Data management

[ghost]

I’m developing an application that needs to cache the map as it is viewed to reduce server loads, and using the examples and documentation given so far I’ve got the following:

      const tileLayerOffline = L.tileLayer.offline(urlTemplate, {
        attribution:
          '&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors',
        minZoom: 12,
      });

      tileLayerOffline.addTo(mapState);

      tileLayerOffline.on("tileload", (event) => {
        const { tile } = event;
        const url = tile.src;
        if (url.search("blob:") !== -1) {
         console.debug(`Loaded ${url} from idb`);
          return;
        }
        const { x, y, z } = event.coords;
        const { _url: urlTemplate } = event.target;
        const tileInfo = {
          key: url,
          url,
          x,
          y,
          z,
          urlTemplate,
          createdAt: Date.now(),
        };
        downloadTile(url)
          .then((dl) => saveTile(tileInfo, dl))
          .then(() => console.debug(`Saved ${url} in idb`));
      });

Which is basically a modified version of one of the examples to use tileLayer.offline

This works great for an individual session, but I’m struggling to understand where data is stored. In my case, I need to apply this to an ionic application where I can save data locally, and I would need to reload the database (I assume), to “resume” the download session instead of starting from scratch every time. That is, I want to save the map data that was loaded during a session, and then be able to load it on the next.

Is there a way to do this? And if so, where is this information stored and accessed from (loaded images/blobs, db)? Finally, is there any method to delete the oldest storage entries by date? So far the only method I could find is modifying:

async () => {
    const tiles = await getStorageInfo(urlTemplate);
    const minCreatedAt = new Date().setDate(-30);
    await Promise.all(
      tiles.map((tile) =>
        tile.createdAt < minCreatedAt ? removeTile(tile.key) : Promise.resolve()
      )
    );
  }

to sort tiles by date of creation, and deleting them that way, but I don’t know if that would be the recommended way.

Thanks for the excellent library btw!