flutter_map_cache 1.2.0

A slim yet powerful caching plugin for flutter_map tile layers.

flutter_map_cache

A slim yet powerful caching plugin for flutter_map tile layers.

Features

The package is using dio with the dio_cache_interceptor package and supports the storage backend that you like.

Supported storage backends are:

• ✅ In-Memory (for testing)
• ✅ File System
• ✅ Drift (SQLite)
• ✅ Hive
• ✅ ObjectBox
• ❌ Isar (planned, see dio_cache_interceptor#122)
• ❌ Sembast (currently broken)

Getting started

1. Add the packages you want to use to your pubspec.yaml file. Only add the packages for the backend you want to use.

dependencies:
  flutter_map: ^5.0.0 # in case you don't have it yet 
  flutter_map_cache: ^1.0.0 # this package

  dio_cache_interceptor_db_store: ^5.1.0 # drift
  sqlite3_flutter_libs: ^0.5.15 # drift

  dio_cache_interceptor_file_store: ^1.2.2 # file system

  dio_cache_interceptor_hive_store: ^3.2.1 # hive

  dio_cache_interceptor_objectbox_store: ^1.1.1 # objectbox
  objectbox_flutter_libs: ^1.4.1 # objectbox  

2. The storage backends might have their own required setups. Please check them out in their package documentations.

Usage

Using the cache is easy. Here is an example how to use the Hive backend:

First get the cache directory of the app (i.e. with the path_provider package).

import 'package:path_provider/path_provider.dart';

Future<String> getPath() async {
  final cacheDirectory = await getTemporaryDirectory();
  return cacheDirectory.path;
}

Then use the directory path to initialize the HiveCacheStore. You can wrap FlutterMap inside a FutureBuilder to use the getPath() method.

@override
Widget build(BuildContext context) {
  return FlutterMap(
    options: MapOptions(),
    children: [
      TileLayer(
        urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
        tileProvider: CachedTileProvider(
          // maxStale keeps the tile cached for the given Duration and 
          // tries to revalidate the next time it gets requested
          maxStale: const Duration(days: 30),
          store: HiveCacheStore(
            path,
            hiveBoxName: 'HiveCacheStore',
          ),
        ),
      ),
    ],
  );
}

Common use cases

Remove the api key from the url before it gets used for caching

Commercial tile providers often use an api key that is attached as a parameter to the url. While this shouldn't be a problem when the api key stays the same you might want to make it immune to api key changes anyway.

final _uuid = Uuid(); 

CachedTileProvider(
  keyBuilder: (request) {
    return _uuid.v5(
      Uuid.NAMESPACE_URL, 
      request.uri.replace(queryParameters: {}).toString(),
    );
  },
  ...
),

Additional information

Pull requests are welcome. If you want to add support for another storage backend you can check out dio_cache_interceptor.

If you need help you can open an issue or join the flutter_map discord server.