sling_gql_sqflite 1.4.0

Persist sling_gql's normalized cache in SQLite with sqflite: a bounded write-behind copy saved as deltas and loaded before the client starts.

example/sling_gql_sqflite_example.dart

// sling_gql's cache persisted in SQLite: opened before the client exists, so
// the first frame of the second launch paints the previous run's data.
//
// In a real app `Query` / `User` / `slingSchema` below are generated by
// `sling_gql_gen` (which also fills in `hash:`); they are written out here so
// the example stands on its own.
//
//   type Query { me: User! }
//   type User  { id: ID!  name: String! }

import 'package:flutter/widgets.dart';
import 'package:sling_gql/sling_gql.dart';
import 'package:sling_gql_sqflite/sling_gql_sqflite.dart';

class Query extends Accessor {
  Query(super.recorder, super.selection, super.path);
  Query.root(Recorder r) : super(r, r.root, const []);

  User? get me => object('me', User.new, keyed: true);
}

class User extends Accessor {
  User(super.recorder, super.selection, super.path);

  String? get id => scalar<String>('id');
  String? get name => scalar<String>('name');
}

const slingSchema = SlingSchema<Query, Accessor>(
  query: Query.root,
  hash: 'example-1',
);

Future<void> main() async {
  // sqflite and the lifecycle flush both need the binding.
  WidgetsFlutterBinding.ensureInitialized();

  final persistence = await SqflitePersistence.open(
    'sling_cache.db', // in sqflite's getDatabasesPath()
    schema: slingSchema,
    maxAge: const Duration(days: 7), // root fields unused for a week go
    maxEntities: 10000,
  );
  debugPrint('${persistence.loaded}');

  final client = SlingClient<Query>(
    endpoint: Uri.parse('https://api.example.com/graphql'),
    schema: slingSchema,
    cache: persistence.cache,
    // Restored data has no fetch time, so it counts as stale: shown at once,
    // then revalidated. Without maxAge (plain cacheFirst) it would never be
    // refetched.
    maxAge: const Duration(minutes: 5),
  );

  runApp(
    SlingScope<Query>(
      client: client,
      child: Directionality(
        textDirection: TextDirection.ltr,
        child: QueryBuilder<Query>(
          builder: (context, q, state) => GestureDetector(
            // Logout: empties the cache and the database.
            onLongPress: persistence.clear,
            child: Text(q.me?.name ?? '…'),
          ),
        ),
      ),
    ),
  );
}