Offline mode for the PWA

[Clancy508]

Describe feature

Trilium uses Electron for the desktop app which supports fully offline operation and synchronisation to a server. The server also provides a web interface which is implemented as a Progressive Web App, however despite the Electron app being written to run in what is effectively a browser the PWA does not support offline functioning with sync, it must be connected at all times to work. This results in issues with the PWA when internet connectivity is poor with either slow speeds or outright loss of connectivity.

Instead, the PWA should use the same implementation as the Electron wrapped desktop app, allowing it to run offline and sync back to the server. Pre-configuring sync in this instance would be desirable but could be done manually by the user (e.g. default to the current web app with an option to switch to the offline capable one for advanced users who can then configure sync to the server).

Additional Information

No response

[questamor]

I think the main difficulty here is that the desktop Trilium app already includes a full-featured server running locally alongside the frontend. All data and settings are stored in a SQLite database.

An offline-capable PWA would therefore need to ship not only the frontend, but also the server-side logic to the browser and provide a local SQLite database. After connectivity is restored, the two databases (server and offline) would then need to be synchronized.
The alternative would be to make the PWA extremely limited, storing only incremental changes instead of a full SQLite copy.

Both approaches are hard to maintain and sit right on the edge of usability and comfort. Moving server-side logic to the client is extremely difficult and, frankly, a bad idea. The same applies to keeping a local SQLite copy in the browser - yes, sqlite.wasm exists, but it’s hard to imagine a reliable synchronization process.

A very simplified “potato notes”-style mini app, later synchronized with the main (non-PWA) Trilium instance, would also be barely usable. Many users rely on Trilium specifically for advanced features such as collections, widgets, custom pages, geo maps, and more.