Add a SafeHttpServer shim to work around issue 9140.

utils/pub/safe_http_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.
+
+library safe_http_server;
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:uri';
+
+// TODO(nweiz): remove this when issue 9140 is fixed.
+/// A wrapper around [HttpServer] that swallows errors caused by requests
+/// behaving badly. This provides the following guarantees:
+///
+/// * The [SafeHttpServer.listen] onError callback will only emit server-wide
+///   errors. It will not emit errors for requests that were unparseable or
+///   where the connection was closed too soon.
+/// * [HttpResponse.done] will emit no errors.
+///
+/// The [HttpRequest] data stream can still emit errors.
+class SafeHttpServer extends StreamView<HttpRequest> implements HttpServer {
+  final HttpServer _inner;
+
+  static Future<SafeHttpServer> bind([String host = "127.0.0.1",
+      int port = 0, int backlog = 0]) {
+    return HttpServer.bind(host, port, backlog)
+        .then((server) => new SafeHttpServer(server));
+  }
+
+  SafeHttpServer(HttpServer server)
+      : super(server),
+        _inner = server;
+
+  void close() => _inner.close();
+
+  int get port => _inner.port;
+
+  set sessionTimeout(int timeout) {
+    _inner.sessionTimeout = timeout;
+  }
+
+  HttpConnectionsInfo connectionsInfo() => _inner.connectionsInfo();
+
+  StreamSubscription<HttpRequest> listen(void onData(HttpRequest value),
+      {void onError(AsyncError error), void onDone(),
+      bool unsubscribeOnError: false}) {
+    var subscription;
+    subscription = super.listen((request) {
+      onData(new _HttpRequestWrapper(request));
+    }, onError: (e) {
+      var error = e.error;
+      // Ignore socket error 104, which is caused by a request being cancelled
+      // before it writes any headers. There's no reason to care about such
+      // requests.
+      if (error is SocketIOException && error.osError.errorCode == 104) return;
+      // Ignore any parsing errors, which come from malformed requests.
+      if (error is HttpParserException) return;
+      // Manually handle unsubscribeOnError so the above (ignored) errors don't
+      // cause unsubscription.
+      if (unsubscribeOnError) subscription.cancel();
+      if (onError != null) onError(e);
+    }, onDone: onDone);
+    return subscription;
+  }
+}
+
+/// A wrapper around [HttpRequest] for the sole purpose of swallowing errors on
+/// [HttpResponse.done].
+class _HttpRequestWrapper extends StreamView<List<int>> implements HttpRequest {
+  final HttpRequest _inner;
+  final HttpResponse response;
+
+  _HttpRequestWrapper(HttpRequest inner)
+      : super(inner),
+        _inner = inner,
+        response = new _HttpResponseWrapper(inner.response);
+
+  int get contentLength => _inner.contentLength;
+  String get method => _inner.method;
+  Uri get uri => _inner.uri;
+  Map<String, String> get queryParameters => _inner.queryParameters;
+  HttpHeaders get headers => _inner.headers;
+  List<Cookie> get cookies => _inner.cookies;
+  bool get persistentConnection => _inner.persistentConnection;
+  X509Certificate get certificate => _inner.certificate;
+  HttpSession get session => _inner.session;
+  String get protocolVersion => _inner.protocolVersion;
+  HttpConnectionInfo get connectionInfo => _inner.connectionInfo;
+}
+
+/// A wrapper around [HttpResponse] for the sole purpose of swallowing errors on
+/// [done].
+class _HttpResponseWrapper implements HttpResponse {
+  final HttpResponse _inner;
+  Future<HttpResponse> _done;
+
+  _HttpResponseWrapper(this._inner);
+
+  /// Swallows all errors from writing to the response.
+  Future<HttpResponse> get done {
+    if (_done == null) _done = _inner.done.catchError((_) {});
+    return _done;
+  }
+
+  int get contentLength => _inner.contentLength;
+  set contentLength(int value) {
+    _inner.contentLength = value;
+  }
+
+  int get statusCode => _inner.statusCode;
+  set statusCode(int value) {
+    _inner.statusCode = value;
+  }
+
+  String get reasonPhrase => _inner.reasonPhrase;
+  set reasonPhrase(String value) {
+    _inner.reasonPhrase = value;
+  }
+
+  bool get persistentConnection => _inner.persistentConnection;
+  set persistentConnection(bool value) {
+    _inner.persistentConnection = value;
+  }
+
+  Encoding get encoding => _inner.encoding;
+  set encoding(Encoding value) {
+    _inner.encoding = value;
+  }
+
+  HttpHeaders get headers => _inner.headers;
+  List<Cookie> get cookies => _inner.cookies;
+  Future<Socket> detachSocket() => _inner.detachSocket();
+  HttpConnectionInfo get connectionInfo => _inner.connectionInfo;
+  void writeBytes(List<int> data) => _inner.writeBytes(data);
+  Future<HttpResponse> consume(Stream<List<int>> stream) =>
+    _inner.consume(stream);
+  Future<HttpResponse> writeStream(Stream<List<int>> stream) =>
+    _inner.writeStream(stream);
+  void close() => _inner.close();
+  void write(Object obj) => _inner.write(obj);
+  void writeAll(Iterable objects) => _inner.writeAll(objects);
+  void writeCharCode(int charCode) => _inner.writeCharCode(charCode);
+  void writeln(Object obj) => _inner.writeln(obj);
+}