Add top-level server

pkg/analysis_server/lib/src/http_server.dart

Index: pkg/analysis_server/lib/src/http_server.dart
diff --git a/pkg/analysis_server/lib/src/http_server.dart b/pkg/analysis_server/lib/src/http_server.dart
new file mode 100644
index 0000000000000000000000000000000000000000..674f5e550038355dde3783d8cdc227fb7e6e28bf
--- /dev/null
+++ b/pkg/analysis_server/lib/src/http_server.dart
@@ -0,0 +1,182 @@
+// 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 http.server;
+
+import 'dart:io';
+
+import 'package:args/args.dart';
+
+import 'analysis_server.dart';
+import 'channel.dart';
+import 'domain_context.dart';
+import 'domain_server.dart';
+import 'get_handler.dart';
+
+/**
+ * Instances of the class [HttpServer] implement a simple HTTP server. The
+ * primary responsibility of this server is to listen for an UPGRADE request and
+ * to start an analysis server
+ */
+class HttpAnalysisServer {

[danrubel, 2014/01/21 22:36:27]

Consider moving this to /lib if others can instantiate it

[Brian Wilkerson, 2014/01/22 01:05:49]

Done

+  /**
+   * The name of the application that is used to start a server.
+   */
+  static const BINARY_NAME = 'server';
+
+  /**
+   * The name of the option used to print usage information.
+   */
+  static const String HELP_OPTION = "help";
+
+  /**
+   * The name of the option used to specify the port to which the server will
+   * connect.
+   */
+  static const String PORT_OPTION = "port";
+
+  /**
+   * The analysis server that was created when an UPGRADE request was received,
+   * or `null` if no such request has yet been received.
+   */
+  AnalysisServer server;
+
+  /**
+   * An object that can handle GET requests.
+   */
+  GetHandler getHandler;
+
+  /**
+   * Initialize a newly created HTTP server.
+   */
+  HttpAnalysisServer();
+
+  /**
+   * Use the given command-line arguments to start this server.
+   */
+  void start(List<String> args) {
+    ArgParser parser = new ArgParser();
+    parser.addFlag(
+        HELP_OPTION,
+        help: "print this help message without starting a server",
+        defaultsTo: false,
+        negatable: false);
+    parser.addOption(
+        PORT_OPTION,
+        help: "[port] the port on which the server will listen");
+
+    ArgResults results = parser.parse(args);
+    if (results[HELP_OPTION]) {
+      _printUsage(parser);
+      return;
+    }
+    if (results[PORT_OPTION] == null) {
+      print('Missing required port number');
+      print('');
+      _printUsage(parser);
+      return;
+    }
+
+    try {
+      int port = int.parse(results[PORT_OPTION]);
+      HttpServer.bind(InternetAddress.LOOPBACK_IP_V4, port).then(_handleServer);
+      print('Listening on port $port');
+    } on FormatException {
+      print('Invalid port number: ${results[PORT_OPTION]}');
+      print('');
+      _printUsage(parser);
+      return;
+    }
+  }
+
+  /**
+   * Attach a listener to a newly created HTTP server.
+   */
+  void _handleServer(HttpServer server) {
+    server.listen((HttpRequest request) {
+      List<String> updateValues = request.headers[HttpHeaders.UPGRADE];
+      if (updateValues != null && updateValues.indexOf('websocket') >= 0) {
+        if (server != null) {
+          _returnServerAlreadyStarted(request);
+          return;
+        }
+        WebSocketTransformer.upgrade(request).then((WebSocket websocket) {
+          _handleWebSocket(websocket);
+        });
+      } else if (request.method == 'GET') {
+        _handleGetRequest(request);
+      } else {
+        _returnUnknownRequest(request);
+      }
+    });
+  }
+
+  /**
+   * Handle a GET request received by the HTTP server.
+   */
+  void _handleGetRequest(HttpRequest request) {
+    if (getHandler == null) {
+      getHandler = new GetHandler();
+      getHandler.server = server;
+    }
+    getHandler.handleGetRequest(request);
+  }
+
+  /**
+   * Handle an UPGRADE request received by the HTTP server by creating and
+   * running an analysis server on a [WebSocket]-based communication channel.
+   */
+  void _handleWebSocket(WebSocket socket) {
+    server = new AnalysisServer(new WebSocketChannel(socket));
+    _initializeHandlers(server);
+    if (getHandler != null) {
+      getHandler.server = server;
+    }
+    server.run();
+  }
+
+  /**
+   * Initialize the handlers to be used by the given [server].
+   */
+  void _initializeHandlers(AnalysisServer server) {
+    server.handlers = [
+        new ServerDomainHandler(server),
+        new ContextDomainHandler(server),
+    ];
+  }
+
+  /**
+   * Print information about how to use the server.
+   */
+  void _printUsage(ArgParser parser) {
+    print('Usage: $BINARY_NAME [flags]');
+    print('');
+    print('Supported flags are:');
+    print(parser.getUsage());
+  }
+
+  /**
+   * Return an error in response to an UPGRADE request received after the server
+   * has already been started by a previous UPGRADE request.
+   */
+  void _returnServerAlreadyStarted(HttpRequest request) {
+    HttpResponse response = request.response;
+    response.statusCode = HttpStatus.SERVICE_UNAVAILABLE;
+    response.headers.add(HttpHeaders.CONTENT_TYPE, "text/plain");
+    response.write('The server has already been started');
+    response.close();
+  }
+
+  /**
+   * Return an error in response to an unrecognized request received by the HTTP
+   * server.
+   */
+  void _returnUnknownRequest(HttpRequest request) {
+    HttpResponse response = request.response;
+    response.statusCode = HttpStatus.NOT_FOUND;
+    response.headers.add(HttpHeaders.CONTENT_TYPE, "text/plain");
+    response.write('Not found');
+    response.close();
+  }
+}