Cache user information

lib/helpers/database/database_contract.dart

@@ -0,0 +1,20 @@
+/// Database contract
+///
+/// @author Pierre HUBERT
+
+/// Main information
+class DatabaseContract {
+  static const DATABASE_VERSION = 1;
+  static const DATABASE_FILE_NAME = "database.sqlite";
+}
+
+/// User table contract
+abstract class UserTableContract {
+  static const TABLE_NAME = "users";
+  static const C_ID = "id";
+  static const C_FIRST_NAME = "first_name";
+  static const C_LAST_NAME = "last_name";
+  static const C_VISIBILITY  = "visibility";
+  static const C_VIRTUAL_DIRECTORY = "virtual_directory";
+  static const C_ACCOUNT_IMAGE_URL = "account_image_url";
+}

lib/helpers/database/database_helper.dart

@@ -0,0 +1,53 @@
+import 'package:comunic/helpers/database/database_contract.dart';
+import 'package:path/path.dart';
+import 'package:sqflite/sqflite.dart';
+
+/// Database Helper
+///
+/// Manage the connection to the local SQLite database
+///
+/// @author Pierre HUBERT
+
+abstract class DatabaseHelper {
+  static Database _db;
+
+  /// Open the database
+  static Future<void> open() async {
+    if (_db != null && _db.isOpen) return;
+
+    var databasePath = await getDatabasesPath();
+    _db = await openDatabase(
+        join(databasePath, DatabaseContract.DATABASE_FILE_NAME),
+        version: DatabaseContract.DATABASE_VERSION,
+        onUpgrade: _performDatabaseUpdate,
+        onCreate: _initializeDatabase);
+  }
+
+  /// Get a database instance
+  static Future<Database> get() async {
+    await open();
+    return _db;
+  }
+
+  /// Perform database update
+  ///
+  /// Currently : delete all the database tables and initialize it again
+  static Future<void> _performDatabaseUpdate(
+      Database db, int oldVersion, int newVersion) async {
+    //Initialize database again
+    await _initializeDatabase(db, newVersion);
+  }
+
+  /// Initialize the database
+  static Future<void> _initializeDatabase(Database db, int version) async {
+    //Create users table
+    await db.execute("CREATE TABLE ${UserTableContract.TABLE_NAME} ("
+        "${UserTableContract.C_ID} INTEGER PRIMARY KEY, "
+        "${UserTableContract.C_FIRST_NAME} TEXT, "
+        "${UserTableContract.C_LAST_NAME} TEXT, "
+        "${UserTableContract.C_VISIBILITY} TEXT,"
+        "${UserTableContract.C_VIRTUAL_DIRECTORY} TEXT,"
+        "${UserTableContract.C_ACCOUNT_IMAGE_URL} TEXT"
+        ")");
+  }
+}

lib/helpers/database/users_database_helper.dart

@@ -0,0 +1,62 @@
+import 'package:comunic/models/user.dart';
+
+import 'database_contract.dart';
+import 'database_helper.dart';
+
+/// User database helper
+///
+/// @author Pierre HUBERT
+
+class UsersDatabaseHelper {
+  /// Insert a user in the database
+  Future<void> _insertDB(User user) async {
+    await (await DatabaseHelper.get())
+        .insert(UserTableContract.TABLE_NAME, user.toMap());
+  }
+
+  /// Update a user in the database
+  Future<void> _updateDB(User user) async {
+    await (await DatabaseHelper.get()).update(
+      UserTableContract.TABLE_NAME,
+      user.toMap(),
+      where: "${UserTableContract.C_ID} = ?",
+      whereArgs: [user.id],
+    );
+  }
+
+  /// Get a user from the database with a specified [id]
+  ///
+  /// Returns null if none found
+  Future<User> get(int id) async {
+    List<Map> maps = await (await DatabaseHelper.get()).query(
+      UserTableContract.TABLE_NAME,
+      where: '${UserTableContract.C_ID} = ?',
+      whereArgs: [id],
+    );
+
+    if (maps.length > 0) return User.fromMap(maps[0]);
+
+    return null;
+  }
+
+  /// Check out whether a user information specified with its [id] is present
+  /// or not in the local database
+  Future<bool> has(int id) async {
+    return (await get(id)) != null;
+  }
+
+  /// Insert or update information about a user (depends of the presence
+  /// of previous user information in the database
+  Future<void> insertOrUpdate(User user) async {
+    if (await has(user.id))
+      await _updateDB(user);
+    else
+      await _insertDB(user);
+  }
+
+  /// Insert or update an important amount of user information
+  Future<void> insertOrUpdateAll(List<User> list) async {
+    for(int i = 0; i < list.length; i++)
+      await insertOrUpdate(list[i]);
+  }
+}