Cleanup VM service

runtime/bin/vmservice/server.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of vmservice_io;
 
 class Server {
   int port;
   static ContentType jsonContentType = ContentType.parse('application/json');
   final VmService service;
   HttpServer _server;
 
   Server(this.service, this.port);
 
+  void _sendResponse(HttpRequest request, String response) {
+    request.response..headers.contentType = jsonContentType
+                    ..write(response)
+                    ..close();
+  }
+
   void _requestHandler(HttpRequest request) {
     // Allow cross origin requests.
     request.response.headers.add('Access-Control-Allow-Origin', '*');
 
     final String path =
           request.uri.path == '/' ? '/index.html' : request.uri.path;
 
     var resource = Resource.resources[path];
     if (resource != null) {
       // Serving up a static resource (e.g. .css, .html, .png).
       request.response.headers.contentType =
           ContentType.parse(resource.mimeType);
       request.response.add(resource.data);
       request.response.close();
       return;
     }
 
     var serviceRequest = new ServiceRequest();
     var r = serviceRequest.parse(request.uri);
-    if (!r) {
-      // Did not understand the request uri.
-      serviceRequest.setErrorResponse('Invalid request uri: ${request.uri}');
-    } else {
+    if (r) {
       var f = service.runningIsolates.route(serviceRequest);
-      if (f != null) {
-        f.then((_) {
-          request.response.headers.contentType = jsonContentType;
-          request.response.write(serviceRequest.response);
-          request.response.close();
-        }).catchError((e) { });
-        return;
-      } else {
-        // Nothing responds to this type of request.
-        serviceRequest.setErrorResponse('No route for: $path');
-      }
+      assert(f != null);
+      f.then((_) {
+        _sendResponse(request, serviceRequest.response);
+      }).catchError((e) {
+        // Error replying over HTTP.
+      });
+      return;
     }
-
-    request.response.headers.contentType = jsonContentType;
-    request.response.write(serviceRequest.response);
-    request.response.close();
+    _sendResponse(request, serviceRequest.response);
   }
 
   Future startServer() {
     return HttpServer.bind(InternetAddress.LOOPBACK_IP_V4, port).then((s) {
       // Only display message when port is automatically selected.
       var display_message = (port == 0);
       // Retrieve port.
       port = s.port;
       _server = s;
       _server.listen(_requestHandler);
       if (display_message) {
         print('VmService listening on port $port');
       }
       return s;
     });
   }
 }