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 'path.dart';
 import 'test_suite.dart';  // For TestUtils.
 // TODO(efortuna): Rewrite to not use the args library and simply take an
 // expected number of arguments, so test.dart doesn't rely on the args library?
 // See discussion on https://codereview.chromium.org/11931025/.
 import 'vendored_pkg/args/args.dart';
 import 'utils.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/BAR: This will serve the corresponding file from the packages
 ///                    directory (i.e. '$BuildDirectory/packages/BAR') or the
 ///                    passed-in package root
 /// /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';

 // TODO(kustermann,ricow): We could change this to the following scheme:
 // http://host:port/root_packages/X -> $BuildDir/packages/X
 // Issue: 8368

 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('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(new Path(args['build-directory']),
                                      args['csp'],
                                      args['runtime'],
                                      null,
                                      args['package-root']);
     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 = [];
   Path _buildDirectory = null;
   Path _dartDirectory = null;
   Path _packageRoot;
   final bool useContentSecurityPolicy;
   final String runtime;
   DispatchingServer _server;

   TestingServers(Path buildDirectory,
                  this.useContentSecurityPolicy,
                  [String this.runtime = 'none', String dartDirectory,
                   String packageRoot]) {
     _buildDirectory = TestUtils.absolutePath(buildDirectory);
     _dartDirectory = dartDirectory == null ? TestUtils.dartDir
         : new Path(dartDirectory);
     _packageRoot = packageRoot == null ?
       _buildDirectory.append('packages') :
       new Path(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}) {
     return _startHttpServer(host, port: port).then((server) {
       _server = server;
       return _startHttpServer(host,
                               port: crossOriginPort,
                               allowedPort:_serverList[0].port);
     });
   }

   String httpServerCommandline() {
     var dart = TestUtils.dartTestExecutable.toNativePath();
     var dartDir = TestUtils.dartDir;
     var script = dartDir.join(new Path("tools/testing/dart/http_server.dart"));
     var buildDirectory = _buildDirectory.toNativePath();
     var csp = useContentSecurityPolicy ? '--csp ' : '';
     return '$dart $script -p $port -c $crossOriginPort $csp'
            '--build-directory=$buildDirectory --runtime=$runtime '
            '--package-root=$_packageRoot';
   }

   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;
     });
   }

   void _handleFileOrDirectoryRequest(HttpRequest request,
                                      int allowedPort) {
     // Enable browsers to cache file/directory responses.
     var response = request.response;
     response.headers.set("Cache-Control",
                          "max-age=$_CACHE_EXPIRATION_IN_SECONDS");
     var path = _getFilePathFromRequestPath(request.uri.path);
     if (path != null) {
       var file = new File(path.toNativePath());
       file.exists().then((exists) {
         if (exists) {
           _sendFileContent(request, response, allowedPort, path, file);
         } else {
           var directory = new Directory(path.toNativePath());
           directory.exists().then((exists) {
             if (exists) {
               _listDirectory(directory).then((entries) {
                 _sendDirectoryListing(entries, 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);
         websocket.close();
       }, onError: (e) {
         DebugLogger.warning('HttpServer: error while echoing to WebSocket', e);
       });
     }).catchError((e) {
       DebugLogger.warning(
           'HttpServer: error while transforming to WebSocket', e);
     });
   }

   Path _getFilePathFromRequestPath(String urlRequestPath) {
     // Go to the top of the file to see an explanation of the URL path scheme.
     var requestPath = new Path(urlRequestPath.substring(1)).canonicalize();
     var pathSegments = requestPath.segments();
     if (pathSegments.length > 0) {
       var basePath;
       var relativePath;
       if (pathSegments[0] == PREFIX_BUILDDIR) {
         basePath = _buildDirectory;
         relativePath = new Path(
             pathSegments.skip(1).join('/'));
       } else if (pathSegments[0] == PREFIX_DARTDIR) {
         basePath = _dartDirectory;
         relativePath = new Path(
             pathSegments.skip(1).join('/'));
       }
       var packagesIndex = pathSegments.indexOf('packages');
       if (packagesIndex != -1) {
         var start = packagesIndex + 1;
         basePath = _packageRoot;
         relativePath = new Path(pathSegments.skip(start).join('/'));
       }
       if (basePath != null && relativePath != null) {
         return basePath.join(relativePath);
       }
     }
     return null;
   }

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

     directory.list().listen(
       (FileSystemEntity fse) {
         var filename = new Path(fse.path).filename;
         if (fse is File) {
           entries.add(new _Entry(filename, filename));
         } else if (fse is Directory) {
           entries.add(new _Entry(filename, '$filename/'));
         }
       },
       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="${new Path(request.uri.path).append(entry.name)}">'
           '${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,
                         Path path,
                         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 (path.filename.endsWith('.html')) {
       response.headers.set('Content-Type', 'text/html');
     } else if (path.filename.endsWith('.js')) {
       response.headers.set('Content-Type', 'application/javascript');
     } else if (path.filename.endsWith('.dart')) {
       response.headers.set('Content-Type', 'application/dart');
     } else if (path.filename.endsWith('.css')) {
       response.headers.set('Content-Type', 'text/css');
     } else if (path.filename.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 'path.dart';
	import 'test_suite.dart'; // For TestUtils.
	// TODO(efortuna): Rewrite to not use the args library and simply take an
	// expected number of arguments, so test.dart doesn't rely on the args library?
	// See discussion on https://codereview.chromium.org/11931025/.
	import 'vendored_pkg/args/args.dart';
	import 'utils.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/BAR: This will serve the corresponding file from the packages
	/// directory (i.e. '$BuildDirectory/packages/BAR') or the
	/// passed-in package root
	/// /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';

	// TODO(kustermann,ricow): We could change this to the following scheme:
	// http://host:port/root_packages/X -> $BuildDir/packages/X
	// Issue: 8368

	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('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(new Path(args['build-directory']),
	args['csp'],
	args['runtime'],
	null,
	args['package-root']);
	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 = [];
	Path _buildDirectory = null;
	Path _dartDirectory = null;
	Path _packageRoot;
	final bool useContentSecurityPolicy;
	final String runtime;
	DispatchingServer _server;

	TestingServers(Path buildDirectory,
	this.useContentSecurityPolicy,
	[String this.runtime = 'none', String dartDirectory,
	String packageRoot]) {
	_buildDirectory = TestUtils.absolutePath(buildDirectory);
	_dartDirectory = dartDirectory == null ? TestUtils.dartDir
	: new Path(dartDirectory);
	_packageRoot = packageRoot == null ?
	_buildDirectory.append('packages') :
	new Path(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}) {
	return _startHttpServer(host, port: port).then((server) {
	_server = server;
	return _startHttpServer(host,
	port: crossOriginPort,
	allowedPort:_serverList[0].port);
	});
	}

	String httpServerCommandline() {
	var dart = TestUtils.dartTestExecutable.toNativePath();
	var dartDir = TestUtils.dartDir;
	var script = dartDir.join(new Path("tools/testing/dart/http_server.dart"));
	var buildDirectory = _buildDirectory.toNativePath();
	var csp = useContentSecurityPolicy ? '--csp ' : '';
	return '$dart $script -p $port -c $crossOriginPort $csp'
	'--build-directory=$buildDirectory --runtime=$runtime '
	'--package-root=$_packageRoot';
	}

	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;
	});
	}

	void _handleFileOrDirectoryRequest(HttpRequest request,
	int allowedPort) {
	// Enable browsers to cache file/directory responses.
	var response = request.response;
	response.headers.set("Cache-Control",
	"max-age=$_CACHE_EXPIRATION_IN_SECONDS");
	var path = _getFilePathFromRequestPath(request.uri.path);
	if (path != null) {
	var file = new File(path.toNativePath());
	file.exists().then((exists) {
	if (exists) {
	_sendFileContent(request, response, allowedPort, path, file);
	} else {
	var directory = new Directory(path.toNativePath());
	directory.exists().then((exists) {
	if (exists) {
	_listDirectory(directory).then((entries) {
	_sendDirectoryListing(entries, 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);
	websocket.close();
	}, onError: (e) {
	DebugLogger.warning('HttpServer: error while echoing to WebSocket', e);
	});
	}).catchError((e) {
	DebugLogger.warning(
	'HttpServer: error while transforming to WebSocket', e);
	});
	}

	Path _getFilePathFromRequestPath(String urlRequestPath) {
	// Go to the top of the file to see an explanation of the URL path scheme.
	var requestPath = new Path(urlRequestPath.substring(1)).canonicalize();
	var pathSegments = requestPath.segments();
	if (pathSegments.length > 0) {
	var basePath;
	var relativePath;
	if (pathSegments[0] == PREFIX_BUILDDIR) {
	basePath = _buildDirectory;
	relativePath = new Path(
	pathSegments.skip(1).join('/'));
	} else if (pathSegments[0] == PREFIX_DARTDIR) {
	basePath = _dartDirectory;
	relativePath = new Path(
	pathSegments.skip(1).join('/'));
	}
	var packagesIndex = pathSegments.indexOf('packages');
	if (packagesIndex != -1) {
	var start = packagesIndex + 1;
	basePath = _packageRoot;
	relativePath = new Path(pathSegments.skip(start).join('/'));
	}
	if (basePath != null && relativePath != null) {
	return basePath.join(relativePath);
	}
	}
	return null;
	}

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

	directory.list().listen(
	(FileSystemEntity fse) {
	var filename = new Path(fse.path).filename;
	if (fse is File) {
	entries.add(new _Entry(filename, filename));
	} else if (fse is Directory) {
	entries.add(new _Entry(filename, '$filename/'));
	}
	},
	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="${new Path(request.uri.path).append(entry.name)}">'
	'${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,
	Path path,
	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 (path.filename.endsWith('.html')) {
	response.headers.set('Content-Type', 'text/html');
	} else if (path.filename.endsWith('.js')) {
	response.headers.set('Content-Type', 'application/javascript');
	} else if (path.filename.endsWith('.dart')) {
	response.headers.set('Content-Type', 'application/dart');
	} else if (path.filename.endsWith('.css')) {
	response.headers.set('Content-Type', 'text/css');
	} else if (path.filename.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);
	}
	}