tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate - sdk.git - Git at Google

 // Copyright (c) 2012, 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 $LIBRARYNAME;

  /**
   * A client-side XHR request for getting data from a URL,
   * formally known as XMLHttpRequest.
   *
   * HttpRequest can be used to obtain data from HTTP and FTP protocols,
   * and is useful for AJAX-style page updates.
   *
   * The simplest way to get the contents of a text file, such as a
   * JSON-formatted file, is with [getString].
   * For example, the following code gets the contents of a JSON file
   * and prints its length:
   *
   *     var path = 'myData.json';
   *     HttpRequest.getString(path).then((String fileContents) {
   *       print(fileContents.length);
   *     }).catchError((error) {
   *       print(error.toString());
   *     });
   *
   * ## Fetching data from other servers
   *
   * For security reasons, browsers impose restrictions on requests
   * made by embedded apps.
   * With the default behavior of this class,
   * the code making the request must be served from the same origin
   * (domain name, port, and application layer protocol)
   * as the requested resource.
   * In the example above, the myData.json file must be co-located with the
   * app that uses it.
   *
   * ## Other resources
   *
   * * [Fetch data dynamically](https://dart.dev/tutorials/web/fetch-data/),
   * a tutorial shows how to load data from a static file or from a server.
   * * [Dart article on using HttpRequests](https://dart.dev/guides/libraries/library-tour#using-http-resources-with-httprequest)
   * * [JS XMLHttpRequest](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest)
   * * [Using XMLHttpRequest](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest/Using_XMLHttpRequest)
  */
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {

   /**
    * Creates a GET request for the specified [url].
    *
    * This is similar to [request] but specialized for HTTP GET requests which
    * return text content.
    *
    * To add query parameters, append them to the [url] following a `?`,
    * joining each key to its value with `=` and separating key-value pairs with
    * `&`.
    *
    *     var name = Uri.encodeQueryComponent('John');
    *     var id = Uri.encodeQueryComponent('42');
    *     HttpRequest.getString('users.json?name=$name&id=$id')
    *       .then((String resp) {
    *         // Do something with the response.
    *     });
    *
    * See also:
    *
    * * [request]
    */
   static Future<String> getString(String url,
       {bool$NULLABLE withCredentials, void onProgress(ProgressEvent e)$NULLABLE}) {
     return request(url, withCredentials: withCredentials,
         onProgress: onProgress).then(
             (HttpRequest xhr) => xhr.responseText$NULLASSERT);
   }

   /**
    * Makes a server POST request with the specified data encoded as form data.
    *
    * This is roughly the POST equivalent of [getString]. This method is similar
    * to sending a [FormData] object with broader browser support but limited to
    * String values.
    *
    * If [data] is supplied, the key/value pairs are URI encoded with
    * [Uri.encodeQueryComponent] and converted into an HTTP query string.
    *
    * Unless otherwise specified, this method appends the following header:
    *
    *     Content-Type: application/x-www-form-urlencoded; charset=UTF-8
    *
    * Here's an example of using this method:
    *
    *     var data = { 'firstName' : 'John', 'lastName' : 'Doe' };
    *     HttpRequest.postFormData('/send', data).then((HttpRequest resp) {
    *       // Do something with the response.
    *     });
    *
    * See also:
    *
    * * [request]
    */
   static Future<HttpRequest> postFormData(String url, Map<String, String> data,
       {bool$NULLABLE withCredentials, String$NULLABLE responseType,
       Map<String, String>$NULLABLE requestHeaders,
       void onProgress(ProgressEvent e)$NULLABLE}) {

     var parts = [];
     data.forEach((key, value) {
       parts.add('${Uri.encodeQueryComponent(key)}='
           '${Uri.encodeQueryComponent(value)}');
     });
     var formData = parts.join('&');

     if (requestHeaders == null) {
       requestHeaders = <String, String>{};
     }
     requestHeaders.putIfAbsent('Content-Type',
         () => 'application/x-www-form-urlencoded; charset=UTF-8');

     return request(url, method: 'POST', withCredentials: withCredentials,
         responseType: responseType,
         requestHeaders: requestHeaders, sendData: formData,
         onProgress: onProgress);
   }

   /**
    * Creates and sends a URL request for the specified [url].
    *
    * By default `request` will perform an HTTP GET request, but a different
    * method (`POST`, `PUT`, `DELETE`, etc) can be used by specifying the
    * [method] parameter. (See also [HttpRequest.postFormData] for `POST`
    * requests only.
    *
    * The Future is completed when the response is available.
    *
    * If specified, `sendData` will send data in the form of a [ByteBuffer],
    * [Blob], [Document], [String], or [FormData] along with the HttpRequest.
    *
    * If specified, [responseType] sets the desired response format for the
    * request. By default it is [String], but can also be 'arraybuffer', 'blob',
    * 'document', 'json', or 'text'. See also [HttpRequest.responseType]
    * for more information.
    *
    * The [withCredentials] parameter specified that credentials such as a cookie
    * (already) set in the header or
    * [authorization headers](http://tools.ietf.org/html/rfc1945#section-10.2)
    * should be specified for the request. Details to keep in mind when using
    * credentials:
    *
    * * Using credentials is only useful for cross-origin requests.
    * * The `Access-Control-Allow-Origin` header of `url` cannot contain a wildcard (*).
    * * The `Access-Control-Allow-Credentials` header of `url` must be set to true.
    * * If `Access-Control-Expose-Headers` has not been set to true, only a subset of all the response headers will be returned when calling [getAllRequestHeaders].
    *
    * The following is equivalent to the [getString] sample above:
    *
    *     var name = Uri.encodeQueryComponent('John');
    *     var id = Uri.encodeQueryComponent('42');
    *     HttpRequest.request('users.json?name=$name&id=$id')
    *       .then((HttpRequest resp) {
    *         // Do something with the response.
    *     });
    *
    * Here's an example of submitting an entire form with [FormData].
    *
    *     var myForm = querySelector('form#myForm');
    *     var data = new FormData(myForm);
    *     HttpRequest.request('/submit', method: 'POST', sendData: data)
    *       .then((HttpRequest resp) {
    *         // Do something with the response.
    *     });
    *
    * Note that requests for file:// URIs are only supported by Chrome extensions
    * with appropriate permissions in their manifest. Requests to file:// URIs
    * will also never fail- the Future will always complete successfully, even
    * when the file cannot be found.
    *
    * See also: [authorization headers](http://en.wikipedia.org/wiki/Basic_access_authentication).
    */
   static Future<HttpRequest> request(String url,
       {String$NULLABLE method, bool$NULLABLE withCredentials,
       String$NULLABLE responseType, String$NULLABLE mimeType,
       Map<String, String>$NULLABLE requestHeaders, sendData,
       void onProgress(ProgressEvent e)$NULLABLE}) {
     var completer = new Completer<HttpRequest>();

     var xhr = new HttpRequest();
     if (method == null) {
       method = 'GET';
     }
     xhr.open(method, url, async: true);

     if (withCredentials != null) {
       xhr.withCredentials = withCredentials;
     }

     if (responseType != null) {
       xhr.responseType = responseType;
     }

     if (mimeType != null) {
       xhr.overrideMimeType(mimeType);
     }

     if (requestHeaders != null) {
       requestHeaders.forEach((header, value) {
         xhr.setRequestHeader(header, value);
       });
     }

     if (onProgress != null) {
       xhr.onProgress.listen(onProgress);
     }

     xhr.onLoad.listen((e) {
       var status = xhr.status$NULLASSERT;
       var accepted = status >= 200 && status < 300;
       var fileUri = status == 0; // file:// URIs have status of 0.
       var notModified = status == 304;
       // Redirect status is specified up to 307, but others have been used in
       // practice. Notably Google Drive uses 308 Resume Incomplete for
       // resumable uploads, and it's also been used as a redirect. The
       // redirect case will be handled by the browser before it gets to us,
       // so if we see it we should pass it through to the user.
       var unknownRedirect = status > 307 && status < 400;

       if (accepted || fileUri || notModified || unknownRedirect) {
         completer.complete(xhr);
       } else {
         completer.completeError(e);
       }
     });

     xhr.onError.listen(completer.completeError);

     if (sendData != null) {
       xhr.send(sendData);
     } else {
       xhr.send();
     }

     return completer.future;
   }

   /**
    * Checks to see if the Progress event is supported on the current platform.
    */
   static bool get supportsProgressEvent {
     var xhr = new HttpRequest();
     return JS('bool', '("onprogress" in #)', xhr);
   }

   /**
    * Checks to see if the current platform supports making cross origin
    * requests.
    *
    * Note that even if cross origin requests are supported, they still may fail
    * if the destination server does not support CORS requests.
    */
   static bool get supportsCrossOrigin {
     var xhr = new HttpRequest();
     return JS('bool', '("withCredentials" in #)', xhr);
   }

   /**
    * Checks to see if the LoadEnd event is supported on the current platform.
    */
   static bool get supportsLoadEndEvent {
     var xhr = new HttpRequest();
     return JS('bool', '("onloadend" in #)', xhr);
   }

   /**
    * Checks to see if the overrideMimeType method is supported on the current
    * platform.
    */
   static bool get supportsOverrideMimeType {
     var xhr = new HttpRequest();
     return JS('bool', '("overrideMimeType" in #)', xhr);
   }

   /**
    * Makes a cross-origin request to the specified URL.
    *
    * This API provides a subset of [request] which works on IE9. If IE9
    * cross-origin support is not required then [request] should be used instead.
    */
   static Future<String> requestCrossOrigin(String url,
       {String$NULLABLE method, String$NULLABLE sendData}) {
     if (supportsCrossOrigin) {
       return request(url, method: method, sendData: sendData).then((xhr) {
         return xhr.responseText$NULLASSERT;
       });
     }
     var completer = new Completer<String>();
     if (method == null) {
       method = 'GET';
     }
     var xhr = JS('var', 'new XDomainRequest()');
     JS('', '#.open(#, #)', xhr, method, url);
     JS('', '#.onload = #', xhr, convertDartClosureToJS((e) {
       var response = JS('String', '#.responseText', xhr);
       completer.complete(response $#NULLSAFECAST(as FutureOr<String>$NULLABLE));
     }, 1));
     JS('', '#.onerror = #', xhr, convertDartClosureToJS((e) {
       completer.completeError(e);
     }, 1));

     // IE9 RTM - XDomainRequest issued requests may abort if all event handlers
     // not specified
     // http://social.msdn.microsoft.com/Forums/ie/en-US/30ef3add-767c-4436-b8a9-f1ca19b4812e/ie9-rtm-xdomainrequest-issued-requests-may-abort-if-all-event-handlers-not-specified
     JS('', '#.onprogress = {}', xhr);
     JS('', '#.ontimeout = {}', xhr);
     JS('', '#.timeout = Number.MAX_VALUE', xhr);

     if (sendData != null) {
       JS('', '#.send(#)', xhr, sendData);
     } else {
       JS('', '#.send()', xhr);
     }

     return completer.future;
   }

   /**
    * Returns all response headers as a key-value map.
    *
    * Multiple values for the same header key can be combined into one,
    * separated by a comma and a space.
    *
    * See: http://www.w3.org/TR/XMLHttpRequest/#the-getresponseheader()-method
    */
   Map<String, String> get responseHeaders {
     // from Closure's goog.net.Xhrio.getResponseHeaders.
     var headers = <String, String>{};
     var headersString = this.getAllResponseHeaders();
     if (headersString == null) {
       return headers;
     }
     var headersList = headersString.split('\r\n');
     for (var header in headersList) {
       if (header.isEmpty) {
         continue;
       }

       var splitIdx = header.indexOf(': ');
       if (splitIdx == -1) {
         continue;
       }
       var key = header.substring(0, splitIdx).toLowerCase();
       var value = header.substring(splitIdx + 2);
       if (headers.containsKey(key)) {
         headers[key] = '${headers[key]}, $value';
       } else {
         headers[key] = value;
       }
     }
     return headers;
   }

   /**
    * Specify the desired `url`, and `method` to use in making the request.
    *
    * By default the request is done asyncronously, with no user or password
    * authentication information. If `async` is false, the request will be sent
    * synchronously.
    *
    * Calling `open` again on a currently active request is equivalent to
    * calling [abort].
    *
    * Note: Most simple HTTP requests can be accomplished using the [getString],
    * [request], [requestCrossOrigin], or [postFormData] methods. Use of this
    * `open` method is intended only for more complex HTTP requests where
    * finer-grained control is needed.
    */
   void open(String method, String url, {bool$NULLABLE async,
       String$NULLABLE user, String$NULLABLE password}) native;

 $!MEMBERS
 }
	// Copyright (c) 2012, 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 $LIBRARYNAME;

	/**
	* A client-side XHR request for getting data from a URL,
	* formally known as XMLHttpRequest.
	*
	* HttpRequest can be used to obtain data from HTTP and FTP protocols,
	* and is useful for AJAX-style page updates.
	*
	* The simplest way to get the contents of a text file, such as a
	* JSON-formatted file, is with [getString].
	* For example, the following code gets the contents of a JSON file
	* and prints its length:
	*
	* var path = 'myData.json';
	* HttpRequest.getString(path).then((String fileContents) {
	* print(fileContents.length);
	* }).catchError((error) {
	* print(error.toString());
	* });
	*
	* ## Fetching data from other servers
	*
	* For security reasons, browsers impose restrictions on requests
	* made by embedded apps.
	* With the default behavior of this class,
	* the code making the request must be served from the same origin
	* (domain name, port, and application layer protocol)
	* as the requested resource.
	* In the example above, the myData.json file must be co-located with the
	* app that uses it.
	*
	* ## Other resources
	*
	* * [Fetch data dynamically](https://dart.dev/tutorials/web/fetch-data/),
	* a tutorial shows how to load data from a static file or from a server.
	* * [Dart article on using HttpRequests](https://dart.dev/guides/libraries/library-tour#using-http-resources-with-httprequest)
	* * [JS XMLHttpRequest](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest)
	* * [Using XMLHttpRequest](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest/Using_XMLHttpRequest)
	*/
	$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {

	/**
	* Creates a GET request for the specified [url].
	*
	* This is similar to [request] but specialized for HTTP GET requests which
	* return text content.
	*
	* To add query parameters, append them to the [url] following a `?`,
	* joining each key to its value with `=` and separating key-value pairs with
	* `&`.
	*
	* var name = Uri.encodeQueryComponent('John');
	* var id = Uri.encodeQueryComponent('42');
	* HttpRequest.getString('users.json?name=$name&id=$id')
	* .then((String resp) {
	* // Do something with the response.
	* });
	*
	* See also:
	*
	* * [request]
	*/
	static Future<String> getString(String url,
	{bool$NULLABLE withCredentials, void onProgress(ProgressEvent e)$NULLABLE}) {
	return request(url, withCredentials: withCredentials,
	onProgress: onProgress).then(
	(HttpRequest xhr) => xhr.responseText$NULLASSERT);
	}

	/**
	* Makes a server POST request with the specified data encoded as form data.
	*
	* This is roughly the POST equivalent of [getString]. This method is similar
	* to sending a [FormData] object with broader browser support but limited to
	* String values.
	*
	* If [data] is supplied, the key/value pairs are URI encoded with
	* [Uri.encodeQueryComponent] and converted into an HTTP query string.
	*
	* Unless otherwise specified, this method appends the following header:
	*
	* Content-Type: application/x-www-form-urlencoded; charset=UTF-8
	*
	* Here's an example of using this method:
	*
	* var data = { 'firstName' : 'John', 'lastName' : 'Doe' };
	* HttpRequest.postFormData('/send', data).then((HttpRequest resp) {
	* // Do something with the response.
	* });
	*
	* See also:
	*
	* * [request]
	*/
	static Future<HttpRequest> postFormData(String url, Map<String, String> data,
	{bool$NULLABLE withCredentials, String$NULLABLE responseType,
	Map<String, String>$NULLABLE requestHeaders,
	void onProgress(ProgressEvent e)$NULLABLE}) {

	var parts = [];
	data.forEach((key, value) {
	parts.add('${Uri.encodeQueryComponent(key)}='
	'${Uri.encodeQueryComponent(value)}');
	});
	var formData = parts.join('&');

	if (requestHeaders == null) {
	requestHeaders = <String, String>{};
	}
	requestHeaders.putIfAbsent('Content-Type',
	() => 'application/x-www-form-urlencoded; charset=UTF-8');

	return request(url, method: 'POST', withCredentials: withCredentials,
	responseType: responseType,
	requestHeaders: requestHeaders, sendData: formData,
	onProgress: onProgress);
	}

	/**
	* Creates and sends a URL request for the specified [url].
	*
	* By default `request` will perform an HTTP GET request, but a different
	* method (`POST`, `PUT`, `DELETE`, etc) can be used by specifying the
	* [method] parameter. (See also [HttpRequest.postFormData] for `POST`
	* requests only.
	*
	* The Future is completed when the response is available.
	*
	* If specified, `sendData` will send data in the form of a [ByteBuffer],
	* [Blob], [Document], [String], or [FormData] along with the HttpRequest.
	*
	* If specified, [responseType] sets the desired response format for the
	* request. By default it is [String], but can also be 'arraybuffer', 'blob',
	* 'document', 'json', or 'text'. See also [HttpRequest.responseType]
	* for more information.
	*
	* The [withCredentials] parameter specified that credentials such as a cookie
	* (already) set in the header or
	* [authorization headers](http://tools.ietf.org/html/rfc1945#section-10.2)
	* should be specified for the request. Details to keep in mind when using
	* credentials:
	*
	* * Using credentials is only useful for cross-origin requests.
	* * The `Access-Control-Allow-Origin` header of `url` cannot contain a wildcard (*).
	* * The `Access-Control-Allow-Credentials` header of `url` must be set to true.
	* * If `Access-Control-Expose-Headers` has not been set to true, only a subset of all the response headers will be returned when calling [getAllRequestHeaders].
	*
	* The following is equivalent to the [getString] sample above:
	*
	* var name = Uri.encodeQueryComponent('John');
	* var id = Uri.encodeQueryComponent('42');
	* HttpRequest.request('users.json?name=$name&id=$id')
	* .then((HttpRequest resp) {
	* // Do something with the response.
	* });
	*
	* Here's an example of submitting an entire form with [FormData].
	*
	* var myForm = querySelector('form#myForm');
	* var data = new FormData(myForm);
	* HttpRequest.request('/submit', method: 'POST', sendData: data)
	* .then((HttpRequest resp) {
	* // Do something with the response.
	* });
	*
	* Note that requests for file:// URIs are only supported by Chrome extensions
	* with appropriate permissions in their manifest. Requests to file:// URIs
	* will also never fail- the Future will always complete successfully, even
	* when the file cannot be found.
	*
	* See also: [authorization headers](http://en.wikipedia.org/wiki/Basic_access_authentication).
	*/
	static Future<HttpRequest> request(String url,
	{String$NULLABLE method, bool$NULLABLE withCredentials,
	String$NULLABLE responseType, String$NULLABLE mimeType,
	Map<String, String>$NULLABLE requestHeaders, sendData,
	void onProgress(ProgressEvent e)$NULLABLE}) {
	var completer = new Completer<HttpRequest>();

	var xhr = new HttpRequest();
	if (method == null) {
	method = 'GET';
	}
	xhr.open(method, url, async: true);

	if (withCredentials != null) {
	xhr.withCredentials = withCredentials;
	}

	if (responseType != null) {
	xhr.responseType = responseType;
	}

	if (mimeType != null) {
	xhr.overrideMimeType(mimeType);
	}

	if (requestHeaders != null) {
	requestHeaders.forEach((header, value) {
	xhr.setRequestHeader(header, value);
	});
	}

	if (onProgress != null) {
	xhr.onProgress.listen(onProgress);
	}

	xhr.onLoad.listen((e) {
	var status = xhr.status$NULLASSERT;
	var accepted = status >= 200 && status < 300;
	var fileUri = status == 0; // file:// URIs have status of 0.
	var notModified = status == 304;
	// Redirect status is specified up to 307, but others have been used in
	// practice. Notably Google Drive uses 308 Resume Incomplete for
	// resumable uploads, and it's also been used as a redirect. The
	// redirect case will be handled by the browser before it gets to us,
	// so if we see it we should pass it through to the user.
	var unknownRedirect = status > 307 && status < 400;

	if (accepted \|\| fileUri \|\| notModified \|\| unknownRedirect) {
	completer.complete(xhr);
	} else {
	completer.completeError(e);
	}
	});

	xhr.onError.listen(completer.completeError);

	if (sendData != null) {
	xhr.send(sendData);
	} else {
	xhr.send();
	}

	return completer.future;
	}

	/**
	* Checks to see if the Progress event is supported on the current platform.
	*/
	static bool get supportsProgressEvent {
	var xhr = new HttpRequest();
	return JS('bool', '("onprogress" in #)', xhr);
	}

	/**
	* Checks to see if the current platform supports making cross origin
	* requests.
	*
	* Note that even if cross origin requests are supported, they still may fail
	* if the destination server does not support CORS requests.
	*/
	static bool get supportsCrossOrigin {
	var xhr = new HttpRequest();
	return JS('bool', '("withCredentials" in #)', xhr);
	}

	/**
	* Checks to see if the LoadEnd event is supported on the current platform.
	*/
	static bool get supportsLoadEndEvent {
	var xhr = new HttpRequest();
	return JS('bool', '("onloadend" in #)', xhr);
	}

	/**
	* Checks to see if the overrideMimeType method is supported on the current
	* platform.
	*/
	static bool get supportsOverrideMimeType {
	var xhr = new HttpRequest();
	return JS('bool', '("overrideMimeType" in #)', xhr);
	}

	/**
	* Makes a cross-origin request to the specified URL.
	*
	* This API provides a subset of [request] which works on IE9. If IE9
	* cross-origin support is not required then [request] should be used instead.
	*/
	static Future<String> requestCrossOrigin(String url,
	{String$NULLABLE method, String$NULLABLE sendData}) {
	if (supportsCrossOrigin) {
	return request(url, method: method, sendData: sendData).then((xhr) {
	return xhr.responseText$NULLASSERT;
	});
	}
	var completer = new Completer<String>();
	if (method == null) {
	method = 'GET';
	}
	var xhr = JS('var', 'new XDomainRequest()');
	JS('', '#.open(#, #)', xhr, method, url);
	JS('', '#.onload = #', xhr, convertDartClosureToJS((e) {
	var response = JS('String', '#.responseText', xhr);
	completer.complete(response $#NULLSAFECAST(as FutureOr<String>$NULLABLE));
	}, 1));
	JS('', '#.onerror = #', xhr, convertDartClosureToJS((e) {
	completer.completeError(e);
	}, 1));

	// IE9 RTM - XDomainRequest issued requests may abort if all event handlers
	// not specified
	// http://social.msdn.microsoft.com/Forums/ie/en-US/30ef3add-767c-4436-b8a9-f1ca19b4812e/ie9-rtm-xdomainrequest-issued-requests-may-abort-if-all-event-handlers-not-specified
	JS('', '#.onprogress = {}', xhr);
	JS('', '#.ontimeout = {}', xhr);
	JS('', '#.timeout = Number.MAX_VALUE', xhr);

	if (sendData != null) {
	JS('', '#.send(#)', xhr, sendData);
	} else {
	JS('', '#.send()', xhr);
	}

	return completer.future;
	}

	/**
	* Returns all response headers as a key-value map.
	*
	* Multiple values for the same header key can be combined into one,
	* separated by a comma and a space.
	*
	* See: http://www.w3.org/TR/XMLHttpRequest/#the-getresponseheader()-method
	*/
	Map<String, String> get responseHeaders {
	// from Closure's goog.net.Xhrio.getResponseHeaders.
	var headers = <String, String>{};
	var headersString = this.getAllResponseHeaders();
	if (headersString == null) {
	return headers;
	}
	var headersList = headersString.split('\r\n');
	for (var header in headersList) {
	if (header.isEmpty) {
	continue;
	}

	var splitIdx = header.indexOf(': ');
	if (splitIdx == -1) {
	continue;
	}
	var key = header.substring(0, splitIdx).toLowerCase();
	var value = header.substring(splitIdx + 2);
	if (headers.containsKey(key)) {
	headers[key] = '${headers[key]}, $value';
	} else {
	headers[key] = value;
	}
	}
	return headers;
	}

	/**
	* Specify the desired `url`, and `method` to use in making the request.
	*
	* By default the request is done asyncronously, with no user or password
	* authentication information. If `async` is false, the request will be sent
	* synchronously.
	*
	* Calling `open` again on a currently active request is equivalent to
	* calling [abort].
	*
	* Note: Most simple HTTP requests can be accomplished using the [getString],
	* [request], [requestCrossOrigin], or [postFormData] methods. Use of this
	* `open` method is intended only for more complex HTTP requests where
	* finer-grained control is needed.
	*/
	void open(String method, String url, {bool$NULLABLE async,
	String$NULLABLE user, String$NULLABLE password}) native;

	$!MEMBERS
	}