Adding HttpRequest.responseHeaders

tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate

 // 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 utility for retrieving data from a URL.
  *
  * HttpRequest can be used to obtain data from http, ftp, and file
@@ skipping 36 matching lines @@
    */
   static Future<String> getString(String url,
       {bool withCredentials, void onProgress(ProgressEvent e)}) {
     return request(url, withCredentials: withCredentials,
         onProgress: onProgress).then((xhr) => xhr.responseText);
   }
 
   /**
    * 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 
+   * 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.
    *
    * See also:
    *
    * * [request]
    */
   static Future<HttpRequest> postFormData(String url, Map<String, String> data,
       {bool withCredentials, String responseType,
       Map<String, String> requestHeaders,
       void onProgress(ProgressEvent e)}) {
@@ skipping 14 matching lines @@
     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 (`POST`, `PUT`, `DELETE`, etc) can be used by specifying the
    * [method] parameter.
    *
    * 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.
    *
    * 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)
@@ skipping 159 matching lines @@
     if (sendData != null) {
       JS('', '#.send(#)', xhr, sendData);
     } else {
       JS('', '#.send()', xhr);
     }
 
     return completer.future;
 $endif
   }
 
+  /**
+   * 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;
+  }
+
 $!MEMBERS
 }