Manga Bookmark

Track manga read-progress on asurascans.com (a.k.a. asuracomic.net) and demonicscans.org from a phone (Bromite / mobile Chromium), synced to a self-hosted Go backend so bookmarks unify across both sites and all devices.

Two parts:

• backend/ — tiny Go (net/http + pure-Go SQLite) sync service. 4 routes, static binary, distroless container.
• userscript/manga-bookmark.user.js — single Bromite-compatible userscript (no GM_* APIs) that injects an on-page bookmark UI and syncs via fetch().

Bromite userscript (isolated world, Shadow DOM UI, localStorage cache)
    -- fetch() HTTPS -->  reverse proxy (TLS + CORS)  -->  Go net/http  -->  SQLite (volume)

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1. Backend

Config (env)

Var	Default	Notes
API_TOKEN	(required)	Bearer token shared with the userscript.
ALLOWED_ORIGINS	Asura + Demonic origins	Comma-separated CORS allowlist.
DB_PATH	/data/bookmarks.db	SQLite file location.
PORT	8080	Plain HTTP; TLS terminated by the proxy.

Endpoints

Method	Path	Auth	Description
GET	/bookmarks	Bearer	All bookmarks (single-user).
PUT	/bookmarks/{key}	Bearer	Upsert one series; returns the row as stored.
DELETE	/bookmarks/{key}	Bearer	Remove one.
GET	/healthz	none	200 ok.

key is <site>:<series_id> — e.g. asura:trash-of-the-counts-family-f886a8af or demonic:Infinite-Level-Up-in-Murim. Sync is last-write-wins.

updated_at orders the bookmark list, so it moves only on real reading progress: the server applies its timestamp when the row is new or last_chapter_num changes, and otherwise keeps the stored one. Favouriting a series or recording a newly published chapter therefore leaves the order alone. Because the timestamp a client sends is only a candidate, PUT echoes the row as stored and clients adopt that rather than their own payload.

Develop / test

cd backend
go test ./...                          # unit + handler tests
CGO_ENABLED=0 go build                 # static binary

Run the stack

cp .env.example .env
# edit .env: set API_TOKEN (openssl rand -hex 32)

docker compose up -d --build           # binds 127.0.0.1:8080

Smoke test:

TOKEN=$(grep '^API_TOKEN=' .env | cut -d= -f2)
curl -s localhost:8080/healthz                                    # ok
curl -s localhost:8080/bookmarks                                  # 401
curl -s -H "Authorization: Bearer $TOKEN" localhost:8080/bookmarks # []
curl -s -X PUT -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' \
  -d '{"title":"Test","last_chapter":"Chapter 1","last_chapter_num":1}' \
  localhost:8080/bookmarks/asura:test-1
curl -s -i -X OPTIONS -H 'Origin: https://asurascans.com' \
  -H 'Access-Control-Request-Method: PUT' \
  localhost:8080/bookmarks/asura:test-1 | grep -i access-control   # 204 + CORS headers

Deploy behind your reverse proxy

Route https://manga-api.<domain> → the service on :8080 (TLS at the proxy).

• Host proxy (nginx/Caddy on the host): the base compose already binds 127.0.0.1:8080; point the proxy proxy_pass http://127.0.0.1:8080;.

• Docker proxy (Traefik/nginx in a container on its own network): use the override, which drops the published port and joins the shared network:

  docker network create proxy            # once, if it doesn't exist
  docker compose -f docker-compose.yml -f docker-compose.prod.yml up -d --build
  

  Set PROXY_NETWORK in .env if your network isn't named proxy.

Verify: https://manga-api.<domain>/healthz returns ok over valid TLS (no mixed-content), and an OPTIONS preflight from a real site origin returns the CORS headers.

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2. Userscript

Configure

Edit the config block at the top of userscript/manga-bookmark.user.js:

const API_BASE = "https://manga-api.<domain>"; // no trailing slash
const API_TOKEN = "<same token as backend>";

The token lives in the userscript's isolated world — the manga sites' own JS cannot read it.

Install on Bromite (mobile)

Bromite runs Chromium's native userscript engine (no Tampermonkey needed):

1. Bromite → Settings → User scripts → enable user scripts (allow the permission prompt).
2. Save the configured manga-bookmark.user.js to the device (or open its raw URL). Bromite detects the .user.js and offers to install it.
3. Confirm the install; the @match list covers both sites.
4. Open a series on either site — a 📑 button appears bottom-right.

Exact menu wording varies by Bromite build; if "User scripts" is absent, update Bromite or use a build with userscript support.

Desktop iteration (optional)

The script is GM_*-free, so it also runs in Tampermonkey/Violentmonkey on desktop for faster testing — install the same file unchanged.

Use

• Bookmark: on a series or chapter page, open the panel → + Bookmark this.
• Auto-progress: opening a chapter of a bookmarked series records it when the chapter number ≥ the stored one (re-reading older chapters never regresses progress; unparseable numbers set the current chapter).
• Manual override: panel → Edit on any row forces a specific chapter.
• Continue: jumps to the last-read chapter (or the series page).
• Latest chapter: rows read Read: … · Latest: … once the newest published chapter is known and it is ahead of your progress. See below for how that is found.
• Favourites: the ☆ on any row toggles it; the ★ Favourites tab narrows the list. Favourited series still appear under All. The flag syncs, so it follows you across devices; the chosen tab does not persist.
• Archive: the Archive button on any row parks a series — it drops out of All and ★ Favourites and moves to the Archived tab. The server keeps checking it for new chapters, so it is worth coming back to. Archiving does not touch read progress, and reading an archived series leaves it archived.
• Finished: series you have completed live in a Finished tab in the web UI only. It is set there and nowhere else — the API rejects the value — and finished series are hidden from every userscript tab and are no longer polled for new chapters.
• Bookmarks made on Asura appear when the panel is opened on Demonic, and vice versa — the backend is the shared store.

Neither favouriting nor learning a new chapter reorders the list — only reading progress does.

Offline / backend down: changes are cached in localStorage and retried on the next successful load (last-write-wins).

How "latest chapter" is found

Only a series page lists every chapter (a reader page links just its neighbours), and the backend cannot fetch either site — Cloudflare blocks server-side requests, and neither site offers an API or feed to poll. So the userscript does the looking, from your own browser session:

• Opening a bookmarked series page records its newest chapter directly.
• Otherwise it fetches series pages in the background — same-origin only, so browsing Asura refreshes Asura bookmarks and Demonic refreshes Demonic. One series per navigation, and at most one check per series every 4 hours (LATEST_CHECK_BATCH / LATEST_CHECK_THROTTLE_MS). Failures are silent and simply retried after the window.

Freshness is tracked per device in localStorage under mangabm:lastchecked and is deliberately not synced, since each device checks on its own.

This means a bookmark is as current as its last check — not the moment a chapter drops. Nothing can be instant here: neither site offers push, feeds, or an API.

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Adapter reference (verified live 2026-07-24)

The site adapters key everything off URL regex, with title/cover from og:title / og:image. Confirmed against live pages via Playwright:

Site	Series URL	Chapter URL	series_id
Asura (asurascans.com)	/comics/<slug-hash>	/comics/<slug-hash>/chapter/<n>	<slug-hash>
Demonic (demonicscans.org)	/manga/<slug>	/title/<slug>/chapter/<n>/<page> (chaptered.php?manga=<id>&chapter=<n> 301s here)	<slug>

Notes:

• asuracomic.net deep links are dead (re-checked 2026-07-25). They 301 to the asurascans.com root, discarding the path, at the edge — before the userscript gets a document — so nothing client-side can rescue them. Reach series through asurascans.com. The host stays matched in case the redirect starts preserving paths again.
• Asura og:title carries a Chapter N - Read Online \| Asura Scans suffix that the adapter strips; Demonic chapter og:title is <Title> Chapter N.
• Demonic's <slug> is identical on /manga/… and the canonical /title/… reader, so a bookmark set from the series page and the auto-update from the reader resolve to the same key.
• Asura showed no Next.js markers on the live site, so navigation uses a framework-agnostic watcher (history patch + polling) rather than a Next-only hook — works for client-routed and full-reload sites alike.

If either site changes its URL shape, update the regex in the matching adapter in userscript/manga-bookmark.user.js and re-verify.