sqflite_platform_interface

The platform interface of the sqflite Flutter plugin: the base of a platform implementation of sqflite, like sqflite_android and sqflite_darwin.

An application does not depend on it. It uses sqflite (Android, iOS, macOS), sqflite_common_ffi (Windows, Linux, Dart VM, unit tests) or sqflite_common_ffi_web (web).

Getting started

In your implementation package (a Flutter plugin package):

flutter pub add sqflite_platform_interface sqflite_common

If the native side of your package speaks the sqflite method channel protocol (as the Android and iOS/macOS code does), register the method channel factory from the registerWith() of a SqflitePlatform subclass:

import 'package:sqflite_platform_interface/sqflite_platform_interface.dart';

/// sqflite implementation for "myos".
class SqfliteMyOs extends SqflitePlatform {
  /// Called by Flutter before `main()` (the `dartPluginClass`).
  static void registerWith() {
    SqflitePlatform.initWithDatabaseFactoryMethodChannel();
  }
}

and declare it in its pubspec.yaml:

flutter:
  plugin:
    implements: sqflite
    platforms:
      myos:
        pluginClass: SqflitePlugin
        dartPluginClass: SqfliteMyOs

An app using sqflite then calls openDatabase() as usual on this platform.

What it provides

The method channel factory runs the shared sqflite Dart code of sqflite_common (versions, transactions, batches, single instances) and sends the SQL to the native side. The messages are described in method_call_protocol.md. readDatabaseBytes() and writeDatabaseBytes() do not go through the channel: they read and write the file in Dart (dart:io), a relative path being in the databases path, as for openDatabase().

A Dart implementation (ffi, web) does not need the channel: its registerWith() sets its own factory, keeping one already set, as sqflite_ffi does:

import 'package:sqflite_common/sqflite.dart';

/// [factory] is built with the sqflite_common helpers (for example
/// `databaseFactoryFfi` of sqflite_common_ffi).
void registerDartFactory(DatabaseFactory factory) {
  databaseFactoryOrNull ??= factory;
}

Common mistakes

• Depending on this package from an app: use sqflite.
• No dartPluginClass in the pubspec: registerWith() never runs and openDatabase() throws StateError: databaseFactory not initialized.
• Native errors with a code other than sqlite_error: the app gets a PlatformException instead of a DatabaseException.
• Setting a class that only implements DatabaseFactory: the setter throws ArgumentError (Unsupported sqflite factory). Build the factory with the sqflite_common helpers (buildDatabaseFactory).

Implementations

• sqflite_android (Android, example)
• sqflite_darwin (iOS and macOS, example)
• sqflite, the app-facing package, and its example