Tauri + Rusqlite
A minimal example of how to set up a backend SQLite store with Tauri.
I'm using Rusqlite to provide a nicer wrapper for SQLite.
Setting up the database
In setup() inside main.rs, we initialize the database and put the Connection inside Tauri state.
initialize_database() creates the expected path for our .sqlite file, using app_handle.path_resolver().app_data_dir(). It uses PRAGMA user_version to track the DB version. 0 means newly-created, and 1 means created. Further versions can be added as the schema changes. upgrade_database_if_needed() checks user_version and upgrades inside a transaction, to maintain database integrity.
state.rs sets up the Tauri app state to hold the Connection object, to be re-used across the app. It provides some trait methods to grab the Mutex for the connection, run an operation and release it again.
Accessing the Connection from commmands
Inside Tauri commands we can supply a app_handle: AppHandle argument, which will be automatically populated by the Tauri framework. From there we can call our db() trait method on app_handle to do database operations. Anything returned from the closure will be passed through.
let my_result = app_handle.db(|db: &Connection| /* Do something with the DB connection and return a value */);I pass the AppHandle through to any other modules that need it, so they also have access to the Connection. You can also call app_handle.clone() in case you run into ownership issues.