Migrate dart2js stubs for dart:io

tool/input_sdk/lib/io/http.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.
+
+part of dart.io;
+
+/**
+ * HTTP status codes.
+ */
+abstract class HttpStatus {
+  static const int CONTINUE = 100;
+  static const int SWITCHING_PROTOCOLS = 101;
+  static const int OK = 200;
+  static const int CREATED = 201;
+  static const int ACCEPTED = 202;
+  static const int NON_AUTHORITATIVE_INFORMATION = 203;
+  static const int NO_CONTENT = 204;
+  static const int RESET_CONTENT = 205;
+  static const int PARTIAL_CONTENT = 206;
+  static const int MULTIPLE_CHOICES = 300;
+  static const int MOVED_PERMANENTLY = 301;
+  static const int FOUND = 302;
+  static const int MOVED_TEMPORARILY = 302; // Common alias for FOUND.
+  static const int SEE_OTHER = 303;
+  static const int NOT_MODIFIED = 304;
+  static const int USE_PROXY = 305;
+  static const int TEMPORARY_REDIRECT = 307;
+  static const int BAD_REQUEST = 400;
+  static const int UNAUTHORIZED = 401;
+  static const int PAYMENT_REQUIRED = 402;
+  static const int FORBIDDEN = 403;
+  static const int NOT_FOUND = 404;
+  static const int METHOD_NOT_ALLOWED = 405;
+  static const int NOT_ACCEPTABLE = 406;
+  static const int PROXY_AUTHENTICATION_REQUIRED = 407;
+  static const int REQUEST_TIMEOUT = 408;
+  static const int CONFLICT = 409;
+  static const int GONE = 410;
+  static const int LENGTH_REQUIRED = 411;
+  static const int PRECONDITION_FAILED = 412;
+  static const int REQUEST_ENTITY_TOO_LARGE = 413;
+  static const int REQUEST_URI_TOO_LONG = 414;
+  static const int UNSUPPORTED_MEDIA_TYPE = 415;
+  static const int REQUESTED_RANGE_NOT_SATISFIABLE = 416;
+  static const int EXPECTATION_FAILED = 417;
+  static const int INTERNAL_SERVER_ERROR = 500;
+  static const int NOT_IMPLEMENTED = 501;
+  static const int BAD_GATEWAY = 502;
+  static const int SERVICE_UNAVAILABLE = 503;
+  static const int GATEWAY_TIMEOUT = 504;
+  static const int HTTP_VERSION_NOT_SUPPORTED = 505;
+  // Client generated status code.
+  static const int NETWORK_CONNECT_TIMEOUT_ERROR = 599;
+}
+
+
+/**
+ * A server that delivers content, such as web pages, using the HTTP protocol.
+ *
+ * The HttpServer is a [Stream] that provides [HttpRequest] objects. Each
+ * HttpRequest has an associated [HttpResponse] object.
+ * The server responds to a request by writing to that HttpResponse object.
+ * The following example shows how to bind an HttpServer to an IPv6
+ * [InternetAddress] on port 80 (the standard port for HTTP servers)
+ * and how to listen for requests.
+ * Port 80 is the default HTTP port. However, on most systems accessing
+ * this requires super-user privileges. For local testing consider
+ * using a non-reserved port (1024 and above).
+ *
+ *     import 'dart:io';
+ *
+ *     main() {
+ *       HttpServer
+ *           .bind(InternetAddress.ANY_IP_V6, 80)
+ *           .then((server) {
+ *             server.listen((HttpRequest request) {
+ *               request.response.write('Hello, world!');
+ *               request.response.close();
+ *             });
+ *           });
+ *     }
+ *
+ * Incomplete requests, in which all or part of the header is missing, are
+ * ignored, and no exceptions or HttpRequest objects are generated for them.
+ * Likewise, when writing to an HttpResponse, any [Socket] exceptions are
+ * ignored and any future writes are ignored.
+ *
+ * The HttpRequest exposes the request headers and provides the request body,
+ * if it exists, as a Stream of data. If the body is unread, it is drained
+ * when the server writes to the HttpResponse or closes it.
+ *
+ * ## Bind with a secure HTTPS connection
+ *
+ * Use [bindSecure] to create an HTTPS server.
+ *
+ * The server presents a certificate to the client. The certificate
+ * chain and the private key are set in the [SecurityContext]
+ * object that is passed to [bindSecure].
+ *
+ *     import 'dart:io';
+ *     import "dart:isolate";
+ *
+ *     main() {
+ *       SecurityContext context = new SecurityContext();
+ *       var chain =
+ *           Platform.script.resolve('certificates/server_chain.pem')
+ *           .toFilePath();
+ *       var key =
+ *           Platform.script.resolve('certificates/server_key.pem')
+ *           .toFilePath();
+ *       context.useCertificateChain(chain);
+ *       context.usePrivateKey(key, password: 'dartdart');
+ *
+ *       HttpServer
+ *           .bindSecure(InternetAddress.ANY_IP_V6,
+ *                       443,
+ *                       context)
+ *           .then((server) {
+ *             server.listen((HttpRequest request) {
+ *               request.response.write('Hello, world!');
+ *               request.response.close();
+ *             });
+ *           });
+ *     }
+ *
+ *  The certificates and keys are PEM files, which can be created and
+ *  managed with the tools in OpenSSL.
+ *
+ * ## Connect to a server socket
+ *
+ * You can use the [listenOn] constructor to attach an HTTP server to
+ * a [ServerSocket].
+ *
+ *     import 'dart:io';
+ *
+ *     main() {
+ *       ServerSocket.bind(InternetAddress.ANY_IP_V6, 80)
+ *         .then((serverSocket) {
+ *           HttpServer httpserver = new HttpServer.listenOn(serverSocket);
+ *           serverSocket.listen((Socket socket) {
+ *             socket.write('Hello, client.');
+ *           });
+ *         });
+ *     }
+ *
+ * ## Other resources
+ *
+ * * HttpServer is a Stream. Refer to the [Stream] class for information
+ * about the streaming qualities of an HttpServer.
+ * Pausing the subscription of the stream, pauses at the OS level.
+ *
+ * * The [http_server](https://pub.dartlang.org/packages/http_server)
+ * package on pub.dartlang.org contains a set of high-level classes that,
+ * together with this class, makes it easy to provide content through HTTP
+ * servers.
+ */
+abstract class HttpServer implements Stream<HttpRequest> {
+  /**
+   * Get and set the default value of the `Server` header for all responses
+   * generated by this [HttpServer].
+   *
+   * If [serverHeader] is `null`, no `Server` header will be added to each
+   * response.
+   *
+   * The default value is `null`.
+   */
+  String serverHeader;
+
+  /**
+   * Default set of headers added to all response objects.
+   *
+   * By default the following headers are in this set:
+   *
+   *     Content-Type: text/plain; charset=utf-8
+   *     X-Frame-Options: SAMEORIGIN
+   *     X-Content-Type-Options: nosniff
+   *     X-XSS-Protection: 1; mode=block
+   *
+   * If the `Server` header is added here and the `serverHeader` is set as
+   * well then the value of `serverHeader` takes precedence.
+   */
+  HttpHeaders get defaultResponseHeaders;
+
+   /**
+   * Whether the [HttpServer] should compress the content, if possible.
+   *
+   * The content can only be compressed when the response is using
+   * chunked Transfer-Encoding and the incoming request has `gzip`
+   * as an accepted encoding in the Accept-Encoding header.
+   *
+   * The default value is `false` (compression disabled).
+   * To enable, set `autoCompress` to `true`.
+   */
+  bool autoCompress;
+
+  /**
+   * Get or set the timeout used for idle keep-alive connections. If no further
+   * request is seen within [idleTimeout] after the previous request was
+   * completed, the connection is dropped.
+   *
+   * Default is 120 seconds.
+   *
+   * Note that it may take up to `2 * idleTimeout` before a idle connection is
+   * aborted.
+   *
+   * To disable, set [idleTimeout] to `null`.
+   */
+  Duration idleTimeout;
+
+
+  /**
+   * Starts listening for HTTP requests on the specified [address] and
+   * [port].
+   *
+   * The [address] can either be a [String] or an
+   * [InternetAddress]. If [address] is a [String], [bind] will
+   * perform a [InternetAddress.lookup] and use the first value in the
+   * list. To listen on the loopback adapter, which will allow only
+   * incoming connections from the local host, use the value
+   * [InternetAddress.LOOPBACK_IP_V4] or
+   * [InternetAddress.LOOPBACK_IP_V6]. To allow for incoming
+   * connection from the network use either one of the values
+   * [InternetAddress.ANY_IP_V4] or [InternetAddress.ANY_IP_V6] to
+   * bind to all interfaces or the IP address of a specific interface.
+   *
+   * If an IP version 6 (IPv6) address is used, both IP version 6
+   * (IPv6) and version 4 (IPv4) connections will be accepted. To
+   * restrict this to version 6 (IPv6) only, use [v6Only] to set
+   * version 6 only.
+   *
+   * If [port] has the value [:0:] an ephemeral port will be chosen by
+   * the system. The actual port used can be retrieved using the
+   * [port] getter.
+   *
+   * The optional argument [backlog] can be used to specify the listen
+   * backlog for the underlying OS listen setup. If [backlog] has the
+   * value of [:0:] (the default) a reasonable value will be chosen by
+   * the system.
+   *
+   * The optional argument [shared] specifies whether additional HttpServer
+   * objects can bind to the same combination of `address`, `port` and `v6Only`.
+   * If `shared` is `true` and more `HttpServer`s from this isolate or other
+   * isolates are bound to the port, then the incoming connections will be
+   * distributed among all the bound `HttpServer`s. Connections can be
+   * distributed over multiple isolates this way.
+   */
+  static Future<HttpServer> bind(address,
+                                 int port,
+                                 {int backlog: 0,
+                                  bool v6Only: false,
+                                  bool shared: false})
+      => _HttpServer.bind(address, port, backlog, v6Only, shared);
+
+  /**
+   * The [address] can either be a [String] or an
+   * [InternetAddress]. If [address] is a [String], [bind] will
+   * perform a [InternetAddress.lookup] and use the first value in the
+   * list. To listen on the loopback adapter, which will allow only
+   * incoming connections from the local host, use the value
+   * [InternetAddress.LOOPBACK_IP_V4] or
+   * [InternetAddress.LOOPBACK_IP_V6]. To allow for incoming
+   * connection from the network use either one of the values
+   * [InternetAddress.ANY_IP_V4] or [InternetAddress.ANY_IP_V6] to
+   * bind to all interfaces or the IP address of a specific interface.
+   *
+   * If an IP version 6 (IPv6) address is used, both IP version 6
+   * (IPv6) and version 4 (IPv4) connections will be accepted. To
+   * restrict this to version 6 (IPv6) only, use [v6Only] to set
+   * version 6 only.
+   *
+   * If [port] has the value [:0:] an ephemeral port will be chosen by
+   * the system. The actual port used can be retrieved using the
+   * [port] getter.
+   *
+   * The optional argument [backlog] can be used to specify the listen
+   * backlog for the underlying OS listen setup. If [backlog] has the
+   * value of [:0:] (the default) a reasonable value will be chosen by
+   * the system.
+   *
+   * If [requestClientCertificate] is true, the server will
+   * request clients to authenticate with a client certificate.
+   * The server will advertise the names of trusted issuers of client
+   * certificates, getting them from [context], where they have been
+   * set using [SecurityContext.setClientAuthorities].
+   *
+   * The optional argument [shared] specifies whether additional HttpServer
+   * objects can bind to the same combination of `address`, `port` and `v6Only`.
+   * If `shared` is `true` and more `HttpServer`s from this isolate or other
+   * isolates are bound to the port, then the incoming connections will be
+   * distributed among all the bound `HttpServer`s. Connections can be
+   * distributed over multiple isolates this way.
+   */
+
+  static Future<HttpServer> bindSecure(address,
+                                       int port,
+                                       SecurityContext context,
+                                       {int backlog: 0,
+                                        bool v6Only: false,
+                                        bool requestClientCertificate: false,
+                                        bool shared: false})
+      => _HttpServer.bindSecure(address,
+                                port,
+                                context,
+                                backlog,
+                                v6Only,
+                                requestClientCertificate,
+                                shared);
+
+  /**
+   * Attaches the HTTP server to an existing [ServerSocket]. When the
+   * [HttpServer] is closed, the [HttpServer] will just detach itself,
+   * closing current connections but not closing [serverSocket].
+   */
+  factory HttpServer.listenOn(ServerSocket serverSocket)
+      => new _HttpServer.listenOn(serverSocket);
+
+  /**
+   * Permanently stops this [HttpServer] from listening for new
+   * connections.  This closes the [Stream] of [HttpRequest]s with a
+   * done event. The returned future completes when the server is
+   * stopped. For a server started using [bind] or [bindSecure] this
+   * means that the port listened on no longer in use.
+   *
+   * If [force] is `true`, active connections will be closed immediately.
+   */
+  Future close({bool force: false});
+
+  /**
+   * Returns the port that the server is listening on. This can be
+   * used to get the actual port used when a value of 0 for [:port:] is
+   * specified in the [bind] or [bindSecure] call.
+   */
+  int get port;
+
+  /**
+   * Returns the address that the server is listening on. This can be
+   * used to get the actual address used, when the address is fetched by
+   * a lookup from a hostname.
+   */
+  InternetAddress get address;
+
+  /**
+   * Sets the timeout, in seconds, for sessions of this [HttpServer].
+   * The default timeout is 20 minutes.
+   */
+  set sessionTimeout(int timeout);
+
+  /**
+   * Returns an [HttpConnectionsInfo] object summarizing the number of
+   * current connections handled by the server.
+   */
+  HttpConnectionsInfo connectionsInfo();
+}
+
+
+/**
+ * Summary statistics about an [HttpServer]s current socket connections.
+ */
+class HttpConnectionsInfo {
+  /**
+   * Total number of socket connections.
+   */
+  int total = 0;
+
+  /**
+   * Number of active connections where actual request/response
+   * processing is active.
+   */
+  int active = 0;
+
+  /**
+   * Number of idle connections held by clients as persistent connections.
+   */
+  int idle = 0;
+
+  /**
+   * Number of connections which are preparing to close. Note: These
+   * connections are also part of the [:active:] count as they might
+   * still be sending data to the client before finally closing.
+   */
+  int closing = 0;
+}
+
+
+/**
+ * Headers for HTTP requests and responses.
+ *
+ * In some situations, headers are immutable:
+ *
+ * * HttpRequest and HttpClientResponse always have immutable headers.
+ *
+ * * HttpResponse and HttpClientRequest have immutable headers
+ *   from the moment the body is written to.
+ *
+ * In these situations, the mutating methods throw exceptions.
+ *
+ * For all operations on HTTP headers the header name is
+ * case-insensitive.
+ *
+ * To set the value of a header use the `set()` method:
+ *
+ *     request.headers.set(HttpHeaders.CACHE_CONTROL,
+                           'max-age=3600, must-revalidate');
+ *
+ * To retrieve the value of a header use the `value()` method:
+ *
+ *     print(request.headers.value(HttpHeaders.USER_AGENT));
+ *
+ * An HttpHeaders object holds a list of values for each name
+ * as the standard allows. In most cases a name holds only a single value,
+ * The most common mode of operation is to use `set()` for setting a value,
+ * and `value()` for retrieving a value.
+ */
+abstract class HttpHeaders {
+  static const ACCEPT = "accept";
+  static const ACCEPT_CHARSET = "accept-charset";
+  static const ACCEPT_ENCODING = "accept-encoding";
+  static const ACCEPT_LANGUAGE = "accept-language";
+  static const ACCEPT_RANGES = "accept-ranges";
+  static const AGE = "age";
+  static const ALLOW = "allow";
+  static const AUTHORIZATION = "authorization";
+  static const CACHE_CONTROL = "cache-control";
+  static const CONNECTION = "connection";
+  static const CONTENT_ENCODING = "content-encoding";
+  static const CONTENT_LANGUAGE = "content-language";
+  static const CONTENT_LENGTH = "content-length";
+  static const CONTENT_LOCATION = "content-location";
+  static const CONTENT_MD5 = "content-md5";
+  static const CONTENT_RANGE = "content-range";
+  static const CONTENT_TYPE = "content-type";
+  static const DATE = "date";
+  static const ETAG = "etag";
+  static const EXPECT = "expect";
+  static const EXPIRES = "expires";
+  static const FROM = "from";
+  static const HOST = "host";
+  static const IF_MATCH = "if-match";
+  static const IF_MODIFIED_SINCE = "if-modified-since";
+  static const IF_NONE_MATCH = "if-none-match";
+  static const IF_RANGE = "if-range";
+  static const IF_UNMODIFIED_SINCE = "if-unmodified-since";
+  static const LAST_MODIFIED = "last-modified";
+  static const LOCATION = "location";
+  static const MAX_FORWARDS = "max-forwards";
+  static const PRAGMA = "pragma";
+  static const PROXY_AUTHENTICATE = "proxy-authenticate";
+  static const PROXY_AUTHORIZATION = "proxy-authorization";
+  static const RANGE = "range";
+  static const REFERER = "referer";
+  static const RETRY_AFTER = "retry-after";
+  static const SERVER = "server";
+  static const TE = "te";
+  static const TRAILER = "trailer";
+  static const TRANSFER_ENCODING = "transfer-encoding";
+  static const UPGRADE = "upgrade";
+  static const USER_AGENT = "user-agent";
+  static const VARY = "vary";
+  static const VIA = "via";
+  static const WARNING = "warning";
+  static const WWW_AUTHENTICATE = "www-authenticate";
+
+  // Cookie headers from RFC 6265.
+  static const COOKIE = "cookie";
+  static const SET_COOKIE = "set-cookie";
+
+  static const GENERAL_HEADERS = const [CACHE_CONTROL,
+                                        CONNECTION,
+                                        DATE,
+                                        PRAGMA,
+                                        TRAILER,
+                                        TRANSFER_ENCODING,
+                                        UPGRADE,
+                                        VIA,
+                                        WARNING];
+
+  static const ENTITY_HEADERS = const [ALLOW,
+                                       CONTENT_ENCODING,
+                                       CONTENT_LANGUAGE,
+                                       CONTENT_LENGTH,
+                                       CONTENT_LOCATION,
+                                       CONTENT_MD5,
+                                       CONTENT_RANGE,
+                                       CONTENT_TYPE,
+                                       EXPIRES,
+                                       LAST_MODIFIED];
+
+
+  static const RESPONSE_HEADERS = const [ACCEPT_RANGES,
+                                         AGE,
+                                         ETAG,
+                                         LOCATION,
+                                         PROXY_AUTHENTICATE,
+                                         RETRY_AFTER,
+                                         SERVER,
+                                         VARY,
+                                         WWW_AUTHENTICATE];
+
+  static const REQUEST_HEADERS = const [ACCEPT,
+                                        ACCEPT_CHARSET,
+                                        ACCEPT_ENCODING,
+                                        ACCEPT_LANGUAGE,
+                                        AUTHORIZATION,
+                                        EXPECT,
+                                        FROM,
+                                        HOST,
+                                        IF_MATCH,
+                                        IF_MODIFIED_SINCE,
+                                        IF_NONE_MATCH,
+                                        IF_RANGE,
+                                        IF_UNMODIFIED_SINCE,
+                                        MAX_FORWARDS,
+                                        PROXY_AUTHORIZATION,
+                                        RANGE,
+                                        REFERER,
+                                        TE,
+                                        USER_AGENT];
+
+  /**
+   * Gets and sets the date. The value of this property will
+   * reflect the 'date' header.
+   */
+  DateTime date;
+
+  /**
+   * Gets and sets the expiry date. The value of this property will
+   * reflect the 'expires' header.
+   */
+  DateTime expires;
+
+  /**
+   * Gets and sets the "if-modified-since" date. The value of this property will
+   * reflect the "if-modified-since" header.
+   */
+  DateTime ifModifiedSince;
+
+  /**
+   * Gets and sets the host part of the 'host' header for the
+   * connection.
+   */
+  String host;
+
+  /**
+   * Gets and sets the port part of the 'host' header for the
+   * connection.
+   */
+  int port;
+
+  /**
+   * Gets and sets the content type. Note that the content type in the
+   * header will only be updated if this field is set
+   * directly. Mutating the returned current value will have no
+   * effect.
+   */
+  ContentType contentType;
+
+  /**
+   * Gets and sets the content length header value.
+   */
+  int contentLength;
+
+  /**
+   * Gets and sets the persistent connection header value.
+   */
+  bool persistentConnection;
+
+  /**
+   * Gets and sets the chunked transfer encoding header value.
+   */
+  bool chunkedTransferEncoding;
+
+  /**
+   * Returns the list of values for the header named [name]. If there
+   * is no header with the provided name, [:null:] will be returned.
+   */
+  List<String> operator[](String name);
+
+  /**
+   * Convenience method for the value for a single valued header. If
+   * there is no header with the provided name, [:null:] will be
+   * returned. If the header has more than one value an exception is
+   * thrown.
+   */
+  String value(String name);
+
+  /**
+   * Adds a header value. The header named [name] will have the value
+   * [value] added to its list of values. Some headers are single
+   * valued, and for these adding a value will replace the previous
+   * value. If the value is of type DateTime a HTTP date format will be
+   * applied. If the value is a [:List:] each element of the list will
+   * be added separately. For all other types the default [:toString:]
+   * method will be used.
+   */
+  void add(String name, Object value);
+
+  /**
+   * Sets a header. The header named [name] will have all its values
+   * cleared before the value [value] is added as its value.
+   */
+  void set(String name, Object value);
+
+  /**
+   * Removes a specific value for a header name. Some headers have
+   * system supplied values and for these the system supplied values
+   * will still be added to the collection of values for the header.
+   */
+  void remove(String name, Object value);
+
+  /**
+   * Removes all values for the specified header name. Some headers
+   * have system supplied values and for these the system supplied
+   * values will still be added to the collection of values for the
+   * header.
+   */
+  void removeAll(String name);
+
+  /**
+   * Enumerates the headers, applying the function [f] to each
+   * header. The header name passed in [:name:] will be all lower
+   * case.
+   */
+  void forEach(void f(String name, List<String> values));
+
+  /**
+   * Disables folding for the header named [name] when sending the HTTP
+   * header. By default, multiple header values are folded into a
+   * single header line by separating the values with commas. The
+   * 'set-cookie' header has folding disabled by default.
+   */
+  void noFolding(String name);
+
+  /**
+   * Remove all headers. Some headers have system supplied values and
+   * for these the system supplied values will still be added to the
+   * collection of values for the header.
+   */
+  void clear();
+}
+
+
+/**
+ * Representation of a header value in the form:
+ *
+ *   [:value; parameter1=value1; parameter2=value2:]
+ *
+ * [HeaderValue] can be used to conveniently build and parse header
+ * values on this form.
+ *
+ * To build an [:accepts:] header with the value
+ *
+ *     text/plain; q=0.3, text/html
+ *
+ * use code like this:
+ *
+ *     HttpClientRequest request = ...;
+ *     var v = new HeaderValue("text/plain", {"q": "0.3"});
+ *     request.headers.add(HttpHeaders.ACCEPT, v);
+ *     request.headers.add(HttpHeaders.ACCEPT, "text/html");
+ *
+ * To parse the header values use the [:parse:] static method.
+ *
+ *     HttpRequest request = ...;
+ *     List<String> values = request.headers[HttpHeaders.ACCEPT];
+ *     values.forEach((value) {
+ *       HeaderValue v = HeaderValue.parse(value);
+ *       // Use v.value and v.parameters
+ *     });
+ *
+ * An instance of [HeaderValue] is immutable.
+ */
+abstract class HeaderValue {
+  /**
+   * Creates a new header value object setting the value and parameters.
+   */
+  factory HeaderValue([String value = "", Map<String, String> parameters]) {
+    return new _HeaderValue(value, parameters);
+  }
+
+  /**
+   * Creates a new header value object from parsing a header value
+   * string with both value and optional parameters.
+   */
+  static HeaderValue parse(String value,
+                           {String parameterSeparator: ";",
+                            String valueSeparator: null,
+                            bool preserveBackslash: false}) {
+    return _HeaderValue.parse(value,
+                              parameterSeparator: parameterSeparator,
+                              valueSeparator: valueSeparator,
+                              preserveBackslash: preserveBackslash);
+  }
+
+  /**
+   * Gets the header value.
+   */
+  String get value;
+
+  /**
+   * Gets the map of parameters.
+   *
+   * This map cannot be modified. invoking any operation which would
+   * modify the map will throw [UnsupportedError].
+   */
+  Map<String, String> get parameters;
+
+  /**
+   * Returns the formatted string representation in the form:
+   *
+   *     value; parameter1=value1; parameter2=value2
+   */
+  String toString();
+}
+
+abstract class HttpSession implements Map {
+  /**
+   * Gets the id for the current session.
+   */
+  String get id;
+
+  /**
+   * Destroys the session. This will terminate the session and any further
+   * connections with this id will be given a new id and session.
+   */
+  void destroy();
+
+  /**
+   * Sets a callback that will be called when the session is timed out.
+   */
+  void set onTimeout(void callback());
+
+  /**
+   * Is true if the session has not been sent to the client yet.
+   */
+  bool get isNew;
+}
+
+
+/**
+ * Representation of a content type. An instance of [ContentType] is
+ * immutable.
+ */
+abstract class ContentType implements HeaderValue {
+  /**
+   * Content type for plain text using UTF-8 encoding.
+   *
+   *     text/plain; charset=utf-8
+   */
+  static final TEXT = new ContentType("text", "plain", charset: "utf-8");
+
+  /**
+   *  Content type for HTML using UTF-8 encoding.
+   *
+   *     text/html; charset=utf-8
+   */
+  static final HTML = new ContentType("text", "html", charset: "utf-8");
+
+  /**
+   *  Content type for JSON using UTF-8 encoding.
+   *
+   *     application/json; charset=utf-8
+   */
+  static final JSON = new ContentType("application", "json", charset: "utf-8");
+
+  /**
+   *  Content type for binary data.
+   *
+   *     application/octet-stream
+   */
+  static final BINARY = new ContentType("application", "octet-stream");
+
+  /**
+   * Creates a new content type object setting the primary type and
+   * sub type. The charset and additional parameters can also be set
+   * using [charset] and [parameters]. If charset is passed and
+   * [parameters] contains charset as well the passed [charset] will
+   * override the value in parameters. Keys passed in parameters will be
+   * converted to lower case. The `charset` entry, whether passed as `charset`
+   * or in `parameters`, will have its value converted to lower-case.
+   */
+  factory ContentType(String primaryType,
+                      String subType,
+                      {String charset, Map<String, String> parameters}) {
+    return new _ContentType(primaryType, subType, charset, parameters);
+  }
+
+  /**
+   * Creates a new content type object from parsing a Content-Type
+   * header value. As primary type, sub type and parameter names and
+   * values are not case sensitive all these values will be converted
+   * to lower case. Parsing this string
+   *
+   *     text/html; charset=utf-8
+   *
+   * will create a content type object with primary type [:text:], sub
+   * type [:html:] and parameter [:charset:] with value [:utf-8:].
+   */
+  static ContentType parse(String value) {
+    return _ContentType.parse(value);
+  }
+
+  /**
+   * Gets the mime-type, without any parameters.
+   */
+  String get mimeType;
+
+  /**
+   * Gets the primary type.
+   */
+  String get primaryType;
+
+  /**
+   * Gets the sub type.
+   */
+  String get subType;
+
+  /**
+   * Gets the character set.
+   */
+  String get charset;
+}
+
+
+/**
+ * Representation of a cookie. For cookies received by the server as
+ * Cookie header values only [:name:] and [:value:] fields will be
+ * set. When building a cookie for the 'set-cookie' header in the server
+ * and when receiving cookies in the client as 'set-cookie' headers all
+ * fields can be used.
+ */
+abstract class Cookie {
+  /**
+   * Gets and sets the name.
+   */
+  String name;
+
+  /**
+   * Gets and sets the value.
+   */
+  String value;
+
+  /**
+   * Gets and sets the expiry date.
+   */
+  DateTime expires;
+
+  /**
+   * Gets and sets the max age. A value of [:0:] means delete cookie
+   * now.
+   */
+  int maxAge;
+
+  /**
+   * Gets and sets the domain.
+   */
+  String domain;
+
+  /**
+   * Gets and sets the path.
+   */
+  String path;
+
+  /**
+   * Gets and sets whether this cookie is secure.
+   */
+  bool secure;
+
+  /**
+   * Gets and sets whether this cookie is HTTP only.
+   */
+  bool httpOnly;
+
+  /**
+   * Creates a new cookie optionally setting the name and value.
+   *
+   * By default the value of `httpOnly` will be set to `true`.
+   */
+  factory Cookie([String name, String value]) => new _Cookie(name, value);
+
+  /**
+   * Creates a new cookie by parsing a header value from a 'set-cookie'
+   * header.
+   */
+  factory Cookie.fromSetCookieValue(String value) {
+    return new _Cookie.fromSetCookieValue(value);
+  }
+
+  /**
+   * Returns the formatted string representation of the cookie. The
+   * string representation can be used for for setting the Cookie or
+   * 'set-cookie' headers
+   */
+  String toString();
+}
+
+
+/**
+ * A server-side object
+ * that contains the content of and information about an HTTP request.
+ *
+ * __Note__: Check out the
+ * [http_server](http://pub.dartlang.org/packages/http_server)
+ * package, which makes working with the low-level
+ * dart:io HTTP server subsystem easier.
+ *
+ * `HttpRequest` objects are generated by an [HttpServer],
+ * which listens for HTTP requests on a specific host and port.
+ * For each request received, the HttpServer, which is a [Stream],
+ * generates an `HttpRequest` object and adds it to the stream.
+ *
+ * An `HttpRequest` object delivers the body content of the request
+ * as a stream of byte lists.
+ * The object also contains information about the request,
+ * such as the method, URI, and headers.
+ *
+ * In the following code, an HttpServer listens
+ * for HTTP requests. When the server receives a request,
+ * it uses the HttpRequest object's `method` property to dispatch requests.
+ *
+ *     final HOST = InternetAddress.LOOPBACK_IP_V4;
+ *     final PORT = 80;
+ *
+ *     HttpServer.bind(HOST, PORT).then((_server) {
+ *       _server.listen((HttpRequest request) {
+ *         switch (request.method) {
+ *           case 'GET':
+ *             handleGetRequest(request);
+ *             break;
+ *           case 'POST':
+ *             ...
+ *         }
+ *       },
+ *       onError: handleError);    // listen() failed.
+ *     }).catchError(handleError);
+ *
+ * An HttpRequest object provides access to the associated [HttpResponse]
+ * object through the response property.
+ * The server writes its response to the body of the HttpResponse object.
+ * For example, here's a function that responds to a request:
+ *
+ *     void handleGetRequest(HttpRequest req) {
+ *       HttpResponse res = req.response;
+ *       res.write('Received request ${req.method}: ${req.uri.path}');
+ *       res.close();
+ *     }
+ */
+abstract class HttpRequest implements Stream<List<int>> {
+  /**
+   * The content length of the request body.
+   *
+   * If the size of the request body is not known in advance,
+   * this value is -1.
+   */
+  int get contentLength;
+
+  /**
+   * The method, such as 'GET' or 'POST', for the request.
+   */
+  String get method;
+
+  /**
+   * The URI for the request.
+   *
+   * This provides access to the
+   * path and query string for the request.
+   */
+  Uri get uri;
+
+  /**
+   * The requested URI for the request.
+   *
+   * The returend URI is reconstructed by using http-header fields, to access
+   * otherwise lost information, e.g. host and scheme.
+   *
+   * To reconstruct the scheme, first 'X-Forwarded-Proto' is checked, and then
+   * falling back to server type.
+   *
+   * To reconstruct the host, fisrt 'X-Forwarded-Host' is checked, then 'Host'
+   * and finally calling back to server.
+   */
+  Uri get requestedUri;
+
+  /**
+   * The request headers.
+   *
+   * The returned [HttpHeaders] are immutable.
+   */
+  HttpHeaders get headers;
+
+  /**
+   * The cookies in the request, from the Cookie headers.
+   */
+  List<Cookie> get cookies;
+
+  /**
+   * The persistent connection state signaled by the client.
+   */
+  bool get persistentConnection;
+
+  /**
+   * The client certificate of the client making the request.
+   *
+   * This value is null if the connection is not a secure TLS or SSL connection,
+   * or if the server does not request a client certificate, or if the client
+   * does not provide one.
+   */
+  X509Certificate get certificate;
+
+  /**
+   * The session for the given request.
+   *
+   * If the session is
+   * being initialized by this call, [:isNew:] is true for the returned
+   * session.
+   * See [HttpServer.sessionTimeout] on how to change default timeout.
+   */
+  HttpSession get session;
+
+  /**
+   * The HTTP protocol version used in the request,
+   * either "1.0" or "1.1".
+   */
+  String get protocolVersion;
+
+  /**
+   * Information about the client connection.
+   *
+   * Returns [:null:] if the socket is not available.
+   */
+  HttpConnectionInfo get connectionInfo;
+
+  /**
+   * The [HttpResponse] object, used for sending back the response to the
+   * client.
+   *
+   * If the [contentLength] of the body isn't 0, and the body isn't being read,
+   * any write calls on the [HttpResponse] automatically drain the request
+   * body.
+   */
+  HttpResponse get response;
+}
+
+
+/**
+ * An HTTP response, which returns the headers and data
+ * from the server to the client in response to an HTTP request.
+ *
+ * Every HttpRequest object provides access to the associated [HttpResponse]
+ * object through the `response` property.
+ * The server sends its response to the client by writing to the
+ * HttpResponse object.
+ *
+ * ## Writing the response
+ *
+ * This class implements [IOSink].
+ * After the header has been set up, the methods
+ * from IOSink, such as `writeln()`, can be used to write
+ * the body of the HTTP response.
+ * Use the `close()` method to close the response and send it to the client.
+ *
+ *     server.listen((HttpRequest request) {
+ *       request.response.write('Hello, world!');
+ *       request.response.close();
+ *     });
+ *
+ * When one of the IOSink methods is used for the
+ * first time, the request header is sent. Calling any methods that
+ * change the header after it is sent throws an exception.
+ *
+ * ## Setting the headers
+ *
+ * The HttpResponse object has a number of properties for setting up
+ * the HTTP headers of the response.
+ * When writing string data through the IOSink, the encoding used
+ * is determined from the "charset" parameter of the
+ * "Content-Type" header.
+ *
+ *     HttpResponse response = ...
+ *     response.headers.contentType
+ *         = new ContentType("application", "json", charset: "utf-8");
+ *     response.write(...);  // Strings written will be UTF-8 encoded.
+ *
+ * If no charset is provided the default of ISO-8859-1 (Latin 1) will
+ * be used.
+ *
+ *     HttpResponse response = ...
+ *     response.headers.add(HttpHeaders.CONTENT_TYPE, "text/plain");
+ *     response.write(...);  // Strings written will be ISO-8859-1 encoded.
+ *
+ * An exception is thrown if you use the `write()` method
+ * while an unsupported content-type is set.
+ */
+abstract class HttpResponse implements IOSink {
+  // TODO(ajohnsen): Add documentation of how to pipe a file to the response.
+  /**
+   * Gets and sets the content length of the response. If the size of
+   * the response is not known in advance set the content length to
+   * -1 - which is also the default if not set.
+   */
+  int contentLength;
+
+  /**
+   * Gets and sets the status code. Any integer value is accepted. For
+   * the official HTTP status codes use the fields from
+   * [HttpStatus]. If no status code is explicitly set the default
+   * value [HttpStatus.OK] is used.
+   *
+   * The status code must be set before the body is written
+   * to. Setting the status code after writing to the response body or
+   * closing the response will throw a `StateError`.
+   */
+  int statusCode;
+
+  /**
+   * Gets and sets the reason phrase. If no reason phrase is explicitly
+   * set a default reason phrase is provided.
+   *
+   * The reason phrase must be set before the body is written
+   * to. Setting the reason phrase after writing to the response body
+   * or closing the response will throw a `StateError`.
+   */
+  String reasonPhrase;
+
+  /**
+   * Gets and sets the persistent connection state. The initial value
+   * of this property is the persistent connection state from the
+   * request.
+   */
+  bool persistentConnection;
+
+  /**
+   * Set and get the [deadline] for the response. The deadline is timed from the
+   * time it's set. Setting a new deadline will override any previous deadline.
+   * When a deadline is exceeded, the response will be closed and any further
+   * data ignored.
+   *
+   * To disable a deadline, set the [deadline] to `null`.
+   *
+   * The [deadline] is `null` by default.
+   */
+  Duration deadline;
+
+  /**
+   * Get or set if the [HttpResponse] should buffer output.
+   *
+   * Default value is `true`.
+   *
+   * __Note__: Disabling buffering of the output can result in very poor
+   * performance, when writing many small chunks.
+   */
+  bool bufferOutput;
+
+  /**
+   * Returns the response headers.
+   *
+   * The response headers can be modified until the response body is
+   * written to or closed. After that they become immutable.
+   */
+  HttpHeaders get headers;
+
+  /**
+   * Cookies to set in the client (in the 'set-cookie' header).
+   */
+  List<Cookie> get cookies;
+
+  /**
+   * Respond with a redirect to [location].
+   *
+   * The URI in [location] should be absolute, but there are no checks
+   * to enforce that.
+   *
+   * By default the HTTP status code `HttpStatus.MOVED_TEMPORARILY`
+   * (`302`) is used for the redirect, but an alternative one can be
+   * specified using the [status] argument.
+   *
+   * This method will also call `close`, and the returned future is
+   * the furure returned by `close`.
+   */
+  Future redirect(Uri location, {int status: HttpStatus.MOVED_TEMPORARILY});
+
+  /**
+   * Detaches the underlying socket from the HTTP server. When the
+   * socket is detached the HTTP server will no longer perform any
+   * operations on it.
+   *
+   * This is normally used when a HTTP upgrade request is received
+   * and the communication should continue with a different protocol.
+   *
+   * If [writeHeaders] is `true`, the status line and [headers] will be written
+   * to the socket before it's detached. If `false`, the socket is detached
+   * immediately, without any data written to the socket. Default is `true`.
+   */
+  Future<Socket> detachSocket({bool writeHeaders: true});
+
+  /**
+   * Gets information about the client connection. Returns [:null:] if the
+   * socket is not available.
+   */
+  HttpConnectionInfo get connectionInfo;
+}
+
+
+/**
+ * A client that receives content, such as web pages, from
+ * a server using the HTTP protocol.
+ *
+ * HttpClient contains a number of methods to send an [HttpClientRequest]
+ * to an Http server and receive an [HttpClientResponse] back.
+ * For example, you can use the [get], [getUrl], [post], and [postUrl] methods
+ * for GET and POST requests, respectively.
+ *
+ * ## Making a simple GET request: an example
+ *
+ * A `getUrl` request is a two-step process, triggered by two [Future]s.
+ * When the first future completes with a [HttpClientRequest], the underlying
+ * network connection has been established, but no data has been sent.
+ * In the callback function for the first future, the HTTP headers and body
+ * can be set on the request. Either the first write to the request object
+ * or a call to [close] sends the request to the server.
+ *
+ * When the HTTP response is received from the server,
+ * the second future, which is returned by close,
+ * completes with an [HttpClientResponse] object.
+ * This object provides access to the headers and body of the response.
+ * The body is available as a stream implemented by HttpClientResponse.
+ * If a body is present, it must be read. Otherwise, it leads to resource
+ * leaks. Consider using [HttpClientResponse.drain] if the body is unused.
+ *
+ *     HttpClient client = new HttpClient();
+ *     client.getUrl(Uri.parse("http://www.example.com/"))
+ *         .then((HttpClientRequest request) {
+ *           // Optionally set up headers...
+ *           // Optionally write to the request object...
+ *           // Then call close.
+ *           ...
+ *           return request.close();
+ *         })
+ *         .then((HttpClientResponse response) {
+ *           // Process the response.
+ *           ...
+ *         });
+ *
+ * The future for [HttpClientRequest] is created by methods such as
+ * [getUrl] and [open].
+ *
+ * ## HTTPS connections
+ *
+ * An HttpClient can make HTTPS requests, connecting to a server using
+ * the TLS (SSL) secure networking protocol. Calling [getUrl] with an
+ * https: scheme will work automatically, if the server's certificate is
+ * signed by a root CA (certificate authority) on the default list of
+ * well-known trusted CAs, compiled by Mozilla.
+ *
+ * To add a custom trusted certificate authority, or to send a client
+ * certificate to servers that request one, pass a [SecurityContext] object
+ * as the optional [context] argument to the `HttpClient` constructor.
+ * The desired security options can be set on the [SecurityContext] object.
+ *
+ * ## Headers
+ *
+ * All HttpClient requests set the following header by default:
+ *
+ *     Accept-Encoding: gzip
+ *
+ * This allows the HTTP server to use gzip compression for the body if
+ * possible. If this behavior is not desired set the
+ * `Accept-Encoding` header to something else.
+ * To turn off gzip compression of the response, clear this header:
+ *
+ *      request.headers.removeAll(HttpHeaders.ACCEPT_ENCODING)
+ *
+ * ## Closing the HttpClient
+ *
+ * The HttpClient supports persistent connections and caches network
+ * connections to reuse them for multiple requests whenever
+ * possible. This means that network connections can be kept open for
+ * some time after a request has completed. Use HttpClient.close
+ * to force the HttpClient object to shut down and to close the idle
+ * network connections.
+ *
+ * ## Turning proxies on and off
+ *
+ * By default the HttpClient uses the proxy configuration available
+ * from the environment, see [findProxyFromEnvironment]. To turn off
+ * the use of proxies set the [findProxy] property to
+ * [:null:].
+ *
+ *     HttpClient client = new HttpClient();
+ *     client.findProxy = null;
+ */
+abstract class HttpClient {
+  static const int DEFAULT_HTTP_PORT = 80;
+  static const int DEFAULT_HTTPS_PORT = 443;
+
+  /**
+   * Get and set the idle timeout of non-active persistent (keep-alive)
+   * connections. The default value is 15 seconds.
+   */
+  Duration idleTimeout;
+
+  /**
+   * Get and set the maximum number of live connections, to a single host.
+   *
+   * Increasing this number may lower performance and take up unwanted
+   * system resources.
+   *
+   * To disable, set to `null`.
+   *
+   * Default is `null`.
+   */
+  int maxConnectionsPerHost;
+
+  /**
+   * Get and set whether the body of a response will be automatically
+   * uncompressed.
+   *
+   * The body of an HTTP response can be compressed. In most
+   * situations providing the un-compressed body is most
+   * convenient. Therefore the default behavior is to un-compress the
+   * body. However in some situations (e.g. implementing a transparent
+   * proxy) keeping the uncompressed stream is required.
+   *
+   * NOTE: Headers in from the response is never modified. This means
+   * that when automatic un-compression is turned on the value of the
+   * header `Content-Length` will reflect the length of the original
+   * compressed body. Likewise the header `Content-Encoding` will also
+   * have the original value indicating compression.
+   *
+   * NOTE: Automatic un-compression is only performed if the
+   * `Content-Encoding` header value is `gzip`.
+   *
+   * This value affects all responses produced by this client after the
+   * value is changed.
+   *
+   * To disable, set to `false`.
+   *
+   * Default is `true`.
+   */
+  bool autoUncompress;
+
+  /**
+   * Set and get the default value of the `User-Agent` header for all requests
+   * generated by this [HttpClient]. The default value is
+   * `Dart/<version> (dart:io)`.
+   *
+   * If the userAgent is set to `null`, no default `User-Agent` header will be
+   * added to each request.
+   */
+  String userAgent;
+
+  factory HttpClient({SecurityContext context}) => new _HttpClient(context);
+
+  /**
+   * Opens a HTTP connection.
+   *
+   * The HTTP method to use is specified in [method], the server is
+   * specified using [host] and [port], and the path (including
+   * a possible query) is specified using [path].
+   * The path may also contain a URI fragment, which will be ignored.
+   *
+   * The `Host` header for the request will be set to the value
+   * [host]:[port]. This can be overridden through the
+   * [HttpClientRequest] interface before the request is sent.  NOTE
+   * if [host] is an IP address this will still be set in the `Host`
+   * header.
+   *
+   * For additional information on the sequence of events during an
+   * HTTP transaction, and the objects returned by the futures, see
+   * the overall documentation for the class [HttpClient].
+   */
+  Future<HttpClientRequest> open(String method,
+                                 String host,
+                                 int port,
+                                 String path);
+
+  /**
+   * Opens a HTTP connection.
+   *
+   * The HTTP method is specified in [method] and the URL to use in
+   * [url].
+   *
+   * The `Host` header for the request will be set to the value
+   * [host]:[port]. This can be overridden through the
+   * [HttpClientRequest] interface before the request is sent.  NOTE
+   * if [host] is an IP address this will still be set in the `Host`
+   * header.
+   *
+   * For additional information on the sequence of events during an
+   * HTTP transaction, and the objects returned by the futures, see
+   * the overall documentation for the class [HttpClient].
+   */
+  Future<HttpClientRequest> openUrl(String method, Uri url);
+
+  /**
+   * Opens a HTTP connection using the GET method.
+   *
+   * The server is specified using [host] and [port], and the path
+   * (including a possible query) is specified using
+   * [path].
+   *
+   * See [open] for details.
+   */
+  Future<HttpClientRequest> get(String host, int port, String path);
+
+  /**
+   * Opens a HTTP connection using the GET method.
+   *
+   * The URL to use is specified in [url].
+   *
+   * See [openUrl] for details.
+   */
+  Future<HttpClientRequest> getUrl(Uri url);
+
+  /**
+   * Opens a HTTP connection using the POST method.
+   *
+   * The server is specified using [host] and [port], and the path
+   * (including a possible query) is specified using
+   * [path].
+   *
+   * See [open] for details.
+   */
+  Future<HttpClientRequest> post(String host, int port, String path);
+
+  /**
+   * Opens a HTTP connection using the POST method.
+   *
+   * The URL to use is specified in [url].
+   *
+   * See [openUrl] for details.
+   */
+  Future<HttpClientRequest> postUrl(Uri url);
+
+  /**
+   * Opens a HTTP connection using the PUT method.
+   *
+   * The server is specified using [host] and [port], and the path
+   * (including a possible query) is specified using [path].
+   *
+   * See [open] for details.
+   */
+  Future<HttpClientRequest> put(String host, int port, String path);
+
+  /**
+   * Opens a HTTP connection using the PUT method.
+   *
+   * The URL to use is specified in [url].
+   *
+   * See [openUrl] for details.
+   */
+  Future<HttpClientRequest> putUrl(Uri url);
+
+  /**
+   * Opens a HTTP connection using the DELETE method.
+   *
+   * The server is specified using [host] and [port], and the path
+   * (including s possible query) is specified using [path].
+   *
+   * See [open] for details.
+   */
+  Future<HttpClientRequest> delete(String host, int port, String path);
+
+  /**
+   * Opens a HTTP connection using the DELETE method.
+   *
+   * The URL to use is specified in [url].
+   *
+   * See [openUrl] for details.
+   */
+  Future<HttpClientRequest> deleteUrl(Uri url);
+
+  /**
+   * Opens a HTTP connection using the PATCH method.
+   *
+   * The server is specified using [host] and [port], and the path
+   * (including a possible query) is specified using [path].
+   *
+   * See [open] for details.
+   */
+  Future<HttpClientRequest> patch(String host, int port, String path);
+
+  /**
+   * Opens a HTTP connection using the PATCH method.
+   *
+   * The URL to use is specified in [url].
+   *
+   * See [openUrl] for details.
+   */
+  Future<HttpClientRequest> patchUrl(Uri url);
+
+  /**
+   * Opens a HTTP connection using the HEAD method.
+   *
+   * The server is specified using [host] and [port], and the path
+   * (including a possible query) is specified using [path].
+   *
+   * See [open] for details.
+   */
+  Future<HttpClientRequest> head(String host, int port, String path);
+
+  /**
+   * Opens a HTTP connection using the HEAD method.
+   *
+   * The URL to use is specified in [url].
+   *
+   * See [openUrl] for details.
+   */
+  Future<HttpClientRequest> headUrl(Uri url);
+
+  /**
+   * Sets the function to be called when a site is requesting
+   * authentication. The URL requested and the security realm from the
+   * server are passed in the arguments [url] and [realm].
+   *
+   * The function returns a [Future] which should complete when the
+   * authentication has been resolved. If credentials cannot be
+   * provided the [Future] should complete with [:false:]. If
+   * credentials are available the function should add these using
+   * [addCredentials] before completing the [Future] with the value
+   * [:true:].
+   *
+   * If the [Future] completes with true the request will be retried
+   * using the updated credentials. Otherwise response processing will
+   * continue normally.
+   */
+  set authenticate(Future<bool> f(Uri url, String scheme, String realm));
+
+  /**
+   * Add credentials to be used for authorizing HTTP requests.
+   */
+  void addCredentials(Uri url, String realm, HttpClientCredentials credentials);
+
+  /**
+   * Sets the function used to resolve the proxy server to be used for
+   * opening a HTTP connection to the specified [url]. If this
+   * function is not set, direct connections will always be used.
+   *
+   * The string returned by [f] must be in the format used by browser
+   * PAC (proxy auto-config) scripts. That is either
+   *
+   *     "DIRECT"
+   *
+   * for using a direct connection or
+   *
+   *     "PROXY host:port"
+   *
+   * for using the proxy server [:host:] on port [:port:].
+   *
+   * A configuration can contain several configuration elements
+   * separated by semicolons, e.g.
+   *
+   *     "PROXY host:port; PROXY host2:port2; DIRECT"
+   *
+   * The static function [findProxyFromEnvironment] on this class can
+   * be used to implement proxy server resolving based on environment
+   * variables.
+   */
+  set findProxy(String f(Uri url));
+
+  /**
+   * Function for resolving the proxy server to be used for a HTTP
+   * connection from the proxy configuration specified through
+   * environment variables.
+   *
+   * The following environment variables are taken into account:
+   *
+   *     http_proxy
+   *     https_proxy
+   *     no_proxy
+   *     HTTP_PROXY
+   *     HTTPS_PROXY
+   *     NO_PROXY
+   *
+   * [:http_proxy:] and [:HTTP_PROXY:] specify the proxy server to use for
+   * http:// urls. Use the format [:hostname:port:]. If no port is used a
+   * default of 1080 will be used. If both are set the lower case one takes
+   * precedence.
+   *
+   * [:https_proxy:] and [:HTTPS_PROXY:] specify the proxy server to use for
+   * https:// urls. Use the format [:hostname:port:]. If no port is used a
+   * default of 1080 will be used. If both are set the lower case one takes
+   * precedence.
+   *
+   * [:no_proxy:] and [:NO_PROXY:] specify a comma separated list of
+   * postfixes of hostnames for which not to use the proxy
+   * server. E.g. the value "localhost,127.0.0.1" will make requests
+   * to both "localhost" and "127.0.0.1" not use a proxy. If both are set
+   * the lower case one takes precedence.
+   *
+   * To activate this way of resolving proxies assign this function to
+   * the [findProxy] property on the [HttpClient].
+   *
+   *     HttpClient client = new HttpClient();
+   *     client.findProxy = HttpClient.findProxyFromEnvironment;
+   *
+   * If you don't want to use the system environment you can use a
+   * different one by wrapping the function.
+   *
+   *     HttpClient client = new HttpClient();
+   *     client.findProxy = (url) {
+   *       return HttpClient.findProxyFromEnvironment(
+   *           url, {"http_proxy": ..., "no_proxy": ...});
+   *     }
+   *
+   * If a proxy requires authentication it is possible to configure
+   * the username and password as well. Use the format
+   * [:username:password@hostname:port:] to include the username and
+   * password. Alternatively the API [addProxyCredentials] can be used
+   * to set credentials for proxies which require authentication.
+   */
+  static String findProxyFromEnvironment(Uri url,
+                                         {Map<String, String> environment}) {
+    return _HttpClient._findProxyFromEnvironment(url, environment);
+  }
+
+  /**
+   * Sets the function to be called when a proxy is requesting
+   * authentication. Information on the proxy in use and the security
+   * realm for the authentication are passed in the arguments [host],
+   * [port] and [realm].
+   *
+   * The function returns a [Future] which should complete when the
+   * authentication has been resolved. If credentials cannot be
+   * provided the [Future] should complete with [:false:]. If
+   * credentials are available the function should add these using
+   * [addProxyCredentials] before completing the [Future] with the value
+   * [:true:].
+   *
+   * If the [Future] completes with [:true:] the request will be retried
+   * using the updated credentials. Otherwise response processing will
+   * continue normally.
+   */
+  set authenticateProxy(
+      Future<bool> f(String host, int port, String scheme, String realm));
+
+  /**
+   * Add credentials to be used for authorizing HTTP proxies.
+   */
+  void addProxyCredentials(String host,
+                           int port,
+                           String realm,
+                           HttpClientCredentials credentials);
+
+  /**
+   * Sets a callback that will decide whether to accept a secure connection
+   * with a server certificate that cannot be authenticated by any of our
+   * trusted root certificates.
+   *
+   * When an secure HTTP request if made, using this HttpClient, and the
+   * server returns a server certificate that cannot be authenticated, the
+   * callback is called asynchronously with the [X509Certificate] object and
+   * the server's hostname and port.  If the value of [badCertificateCallback]
+   * is [:null:], the bad certificate is rejected, as if the callback
+   * returned [:false:]
+   *
+   * If the callback returns true, the secure connection is accepted and the
+   * [:Future<HttpClientRequest>:] that was returned from the call making the
+   * request completes with a valid HttpRequest object. If the callback returns
+   * false, the [:Future<HttpClientRequest>:] completes with an exception.
+   *
+   * If a bad certificate is received on a connection attempt, the library calls
+   * the function that was the value of badCertificateCallback at the time
+   * the request is made, even if the value of badCertificateCallback
+   * has changed since then.
+   */
+  set badCertificateCallback(bool callback(X509Certificate cert,
+                                           String host,
+                                           int port));
+
+  /**
+   * Shutdown the HTTP client. If [force] is [:false:] (the default)
+   * the [:HttpClient:] will be kept alive until all active
+   * connections are done. If [force] is [:true:] any active
+   * connections will be closed to immediately release all
+   * resources. These closed connections will receive an [:onError:]
+   * callback to indicate that the client was shutdown. In both cases
+   * trying to establish a new connection after calling [shutdown]
+   * will throw an exception.
+   */
+  void close({bool force: false});
+}
+
+
+/**
+ * HTTP request for a client connection.
+ *
+ * To set up a request, set the headers using the headers property
+ * provided in this class and write the data to the body of the request.
+ * HttpClientRequest is an [IOSink]. Use the methods from IOSink,
+ * such as writeCharCode(), to write the body of the HTTP
+ * request. When one of the IOSink methods is used for the first
+ * time, the request header is sent. Calling any methods that
+ * change the header after it is sent throws an exception.
+ *
+ * When writing string data through the [IOSink] the
+ * encoding used is determined from the "charset" parameter of
+ * the "Content-Type" header.
+ *
+ *     HttpClientRequest request = ...
+ *     request.headers.contentType
+ *         = new ContentType("application", "json", charset: "utf-8");
+ *     request.write(...);  // Strings written will be UTF-8 encoded.
+ *
+ * If no charset is provided the default of ISO-8859-1 (Latin 1) is
+ * be used.
+ *
+ *     HttpClientRequest request = ...
+ *     request.headers.add(HttpHeaders.CONTENT_TYPE, "text/plain");
+ *     request.write(...);  // Strings written will be ISO-8859-1 encoded.
+ *
+ * An exception is thrown if you use an unsupported encoding and the
+ * `write()` method being used takes a string parameter.
+ */
+abstract class HttpClientRequest implements IOSink {
+  /**
+   * Gets and sets the requested persistent connection state.
+   *
+   * The default value is [:true:].
+   */
+  bool persistentConnection;
+
+  /**
+   * Set this property to [:true:] if this request should
+   * automatically follow redirects. The default is [:true:].
+   *
+   * Automatic redirect will only happen for "GET" and "HEAD" requests
+   * and only for the status codes [:HttpHeaders.MOVED_PERMANENTLY:]
+   * (301), [:HttpStatus.FOUND:] (302),
+   * [:HttpStatus.MOVED_TEMPORARILY:] (302, alias for
+   * [:HttpStatus.FOUND:]), [:HttpStatus.SEE_OTHER:] (303) and
+   * [:HttpStatus.TEMPORARY_REDIRECT:] (307). For
+   * [:HttpStatus.SEE_OTHER:] (303) autmatic redirect will also happen
+   * for "POST" requests with the method changed to "GET" when
+   * following the redirect.
+   *
+   * All headers added to the request will be added to the redirection
+   * request(s). However, any body send with the request will not be
+   * part of the redirection request(s).
+   */
+  bool followRedirects;
+
+  /**
+   * Set this property to the maximum number of redirects to follow
+   * when [followRedirects] is [:true:]. If this number is exceeded the
+   * [onError] callback will be called with a [RedirectException].
+   *
+   * The default value is 5.
+   */
+  int maxRedirects;
+
+  /**
+   * The method of the request.
+   */
+  String get method;
+
+  /**
+   * The uri of the request.
+   */
+  Uri get uri;
+
+  /**
+   * Gets and sets the content length of the request. If the size of
+   * the request is not known in advance set content length to -1,
+   * which is also the default.
+   */
+  int contentLength;
+
+  /**
+   * Get or set if the [HttpClientRequest] should buffer output.
+   *
+   * Default value is `true`.
+   *
+   * __Note__: Disabling buffering of the output can result in very poor
+   * performance, when writing many small chunks.
+   */
+  bool bufferOutput;
+
+  /**
+   * Returns the client request headers.
+   *
+   * The client request headers can be modified until the client
+   * request body is written to or closed. After that they become
+   * immutable.
+   */
+  HttpHeaders get headers;
+
+  /**
+   * Cookies to present to the server (in the 'cookie' header).
+   */
+  List<Cookie> get cookies;
+
+  /**
+   * A [HttpClientResponse] future that will complete once the response is
+   * available. If an error occurs before the response is available, this
+   * future will complete with an error.
+   */
+  Future<HttpClientResponse> get done;
+
+  /**
+   * Close the request for input. Returns the value of [done].
+   */
+  Future<HttpClientResponse> close();
+
+  /**
+   * Get information about the client connection. Returns [:null:] if the socket
+   * is not available.
+   */
+  HttpConnectionInfo get connectionInfo;
+}
+
+
+/**
+ * HTTP response for a client connection.
+ *
+ * The body of a [HttpClientResponse] object is a
+ * [Stream] of data from the server. Listen to the body to handle
+ * the data and be notified when the entire body is received.
+ *
+ *     new HttpClient().get('localhost', 80, '/file.txt')
+ *          .then((HttpClientRequest request) => request.close())
+ *          .then((HttpClientResponse response) {
+ *            response.transform(UTF8.decoder).listen((contents) {
+ *              // handle data
+ *            });
+ *          });
+ */
+abstract class HttpClientResponse implements Stream<List<int>> {
+  /**
+   * Returns the status code.
+   *
+   * The status code must be set before the body is written
+   * to. Setting the status code after writing to the body will throw
+   * a `StateError`.
+   */
+  int get statusCode;
+
+  /**
+   * Returns the reason phrase associated with the status code.
+   *
+   * The reason phrase must be set before the body is written
+   * to. Setting the reason phrase after writing to the body will throw
+   * a `StateError`.
+   */
+  String get reasonPhrase;
+
+  /**
+   * Returns the content length of the response body. Returns -1 if the size of
+   * the response body is not known in advance.
+   *
+   * If the content length needs to be set, it must be set before the
+   * body is written to. Setting the reason phrase after writing to
+   * the body will throw a `StateError`.
+   */
+  int get contentLength;
+
+  /**
+   * Gets the persistent connection state returned by the server.
+   *
+   * if the persistent connection state needs to be set, it must be
+   * set before the body is written to. Setting the reason phrase
+   * after writing to the body will throw a `StateError`.
+   */
+  bool get persistentConnection;
+
+  /**
+   * Returns whether the status code is one of the normal redirect
+   * codes [HttpStatus.MOVED_PERMANENTLY], [HttpStatus.FOUND],
+   * [HttpStatus.MOVED_TEMPORARILY], [HttpStatus.SEE_OTHER] and
+   * [HttpStatus.TEMPORARY_REDIRECT].
+   */
+  bool get isRedirect;
+
+  /**
+   * Returns the series of redirects this connection has been through. The
+   * list will be empty if no redirects were followed. [redirects] will be
+   * updated both in the case of an automatic and a manual redirect.
+   */
+  List<RedirectInfo> get redirects;
+
+  /**
+   * Redirects this connection to a new URL. The default value for
+   * [method] is the method for the current request. The default value
+   * for [url] is the value of the [HttpHeaders.LOCATION] header of
+   * the current response. All body data must have been read from the
+   * current response before calling [redirect].
+   *
+   * All headers added to the request will be added to the redirection
+   * request. However, any body sent with the request will not be
+   * part of the redirection request.
+   *
+   * If [followLoops] is set to [:true:], redirect will follow the redirect,
+   * even if the URL was already visited. The default value is [:false:].
+   *
+   * [redirect] will ignore [maxRedirects] and will always perform the redirect.
+   */
+  Future<HttpClientResponse> redirect([String method,
+                                       Uri url,
+                                       bool followLoops]);
+
+
+  /**
+   * Returns the client response headers.
+   *
+   * The client response headers are immutable.
+   */
+  HttpHeaders get headers;
+
+  /**
+   * Detach the underlying socket from the HTTP client. When the
+   * socket is detached the HTTP client will no longer perform any
+   * operations on it.
+   *
+   * This is normally used when a HTTP upgrade is negotiated and the
+   * communication should continue with a different protocol.
+   */
+  Future<Socket> detachSocket();
+
+  /**
+   * Cookies set by the server (from the 'set-cookie' header).
+   */
+  List<Cookie> get cookies;
+
+  /**
+   * Returns the certificate of the HTTPS server providing the response.
+   * Returns null if the connection is not a secure TLS or SSL connection.
+   */
+  X509Certificate get certificate;
+
+  /**
+   * Gets information about the client connection. Returns [:null:] if the socket
+   * is not available.
+   */
+  HttpConnectionInfo get connectionInfo;
+}
+
+
+abstract class HttpClientCredentials { }
+
+
+/**
+ * Represents credentials for basic authentication.
+ */
+abstract class HttpClientBasicCredentials extends HttpClientCredentials {
+  factory HttpClientBasicCredentials(String username, String password) =>
+      new _HttpClientBasicCredentials(username, password);
+}
+
+
+/**
+ * Represents credentials for digest authentication. Digest
+ * authentication is only supported for servers using the MD5
+ * algorithm and quality of protection (qop) of either "none" or
+ * "auth".
+ */
+abstract class HttpClientDigestCredentials extends HttpClientCredentials {
+  factory HttpClientDigestCredentials(String username, String password) =>
+      new _HttpClientDigestCredentials(username, password);
+}
+
+
+/**
+ * Information about an [HttpRequest], [HttpResponse], [HttpClientRequest], or
+ * [HttpClientResponse] connection.
+ */
+abstract class HttpConnectionInfo {
+  InternetAddress get remoteAddress;
+  int get remotePort;
+  int get localPort;
+}
+
+
+/**
+ * Redirect information.
+ */
+abstract class RedirectInfo {
+  /**
+   * Returns the status code used for the redirect.
+   */
+  int get statusCode;
+
+  /**
+   * Returns the method used for the redirect.
+   */
+  String get method;
+
+  /**
+   * Returns the location for the redirect.
+   */
+  Uri get location;
+}
+
+
+/**
+ * When detaching a socket from either the [:HttpServer:] or the
+ * [:HttpClient:] due to a HTTP connection upgrade there might be
+ * unparsed data already read from the socket. This unparsed data
+ * together with the detached socket is returned in an instance of
+ * this class.
+ */
+abstract class DetachedSocket {
+  Socket get socket;
+  List<int> get unparsedData;
+}
+
+
+class HttpException implements IOException {
+  final String message;
+  final Uri uri;
+
+  const HttpException(String this.message, {Uri this.uri});
+
+  String toString() {
+    var b = new StringBuffer()
+        ..write('HttpException: ')
+        ..write(message);
+    if (uri != null) {
+      b.write(', uri = $uri');
+    }
+    return b.toString();
+  }
+}
+
+
+class RedirectException implements HttpException {
+  final String message;
+  final List<RedirectInfo> redirects;
+
+  const RedirectException(this.message, this.redirects);
+
+  String toString() => "RedirectException: $message";
+
+  Uri get uri => redirects.last.location;
+}