Added ServiceList

CHANGELOG.md

@@ -0,0 +1,2 @@
+# 1.1.0+1
+Added `ServiceList`.

README.md

@@ -89,3 +89,18 @@ Logout:
 ```dart
 await app.logout();
 ```
+
+# Live Updates
+Oftentimes, you will want to update a collection based on updates from a service.
+Use `ServiceList` for this case:
+
+```dart
+build(BuildContext context) async {
+  var list = new ServiceList(app.service('api/todos'));
+  
+  return new StreamBuilder(
+    stream: list.onChange,
+    builder: _yourBuildFunction,
+  );
+}
+```

lib/angel_client.dart

@@ -3,6 +3,7 @@ library angel_client;
 
 import 'dart:async';
 import 'dart:convert';
+import 'package:collection/collection.dart';
 import 'package:http/src/response.dart' as http;
 export 'package:angel_http_exception/angel_http_exception.dart';
 
@@ -132,3 +133,80 @@ abstract class Service {
   /// Removes the given resource.
   Future remove(id, [Map params]);
 }
+
+/// A [List] that automatically updates itself whenever the referenced [service] fires an event.
+class ServiceList extends DelegatingList {
+  /// A field name used to compare [Map] by ID.
+  final String idField;
+
+  /// If `true` (default: `false`), then `index` events will be handled as a [Map] containing a `data` field.
+  ///
+  /// See https://github.com/angel-dart/paginate.
+  final bool asPaginated;
+
+  /// A function used to compare two items for equality.
+  final bool Function(dynamic, dynamic) compare;
+
+  final Service service;
+
+  final StreamController<ServiceList> _onChange = new StreamController();
+  final List<StreamSubscription> _subs = [];
+
+  ServiceList(this.service, {this.idField, this.asPaginated: false, this.compare}) : super([]) {
+    // Index
+    _subs.add(service.onIndexed.listen((data) {
+      var items = asPaginated == true ? data['data'] : data;
+      this..clear()..addAll(items);
+    }));
+
+    // Created
+    _subs.add(service.onCreated.listen((item) {
+      add(item);
+      _onChange.add(this);
+    }));
+
+    // Modified/Updated
+    handleModified(item) {
+      var indices = <int>[];
+
+      for (int i = 0; i < length; i++) {
+        if (compareItems(item, this[i]))
+          indices.add(i);
+      }
+
+      if (indices.isNotEmpty) {
+        for (var i in indices)
+          this[i] = item;
+
+        _onChange.add(this);
+      }
+    }
+
+    _subs.addAll([
+      service.onModified.listen(handleModified),
+      service.onUpdated.listen(handleModified),
+    ]);
+
+    // Removed
+    _subs.add(service.onRemoved.listen((item) {
+      removeWhere((x) => compareItems(item, x));
+      _onChange.add(this);
+    }));
+  }
+
+  /// Fires whenever the underlying [service] fires a change event.
+  Stream<ServiceList> get onChange => _onChange.stream;
+
+  Future close() async {
+    _onChange.close();
+  }
+
+  bool compareItems(a, b) {
+    if (compare != null)
+      return compare(a, b);
+    if (a is Map)
+      return a[idField ?? 'id'] == b[idField ?? 'id'];
+    else
+      return a == b;
+  }
+}

pubspec.yaml

@@ -1,5 +1,5 @@
 name: angel_client
-version: 1.1.0
+version: 1.1.0+1
 description: Client library for the Angel framework.
 author: Tobe O <thosakwe@gmail.com>
 homepage: https://github.com/angel-dart/angel_client
@@ -7,6 +7,7 @@ environment:
   sdk: ">=1.21.0"
 dependencies:
   angel_http_exception: ^1.0.0
+  collection: ^1.0.0
   http: ">= 0.11.3 < 0.12.0"
   json_god: ">=2.0.0-beta <3.0.0"
   merge_map: ">=1.0.0 <2.0.0"

test/list_test.dart

@@ -0,0 +1,54 @@
+import 'package:async/async.dart';
+import 'dart:io';
+import 'package:angel_client/io.dart' as c;
+import 'package:angel_framework/angel_framework.dart' as s;
+import 'package:test/test.dart';
+
+main() {
+  HttpServer server;
+  c.Angel app;
+  c.ServiceList list;
+  StreamQueue queue;
+
+  setUp(() async {
+    var serverApp = new s.Angel();
+    serverApp.use('/api/todos', new s.MapService(autoIdAndDateFields: false));
+
+    server = await serverApp.startServer();
+    var uri = 'http://${server.address.address}:${server.port}';
+    app = new c.Rest(uri);
+    list = new c.ServiceList(app.service('api/todos'));
+    queue = new StreamQueue(list.onChange);
+  });
+
+  tearDown(() async {
+    await server.close(force: true);
+    await list.close();
+    await list.service.close();
+    await app.close();
+  });
+
+  test('listens on create', () async {
+    list.service.create({'foo': 'bar'});
+    await list.onChange.first;
+    expect(list, [{'foo': 'bar'}]);
+  });
+
+  test('listens on modify', () async {
+    list.service.create({'id': 1, 'foo': 'bar'});
+    await queue.next;
+
+    await list.service.update(1, {'id': 1, 'bar': 'baz'});
+    await queue.next;
+    expect(list, [{'id': 1, 'bar': 'baz'}]);
+  });
+
+  test('listens on remove', () async {
+    list.service.create({'id': '1', 'foo': 'bar'});
+    await queue.next;
+
+    await list.service.remove('1');
+    await queue.next;
+    expect(list, isEmpty);
+  });
+}