tools/testing/dart/http_server.dart - sdk.git - Git at Google

 // 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.

 library http_server;

 import 'dart:async';
 import 'dart:io';

 import 'dart:convert' show HtmlEscape;

 import 'test_suite.dart'; // For TestUtils.
 import 'vendored_pkg/args/args.dart';
 import 'utils.dart';
 import 'package:package_resolver/package_resolver.dart';

 class DispatchingServer {
   HttpServer server;
   Map<String, Function> _handlers = new Map<String, Function>();
   Function _notFound;

   DispatchingServer(
       this.server, void onError(e), void this._notFound(HttpRequest request)) {
     server.listen(_dispatchRequest, onError: onError);
   }

   void addHandler(String prefix, void handler(HttpRequest request)) {
     _handlers[prefix] = handler;
   }

   void _dispatchRequest(HttpRequest request) {
     // If the request path matches a prefix in _handlers, send it to that
     // handler.  Otherwise, run the notFound handler.
     for (String prefix in _handlers.keys) {
       if (request.uri.path.startsWith(prefix)) {
         _handlers[prefix](request);
         return;
       }
     }
     _notFound(request);
   }
 }

 /// Interface of the HTTP server:
 ///
 /// /echo: This will stream the data received in the request stream back
 ///        to the client.
 /// /root_dart/X: This will serve the corresponding file from the dart
 ///               directory (i.e. '$DartDirectory/X').
 /// /root_build/X: This will serve the corresponding file from the build
 ///                directory (i.e. '$BuildDirectory/X').
 /// /FOO/packages/PAZ/BAR: This will serve files from the packages listed in
 ///      the package spec .packages.  Supports a package
 ///      root or custom package spec, and uses [dart_dir]/.packages
 ///      as the default. This will serve file lib/BAR from the package PAZ.
 /// /ws: This will upgrade the connection to a WebSocket connection and echo
 ///      all data back to the client.
 ///
 /// In case a path does not refer to a file but rather to a directory, a
 /// directory listing will be displayed.

 const PREFIX_BUILDDIR = 'root_build';
 const PREFIX_DARTDIR = 'root_dart';

 main(List<String> arguments) {
   // This script is in [dart]/tools/testing/dart.
   TestUtils.setDartDirUri(Platform.script.resolve('../../..'));
   /** Convenience method for local testing. */
   var parser = new ArgParser();
   parser.addOption('port',
       abbr: 'p',
       help: 'The main server port we wish to respond to requests.',
       defaultsTo: '0');
   parser.addOption('crossOriginPort',
       abbr: 'c',
       help: 'A different port that accepts request from the main server port.',
       defaultsTo: '0');
   parser.addFlag('help',
       abbr: 'h', negatable: false, help: 'Print this usage information.');
   parser.addOption('build-directory', help: 'The build directory to use.');
   parser.addOption('package-root', help: 'The package root to use.');
   parser.addOption('packages', help: 'The package spec file to use.');
   parser.addOption('network',
       help: 'The network interface to use.', defaultsTo: '0.0.0.0');
   parser.addFlag('csp',
       help: 'Use Content Security Policy restrictions.', defaultsTo: false);
   parser.addOption('runtime',
       help: 'The runtime we are using (for csp flags).', defaultsTo: 'none');

   var args = parser.parse(arguments);
   if (args['help']) {
     print(parser.getUsage());
   } else {
     var servers = new TestingServers(args['build-directory'],
         args['csp'], args['runtime'], null, args['package-root'],
         args['packages']);
     var port = int.parse(args['port']);
     var crossOriginPort = int.parse(args['crossOriginPort']);
     servers
         .startServers(args['network'],
             port: port, crossOriginPort: crossOriginPort)
         .then((_) {
       DebugLogger.info('Server listening on port ${servers.port}');
       DebugLogger.info('Server listening on port ${servers.crossOriginPort}');
     });
   }
 }

 /**
  * Runs a set of servers that are initialized specifically for the needs of our
  * test framework, such as dealing with package-root.
  */
 class TestingServers {
   static final _CACHE_EXPIRATION_IN_SECONDS = 30;
   static final _HARMLESS_REQUEST_PATH_ENDINGS = [
     "/apple-touch-icon.png",
     "/apple-touch-icon-precomposed.png",
     "/favicon.ico",
     "/foo",
     "/bar",
     "/NonExistingFile",
     "IntentionallyMissingFile",
   ];

   List _serverList = [];
   Uri _buildDirectory = null;
   Uri _dartDirectory = null;
   Uri _packageRoot;
   Uri _packages;
   final bool useContentSecurityPolicy;
   final String runtime;
   DispatchingServer _server;
   SyncPackageResolver _resolver;

   TestingServers(String buildDirectory, this.useContentSecurityPolicy,
       [String this.runtime = 'none',
       String dartDirectory,
       String packageRoot,
       String packages]) {
     _buildDirectory = Uri.base.resolveUri(new Uri.directory(buildDirectory));
     if (dartDirectory == null) {
       _dartDirectory = TestUtils.dartDirUri;
     } else {
       _dartDirectory = Uri.base.resolveUri(new Uri.directory(dartDirectory));
     }
     if (packageRoot == null ) {
       if (packages == null ) {
         _packages = _dartDirectory.resolve('.packages');
       } else {
         _packages = new Uri.file(packages);
       }
     } else {
       _packageRoot = new Uri.directory(packageRoot);
     }
   }

   int get port => _serverList[0].port;
   int get crossOriginPort => _serverList[1].port;
   DispatchingServer get server => _server;

   /**
    * [startServers] will start two Http servers.
    * The first server listens on [port] and sets
    *   "Access-Control-Allow-Origin: *"
    * The second server listens on [crossOriginPort] and sets
    *   "Access-Control-Allow-Origin: client:port1
    *   "Access-Control-Allow-Credentials: true"
    */
   Future startServers(String host,
                       {int port: 0,
                        int crossOriginPort: 0}) async {
     if (_packages != null) {
       _resolver = await SyncPackageResolver.loadConfig(_packages);
     } else {
       _resolver = new SyncPackageResolver.root(_packageRoot);
     }
     _server = await _startHttpServer(host, port: port);
     await _startHttpServer(host, port: crossOriginPort,
         allowedPort: _serverList[0].port);
   }

   String httpServerCommandline() {
     var dart = Platform.resolvedExecutable;
     var script = _dartDirectory.resolve('tools/testing/dart/http_server.dart');
     var buildDirectory = _buildDirectory.toFilePath();
     var command = [dart, script.toFilePath(),
       '-p', port,
       '-c', crossOriginPort,
       '--build-directory=$buildDirectory',
       '--runtime=$runtime'];
     if (useContentSecurityPolicy) {
       command.add('--csp');
     }
     if (_packages != null) {
       command.add('--packages=${_packages.toFilePath()}');
     } else if (_packageRoot != null) {
       command.add('--package-root=${_packageRoot.toFilePath()}');
     }
     return command.join(' ');
   }

   void stopServers() {
     for (var server in _serverList) {
       server.close();
     }
   }

   void _onError(e) {
     DebugLogger.error('HttpServer: an error occured', e);
   }

   Future _startHttpServer(String host, {int port: 0, int allowedPort: -1}) {
     return HttpServer.bind(host, port).then((HttpServer httpServer) {
       var server = new DispatchingServer(httpServer, _onError, _sendNotFound);
       server.addHandler('/echo', _handleEchoRequest);
       server.addHandler('/ws', _handleWebSocketRequest);
       fileHandler(request) {
         _handleFileOrDirectoryRequest(request, allowedPort);
       }
       server.addHandler('/$PREFIX_BUILDDIR', fileHandler);
       server.addHandler('/$PREFIX_DARTDIR', fileHandler);
       server.addHandler('/packages', fileHandler);
       _serverList.add(httpServer);
       return server;
     });
   }

   _handleFileOrDirectoryRequest(HttpRequest request,
                                 int allowedPort) async {
     // Enable browsers to cache file/directory responses.
     var response = request.response;
     response.headers
         .set("Cache-Control", "max-age=$_CACHE_EXPIRATION_IN_SECONDS");
     var path = _getFileUriFromRequestUri(request.uri);
     if (path != null) {
       var file = new File.fromUri(path);
       var directory = new Directory.fromUri(path);
       if (await file.exists()){
           _sendFileContent(request, response, allowedPort, file);
       } else if (await directory.exists()) {
         _sendDirectoryListing(
             await _listDirectory(directory), request, response);
       } else {
         _sendNotFound(request);
       }
     } else {
       if (request.uri.path == '/') {
         var entries = [
           new _Entry('root_dart', 'root_dart/'),
           new _Entry('root_build', 'root_build/'),
           new _Entry('echo', 'echo')
         ];
         _sendDirectoryListing(entries, request, response);
       } else {
         _sendNotFound(request);
       }
     }
   }

   void _handleEchoRequest(HttpRequest request) {
     request.response.headers.set("Access-Control-Allow-Origin", "*");
     request.pipe(request.response).catchError((e) {
       DebugLogger.warning(
           'HttpServer: error while closing the response stream', e);
     });
   }

   void _handleWebSocketRequest(HttpRequest request) {
     WebSocketTransformer.upgrade(request).then((websocket) {
       // We ignore failures to write to the socket, this happens if the browser
       // closes the connection.
       websocket.done.catchError((_) {});
       websocket.listen((data) {
         websocket.add(data);
         if (data == 'close-with-error') {
           // Note: according to the web-sockets spec, a reason longer than 123
           // bytes will produce a SyntaxError on the client.
           websocket.close(WebSocketStatus.UNSUPPORTED_DATA, 'X' * 124);
         } else {
           websocket.close();
         }
       }, onError: (e) {
         DebugLogger.warning('HttpServer: error while echoing to WebSocket', e);
       });
     }).catchError((e) {
       DebugLogger.warning(
           'HttpServer: error while transforming to WebSocket', e);
     });
   }

   Uri _getFileUriFromRequestUri(Uri request) {
     // Go to the top of the file to see an explanation of the URL path scheme.
     List<String> pathSegments = request.normalizePath().pathSegments;
     if (pathSegments.length == 0) return null;
     int packagesIndex = pathSegments.indexOf('packages');
     if (packagesIndex != -1) {
       var packageUri = new Uri(scheme: 'package',
           pathSegments: pathSegments.skip(packagesIndex + 1));
       return _resolver.resolveUri(packageUri);
     }
     if (pathSegments[0] == PREFIX_BUILDDIR) {
       return _buildDirectory.resolve(pathSegments.skip(1).join('/'));
     }
     if (pathSegments[0] == PREFIX_DARTDIR) {
       return _dartDirectory.resolve(pathSegments.skip(1).join('/'));
     }
     return null;
   }

   Future<List<_Entry>> _listDirectory(Directory directory) {
     var completer = new Completer();
     var entries = [];

     directory.list().listen((FileSystemEntity fse) {
       var segments = fse.uri.pathSegments;
       if (fse is File) {
         var filename = segments.last;
         entries.add(new _Entry(filename, filename));
       } else if (fse is Directory) {
         var dirname = segments[segments.length - 2];
         entries.add(new _Entry(dirname, '$dirname/'));
       }
     }, onDone: () {
       completer.complete(entries);
     });
     return completer.future;
   }

   void _sendDirectoryListing(
       List<_Entry> entries, HttpRequest request, HttpResponse response) {
     response.headers.set('Content-Type', 'text/html');
     var header = '''<!DOCTYPE html>
     <html>
     <head>
       <title>${request.uri.path}</title>
     </head>
     <body>
       <code>
         <div>${request.uri.path}</div>
         <hr/>
         <ul>''';
     var footer = '''
         </ul>
       </code>
     </body>
     </html>''';

     entries.sort();
     response.write(header);
     for (var entry in entries) {
       response.write(
           '<li><a href="${request.uri}/${entry.name}">'
           '${entry.displayName}</a></li>');
     }
     response.write(footer);
     response.close();
     response.done.catchError((e) {
       DebugLogger.warning(
           'HttpServer: error while closing the response stream', e);
     });
   }

   void _sendFileContent(HttpRequest request, HttpResponse response,
       int allowedPort, File file) {
     if (allowedPort != -1) {
       var headerOrigin = request.headers.value('Origin');
       var allowedOrigin;
       if (headerOrigin != null) {
         var origin = Uri.parse(headerOrigin);
         // Allow loading from http://*:$allowedPort in browsers.
         allowedOrigin = '${origin.scheme}://${origin.host}:${allowedPort}';
       } else {
         // IE10 appears to be bugged and is not sending the Origin header
         // when making CORS requests to the same domain but different port.
         allowedOrigin = '*';
       }

       response.headers.set("Access-Control-Allow-Origin", allowedOrigin);
       response.headers.set('Access-Control-Allow-Credentials', 'true');
     } else {
       // No allowedPort specified. Allow from anywhere (but cross-origin
       // requests *with credentials* will fail because you can't use "*").
       response.headers.set("Access-Control-Allow-Origin", "*");
     }
     if (useContentSecurityPolicy) {
       // Chrome respects the standardized Content-Security-Policy header,
       // whereas Firefox and IE10 use X-Content-Security-Policy. Safari
       // still uses the WebKit- prefixed version.
       var content_header_value = "script-src 'self'; object-src 'self'";
       for (var header in [
         "Content-Security-Policy",
         "X-Content-Security-Policy"
       ]) {
         response.headers.set(header, content_header_value);
       }
       if (const ["safari"].contains(runtime)) {
         response.headers.set("X-WebKit-CSP", content_header_value);
       }
     }
     if (file.path.endsWith('.html')) {
       response.headers.set('Content-Type', 'text/html');
     } else if (file.path.endsWith('.js')) {
       response.headers.set('Content-Type', 'application/javascript');
     } else if (file.path.endsWith('.dart')) {
       response.headers.set('Content-Type', 'application/dart');
     } else if (file.path.endsWith('.css')) {
       response.headers.set('Content-Type', 'text/css');
     } else if (file.path.endsWith('.xml')) {
       response.headers.set('Content-Type', 'text/xml');
     }
     response.headers.removeAll("X-Frame-Options");
     file.openRead().pipe(response).catchError((e) {
       DebugLogger.warning(
           'HttpServer: error while closing the response stream', e);
     });
   }

   void _sendNotFound(HttpRequest request) {
     bool isHarmlessPath(String path) {
       return _HARMLESS_REQUEST_PATH_ENDINGS.any((pattern) {
         return path.contains(pattern);
       });
     }
     if (!isHarmlessPath(request.uri.path)) {
       DebugLogger.warning('HttpServer: could not find file for request path: '
           '"${request.uri.path}"');
     }
     var response = request.response;
     response.statusCode = HttpStatus.NOT_FOUND;

     // Send a nice HTML page detailing the error message.  Most browsers expect
     // this, for example, Chrome will simply display a blank page if you don't
     // provide any information.  A nice side effect of this is to work around
     // Firefox bug 1016313
     // (https://bugzilla.mozilla.org/show_bug.cgi?id=1016313).
     response.headers.set(HttpHeaders.CONTENT_TYPE, 'text/html');
     String escapedPath = const HtmlEscape().convert(request.uri.path);
     response.write("""
 <!DOCTYPE html>
 <html lang='en'>
 <head>
 <title>Not Found</title>
 </head>
 <body>
 <h1>Not Found</h1>
 <p style='white-space:pre'>The file '$escapedPath\' could not be found.</p>
 </body>
 </html>
 """);
     response.close();
     response.done.catchError((e) {
       DebugLogger.warning(
           'HttpServer: error while closing the response stream', e);
     });
   }
 }

 // Helper class for displaying directory listings.
 class _Entry implements Comparable {
   final String name;
   final String displayName;

   _Entry(this.name, this.displayName);

   int compareTo(_Entry other) {
     return name.compareTo(other.name);
   }
 }
	// 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.

	library http_server;

	import 'dart:async';
	import 'dart:io';

	import 'dart:convert' show HtmlEscape;

	import 'test_suite.dart'; // For TestUtils.
	import 'vendored_pkg/args/args.dart';
	import 'utils.dart';
	import 'package:package_resolver/package_resolver.dart';

	class DispatchingServer {
	HttpServer server;
	Map<String, Function> _handlers = new Map<String, Function>();
	Function _notFound;

	DispatchingServer(
	this.server, void onError(e), void this._notFound(HttpRequest request)) {
	server.listen(_dispatchRequest, onError: onError);
	}

	void addHandler(String prefix, void handler(HttpRequest request)) {
	_handlers[prefix] = handler;
	}

	void _dispatchRequest(HttpRequest request) {
	// If the request path matches a prefix in _handlers, send it to that
	// handler. Otherwise, run the notFound handler.
	for (String prefix in _handlers.keys) {
	if (request.uri.path.startsWith(prefix)) {
	_handlers[prefix](request);
	return;
	}
	}
	_notFound(request);
	}
	}

	/// Interface of the HTTP server:
	///
	/// /echo: This will stream the data received in the request stream back
	/// to the client.
	/// /root_dart/X: This will serve the corresponding file from the dart
	/// directory (i.e. '$DartDirectory/X').
	/// /root_build/X: This will serve the corresponding file from the build
	/// directory (i.e. '$BuildDirectory/X').
	/// /FOO/packages/PAZ/BAR: This will serve files from the packages listed in
	/// the package spec .packages. Supports a package
	/// root or custom package spec, and uses [dart_dir]/.packages
	/// as the default. This will serve file lib/BAR from the package PAZ.
	/// /ws: This will upgrade the connection to a WebSocket connection and echo
	/// all data back to the client.
	///
	/// In case a path does not refer to a file but rather to a directory, a
	/// directory listing will be displayed.

	const PREFIX_BUILDDIR = 'root_build';
	const PREFIX_DARTDIR = 'root_dart';

	main(List<String> arguments) {
	// This script is in [dart]/tools/testing/dart.
	TestUtils.setDartDirUri(Platform.script.resolve('../../..'));
	/** Convenience method for local testing. */
	var parser = new ArgParser();
	parser.addOption('port',
	abbr: 'p',
	help: 'The main server port we wish to respond to requests.',
	defaultsTo: '0');
	parser.addOption('crossOriginPort',
	abbr: 'c',
	help: 'A different port that accepts request from the main server port.',
	defaultsTo: '0');
	parser.addFlag('help',
	abbr: 'h', negatable: false, help: 'Print this usage information.');
	parser.addOption('build-directory', help: 'The build directory to use.');
	parser.addOption('package-root', help: 'The package root to use.');
	parser.addOption('packages', help: 'The package spec file to use.');
	parser.addOption('network',
	help: 'The network interface to use.', defaultsTo: '0.0.0.0');
	parser.addFlag('csp',
	help: 'Use Content Security Policy restrictions.', defaultsTo: false);
	parser.addOption('runtime',
	help: 'The runtime we are using (for csp flags).', defaultsTo: 'none');

	var args = parser.parse(arguments);
	if (args['help']) {
	print(parser.getUsage());
	} else {
	var servers = new TestingServers(args['build-directory'],
	args['csp'], args['runtime'], null, args['package-root'],
	args['packages']);
	var port = int.parse(args['port']);
	var crossOriginPort = int.parse(args['crossOriginPort']);
	servers
	.startServers(args['network'],
	port: port, crossOriginPort: crossOriginPort)
	.then((_) {
	DebugLogger.info('Server listening on port ${servers.port}');
	DebugLogger.info('Server listening on port ${servers.crossOriginPort}');
	});
	}
	}

	/**
	* Runs a set of servers that are initialized specifically for the needs of our
	* test framework, such as dealing with package-root.
	*/
	class TestingServers {
	static final _CACHE_EXPIRATION_IN_SECONDS = 30;
	static final _HARMLESS_REQUEST_PATH_ENDINGS = [
	"/apple-touch-icon.png",
	"/apple-touch-icon-precomposed.png",
	"/favicon.ico",
	"/foo",
	"/bar",
	"/NonExistingFile",
	"IntentionallyMissingFile",
	];

	List _serverList = [];
	Uri _buildDirectory = null;
	Uri _dartDirectory = null;
	Uri _packageRoot;
	Uri _packages;
	final bool useContentSecurityPolicy;
	final String runtime;
	DispatchingServer _server;
	SyncPackageResolver _resolver;

	TestingServers(String buildDirectory, this.useContentSecurityPolicy,
	[String this.runtime = 'none',
	String dartDirectory,
	String packageRoot,
	String packages]) {
	_buildDirectory = Uri.base.resolveUri(new Uri.directory(buildDirectory));
	if (dartDirectory == null) {
	_dartDirectory = TestUtils.dartDirUri;
	} else {
	_dartDirectory = Uri.base.resolveUri(new Uri.directory(dartDirectory));
	}
	if (packageRoot == null ) {
	if (packages == null ) {
	_packages = _dartDirectory.resolve('.packages');
	} else {
	_packages = new Uri.file(packages);
	}
	} else {
	_packageRoot = new Uri.directory(packageRoot);
	}
	}

	int get port => _serverList[0].port;
	int get crossOriginPort => _serverList[1].port;
	DispatchingServer get server => _server;

	/**
	* [startServers] will start two Http servers.
	* The first server listens on [port] and sets
	* "Access-Control-Allow-Origin: *"
	* The second server listens on [crossOriginPort] and sets
	* "Access-Control-Allow-Origin: client:port1
	* "Access-Control-Allow-Credentials: true"
	*/
	Future startServers(String host,
	{int port: 0,
	int crossOriginPort: 0}) async {
	if (_packages != null) {
	_resolver = await SyncPackageResolver.loadConfig(_packages);
	} else {
	_resolver = new SyncPackageResolver.root(_packageRoot);
	}
	_server = await _startHttpServer(host, port: port);
	await _startHttpServer(host, port: crossOriginPort,
	allowedPort: _serverList[0].port);
	}

	String httpServerCommandline() {
	var dart = Platform.resolvedExecutable;
	var script = _dartDirectory.resolve('tools/testing/dart/http_server.dart');
	var buildDirectory = _buildDirectory.toFilePath();
	var command = [dart, script.toFilePath(),
	'-p', port,
	'-c', crossOriginPort,
	'--build-directory=$buildDirectory',
	'--runtime=$runtime'];
	if (useContentSecurityPolicy) {
	command.add('--csp');
	}
	if (_packages != null) {
	command.add('--packages=${_packages.toFilePath()}');
	} else if (_packageRoot != null) {
	command.add('--package-root=${_packageRoot.toFilePath()}');
	}
	return command.join(' ');
	}

	void stopServers() {
	for (var server in _serverList) {
	server.close();
	}
	}

	void _onError(e) {
	DebugLogger.error('HttpServer: an error occured', e);
	}

	Future _startHttpServer(String host, {int port: 0, int allowedPort: -1}) {
	return HttpServer.bind(host, port).then((HttpServer httpServer) {
	var server = new DispatchingServer(httpServer, _onError, _sendNotFound);
	server.addHandler('/echo', _handleEchoRequest);
	server.addHandler('/ws', _handleWebSocketRequest);
	fileHandler(request) {
	_handleFileOrDirectoryRequest(request, allowedPort);
	}
	server.addHandler('/$PREFIX_BUILDDIR', fileHandler);
	server.addHandler('/$PREFIX_DARTDIR', fileHandler);
	server.addHandler('/packages', fileHandler);
	_serverList.add(httpServer);
	return server;
	});
	}

	_handleFileOrDirectoryRequest(HttpRequest request,
	int allowedPort) async {
	// Enable browsers to cache file/directory responses.
	var response = request.response;
	response.headers
	.set("Cache-Control", "max-age=$_CACHE_EXPIRATION_IN_SECONDS");
	var path = _getFileUriFromRequestUri(request.uri);
	if (path != null) {
	var file = new File.fromUri(path);
	var directory = new Directory.fromUri(path);
	if (await file.exists()){
	_sendFileContent(request, response, allowedPort, file);
	} else if (await directory.exists()) {
	_sendDirectoryListing(
	await _listDirectory(directory), request, response);
	} else {
	_sendNotFound(request);
	}
	} else {
	if (request.uri.path == '/') {
	var entries = [
	new _Entry('root_dart', 'root_dart/'),
	new _Entry('root_build', 'root_build/'),
	new _Entry('echo', 'echo')
	];
	_sendDirectoryListing(entries, request, response);
	} else {
	_sendNotFound(request);
	}
	}
	}

	void _handleEchoRequest(HttpRequest request) {
	request.response.headers.set("Access-Control-Allow-Origin", "*");
	request.pipe(request.response).catchError((e) {
	DebugLogger.warning(
	'HttpServer: error while closing the response stream', e);
	});
	}

	void _handleWebSocketRequest(HttpRequest request) {
	WebSocketTransformer.upgrade(request).then((websocket) {
	// We ignore failures to write to the socket, this happens if the browser
	// closes the connection.
	websocket.done.catchError((_) {});
	websocket.listen((data) {
	websocket.add(data);
	if (data == 'close-with-error') {
	// Note: according to the web-sockets spec, a reason longer than 123
	// bytes will produce a SyntaxError on the client.
	websocket.close(WebSocketStatus.UNSUPPORTED_DATA, 'X' * 124);
	} else {
	websocket.close();
	}
	}, onError: (e) {
	DebugLogger.warning('HttpServer: error while echoing to WebSocket', e);
	});
	}).catchError((e) {
	DebugLogger.warning(
	'HttpServer: error while transforming to WebSocket', e);
	});
	}

	Uri _getFileUriFromRequestUri(Uri request) {
	// Go to the top of the file to see an explanation of the URL path scheme.
	List<String> pathSegments = request.normalizePath().pathSegments;
	if (pathSegments.length == 0) return null;
	int packagesIndex = pathSegments.indexOf('packages');
	if (packagesIndex != -1) {
	var packageUri = new Uri(scheme: 'package',
	pathSegments: pathSegments.skip(packagesIndex + 1));
	return _resolver.resolveUri(packageUri);
	}
	if (pathSegments[0] == PREFIX_BUILDDIR) {
	return _buildDirectory.resolve(pathSegments.skip(1).join('/'));
	}
	if (pathSegments[0] == PREFIX_DARTDIR) {
	return _dartDirectory.resolve(pathSegments.skip(1).join('/'));
	}
	return null;
	}

	Future<List<_Entry>> _listDirectory(Directory directory) {
	var completer = new Completer();
	var entries = [];

	directory.list().listen((FileSystemEntity fse) {
	var segments = fse.uri.pathSegments;
	if (fse is File) {
	var filename = segments.last;
	entries.add(new _Entry(filename, filename));
	} else if (fse is Directory) {
	var dirname = segments[segments.length - 2];
	entries.add(new _Entry(dirname, '$dirname/'));
	}
	}, onDone: () {
	completer.complete(entries);
	});
	return completer.future;
	}

	void _sendDirectoryListing(
	List<_Entry> entries, HttpRequest request, HttpResponse response) {
	response.headers.set('Content-Type', 'text/html');
	var header = '''<!DOCTYPE html>
	<html>
	<head>
	<title>${request.uri.path}</title>
	</head>
	<body>
	<code>
	<div>${request.uri.path}</div>
	<hr/>
	<ul>''';
	var footer = '''
	</ul>
	</code>
	</body>
	</html>''';

	entries.sort();
	response.write(header);
	for (var entry in entries) {
	response.write(
	'<li><a href="${request.uri}/${entry.name}">'
	'${entry.displayName}</a></li>');
	}
	response.write(footer);
	response.close();
	response.done.catchError((e) {
	DebugLogger.warning(
	'HttpServer: error while closing the response stream', e);
	});
	}

	void _sendFileContent(HttpRequest request, HttpResponse response,
	int allowedPort, File file) {
	if (allowedPort != -1) {
	var headerOrigin = request.headers.value('Origin');
	var allowedOrigin;
	if (headerOrigin != null) {
	var origin = Uri.parse(headerOrigin);
	// Allow loading from http://*:$allowedPort in browsers.
	allowedOrigin = '${origin.scheme}://${origin.host}:${allowedPort}';
	} else {
	// IE10 appears to be bugged and is not sending the Origin header
	// when making CORS requests to the same domain but different port.
	allowedOrigin = '*';
	}

	response.headers.set("Access-Control-Allow-Origin", allowedOrigin);
	response.headers.set('Access-Control-Allow-Credentials', 'true');
	} else {
	// No allowedPort specified. Allow from anywhere (but cross-origin
	// requests with credentials will fail because you can't use "*").
	response.headers.set("Access-Control-Allow-Origin", "*");
	}
	if (useContentSecurityPolicy) {
	// Chrome respects the standardized Content-Security-Policy header,
	// whereas Firefox and IE10 use X-Content-Security-Policy. Safari
	// still uses the WebKit- prefixed version.
	var content_header_value = "script-src 'self'; object-src 'self'";
	for (var header in [
	"Content-Security-Policy",
	"X-Content-Security-Policy"
	]) {
	response.headers.set(header, content_header_value);
	}
	if (const ["safari"].contains(runtime)) {
	response.headers.set("X-WebKit-CSP", content_header_value);
	}
	}
	if (file.path.endsWith('.html')) {
	response.headers.set('Content-Type', 'text/html');
	} else if (file.path.endsWith('.js')) {
	response.headers.set('Content-Type', 'application/javascript');
	} else if (file.path.endsWith('.dart')) {
	response.headers.set('Content-Type', 'application/dart');
	} else if (file.path.endsWith('.css')) {
	response.headers.set('Content-Type', 'text/css');
	} else if (file.path.endsWith('.xml')) {
	response.headers.set('Content-Type', 'text/xml');
	}
	response.headers.removeAll("X-Frame-Options");
	file.openRead().pipe(response).catchError((e) {
	DebugLogger.warning(
	'HttpServer: error while closing the response stream', e);
	});
	}

	void _sendNotFound(HttpRequest request) {
	bool isHarmlessPath(String path) {
	return _HARMLESS_REQUEST_PATH_ENDINGS.any((pattern) {
	return path.contains(pattern);
	});
	}
	if (!isHarmlessPath(request.uri.path)) {
	DebugLogger.warning('HttpServer: could not find file for request path: '
	'"${request.uri.path}"');
	}
	var response = request.response;
	response.statusCode = HttpStatus.NOT_FOUND;

	// Send a nice HTML page detailing the error message. Most browsers expect
	// this, for example, Chrome will simply display a blank page if you don't
	// provide any information. A nice side effect of this is to work around
	// Firefox bug 1016313
	// (https://bugzilla.mozilla.org/show_bug.cgi?id=1016313).
	response.headers.set(HttpHeaders.CONTENT_TYPE, 'text/html');
	String escapedPath = const HtmlEscape().convert(request.uri.path);
	response.write("""
	<!DOCTYPE html>
	<html lang='en'>
	<head>
	<title>Not Found</title>
	</head>
	<body>
	<h1>Not Found</h1>
	<p style='white-space:pre'>The file '$escapedPath\' could not be found.</p>
	</body>
	</html>
	""");
	response.close();
	response.done.catchError((e) {
	DebugLogger.warning(
	'HttpServer: error while closing the response stream', e);
	});
	}
	}

	// Helper class for displaying directory listings.
	class _Entry implements Comparable {
	final String name;
	final String displayName;

	_Entry(this.name, this.displayName);

	int compareTo(_Entry other) {
	return name.compareTo(other.name);
	}
	}