.user.js`,
defaults `/userscript/manga-bookmark.user.js` and
`/userscript/novel-bookmark.user.js`, both supplied by bindmount).
`BROWSER_WS_URL` (headless-shell CDP endpoint for kagane and novelfull;
unset disables browser polling and leaves those sites to the userscript
alone).