BookFusion sync integration for CWA — wrapper image + sidecar (no fork required)

[Fguarien]

Hi @crocodilestick and CWA community,

I built a small integration that adds a Sync to BookFusion button (single / multi-select / all) to the CWA library and book-detail pages, without forking CWA.

Repos : calibre-web-automated-bookfusion (wrapper image) + FGU-bookfusion (sidecar).

Architecture

Browser ──HTTPS──► CWA (cwabf:local)  ──docker net──► bookfusion-mcp:8765
                   │                                    │
                   ├─ blueprint /bookfusion/api/*       └─ async client →
                   │   (admin gate + reverse proxy)        BookFusion.com API
                   └─ after_app_request injects JS
                       only for admin users

• FROM crocodilestick/calibre-web-automated:dev + a Flask blueprint, JS bundle, CSS overlay.
• cps/main.py is patched at build time on a stable anchor (switch_theme registration line) — no CWA file overwritten, so the image rebases trivially on a new CWA release.
• The blueprint reverse-proxies /bookfusion/api/* to the sidecar (kept on the Docker network only — never exposed on the host).
• The after_app_request hook injects the bootstrap <script> only into HTML responses to admin users; non-admin pages are byte-identical.

Plays nice with CWAs security

• current_user.role_admin() gate (with a BOOKFUSION_ALLOWED_USERNAMES env override for OAuth setups that strip the admin role)
• Flask-WTF CSRF stays on; the JS reads the token from the pages hidden input and forwards it as X-CSRFToken
• Same-origin (no CORS, no mixed content)
• Sidecar bound to the Docker network only, shared-secret token on every proxied call as defense-in-depth

Battle-tested

Running for 2 weeks on a 1500-book library. Sync all finishes in ~1h with BOOKFUSION_UPLOAD_THREADS=4. Already-synced books with unchanged metadata are skipped (digest comparison) so reruns are nearly free.

Happy to open a PR on CWA itself if theres interest in shipping this as an opt-in feature gated by an env var. Otherwise it lives as an ecosystem project. Curious about reactions / suggestions — and let me know if youd like the PR.

— Fred