Add appengine/gcloud/mustache dependencies.

pkg/appengine/lib/src/server/server.dart

+// Copyright (c) 2014, 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.
+
+library application;
+
+import 'dart:async';
+import 'dart:convert' show UTF8;
+import 'dart:io';
+
+import 'context_registry.dart';
+import 'http_wrapper.dart';
+
+void _info(String message) {
+  var formattedMessage = "${new DateTime.now()}: " + message;
+  print(formattedMessage);
+}
+
+String _getHostname() =>
+    (Process.runSync('/bin/hostname', []).stdout as String).trim();
+
+class AppEngineHttpServer {
+  final ContextRegistry _contextRegistry;
+
+  final String _hostname;
+  final int _port;
+
+  final String _localHostname;
+  final Completer _shutdownCompleter = new Completer();
+  int _pendingRequests = 0;
+
+  HttpServer _httpServer;
+
+  AppEngineHttpServer(this._contextRegistry,
+                      {String hostname: '0.0.0.0', int port: 8080})
+      : _localHostname = _getHostname(), _hostname = hostname, _port = port;
+
+  Future get done => _shutdownCompleter.future;
+
+  void run(applicationHandler(request, context)) {
+    var serviceHandlers = {
+        '/_ah/start' : _start,
+        '/_ah/health' : _health,
+        '/_ah/stop' : _stop
+    };
+
+    HttpServer.bind(_hostname, _port).then((HttpServer server) {
+      _httpServer = server;
+
+      server.listen((HttpRequest request) {
+        var hooksBeforeSendingResponse = [];
+        var appengineRequest = new AppengineHttpRequest(request);
+
+        _info("Got request: ${appengineRequest.uri}");
+
+        // Default handling is sending the request to the aplication.
+        var handler = applicationHandler;
+
+        // Check if the request path is one of the service handlers.
+        String path = appengineRequest.uri.path;
+        for (var pattern in serviceHandlers.keys) {
+          if (path.startsWith(pattern)) {
+            handler = serviceHandlers[pattern];
+            break;
+          }
+        }
+
+        _pendingRequests++;
+        var context = _contextRegistry.add(appengineRequest);
+        /*
+         * This sets the 'Server' header in the http response to the hostname
+         * of the machine the application is running on.
+         * It seems like the AppEngine VmRuntime stub (on the other end) will
+         * not accept the response if we use the default value.
+         */
+        appengineRequest.response.headers.set('Server', _localHostname);
+        appengineRequest.response.registerHook(
+            () => _contextRegistry.remove(appengineRequest));
+
+        appengineRequest.response.done.catchError((error) {
+          _info("Error while handling response: $error");
+          _pendingRequests--;
+          _checkShutdown();
+        });
+
+        handler(appengineRequest, context);
+      });
+    });
+  }
+
+  void _start(HttpRequest request, _) {
+    request.drain().then((_) {
+      _sendResponse(request.response, HttpStatus.OK, "ok");
+    });
+  }
+
+  void _health(HttpRequest request, _) {
+    request.drain().then((_) {
+      _sendResponse(request.response, HttpStatus.OK, "ok");
+    });
+  }
+
+  void _stop(HttpRequest request, _) {
+    request.drain().then((_) {
+      if (_httpServer != null) {
+        _httpServer.close().then((_) {
+          _httpServer = null;
+          _sendResponse(request.response, HttpStatus.OK, "ok");
+        });
+      } else {
+        _sendResponse(request.response, HttpStatus.CONFLICT, "fail");
+      }
+    });
+  }
+
+  _checkShutdown() {
+    if (_pendingRequests == 0 && _httpServer == null) {
+      _shutdownCompleter.complete();
+    }
+  }
+
+  void _sendResponse(HttpResponse response, int statusCode, String message) {
+    var data = UTF8.encode(message);
+    response.headers.contentType =
+        new ContentType('text', 'plain', charset: 'utf-8');
+    response.headers.set("Cache-Control", "no-cache");
+    response.headers.set("Server", _hostname);
+    response.contentLength = data.length;
+    response.statusCode = statusCode;
+    response.add(data);
+    response.close();
+  }
+}