Dart: Adds a content handler and a test.

examples/dart/wget.dart

+#!mojo mojo:dart_content_handler
+
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:mojo_application';
+import 'dart:mojo_bindings';
+import 'dart:mojo_core';
+import 'dart:typed_data';
+
+import 'package:mojo/services/network/public/interfaces/network_service.mojom.dart';
+import 'package:mojo/services/network/public/interfaces/url_loader.mojom.dart';
+
+class WGet extends ClientApplication {
+  NetworkServiceClient _networkServiceClient;
+  UrlLoaderClient _urlLoaderClient;
+
+  WGet(MojoMessagePipeEndpoint endpoint) : super(endpoint);
+
+  WGet.fromHandle(MojoHandle shellHandle) : super.fromHandle(shellHandle);
+
+  run(List<String> args) async {
+    if (args.length != 2) {
+      throw "Expected URL argument";
+    }
+
+    ByteData bodyData = await _getUrl(args[1]);
+    print("read ${bodyData.lengthInBytes} bytes");
+
+    _closeClients();
+    close();
+  }
+
+  Future<ByteData> _getUrl(String url) async {
+    _initClientsIfNeeded();
+
+    var urlRequest = new UrlRequest()
+        ..url = url
+        ..autoFollowRedirects = true;
+
+    var urlResponse = await _urlLoaderClient.callStart(urlRequest);
+    print("url => ${urlResponse.response.url}");
+    print("status_line => ${urlResponse.response.statusLine}");
+    print("mime_type => ${urlResponse.response.mimeType}");
+
+    return DataPipeDrainer.drainHandle(urlResponse.response.body);
+  }
+
+  void _initClientsIfNeeded() {
+    if (_networkServiceClient == null) {
+      var networkServiceClientEndpoint = connectToService(
+          "mojo:network_service", NetworkServiceInterface.name);
+      _networkServiceClient =
+          new NetworkServiceClient(networkServiceClientEndpoint);
+    }
+    if (_urlLoaderClient == null) {
+      _urlLoaderClient = new UrlLoaderClient.unbound();
+      _networkServiceClient.callCreateUrlLoader(_urlLoaderClient);
+    }
+  }
+
+  void _closeClients() {
+    _urlLoaderClient.close();
+    _networkServiceClient.close();
+    _urlLoaderClient = null;
+    _networkServiceClient = null;
+  }
+}
+
+main(List args) {
+  MojoHandle shellHandle = new MojoHandle(args[0]);
+  String url = args[1];
+  var wget = new WGet.fromHandle(shellHandle);
+  wget.listen();
+}