Remove the webdriver package; it has moved to github.

pkg/webdriver/lib/webdriver.dart

-// Copyright (c) 2011, 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 webdriver;
-
-import 'dart:async';
-import 'dart:io';
-import 'dart:json' as json;
-
-part 'src/base64decoder.dart';
-
-/**
- * WebDriver bindings for Dart.
- *
-* ## Installing ##
- *
- * Use [pub][] to install this package. Add the following to your `pubspec.yaml`
- * file.
- *
- *     dependencies:
- *       webdriver: any
- *
- * Then run `pub install`.
- *
- * For more information, see the
- * [webdriver package on pub.dartlang.org][pkg].
- *
- * ## Using ##
- *
- * These bindings are based on the WebDriver JSON wire protocol spec
- * (http://code.google.com/p/selenium/wiki/JsonWireProtocol). Not
- * all of these commands are implemented yet by WebDriver itself.
- * Nontheless this is a complete implementation of the spec as the
- * unsupported commands may be supported in the future. Currently,
- * there are known issues with local and session storage, script
- * execution, and log access.
- *
- * To use these bindings, the Selenium standalone server must be running.
- * You can download it at http://code.google.com/p/selenium/downloads/list.
- *
- * There are a number of commands that use ids to access page elements.
- * These ids are not the HTML ids; they are opaque ids internal to
- * WebDriver. To get the id for an element you would first need to do
- * a search, get the results, and extract the WebDriver id from the returned
- * [Map] using the 'ELEMENT' key. For example:
- *
- *     String id;
- *     WebDriverSession session;
- *     Future f = web_driver.newSession('chrome');
- *     f.then((_session) {
- *       session = _session;
- *       return session.setUrl('http://my.web.site.com');
- *    }).then((_) {
- *      return session.findElement('id', 'username');
- *    }).then((element) {
- *      id = element['ELEMENT'];
- *      return session.sendKeyStrokesToElement(id,
- *          [ 'j', 'o', 'e', ' ', 'u', 's', 'e', 'r' ]);
- *    }).then((_) {
- *      return session.submit(id);
- *    }).then((_) {
- *      return session.close();
- *    }).then((_) {
- *      session = null;
- *    });
- *
- * [pub]: http://pub.dartlang.org
- * [pkg]: http://pub.dartlang.org/packages/webdriver
- */
-
-void writeStringToFile(String fileName, String contents) {
-  new File(fileName).writeAsStringSync(contents);
-}
-
-void writeBytesToFile(String fileName, List<int> contents) {
-  new File(fileName).writeAsBytesSync(contents);
-}
-
-class WebDriverError {
-  static List _errorTypes = null;
-  static List _errorDetails = null;
-  int statusCode;
-  String type;
-  String message;
-  String details;
-  String results;
-
-  WebDriverError(this.statusCode, this.message, [this.results = '']) {
-    /** These correspond to WebDrive exception types. */
-    if (_errorTypes == null) {
-      _errorTypes = [
-        null,
-        'IndexOutOfBounds',
-        'NoCollection',
-        'NoString',
-        'NoStringLength',
-        'NoStringWrapper',
-        'NoSuchDriver',
-        'NoSuchElement',
-        'NoSuchFrame',
-        'UnknownCommand',
-        'ObsoleteElement',
-        'ElementNotDisplayed',
-        'InvalidElementState',
-        'Unhandled',
-        'Expected',
-        'ElementNotSelectable',
-        'NoSuchDocument',
-        'UnexpectedJavascript',
-        'NoScriptResult',
-        'XPathLookup',
-        'NoSuchCollection',
-        'TimeOut',
-        'NullPointer',
-        'NoSuchWindow',
-        'InvalidCookieDomain',
-        'UnableToSetCookie',
-        'UnexpectedAlertOpen',
-        'NoAlertOpen',
-        'ScriptTimeout',
-        'InvalidElementCoordinates',
-        'IMENotAvailable',
-        'IMEEngineActivationFailed',
-        'InvalidSelector',
-        'SessionNotCreatedException',
-        'MoveTargetOutOfBounds'
-      ];
-      // Explanations of the eror types. In thoses cases where the
-      // explanation is the same as the type (e.g. NoCollection), that is an
-      // error type used by an old version of the IE driver and is deprecated.
-      _errorDetails = [
-        null,
-        'IndexOutOfBounds',
-        'NoCollection',
-        'NoString',
-        'NoStringLength',
-        'NoStringWrapper',
-        'NoSuchDriver',
-        'An element could not be located on the page using the given '
-            'search parameters.',
-        'A request to switch to a frame could not be satisfied because the '
-            'frame could not be found.',
-        'The requested resource could not be found, or a request was '
-            'received using an HTTP method that is not supported by the '
-            'mapped resource.',
-        'An element command failed because the referenced element is no '
-            'longer attached to the DOM.',
-        'An element command could not be completed because the element '
-            'is not visible on the page.',
-        'An element command could not be completed because the element is in '
-            'an invalid state (e.g. attempting to click a disabled element).',
-        'An unknown server-side error occurred while processing the command.',
-        'Expected',
-        'An attempt was made to select an element that cannot be selected.',
-        'NoSuchDocument',
-        'An error occurred while executing user supplied JavaScript.',
-        'NoScriptResult',
-        'An error occurred while searching for an element by XPath.',
-        'NoSuchCollection',
-        'An operation did not complete before its timeout expired.',
-        'NullPointer',
-        'A request to switch to a different window could not be satisfied '
-            'because the window could not be found.',
-        'An illegal attempt was made to set a cookie under a different '
-            'domain than the current page.',
-        'A request to set a cookie\'s value could not be satisfied.',
-        'A modal dialog was open, blocking this operation.',
-        'An attempt was made to operate on a modal dialog when one was '
-            'not open.',
-        'A script did not complete before its timeout expired.',
-        'The coordinates provided to an interactions operation are invalid.',
-        'IME was not available.',
-        'An IME engine could not be started.',
-        'Argument was an invalid selector (e.g. XPath/CSS).',
-        'A new session could not be created.',
-        'Target provided for a move action is out of bounds.'
-      ];
-    }
-    if (statusCode < 0 || statusCode > 32) {
-      type = 'External';
-      details = '';
-    } else {
-      type = _errorTypes[statusCode];
-      details = _errorDetails[statusCode];
-    }
-  }
-
-  String toString() {
-    return '$statusCode $type: $message $results\n$details';
-  }
-}
-
-/**
- * Base class for all WebDriver request classes. This class wraps up
- * an URL prefix (host, port, and initial path), and provides a client
- * function for doing HTTP requests with JSON payloads.
- */
-class WebDriverBase {
-
-  String _host;
-  int _port;
-  String _path;
-  String _url;
-
-  String get path => _path;
-  String get url => _url;
-
-  /**
-   * The default URL for WebDriver remote server is
-   * http://localhost:4444/wd/hub.
-   */
-  WebDriverBase.fromUrl([this._url = 'http://localhost:4444/wd/hub']) {
-    // Break out the URL components.
-    var re = new RegExp('[^:/]+://([^/]+)(/.*)');
-    var matches = re.firstMatch(_url);
-    _host = matches[1];
-    _path = matches[2];
-    var idx = _host.indexOf(':');
-    if (idx >= 0) {
-      _port = int.parse(_host.substring(idx+1));
-      _host = _host.substring(0, idx);
-    } else {
-      _port = 80;
-    }
-  }
-
-  WebDriverBase([
-      this._host = 'localhost',
-      this._port = 4444,
-      this._path = '/wd/hub']) {
-    _url = 'http://$_host:$_port$_path';
-  }
-
-  void _failRequest(Completer completer, error, [stackTrace]) {
-    if (completer != null) {
-      var trace = stackTrace != null ? stackTrace : getAttachedStackTrace(error);
-      completer.completeError(new WebDriverError(-1, error), trace);
-    }
-  }
-
-  /**
-   * Execute a request to the WebDriver server. [http_method] should be
-   * one of 'GET', 'POST', or 'DELETE'. [command] is the text to append
-   * to the base URL path to get the full URL. [params] are the additional
-   * parameters. If a [List] or [Map] they will be posted as JSON parameters.
-   * If a number or string, "/params" is appended to the URL.
-   */
-  void _serverRequest(String http_method, String command, Completer completer,
-                      {List successCodes, params, Function customHandler}) {
-    var status = 0;
-    var results = null;
-    var message = null;
-    if (successCodes == null) {
-      successCodes = [ 200, 204 ];
-    }
-    try {
-      var path = command;
-      if (params != null) {
-        if (params is num || params is String) {
-          path = '$path/$params';
-          params = null;
-        } else if (http_method != 'POST') {
-          throw new Exception(
-            'The http method called for ${command} is ${http_method} but it '
-            'must be POST if you want to pass the JSON params '
-            '${json.stringify(params)}');
-        }
-      }
-
-      var client = new HttpClient();
-      client.open(http_method, _host, _port, path).then((req) {
-        req.followRedirects = false;
-        req.headers.add(HttpHeaders.ACCEPT, "application/json");
-        req.headers.add(
-            HttpHeaders.CONTENT_TYPE, 'application/json;charset=UTF-8');
-        if (params != null) {
-          var body = json.stringify(params);
-          req.write(body);
-        }
-        req.close().then((rsp) {
-          List<int> body = new List<int>();
-          rsp.listen(body.addAll, onDone: () {
-            var value = null;
-            // For some reason we get a bunch of NULs on the end
-            // of the text and the json.parse blows up on these, so
-            // strip them.
-            // These NULs can be seen in the TCP packet, so it is not
-            // an issue with character encoding; it seems to be a bug
-            // in WebDriver stack.
-            results = new String.fromCharCodes(body)
-                .replaceAll(new RegExp('\u{0}*\$'), '');
-            if (!successCodes.contains(rsp.statusCode)) {
-              _failRequest(completer, 
-                  'Unexpected response ${rsp.statusCode}; $results');
-              completer = null;
-              return;
-            }
-            if (status == 0 && results.length > 0) {
-              // 4xx responses send plain text; others send JSON.
-              if (rsp.statusCode < 400) {
-                results = json.parse(results);
-                status = results['status'];
-              }
-              if (results is Map && (results as Map).containsKey('value')) {
-                value = results['value'];
-              }
-              if (value is Map && value.containsKey('message')) {
-                message = value['message'];
-              }
-            }
-            if (status == 0) {
-              if (customHandler != null) {
-                customHandler(rsp, value);
-              } else if (completer != null) {
-                completer.complete(value);
-              }
-            }
-          }, onError: (error) {
-            _failRequest(completer, error);
-            completer = null;
-          });
-        })
-        .catchError((error) {
-          _failRequest(completer, error);
-          completer = null;
-        });
-      })
-      .catchError((error) {
-        _failRequest(completer, error);
-        completer = null;
-      });
-    } catch (e, s) {
-      _failRequest(completer, e, s);
-      completer = null;
-    }
-  }
-
-  Future _get(String extraPath,
-      [Completer completer, Function customHandler]) {
-    if (completer == null) completer = new Completer();
-    _serverRequest('GET', '${_path}/$extraPath', completer,
-        customHandler: customHandler);
-    return completer.future;
-  }
-
-  Future _post(String extraPath, [params]) {
-    var completer = new Completer();
-    _serverRequest('POST', '${_path}/$extraPath', completer,
-        params: params);
-    return completer.future;
-  }
-
-  Future _delete(String extraPath) {
-    var completer = new Completer();
-    _serverRequest('DELETE', '${_path}/$extraPath', completer);
-    return completer.future;
-  }
-}
-
-class WebDriver extends WebDriverBase {
-
-  WebDriver(host, port, path) : super(host, port, path);
-
-  /**
-   * Create a new session. The server will attempt to create a session that
-   * most closely matches the desired and required capabilities. Required
-   * capabilities have higher priority than desired capabilities and must be
-   * set for the session to be created.
-   *
-   * The capabilities are:
-   *
-   * - browserName (String)  The name of the browser being used; should be one
-   *   of chrome|firefox|htmlunit|internet explorer|iphone.
-   *
-   * - version (String) The browser version, or the empty string if unknown.
-   *
-   * - platform (String) A key specifying which platform the browser is
-   *   running on. This value should be one of WINDOWS|XP|VISTA|MAC|LINUX|UNIX.
-   *   When requesting a new session, the client may specify ANY to indicate
-   *   any available platform may be used.
-   *
-   * - javascriptEnabled (bool) Whether the session supports executing user
-   *   supplied JavaScript in the context of the current page.
-   *
-   * - takesScreenshot (bool) Whether the session supports taking screenshots
-   *   of the current page.
-   *
-   * - handlesAlerts (bool) Whether the session can interact with modal popups,
-   *   such as window.alert and window.confirm.
-   *
-   * - databaseEnabled (bool) Whether the session can interact database storage.
-   *
-   * - locationContextEnabled (bool) Whether the session can set and query the
-   *   browser's location context.
-   *
-   * - applicationCacheEnabled (bool) Whether the session can interact with
-   *   the application cache.
-   *
-   * - browserConnectionEnabled (bool) Whether the session can query for the
-   *   browser's connectivity and disable it if desired.
-   *
-   * - cssSelectorsEnabled (bool) Whether the session supports CSS selectors
-   *   when searching for elements.
-   *
-   * - webStorageEnabled (bool) Whether the session supports interactions with
-   *   storage objects.
-   *
-   * - rotatable (bool) Whether the session can rotate the current page's
-   *   current layout between portrait and landscape orientations (only applies
-   *   to mobile platforms).
-   *
-   * - acceptSslCerts (bool) Whether the session should accept all SSL certs
-   *   by default.
-   *
-   * - nativeEvents (bool) Whether the session is capable of generating native
-   *   events when simulating user input.
-   *
-   * - proxy (proxy object) Details of any proxy to use. If no proxy is
-   *   specified, whatever the system's current or default state is used.
-   *
-   * The format of the proxy object is:
-   *
-   * - proxyType (String) The type of proxy being used. Possible values are:
-   *
-   *   direct - A direct connection - no proxy in use,
-   *
-   *   manual - Manual proxy settings configured,
-   *
-   *   pac - Proxy autoconfiguration from a URL),
-   *
-   *   autodetect (proxy autodetection, probably with WPAD),
-   *
-   *   system - Use system settings
-   *
-   * - proxyAutoconfigUrl (String) Required if proxyType == pac, Ignored
-   *   otherwise. Specifies the URL to be used for proxy autoconfiguration.
-   *
-   * - ftpProxy, httpProxy, sslProxy (String) (Optional, Ignored if
-   *   proxyType != manual) Specifies the proxies to be used for FTP, HTTP
-   *   and HTTPS requests respectively. Behaviour is undefined if a request
-   *   is made, where the proxy for the particular protocol is undefined,
-   *   if proxyType is manual.
-   *
-   * Potential Errors: SessionNotCreatedException (if a required capability
-   * could not be set).
-   */
-  Future<WebDriverSession> newSession([
-      browser = 'chrome', Map additional_capabilities]) {
-    var completer = new Completer();
-    if (additional_capabilities == null) {
-      additional_capabilities = {};
-    }
-
-    additional_capabilities['browserName'] = browser;
-
-    _serverRequest('POST', '${_path}/session', completer,
-        successCodes: [ 302 ],
-        customHandler: (r, v) {
-          var url = r.headers.value(HttpHeaders.LOCATION);
-          var session = new WebDriverSession.fromUrl(url);
-          completer.complete(session);
-        },
-        params: { 'desiredCapabilities': additional_capabilities });
-    return completer.future;
-  }
-
-  /** Get the set of currently active sessions. */
-  Future<List<WebDriverSession>> getSessions() {
-    var completer = new Completer();
-    return _get('sessions', completer, (r, v) {
-      var _sessions = [];
-      for (var session in v) {
-        var url = 'http://${this._host}:${this._port}${this._path}/'
-            'session/${session["id"]}';
-        _sessions.add(new WebDriverSession.fromUrl(url));
-      }
-      completer.complete(_sessions);
-    });
-  }
-
-  /** Query the server's current status. */
-  Future<Map> getStatus() => _get('status');
-}
-
-class WebDriverWindow extends WebDriverBase {
-  WebDriverWindow.fromUrl(url) : super.fromUrl(url);
-
-  /** Get the window size. */
-  Future<Map> getSize() => _get('size');
-
-  /**
-   * Set the window size. Note that this is flaky and often
-   * has no effect.
-   *
-   * Potential Errors:
-   *   NoSuchWindow - If the specified window cannot be found.
-   */
-  Future<String> setSize(int width, int height) =>
-      _post('size', { 'width': width, 'height': height });
-
-  /** Get the window position. */
-  Future<Map> getPosition() => _get('position');
-
-  /**
-   * Set the window position. Note that this is flaky and often
-   * has no effect.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future setPosition(int x, int y) =>
-      _post('position', { 'x': x, 'y': y });
-
-  /** Maximize the specified window if not already maximized. */
-  Future maximize() => _post('maximize');
-}
-
-class WebDriverSession extends WebDriverBase {
-  WebDriverSession.fromUrl(url) : super.fromUrl(url);
-
-  /** Close the session. */
-  Future close() => _delete('');
-
-  /** Get the session capabilities. See [newSession] for details. */
-  Future<Map> getCapabilities() => _get('');
-
-  /**
-   * Configure the amount of time in milliseconds that a script can execute
-   * for before it is aborted and a Timeout error is returned to the client.
-   */
-  Future setScriptTimeout(t) =>
-      _post('timeouts', { 'type': 'script', 'ms': t });
-
-  /*Future<String> setImplicitWaitTimeout(t) =>
-      simplePost('timeouts', { 'type': 'implicit', 'ms': t });*/
-
-  /**
-   * Configure the amount of time in milliseconds that a page can load for
-   * before it is aborted and a Timeout error is returned to the client.
-   */
-  Future setPageLoadTimeout(t) =>
-      _post('timeouts', { 'type': 'page load', 'ms': t });
-
-  /**
-   * Set the amount of time, in milliseconds, that asynchronous scripts
-   * executed by /session/:sessionId/execute_async are permitted to run
-   * before they are aborted and a Timeout error is returned to the client.
-   */
-  Future setAsyncScriptTimeout(t) =>
-      _post('timeouts/async_script', { 'ms': t });
-
-  /**
-   * Set the amount of time the driver should wait when searching for elements.
-   * When searching for a single element, the driver should poll the page until
-   * an element is found or the timeout expires, whichever occurs first. When
-   * searching for multiple elements, the driver should poll the page until at
-   * least one element is found or the timeout expires, at which point it should
-   * return an empty list.
-   *
-   * If this command is never sent, the driver should default to an implicit
-   * wait of 0ms.
-   */
-  Future setImplicitWaitTimeout(t) =>
-      _post('timeouts/implicit_wait', { 'ms': t });
-
-  /**
-   * Retrieve the current window handle.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getWindowHandle() => _get('window_handle');
-
-  /**
-   * Retrieve a [WebDriverWindow] for the specified window. We don't
-   * have to use a Future here but do so to be consistent.
-   */
-  Future<WebDriverWindow> getWindow([handle = 'current']) {
-    var completer = new Completer();
-    completer.complete(new WebDriverWindow.fromUrl('${_url}/window/$handle'));
-    return completer.future;
-  }
-
-  /** Retrieve the list of all window handles available to the session. */
-  Future<List<String>> getWindowHandles() => _get('window_handles');
-
-  /**
-   * Retrieve the URL of the current page.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getUrl() => _get('url');
-
-  /**
-   * Navigate to a new URL.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future setUrl(String url) => _post('url', { 'url': url });
-
-  /**
-   * Navigate forwards in the browser history, if possible.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future navigateForward() => _post('forward');
-
-  /**
-   * Navigate backwards in the browser history, if possible.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future navigateBack() => _post('back');
-
-  /**
-   * Refresh the current page.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future refresh() => _post('refresh');
-
-  /**
-   * Inject a snippet of JavaScript into the page for execution in the context
-   * of the currently selected frame. The executed script is assumed to be
-   * synchronous and the result of evaluating the script is returned to the
-   * client.
-   *
-   * The script argument defines the script to execute in the form of a
-   * function body. The value returned by that function will be returned to
-   * the client. The function will be invoked with the provided args array
-   * and the values may be accessed via the arguments object in the order
-   * specified.
-   *
-   * Arguments may be any JSON-primitive, array, or JSON object. JSON objects
-   * that define a WebElement reference will be converted to the corresponding
-   * DOM element. Likewise, any WebElements in the script result will be
-   * returned to the client as WebElement JSON objects.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference, JavaScriptError.
-   */
-  Future execute(String script, [List args]) {
-    if (args == null) args = [];
-    return _post('execute', { 'script': script, 'args': args });
-  }
-
-  /**
-   * Inject a snippet of JavaScript into the page for execution in the context
-   * of the currently selected frame. The executed script is assumed to be
-   * asynchronous and must signal that it is done by invoking the provided
-   * callback, which is always provided as the final argument to the function.
-   * The value to this callback will be returned to the client.
-   *
-   * Asynchronous script commands may not span page loads. If an unload event
-   * is fired while waiting for a script result, an error should be returned
-   * to the client.
-   *
-   * The script argument defines the script to execute in the form of a function
-   * body. The function will be invoked with the provided args array and the
-   * values may be accessed via the arguments object in the order specified.
-   * The final argument will always be a callback function that must be invoked
-   * to signal that the script has finished.
-   *
-   * Arguments may be any JSON-primitive, array, or JSON object. JSON objects
-   * that define a WebElement reference will be converted to the corresponding
-   * DOM element. Likewise, any WebElements in the script result will be
-   * returned to the client as WebElement JSON objects.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference, Timeout (controlled
-   * by the [setAsyncScriptTimeout] command), JavaScriptError (if the script
-   * callback is not invoked before the timout expires).
-   */
-  Future executeAsync(String script, [List args]) {
-    if (args == null) args = [];
-    return _post('execute_async', { 'script': script, 'args': args });
-  }
-
-  /**
-   * Take a screenshot of the current page (PNG).
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<List<int>> getScreenshot([fname]) {
-    var completer = new Completer();
-    return _get('screenshot', completer, (r, v) {
-      var image = Base64Decoder.decode(v);
-      if (fname != null) {
-        writeBytesToFile(fname, image);
-      }
-      completer.complete(image);
-    });
-  }
-
-  /**
-   * List all available IME (Input Method Editor) engines on the machine.
-   * To use an engine, it has to be present in this list.
-   *
-   * Potential Errors: ImeNotAvailableException.
-   */
-  Future<List<String>> getAvailableImeEngines() =>
-      _get('ime/available_engines');
-
-  /**
-   * Get the name of the active IME engine. The name string is
-   * platform specific.
-   *
-   * Potential Errors: ImeNotAvailableException.
-   */
-  Future<String> getActiveImeEngine() => _get('ime/active_engine');
-
-  /**
-   * Indicates whether IME input is active at the moment (not if
-   * it's available).
-   *
-   * Potential Errors: ImeNotAvailableException.
-   */
-  Future<bool> getIsImeActive() => _get('ime/activated');
-
-  /**
-   * De-activates the currently-active IME engine.
-   *
-   * Potential Errors: ImeNotAvailableException.
-   */
-  Future deactivateIme() => _post('ime/deactivate');
-
-  /**
-   * Make an engine that is available (appears on the list returned by
-   * getAvailableEngines) active. After this call, the engine will be added
-   * to the list of engines loaded in the IME daemon and the input sent using
-   * sendKeys will be converted by the active engine. Note that this is a
-   * platform-independent method of activating IME (the platform-specific way
-   * being using keyboard shortcuts).
-   *
-   * Potential Errors: ImeActivationFailedException, ImeNotAvailableException.
-   */
-  Future activateIme(String engine) =>
-      _post('ime/activate', { 'engine': engine });
-
-  /**
-   * Change focus to another frame on the page. If the frame id is null,
-   * the server should switch to the page's default content.
-   * [id] is the Identifier for the frame to change focus to, and can be
-   * a string, number, null, or JSON Object.
-   *
-   * Potential Errors: NoSuchWindow, NoSuchFrame.
-   */
-  Future setFrameFocus(id) => _post('frame', { 'id': id });
-
-  /**
-   * Change focus to another window. The window to change focus to may be
-   * specified by [name], which is its server assigned window handle, or
-   * the value of its name attribute.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future setWindowFocus(name) => _post('window', { 'name': name });
-
-  /**
-   * Close the current window.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future closeWindow() => _delete('window');
-
-  /**
-   * Retrieve all cookies visible to the current page.
-   *
-   * The returned List contains Maps with the following keys:
-   *
-   * 'name' - The name of the cookie.
-   *
-   * 'value' - The cookie value.
-   *
-   * The following keys may optionally be present:
-   *
-   * 'path' - The cookie path.
-   *
-   * 'domain' - The domain the cookie is visible to.
-   *
-   * 'secure' - Whether the cookie is a secure cookie.
-   *
-   * 'expiry' - When the cookie expires, seconds since midnight, 1/1/1970 UTC.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<List<Map>> getCookies() => _get('cookie');
-
-  /**
-   * Set a cookie. If the cookie path is not specified, it should be set
-   * to "/". Likewise, if the domain is omitted, it should default to the
-   * current page's domain. See [getCookies] for the structure of a cookie
-   * Map.
-   */
-  Future setCookie(Map cookie) => _post('cookie', { 'cookie': cookie });
-
-  /**
-   * Delete all cookies visible to the current page.
-   *
-   * Potential Errors: InvalidCookieDomain (the cookie's domain is not
-   * visible from the current page), NoSuchWindow, UnableToSetCookie (if
-   * attempting to set a cookie on a page that does not support cookies,
-   * e.g. pages with mime-type text/plain).
-   */
-  Future deleteCookies() => _delete('cookie');
-
-  /**
-   * Delete the cookie with the given [name]. This command should be a no-op
-   * if there is no such cookie visible to the current page.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future deleteCookie(String name) => _delete('cookie/$name');
-
-  /**
-   * Get the current page source.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getPageSource() => _get('source');
-
-  /**
-   * Get the current page title.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getPageTitle() => _get('title');
-
-  /**
-   * Search for an element on the page, starting from the document root. The
-   * first matching located element will be returned as a WebElement JSON
-   * object (a [Map] with an 'ELEMENT' key whose value should be used to
-   * identify the element in further requests). The [strategy] should be
-   * one of:
-   *
-   * 'class name' - Returns an element whose class name contains the search
-   *    value; compound class names are not permitted.
-   *
-   * 'css selector' - Returns an element matching a CSS selector.
-   *
-   * 'id' - Returns an element whose ID attribute matches the search value.
-   *
-   * 'name' - Returns an element whose NAME attribute matches the search value.
-   *
-   * 'link text' - Returns an anchor element whose visible text matches the
-   *   search value.
-   *
-   * 'partial link text' - Returns an anchor element whose visible text
-   *   partially matches the search value.
-   *
-   * 'tag name' - Returns an element whose tag name matches the search value.
-   *
-   * 'xpath' - Returns an element matching an XPath expression.
-   *
-   * Potential Errors: NoSuchWindow, NoSuchElement, XPathLookupError (if
-   * using XPath and the input expression is invalid).
-   */
-  Future<String> findElement(String strategy, String searchValue) =>
-      _post('element', { 'using': strategy, 'value' : searchValue });
-
-  /**
-   * Search for multiple elements on the page, starting from the document root.
-   * The located elements will be returned as WebElement JSON objects. See
-   * [findElement] for the locator strategies that each server supports.
-   * Elements are be returned in the order located in the DOM.
-   *
-   * Potential Errors: NoSuchWindow, XPathLookupError.
-   */
-  Future<List<String>> findElements(String strategy, String searchValue) =>
-      _post('elements', { 'using': strategy, 'value' : searchValue });
-
-  /**
-   * Get the element on the page that currently has focus. The element will
-   * be returned as a WebElement JSON object.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getElementWithFocus() => _post('element/active');
-
-  /**
-   * Search for an element on the page, starting from element with id [id].
-   * The located element will be returned as WebElement JSON objects. See
-   * [findElement] for the locator strategies that each server supports.
-   *
-   * Potential Errors: NoSuchWindow, XPathLookupError.
-   */
-  Future<String>
-      findElementFromId(String id, String strategy, String searchValue) =>
-          _post('element/$id/element',
-              { 'using': strategy, 'value' : searchValue });
-
-  /**
-   * Search for multiple elements on the page, starting from the element with
-   * id [id].The located elements will be returned as WebElement JSON objects.
-   * See [findElement] for the locator strategies that each server supports.
-   * Elements are be returned in the order located in the DOM.
-   *
-   * Potential Errors: NoSuchWindow, XPathLookupError.
-   */
-  Future<List<String>>
-      findElementsFromId(String id, String strategy, String searchValue) =>
-          _post('element/$id/elements',
-              { 'using': strategy, 'value' : searchValue });
-  /**
-   * Click on an element specified by [id].
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference, ElementNotVisible
-   * (if the referenced element is not visible on the page, either hidden
-   * by CSS, or has 0-width or 0-height).
-   */
-  Future clickElement(String id) => _post('element/$id/click');
-
-  /**
-   * Submit a FORM element. The submit command may also be applied to any
-   * element that is a descendant of a FORM element.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future submit(String id) => _post('element/$id/submit');
-
-  /** Returns the visible text for the element.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<String> getElementText(String id) => _get('element/$id/text');
-
-  /**
-   * Send a sequence of key strokes to an element.
-   *
-   * Any UTF-8 character may be specified, however, if the server does not
-   * support native key events, it will simulate key strokes for a standard
-   * US keyboard layout. The Unicode Private Use Area code points,
-   * 0xE000-0xF8FF, are used to represent pressable, non-text keys:
-   *
-   * NULL - U+E000
-   *
-   * Cancel - U+E001
-   *
-   * Help - U+E002
-   *
-   * Backspace - U+E003
-   *
-   * Tab - U+E004
-   *
-   * Clear - U+E005
-   *
-   * Return - U+E006
-   *
-   * Enter - U+E007
-   *
-   * Shift - U+E008
-   *
-   * Control - U+E009
-   *
-   * Alt - U+E00A
-   *
-   * Pause - U+E00B
-   *
-   * Escape - U+E00C
-   *
-   * Space - U+E00D
-   *
-   * Pageup - U+E00E
-   *
-   * Pagedown - U+E00F
-   *
-   * End - U+E010
-   *
-   * Home - U+E011
-   *
-   * Left arrow - U+E012
-   *
-   * Up arrow - U+E013
-   *
-   * Right arrow - U+E014
-   *
-   * Down arrow - U+E015
-   *
-   * Insert - U+E016
-   *
-   * Delete - U+E017
-   *
-   * Semicolon - U+E018
-   *
-   * Equals - U+E019
-   *
-   * Numpad 0..9 - U+E01A..U+E023
-   *
-   * Multiply - U+E024
-   *
-   * Add - U+E025
-   *
-   * Separator - U+E026
-   *
-   * Subtract - U+E027
-   *
-   * Decimal - U+E028
-   *
-   * Divide - U+E029
-   *
-   * F1..F12 - U+E031..U+E03C
-   *
-   * Command/Meta U+E03D
-   *
-   * The server processes the key sequence as follows:
-   *
-   * - Each key that appears on the keyboard without requiring modifiers is
-   *   sent as a keydown followed by a key up.
-   *
-   * - If the server does not support native events and must simulate key
-   *   strokes with JavaScript, it will generate keydown, keypress, and keyup
-   *   events, in that order. The keypress event is only fired when the
-   *   corresponding key is for a printable character.
-   *
-   * - If a key requires a modifier key (e.g. "!" on a standard US keyboard),
-   *   the sequence is: modifier down, key down, key up, modifier up, where
-   *   key is the ideal unmodified key value (using the previous example,
-   *   a "1").
-   *
-   * - Modifier keys (Ctrl, Shift, Alt, and Command/Meta) are assumed to be
-   *  "sticky"; each modifier is held down (e.g. only a keydown event) until
-   *   either the modifier is encountered again in the sequence, or the NULL
-   *   (U+E000) key is encountered.
-   *
-   * - Each key sequence is terminated with an implicit NULL key.
-   *   Subsequently, all depressed modifier keys are released (with
-   *   corresponding keyup events) at the end of the sequence.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference, ElementNotVisible.
-   */
-  Future sendKeyStrokesToElement(String id, List<String> keys) =>
-      _post('element/$id/value', { 'value': keys });
-
-  /**
-   * Send a sequence of key strokes to the active element. This command is
-   * similar to [sendKeyStrokesToElement] command in every aspect except the
-   * implicit termination: The modifiers are not released at the end of the
-   * call. Rather, the state of the modifier keys is kept between calls,
-   * so mouse interactions can be performed while modifier keys are depressed.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future sendKeyStrokes(List<String> keys) => _post('keys', { 'value': keys });
-
-  /**
-   * Query for an element's tag name, as a lower-case string.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<String> getElementTagName(String id) => _get('element/$id/name');
-
-  /**
-   * Clear a TEXTAREA or text INPUT element's value.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference, ElementNotVisible,
-   * InvalidElementState.
-   */
-  Future clearValue(String id) => _post('/element/$id/clear');
-
-  /**
-   * Determine if an OPTION element, or an INPUT element of type checkbox
-   * or radiobutton is currently selected.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<bool> isSelected(String id) => _get('element/$id/selected');
-
-  /**
-   * Determine if an element is currently enabled.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<bool> isEnabled(String id) => _get('element/$id/enabled');
-
-  /**
-   * Get the value of an element's attribute, or null if it has no such
-   * attribute.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<String> getAttribute(String id, String attribute) =>
-      _get('element/$id/attribute/$attribute');
-
-  /**
-   * Test if two element IDs refer to the same DOM element.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<bool> areSameElement(String id, String other) =>
-      _get('element/$id/equals/$other');
-
-  /**
-   * Determine if an element is currently displayed.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<bool> isDiplayed(String id) => _get('element/$id/displayed');
-
-  /**
-   * Determine an element's location on the page. The point (0, 0) refers to
-   * the upper-left corner of the page. The element's coordinates are returned
-   * as a [Map] object with x and y properties.
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<Map> getElementLocation(String id) => _get('element/$id/location');
-
-  /**
-   * Determine an element's size in pixels. The size will be returned as a
-   * [Map] object with width and height properties.
-   *
-   * Potential Errors: NoSuchWindow, StalElementReference.
-   */
-  Future<Map> getElementSize(String id) => _get('element/$id/size');
-
-  /**
-   * Query the value of an element's computed CSS property. The CSS property
-   * to query should be specified using the CSS property name, not the
-   * JavaScript property name (e.g. background-color instead of
-   * backgroundColor).
-   *
-   * Potential Errors: NoSuchWindow, StaleElementReference.
-   */
-  Future<String> getElementCssProperty(String id, String property) =>
-      _get('element/$id/css/$property');
-
-  /**
-   * Get the current browser orientation ('LANDSCAPE' or 'PORTRAIT').
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getBrowserOrientation() => _get('orientation');
-
-  /**
-   * Gets the text of the currently displayed JavaScript alert(), confirm(),
-   * or prompt() dialog.
-   *
-   * Potential Errors: NoAlertPresent.
-   */
-  Future<String> getAlertText() => _get('alert_text');
-
-  /**
-   * Sends keystrokes to a JavaScript prompt() dialog.
-   *
-   * Potential Errors: NoAlertPresent.
-   */
-  Future sendKeyStrokesToPrompt(String text) =>
-      _post('alert_text', { 'text': text });
-
-  /**
-   * Accepts the currently displayed alert dialog. Usually, this is equivalent
-   * to clicking on the 'OK' button in the dialog.
-   *
-   * Potential Errors: NoAlertPresent.
-   */
-  Future acceptAlert() => _post('accept_alert');
-
-  /**
-   * Dismisses the currently displayed alert dialog. For confirm() and prompt()
-   * dialogs, this is equivalent to clicking the 'Cancel' button. For alert()
-   * dialogs, this is equivalent to clicking the 'OK' button.
-   *
-   * Potential Errors: NoAlertPresent.
-   */
-  Future dismissAlert() => _post('dismiss_alert');
-
-  /**
-   * Move the mouse by an offset relative to a specified element. If no element
-   * is specified, the move is relative to the current mouse cursor. If an
-   * element is provided but no offset, the mouse will be moved to the center
-   * of the element. If the element is not visible, it will be scrolled
-   * into view.
-   */
-  Future moveTo(String id, int x, int y) {
-    var json = {};
-    if (id != null) {
-      json['element'] = id;
-    }
-    if (x != null) {
-      json['xoffset'] = x;
-    }
-    if (y != null) {
-      json['yoffset'] = y;
-    }
-    return _post('moveto', json);
-  }
-
-  /**
-   * Click a mouse button (at the coordinates set by the last [moveTo] command).
-   * Note that calling this command after calling [buttonDown] and before
-   * calling [buttonUp] (or any out-of-order interactions sequence) will yield
-   * undefined behaviour).
-   *
-   * [button] should be 0 for left, 1 for middle, or 2 for right.
-   */
-  Future clickMouse([button = 0]) => _post('click', { 'button' : button });
-
-  /**
-   * Click and hold the left mouse button (at the coordinates set by the last
-   * [moveTo] command). Note that the next mouse-related command that should
-   * follow is [buttonDown]. Any other mouse command (such as [click] or
-   * another call to [buttonDown]) will yield undefined behaviour.
-   *
-   * [button] should be 0 for left, 1 for middle, or 2 for right.
-   */
-  Future buttonDown([button = 0]) => _post('click', { 'button' : button });
-
-  /**
-   * Releases the mouse button previously held (where the mouse is currently
-   * at). Must be called once for every [buttonDown] command issued. See the
-   * note in [click] and [buttonDown] about implications of out-of-order
-   * commands.
-   *
-   * [button] should be 0 for left, 1 for middle, or 2 for right.
-   */
-  Future buttonUp([button = 0]) => _post('click', { 'button' : button });
-
-  /** Double-clicks at the current mouse coordinates (set by [moveTo]). */
-  Future doubleClick() => _post('doubleclick');
-
-  /** Single tap on the touch enabled device on the element with id [id]. */
-  Future touchClick(String id) => _post('touch/click', { 'element': id });
-
-  /** Finger down on the screen. */
-  Future touchDown(int x, int y) => _post('touch/down', { 'x': x, 'y': y });
-
-  /** Finger up on the screen. */
-  Future touchUp(int x, int y) => _post('touch/up', { 'x': x, 'y': y }); 
-
-  /** Finger move on the screen. */
-  Future touchMove(int x, int y) => _post('touch/move', { 'x': x, 'y': y });
-
-  /**
-   * Scroll on the touch screen using finger based motion events. If [id] is
-   * specified, scrolling will start at a particular screen location.
-   */
-  Future touchScroll(int xOffset, int yOffset, [String id = null]) {
-    if (id == null) {
-      return _post('touch/scroll', { 'xoffset': xOffset, 'yoffset': yOffset });
-    } else {
-      return _post('touch/scroll',
-          { 'element': id, 'xoffset': xOffset, 'yoffset': yOffset });
-    }
-  }
-
-  /** Double tap on the touch screen using finger motion events. */
-  Future touchDoubleClick(String id) =>
-      _post('touch/doubleclick', { 'element': id });
-
-  /** Long press on the touch screen using finger motion events. */
-  Future touchLongClick(String id) =>
-      _post('touch/longclick', { 'element': id });
-
-  /**
-   * Flick on the touch screen using finger based motion events, starting
-   * at a particular screen location. [speed] is in pixels-per-second.
-   */
-  Future touchFlickFrom(String id, int xOffset, int yOffset, int speed) =>
-          _post('touch/flick',
-              { 'element': id, 'xoffset': xOffset, 'yoffset': yOffset,
-                        'speed': speed });
-
-  /**
-   * Flick on the touch screen using finger based motion events. Use this
-   * instead of [touchFlickFrom] if you don'tr care where the flick starts.
-   */
-  Future touchFlick(int xSpeed, int ySpeed) =>
-      _post('touch/flick', { 'xSpeed': xSpeed, 'ySpeed': ySpeed });
-
-  /**
-   * Get the current geo location. Returns a [Map] with latitude,
-   * longitude and altitude properties.
-   */
-  Future<Map> getGeolocation() => _get('location');
-
-  /** Set the current geo location. */
-  Future setLocation(double latitude, double longitude, double altitude) =>
-          _post('location',
-              { 'latitude': latitude,
-                'longitude': longitude,
-                'altitude': altitude });
-
-  /**
-   * Only a few drivers actually support the JSON storage commands.
-   * Currently it looks like this is the Android and iPhone drivers only.
-   * For the rest, we can achieve a similar effect with Javascript
-   * execution. The flag below is used to control whether to do this.
-   */
-  bool useJavascriptForStorageAPIs = true;
-
-  /**
-   * Get all keys of the local storage. Completes with [null] if there
-   * are no keys or the keys could not be retrieved.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<List<String>> getLocalStorageKeys() {
-    if (useJavascriptForStorageAPIs) {
-      return execute(
-          'var rtn = [];'
-          'for (var i = 0; i < window.localStorage.length; i++)'
-          '  rtn.push(window.localStorage.key(i));'
-          'return rtn;'); 
-    } else {
-      return _get('local_storage');
-    }
-  }
-
-  /**
-   * Set the local storage item for the given key.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future setLocalStorageItem(String key, String value) {
-    if (useJavascriptForStorageAPIs) {
-      return execute('window.localStorage.setItem(arguments[0], arguments[1]);',
-          [key, value]); 
-    } else {
-      return _post('local_storage', { 'key': key, 'value': value });
-    }
-  }
-
-  /**
-   * Clear the local storage.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future clearLocalStorage() {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.localStorage.clear();');
-    } else {
-      return _delete('local_storage');
-    }
-  }
-
-  /**
-   * Get the local storage item for the given key.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getLocalStorageValue(String key) {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.localStorage.getItem(arguments[0]);',
-          [key]); 
-    } else {
-      return _get('local_storage/key/$key');
-    }
-  }
-
-  /**
-   * Delete the local storage item for the given key.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future deleteLocalStorageValue(String key) {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.localStorage.removeItem(arguments[0]);',
-          [key]); 
-    } else {
-      return _delete('local_storage/key/$key');
-    }
-  }
-
-  /**
-   * Get the number of items in the local storage.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<int> getLocalStorageCount() {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.localStorage.length;'); 
-    } else {
-      return _get('local_storage/size');
-    }
-  }
-
-  /**
-   * Get all keys of the session storage.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<List<String>> getSessionStorageKeys() {
-    if (useJavascriptForStorageAPIs) {
-      return execute(
-          'var rtn = [];'
-          'for (var i = 0; i < window.sessionStorage.length; i++)'
-          '  rtn.push(window.sessionStorage.key(i));'
-          'return rtn;'); 
-    } else {
-      return _get('session_storage');
-    }
-  }
-
-  /**
-   * Set the sessionstorage item for the given key.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future setSessionStorageItem(String key, String value) {
-    if (useJavascriptForStorageAPIs) {
-      return execute(
-          'window.sessionStorage.setItem(arguments[0], arguments[1]);',
-              [key, value]); 
-    } else {
-      return _post('session_storage', { 'key': key, 'value': value });
-    }
-  }
-
-  /**
-   * Clear the session storage.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future clearSessionStorage() {
-    if (useJavascriptForStorageAPIs) {
-      return execute('window.sessionStorage.clear();');
-    } else {
-      return _delete('session_storage');
-    }
-  }
-
-  /**
-   * Get the session storage item for the given key.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getSessionStorageValue(String key) {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.sessionStorage.getItem(arguments[0]);',
-          [key]); 
-    } else {
-      return _get('session_storage/key/$key');
-    }
-  }
-
-  /**
-   * Delete the session storage item for the given key.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future deleteSessionStorageValue(String key) {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.sessionStorage.removeItem(arguments[0]);',
-          [key]); 
-    } else {
-      return _delete('session_storage/key/$key');
-    }
-  }
-
-  /**
-   * Get the number of items in the session storage.
-   *
-   * Potential Errors: NoSuchWindow.
-   */
-  Future<String> getSessionStorageCount() {
-    if (useJavascriptForStorageAPIs) {
-      return execute('return window.sessionStorage.length;');
-    } else {
-      return _get('session_storage/size');
-    }
-  }
-
-  /**
-   * Get available log types ('client', 'driver', 'browser', 'server').
-   * This works with Firefox but Chrome returns a 500 response due to a 
-   * bad cast.
-   */
-  Future<List<String>> getLogTypes() => _get('log/types');
-
-  /**
-   * Get the log for a given log type. Log buffer is reset after each request.
-   * Each log entry is a [Map] with these fields:
-   *
-   * 'timestamp' (int) - The timestamp of the entry.
-   * 'level' (String) - The log level of the entry, for example, "INFO".
-   * 'message' (String) - The log message.
-   *
-   * This works with Firefox but Chrome returns a 500 response due to a 
-   * bad cast.
-   */
-  Future<List<Map>> getLogs(String type) => _post('log', { 'type': type });
-}