BookShelves
First off, thank you for building BookShelves, the iCloud sync and reading experience are fantastic, and OPDS support already shows you understand the self-hosted community.
I'd like to propose a different sync model as an alternative to full iCloud replication: treating a self-hosted server (WebDAV, or an OPDS-compatible source like Calibre-Web) as the primary storage location for the library, with BookShelves downloading books on-demand rather than syncing the entire collection to every device.
Why this matters:
Large libraries, limited device storage: Readers with hundreds or thousands of ebooks don't want (or can't fit) a full copy of their library duplicated across iPhone, iPad, and Mac via iCloud. A "library lives on the server, device caches what you're actively reading" model solves this.
Self-hosted / NAS-first readers: Many of us already run Calibre-Web or similar on a home NAS (Synology, OMV, etc.) specifically to have one source of truth for our collection. Right now OPDS in BookShelves is great for browsing and downloading, but there's no concept of a book staying "remote" until opened — everything downloaded sticks around locally.
Progress still needs to follow the book: Ideally, reading progress/position would sync per-book regardless of which device downloaded it, similar to how Kosync tracks progress independent of file location.
Complements existing OPDS work: Since BookShelves already speaks OPDS and includes a Calibre wireless sync server, extending that foundation to support "library index from remote source, lazy file download, evict/re-download as needed" feels like a natural next step rather than a whole new subsystem.
Even as an opt-in "Remote Library" mode (separate from the local iCloud-synced library) it would make BookShelves genuinely great for people managing large, self-hosted collections instead of only Apple-ecosystem-local ones.
Thanks for considering it, and keep up the great work!
1 comment
Thank you for the thoughtful and detailed request, and the kind words about BookShelves!
You are right that the current OPDS support is browse-and-download: once you download a book from an OPDS feed, it becomes a regular local library entry. There is no concept of a book staying remote and being fetched on-demand from the OPDS source.
The idea of a "remote library" mode is interesting. BookShelves already has on-demand materialization for iCloud-backed files (books can exist in a "cloud only" state and get downloaded when you open them), so some of the underlying infrastructure exists. Extending that to work with a self-hosted server would be a significant project, though.
I've noted this as a feature request. No timeline, but the OPDS and Calibre foundations are definitely something I would build on if and when I tackle this.