chore: support multiple graphql or rest APIs

packages/amplify_core/lib/src/config/amplify_config.dart

@@ -3,6 +3,7 @@
 
 import 'package:amplify_core/amplify_core.dart';
 import 'package:json_annotation/json_annotation.dart';
+import 'package:meta/meta.dart';
 
 part 'amplify_config.g.dart';
 
@@ -74,12 +75,14 @@ class AmplifyConfig with AWSEquatable<AmplifyConfig>, AWSSerializable {
     );
   }
 
+  @internal
   AmplifyOutputs toAmplifyOutputs() {
     final appSync = auth?.awsPlugin?.appSync;
     return AmplifyOutputs(
       version: '1',
       auth: auth?.toAuthOutputs(),
       data: api?.toDataOutputs(appSync: appSync),
+      restApi: api?.toRestApiOutputs(),
       analytics: analytics?.toAnalyticsOutputs(),
       notifications: notifications?.toNotificationsOutputs(),
       storage: storage?.toStorageOutputs(),

packages/amplify_core/lib/src/config/amplify_outputs/amplify_outputs.dart

@@ -6,7 +6,9 @@ import 'package:amplify_core/src/config/amplify_outputs/analytics/analytics_outp
 import 'package:amplify_core/src/config/amplify_outputs/auth/auth_outputs.dart';
 import 'package:amplify_core/src/config/amplify_outputs/data/data_outputs.dart';
 import 'package:amplify_core/src/config/amplify_outputs/notifications/notifications_outputs.dart';
+import 'package:amplify_core/src/config/amplify_outputs/rest_api/rest_api_outputs.dart';
 import 'package:amplify_core/src/config/amplify_outputs/storage/storage_outputs.dart';
+import 'package:json_annotation/json_annotation.dart';
 import 'package:meta/meta.dart';
 
 part 'amplify_outputs.g.dart';
@@ -26,6 +28,7 @@ class AmplifyOutputs
     this.analytics,
     this.auth,
     this.data,
+    this.restApi,
     this.notifications,
     this.storage,
     this.custom,
@@ -47,7 +50,12 @@ class AmplifyOutputs
   final AuthOutputs? auth;
 
   /// {@macro amplify_core.amplify_outputs.data_outputs}
-  final DataOutputs? data;
+  @JsonKey(fromJson: _dataFromJson, toJson: _dataToJson)
+  final Map<String, DataOutputs>? data;
+
+  /// {@macro amplify_core.amplify_outputs.rest_api_outputs}
+  @internal
+  final Map<String, RestApiOutputs>? restApi;
 
   /// {@macro amplify_core.amplify_outputs.notifications_outputs}
   final NotificationsOutputs? notifications;
@@ -61,8 +69,17 @@ class AmplifyOutputs
   final Map<String, dynamic>? custom;
 
   @override
-  List<Object?> get props =>
-      [schema, version, analytics, auth, data, notifications, storage, custom];
+  List<Object?> get props => [
+        schema,
+        version,
+        analytics,
+        auth,
+        data,
+        restApi,
+        notifications,
+        storage,
+        custom,
+      ];
 
   @override
   String get runtimeTypeName => 'AmplifyOutputs';
@@ -72,3 +89,36 @@ class AmplifyOutputs
     return _$AmplifyOutputsToJson(this);
   }
 }
+
+/// The name of the API plugin when a Gen 2 config is used.
+///
+/// "data" is consistent with the name Gen 2 uses when generating a Gen 1 config.
+/// reference: https://github.com/aws-amplify/amplify-backend/blob/4dd9d5a35c378895d1360c15a3b7ad1f09cc7653/packages/client-config/src/client-config-writer/client_config_to_mobile_legacy_converter.ts#L93
+const _dataPluginName = 'data';
+
+/// Converts a single data json object to a map of [DataOutputs].
+///
+/// This manual mapping is required since the Amplify Outputs schema only supports
+/// a single data object, but Amplify Flutter supports more than 1.
+Map<String, DataOutputs>? _dataFromJson(Map<String, Object?>? object) {
+  if (object == null) return null;
+  return {
+    _dataPluginName: DataOutputs.fromJson(object),
+  };
+}
+
+/// Converts a map of [DataOutputs] to a single data json object.
+///
+/// This manual mapping is required since the Amplify Outputs schema only supports
+/// a single data object, but Amplify Flutter supports more than 1.
+Object? _dataToJson(Map<String, DataOutputs>? outputs) {
+  if (outputs == null) return null;
+  if (outputs.length > 1) {
+    throw ConfigurationError(
+      'Found ${outputs.length} endpoints.'
+      ' Amplify Outputs does not support multiple GraphQL endpoints.',
+    );
+  }
+  final data = outputs[_dataPluginName];
+  return data?.toJson();
+}

packages/amplify_core/lib/src/config/amplify_outputs/rest_api/rest_api_outputs.dart

@@ -0,0 +1,55 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import 'package:amplify_core/amplify_core.dart';
+
+part 'rest_api_outputs.g.dart';
+
+/// {@template amplify_core.amplify_outputs.rest_api_outputs}
+/// An internal representation of Rest API.
+///
+/// This class should not be exposed publicly since the Gen 2 schema does not
+/// support Rest API. This class exists to support Gen 1 configs that use Rest API.
+/// {@endtemplate}
+@zAmplifyOutputsSerializable
+class RestApiOutputs
+    with AWSEquatable<RestApiOutputs>, AWSSerializable, AWSDebuggable {
+  /// {@macro amplify_core.amplify_outputs.rest_api_outputs}
+  const RestApiOutputs({
+    required this.awsRegion,
+    required this.url,
+    this.apiKey,
+    required this.authorizationType,
+  });
+
+  factory RestApiOutputs.fromJson(Map<String, Object?> json) =>
+      _$RestApiOutputsFromJson(json);
+
+  /// The AWS region of Amazon AWS Gateway resources.
+  final String awsRegion;
+
+  /// The AWS Gateway endpoint URL.
+  final String url;
+
+  /// The AppSync API Key.
+  final String? apiKey;
+
+  /// The authorization type.
+  final APIAuthorizationType authorizationType;
+
+  @override
+  List<Object?> get props => [
+        awsRegion,
+        url,
+        apiKey,
+        authorizationType,
+      ];
+
+  @override
+  String get runtimeTypeName => 'RestApiOutputs';
+
+  @override
+  Object? toJson() {
+    return _$RestApiOutputsToJson(this);
+  }
+}

packages/amplify_core/lib/src/config/analytics/analytics_config.dart

@@ -4,6 +4,7 @@
 import 'package:amplify_core/amplify_core.dart';
 import 'package:amplify_core/src/config/amplify_outputs/analytics/amazon_pinpoint_outputs.dart';
 import 'package:amplify_core/src/config/amplify_outputs/analytics/analytics_outputs.dart';
+import 'package:meta/meta.dart';
 
 export 'pinpoint_config.dart' hide PinpointPluginConfigFactory;
 
@@ -33,6 +34,7 @@ class AnalyticsConfig extends AmplifyPluginConfigMap {
   @override
   Map<String, Object?> toJson() => _$AnalyticsConfigToJson(this);
 
+  @internal
   AnalyticsOutputs? toAnalyticsOutputs() {
     final plugin = awsPlugin?.pinpointAnalytics;
     if (plugin == null) {

packages/amplify_core/lib/src/config/api/api_config.dart

@@ -3,6 +3,8 @@
 
 import 'package:amplify_core/amplify_core.dart';
 import 'package:amplify_core/src/config/amplify_outputs/data/data_outputs.dart';
+import 'package:amplify_core/src/config/amplify_outputs/rest_api/rest_api_outputs.dart';
+import 'package:meta/meta.dart';
 
 export 'aws_api_config.dart' hide AWSApiPluginConfigFactory;
 
@@ -32,24 +34,59 @@ class ApiConfig extends AmplifyPluginConfigMap {
   @override
   Map<String, Object?> toJson() => _$ApiConfigToJson(this);
 
-  DataOutputs? toDataOutputs({AWSConfigMap<CognitoAppSyncConfig>? appSync}) {
-    final plugin = appSync?.default$;
+  @internal
+  Map<String, DataOutputs>? toDataOutputs({
+    AWSConfigMap<CognitoAppSyncConfig>? appSync,
+  }) {
+    final plugins = _getPlugins(EndpointType.graphQL);
+    if (plugins == null) {
+      return null;
+    }
+    return plugins.map((key, plugin) {
+      final defaultAuthorizationType = plugin.authorizationType;
+      final awsRegion = plugin.region;
+      final url = plugin.endpoint;
+      final allModes = (appSync?.all.values ?? []);
+      final authorizationTypes = allModes
+          .where((plugin) => plugin.apiUrl == url && plugin.region == awsRegion)
+          .map((config) => config.authMode)
+          .where((mode) => mode != defaultAuthorizationType)
+          .toList();
+      final data = DataOutputs(
+        awsRegion: awsRegion,
+        url: url,
+        defaultAuthorizationType: defaultAuthorizationType,
+        apiKey: plugin.apiKey,
+        authorizationTypes: authorizationTypes,
+      );
+      return MapEntry(key, data);
+    });
+  }
+
+  @internal
+  Map<String, RestApiOutputs>? toRestApiOutputs() {
+    final plugins = _getPlugins(EndpointType.rest);
+    if (plugins == null) {
+      return null;
+    }
+    return plugins.map((key, plugin) {
+      final rest = RestApiOutputs(
+        awsRegion: plugin.region,
+        url: plugin.endpoint,
+        authorizationType: plugin.authorizationType,
+        apiKey: plugin.apiKey,
+      );
+      return MapEntry(key, rest);
+    });
+  }
+
+  Map<String, AWSApiConfig>? _getPlugins(EndpointType endpointType) {
+    final plugin = awsPlugin;
     if (plugin == null) {
       return null;
     }
-    final region = plugin.region;
-    final url = plugin.apiUrl;
-    final apiKey = plugin.apiKey;
-    final defaultAuthorizationType = plugin.authMode;
-    final modes = appSync?.all.values.map((config) => config.authMode) ?? [];
-    final authorizationTypes =
-        modes.where((mode) => mode != defaultAuthorizationType).toList();
-    return DataOutputs(
-      awsRegion: region,
-      url: url,
-      defaultAuthorizationType: defaultAuthorizationType,
-      apiKey: apiKey,
-      authorizationTypes: authorizationTypes,
-    );
+    final entries =
+        plugin.all.entries.where((p) => p.value.endpointType == endpointType);
+    return Map<String, AWSApiConfig>.fromEntries(entries);
   }
 }

packages/amplify_core/lib/src/config/auth/auth_config.dart

@@ -6,6 +6,7 @@ import 'package:amplify_core/src/config/amplify_outputs/auth/auth_outputs.dart';
 import 'package:amplify_core/src/config/amplify_outputs/auth/oauth_outputs.dart';
 import 'package:amplify_core/src/config/amplify_outputs/auth/oauth_response_type.dart';
 import 'package:amplify_core/src/config/amplify_outputs/auth/password_policy.dart';
+import 'package:meta/meta.dart';
 
 export 'cognito_config.dart' hide CognitoPluginConfigFactory;
 
@@ -79,6 +80,7 @@ class AuthConfig extends AmplifyPluginConfigMap {
   @override
   AuthConfig copy() => AuthConfig(plugins: Map.of(plugins));
 
+  @internal
   AuthOutputs? toAuthOutputs() {
     final plugin = awsPlugin?.auth?.default$;
     final userPool = awsPlugin?.cognitoUserPool?.default$;

packages/amplify_core/lib/src/config/storage/storage_config.dart

@@ -3,6 +3,7 @@
 
 import 'package:amplify_core/amplify_core.dart';
 import 'package:amplify_core/src/config/amplify_outputs/storage/storage_outputs.dart';
+import 'package:meta/meta.dart';
 
 export 's3_config.dart' hide S3PluginConfigFactory;
 
@@ -32,6 +33,7 @@ class StorageConfig extends AmplifyPluginConfigMap {
   @override
   Map<String, Object?> toJson() => _$StorageConfigToJson(this);
 
+  @internal
   StorageOutputs? toStorageOutputs() {
     final plugin = awsPlugin;
     if (plugin == null) {