Add readMany

CHANGELOG.md

@@ -1,3 +1,6 @@
+# 2.0.0-alpha.11
+* Add `readMany` to `Service`.
+
 # 2.0.0-alpha.10
 * All calls to `Service.parseId` are now affixed with the `<Id>` argument.
 * Added `uri` getter to `AngelHttp`.

lib/src/core/service.dart

@@ -105,6 +105,14 @@ class Service<Id, Data> extends Routable {
     throw new AngelHttpException.methodNotAllowed();
   }
 
+  /// Reads multiple resources at once.
+  ///
+  /// Service implementations should override this to ensure data is fetched within a
+  /// single round trip.
+  Future<List<Data>> readMany(List<Id> ids, [Map<String, dynamic> params]) {
+    return Future.wait(ids.map((id) => read(id, params)));
+  }
+
   /// Creates a resource.
   Future<Data> create(Data data, [Map<String, dynamic> params]) {
     throw new AngelHttpException.methodNotAllowed();

test/services_test.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:angel_container/mirrors.dart';
 import 'package:angel_framework/angel_framework.dart';
 import 'package:angel_framework/http.dart';
@@ -17,12 +19,13 @@ main() {
     'Content-Type': 'application/json'
   };
   Angel app;
+  MapService service;
   String url;
   http.Client client;
 
   setUp(() async {
     app = new Angel(reflector: MirrorsReflector())
-      ..use('/todos', new MapService())
+      ..use('/todos', service = new MapService())
       ..errorHandler = (e, req, res) {
         print('Whoops: ${e.error}');
         if (e.stackTrace != null) print(new Chain.forTrace(e.stackTrace).terse);
@@ -98,6 +101,17 @@ main() {
       expect(jsons['over'], equals('write'));
     });
 
+    test('readMany', () async {
+      var items = <Map>[
+        await service.create({'foo': 'bar'}),
+        await service.create({'bar': 'baz'}),
+        await service.create({'baz': 'quux'})
+      ];
+
+      var ids = items.map((m) => m['id'] as String).toList();
+      expect(await service.readMany(ids), items);
+    });
+
     test('can delete data', () async {
       String postData = json.encode({'text': 'Hello, world!'});
       var created = await client