user/src/com/google/gwt/http/client/XMLHTTPRequest.java - gwt - Git at Google

 /*
  * Copyright 2007 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
  * use this file except in compliance with the License. You may obtain a copy of
  * the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  * License for the specific language governing permissions and limitations under
  * the License.
  */
 package com.google.gwt.http.client;

 import com.google.gwt.core.client.JavaScriptObject;

 /**
  * Utility class that serves as the one place where we interact with the
  * JavaScript <code>XmlHttpRequest</code> object.
  */
 final class XMLHTTPRequest {

   /*
    * NOTE: Testing discovered that for some bizarre reason, on Mozilla, the
    * JavaScript <code>XmlHttpRequest.onreadystatechange</code> handler
    * function maybe still be called after it is deleted. The theory is that the
    * callback is cached somewhere. Setting it to null or an empty function does
    * seem to work properly, though.
    *
    * On IE, there are two problems: Setting onreadystatechange to null (as
    * opposed to an empty function) sometimes throws an exception. With
    * particular (rare) versions of jscript.dll, setting onreadystatechange from
    * within onreadystatechange causes a crash. Setting it from within a timeout
    * fixes this bug (see issue 1610).
    *
    * End result: *always* set onreadystatechange to an empty function (never to
    * null). Never set onreadystatechange from within onreadystatechange (always
    * in a setTimeout()).
    */

   public static final int UNITIALIZED = 0;
   public static final int OPEN = 1;
   public static final int SENT = 2;
   public static final int RECEIVING = 3;
   public static final int LOADED = 4;

   static native void abort(JavaScriptObject xmlHttpRequest) /*-{
     xmlHttpRequest.onreadystatechange = @com.google.gwt.user.client.impl.HTTPRequestImpl::nullFunc;
     xmlHttpRequest.abort();
   }-*/;

   static native String getAllResponseHeaders(JavaScriptObject xmlHttpRequest) /*-{
     return xmlHttpRequest.getAllResponseHeaders();
   }-*/;

   /**
    * Tests if the JavaScript <code>XmlHttpRequest.status</code> property is
    * readable. This can return failure in two different known scenarios:
    *
    * <ol>
    * <li>On Mozilla, after a network error, attempting to read the status code
    * results in an exception being thrown. See <a
    * href="https://bugzilla.mozilla.org/show_bug.cgi?id=238559">https://bugzilla.mozilla.org/show_bug.cgi?id=238559</a>.
    * </li>
    * <li>On Safari, if the HTTP response does not include any response text.
    * See <a
    * href="http://bugs.webkit.org/show_bug.cgi?id=3810">http://bugs.webkit.org/show_bug.cgi?id=3810</a>.
    * </li>
    * </ol>
    *
    * @param xmlHttpRequest the JavaScript <code>XmlHttpRequest</code> object
    *          to test
    * @return a String message containing an error message if the
    *         <code>XmlHttpRequest.status</code> code is unreadable or null if
    *         the status code could be successfully read.
    */
   static native String getBrowserSpecificFailure(
       JavaScriptObject xmlHttpRequest) /*-{
     try {
       if (xmlHttpRequest.status === undefined) {
         return "XmlHttpRequest.status == undefined, please see Safari bug " +
                "http://bugs.webkit.org/show_bug.cgi?id=3810 for more details";
       }
       return null;
     } catch (e) {
       return "Unable to read XmlHttpRequest.status; likely causes are a " +
              "networking error or bad cross-domain request. Please see " +
              "https://bugzilla.mozilla.org/show_bug.cgi?id=238559 for more " +
              "details";
     }
   }-*/;

   /**
    * Returns an array of headers built by parsing the string of headers returned
    * by the JavaScript <code>XmlHttpRequest</code> object.
    *
    * @param xmlHttpRequest
    * @return array of Header items
    */
   static Header[] getHeaders(JavaScriptObject xmlHttpRequest) {
     String allHeaders = getAllResponseHeaders(xmlHttpRequest);
     String[] unparsedHeaders = allHeaders.split("\n");
     Header[] parsedHeaders = new Header[unparsedHeaders.length];

     for (int i = 0, n = unparsedHeaders.length; i < n; ++i) {
       String unparsedHeader = unparsedHeaders[i];

       if (unparsedHeader.length() == 0) {
         continue;
       }

       int endOfNameIdx = unparsedHeader.indexOf(':');
       if (endOfNameIdx < 0) {
         continue;
       }

       final String name = unparsedHeader.substring(0, endOfNameIdx).trim();
       final String value = unparsedHeader.substring(endOfNameIdx + 1).trim();
       Header header = new Header() {
         @Override
         public String getName() {
           return name;
         }

         @Override
         public String getValue() {
           return value;
         }

         @Override
         public String toString() {
           return name + " : " + value;
         }
       };

       parsedHeaders[i] = header;
     }

     return parsedHeaders;
   }

   static native int getReadyState(JavaScriptObject xmlHttpRequest) /*-{
     return xmlHttpRequest.readyState;
   }-*/;

   static native String getResponseHeader(JavaScriptObject xmlHttpRequest,
       String header) /*-{
     try {
       return xmlHttpRequest.getResponseHeader(header);
     } catch (e) {
       // purposely ignored
     }
     return null;
   }-*/;

   static native String getResponseText(JavaScriptObject xmlHttpRequest) /*-{
     return xmlHttpRequest.responseText;
   }-*/;

   static native int getStatusCode(JavaScriptObject xmlHttpRequest) /*-{
     return xmlHttpRequest.status;
   }-*/;

   static native String getStatusText(JavaScriptObject xmlHttpRequest) /*-{
     return xmlHttpRequest.statusText;
   }-*/;

   static boolean isResponseReady(JavaScriptObject xmlHttpRequest) {
     return getReadyState(xmlHttpRequest) == LOADED;
   }

   /**
    * Opens the request and catches any exceptions thrown. If an exception is
    * caught, its string representation will be returned. This is the only signal
    * that an error has occurred.
    *
    * @param xmlHttpRequest JavaScript <code>XmlHttpRequest</code> object
    * @param httpMethod the method to use for open call
    * @param url the URL to use for the open call
    * @param async true if we should do an asynchronous open
    * @return error message if an exception is thrown or null if there is none
    */
   static native String open(JavaScriptObject xmlHttpRequest, String httpMethod,
       String url, boolean async) /*-{
     try {
       xmlHttpRequest.open(httpMethod, url, async);
       return null;
     } catch (e) {
       return e.message || e.toString();
     }
   }-*/;

   /**
    * Opens the request and catches any exceptions thrown. If an exception is
    * caught, its string representation will be returned. This is the only signal
    * that an error has occurred.
    *
    * @param xmlHttpRequest JavaScript <code>XmlHttpRequest</code> object
    * @param httpMethod the method to use for open call
    * @param url the URL to use for the open call
    * @param async true if we should do an asynchronous open
    * @param user user to use in the URL
    * @return error message if an exception is thrown or null if there is none
    */
   static native String open(JavaScriptObject xmlHttpRequest, String httpMethod,
       String url, boolean async, String user) /*-{
     try {
       xmlHttpRequest.open(httpMethod, url, async, user);
       return null;
     } catch (e) {
       return e.message || e.toString();
     }
   }-*/;

   /**
    * Opens the request and catches any exceptions thrown. If an exception is
    * caught, its string representation will be returned. This is the only signal
    * that an error has occurred.
    *
    * @param xmlHttpRequest JavaScript <code>XmlHttpRequest</code> object
    * @param httpMethod the method to use for open call
    * @param url the URL to use for the open call
    * @param async true if we should do an asynchronous open
    * @param user user to use in the URL
    * @param password password to use in the URL
    * @return error message if an exception is thrown or null if there is none
    */
   static native String open(JavaScriptObject xmlHttpRequest, String httpMethod,
       String url, boolean async, String user, String password) /*-{
     try {
       xmlHttpRequest.open(httpMethod, url, async, user, password);
       return null;
     } catch (e) {
       return e.message || e.toString();
     }
   }-*/;

   /*
    * Creates a closure that calls the HTTPRequest::fireOnResponseRecieved method
    * when the server's response is received and sends the data.
    */
   static native String send(JavaScriptObject xmlHttpRequest, Request httpRequest,
       String requestData, RequestCallback callback) /*-{
     xmlHttpRequest.onreadystatechange = function() {
       if (xmlHttpRequest.readyState == @com.google.gwt.http.client.XMLHTTPRequest::LOADED) {
         $wnd.setTimeout(function() {
           xmlHttpRequest.onreadystatechange = @com.google.gwt.user.client.impl.HTTPRequestImpl::nullFunc;
         }, 0);
         httpRequest.@com.google.gwt.http.client.Request::fireOnResponseReceived(Lcom/google/gwt/http/client/RequestCallback;)(callback);
       }
     };
     try {
       xmlHttpRequest.send(requestData);
       return null;
     } catch (e) {
       xmlHttpRequest.onreadystatechange = @com.google.gwt.user.client.impl.HTTPRequestImpl::nullFunc;
       return e.message || e.toString();
     }
   }-*/;

   static native String setRequestHeader(JavaScriptObject xmlHttpRequest,
       String header, String value) /*-{
     try {
       xmlHttpRequest.setRequestHeader(header, value);
       return null;
     } catch (e) {
       return e.message || e.toString();
     }
   }-*/;

   private XMLHTTPRequest() {
   }
 }
	/*
	* Copyright 2007 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may not
	* use this file except in compliance with the License. You may obtain a copy of
	* the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	* License for the specific language governing permissions and limitations under
	* the License.
	*/
	package com.google.gwt.http.client;

	import com.google.gwt.core.client.JavaScriptObject;

	/**
	* Utility class that serves as the one place where we interact with the
	* JavaScript <code>XmlHttpRequest</code> object.
	*/
	final class XMLHTTPRequest {

	/*
	* NOTE: Testing discovered that for some bizarre reason, on Mozilla, the
	* JavaScript <code>XmlHttpRequest.onreadystatechange</code> handler
	* function maybe still be called after it is deleted. The theory is that the
	* callback is cached somewhere. Setting it to null or an empty function does
	* seem to work properly, though.
	*
	* On IE, there are two problems: Setting onreadystatechange to null (as
	* opposed to an empty function) sometimes throws an exception. With
	* particular (rare) versions of jscript.dll, setting onreadystatechange from
	* within onreadystatechange causes a crash. Setting it from within a timeout
	* fixes this bug (see issue 1610).
	*
	* End result: always set onreadystatechange to an empty function (never to
	* null). Never set onreadystatechange from within onreadystatechange (always
	* in a setTimeout()).
	*/

	public static final int UNITIALIZED = 0;
	public static final int OPEN = 1;
	public static final int SENT = 2;
	public static final int RECEIVING = 3;
	public static final int LOADED = 4;

	static native void abort(JavaScriptObject xmlHttpRequest) /*-{
	xmlHttpRequest.onreadystatechange = @com.google.gwt.user.client.impl.HTTPRequestImpl::nullFunc;
	xmlHttpRequest.abort();
	}-*/;

	static native String getAllResponseHeaders(JavaScriptObject xmlHttpRequest) /*-{
	return xmlHttpRequest.getAllResponseHeaders();
	}-*/;

	/**
	* Tests if the JavaScript <code>XmlHttpRequest.status</code> property is
	* readable. This can return failure in two different known scenarios:
	*
	* <ol>
	* <li>On Mozilla, after a network error, attempting to read the status code
	* results in an exception being thrown. See <a
	* href="https://bugzilla.mozilla.org/show_bug.cgi?id=238559">https://bugzilla.mozilla.org/show_bug.cgi?id=238559</a>.
	* </li>
	* <li>On Safari, if the HTTP response does not include any response text.
	* See <a
	* href="http://bugs.webkit.org/show_bug.cgi?id=3810">http://bugs.webkit.org/show_bug.cgi?id=3810</a>.
	* </li>
	* </ol>
	*
	* @param xmlHttpRequest the JavaScript <code>XmlHttpRequest</code> object
	* to test
	* @return a String message containing an error message if the
	* <code>XmlHttpRequest.status</code> code is unreadable or null if
	* the status code could be successfully read.
	*/
	static native String getBrowserSpecificFailure(
	JavaScriptObject xmlHttpRequest) /*-{
	try {
	if (xmlHttpRequest.status === undefined) {
	return "XmlHttpRequest.status == undefined, please see Safari bug " +
	"http://bugs.webkit.org/show_bug.cgi?id=3810 for more details";
	}
	return null;
	} catch (e) {
	return "Unable to read XmlHttpRequest.status; likely causes are a " +
	"networking error or bad cross-domain request. Please see " +
	"https://bugzilla.mozilla.org/show_bug.cgi?id=238559 for more " +
	"details";
	}
	}-*/;

	/**
	* Returns an array of headers built by parsing the string of headers returned
	* by the JavaScript <code>XmlHttpRequest</code> object.
	*
	* @param xmlHttpRequest
	* @return array of Header items
	*/
	static Header[] getHeaders(JavaScriptObject xmlHttpRequest) {
	String allHeaders = getAllResponseHeaders(xmlHttpRequest);
	String[] unparsedHeaders = allHeaders.split("\n");
	Header[] parsedHeaders = new Header[unparsedHeaders.length];

	for (int i = 0, n = unparsedHeaders.length; i < n; ++i) {
	String unparsedHeader = unparsedHeaders[i];

	if (unparsedHeader.length() == 0) {
	continue;
	}

	int endOfNameIdx = unparsedHeader.indexOf(':');
	if (endOfNameIdx < 0) {
	continue;
	}

	final String name = unparsedHeader.substring(0, endOfNameIdx).trim();
	final String value = unparsedHeader.substring(endOfNameIdx + 1).trim();
	Header header = new Header() {
	@Override
	public String getName() {
	return name;
	}

	@Override
	public String getValue() {
	return value;
	}

	@Override
	public String toString() {
	return name + " : " + value;
	}
	};

	parsedHeaders[i] = header;
	}

	return parsedHeaders;
	}

	static native int getReadyState(JavaScriptObject xmlHttpRequest) /*-{
	return xmlHttpRequest.readyState;
	}-*/;

	static native String getResponseHeader(JavaScriptObject xmlHttpRequest,
	String header) /*-{
	try {
	return xmlHttpRequest.getResponseHeader(header);
	} catch (e) {
	// purposely ignored
	}
	return null;
	}-*/;

	static native String getResponseText(JavaScriptObject xmlHttpRequest) /*-{
	return xmlHttpRequest.responseText;
	}-*/;

	static native int getStatusCode(JavaScriptObject xmlHttpRequest) /*-{
	return xmlHttpRequest.status;
	}-*/;

	static native String getStatusText(JavaScriptObject xmlHttpRequest) /*-{
	return xmlHttpRequest.statusText;
	}-*/;

	static boolean isResponseReady(JavaScriptObject xmlHttpRequest) {
	return getReadyState(xmlHttpRequest) == LOADED;
	}

	/**
	* Opens the request and catches any exceptions thrown. If an exception is
	* caught, its string representation will be returned. This is the only signal
	* that an error has occurred.
	*
	* @param xmlHttpRequest JavaScript <code>XmlHttpRequest</code> object
	* @param httpMethod the method to use for open call
	* @param url the URL to use for the open call
	* @param async true if we should do an asynchronous open
	* @return error message if an exception is thrown or null if there is none
	*/
	static native String open(JavaScriptObject xmlHttpRequest, String httpMethod,
	String url, boolean async) /*-{
	try {
	xmlHttpRequest.open(httpMethod, url, async);
	return null;
	} catch (e) {
	return e.message \|\| e.toString();
	}
	}-*/;

	/**
	* Opens the request and catches any exceptions thrown. If an exception is
	* caught, its string representation will be returned. This is the only signal
	* that an error has occurred.
	*
	* @param xmlHttpRequest JavaScript <code>XmlHttpRequest</code> object
	* @param httpMethod the method to use for open call
	* @param url the URL to use for the open call
	* @param async true if we should do an asynchronous open
	* @param user user to use in the URL
	* @return error message if an exception is thrown or null if there is none
	*/
	static native String open(JavaScriptObject xmlHttpRequest, String httpMethod,
	String url, boolean async, String user) /*-{
	try {
	xmlHttpRequest.open(httpMethod, url, async, user);
	return null;
	} catch (e) {
	return e.message \|\| e.toString();
	}
	}-*/;

	/**
	* Opens the request and catches any exceptions thrown. If an exception is
	* caught, its string representation will be returned. This is the only signal
	* that an error has occurred.
	*
	* @param xmlHttpRequest JavaScript <code>XmlHttpRequest</code> object
	* @param httpMethod the method to use for open call
	* @param url the URL to use for the open call
	* @param async true if we should do an asynchronous open
	* @param user user to use in the URL
	* @param password password to use in the URL
	* @return error message if an exception is thrown or null if there is none
	*/
	static native String open(JavaScriptObject xmlHttpRequest, String httpMethod,
	String url, boolean async, String user, String password) /*-{
	try {
	xmlHttpRequest.open(httpMethod, url, async, user, password);
	return null;
	} catch (e) {
	return e.message \|\| e.toString();
	}
	}-*/;

	/*
	* Creates a closure that calls the HTTPRequest::fireOnResponseRecieved method
	* when the server's response is received and sends the data.
	*/
	static native String send(JavaScriptObject xmlHttpRequest, Request httpRequest,
	String requestData, RequestCallback callback) /*-{
	xmlHttpRequest.onreadystatechange = function() {
	if (xmlHttpRequest.readyState == @com.google.gwt.http.client.XMLHTTPRequest::LOADED) {
	$wnd.setTimeout(function() {
	xmlHttpRequest.onreadystatechange = @com.google.gwt.user.client.impl.HTTPRequestImpl::nullFunc;
	}, 0);
	httpRequest.@com.google.gwt.http.client.Request::fireOnResponseReceived(Lcom/google/gwt/http/client/RequestCallback;)(callback);
	}
	};
	try {
	xmlHttpRequest.send(requestData);
	return null;
	} catch (e) {
	xmlHttpRequest.onreadystatechange = @com.google.gwt.user.client.impl.HTTPRequestImpl::nullFunc;
	return e.message \|\| e.toString();
	}
	}-*/;

	static native String setRequestHeader(JavaScriptObject xmlHttpRequest,
	String header, String value) /*-{
	try {
	xmlHttpRequest.setRequestHeader(header, value);
	return null;
	} catch (e) {
	return e.message \|\| e.toString();
	}
	}-*/;

	private XMLHTTPRequest() {
	}
	}