path: root/lib/dojo/_base/xhr.js

/*
	Copyright (c) 2004-2011, The Dojo Foundation All Rights Reserved.
	Available via Academic Free License >= 2.1 OR the modified BSD license.
	see: http://dojotoolkit.org/license for details
*/


if(!dojo._hasResource["dojo._base.xhr"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojo._base.xhr"] = true;
dojo.provide("dojo._base.xhr");
dojo.require("dojo._base.Deferred");
dojo.require("dojo._base.json");
dojo.require("dojo._base.lang");
dojo.require("dojo._base.query");


(function(){
	var _d = dojo, cfg = _d.config;

	function setValue(/*Object*/obj, /*String*/name, /*String*/value){
		//summary:
		//		For the named property in object, set the value. If a value
		//		already exists and it is a string, convert the value to be an
		//		array of values.

		//Skip it if there is no value
		if(value === null){
			return;
		}

		var val = obj[name];
		if(typeof val == "string"){ // inline'd type check
			obj[name] = [val, value];
		}else if(_d.isArray(val)){
			val.push(value);
		}else{
			obj[name] = value;
		}
	}
	
	dojo.fieldToObject = function(/*DOMNode||String*/ inputNode){
		// summary:
		//		Serialize a form field to a JavaScript object.
		//
		// description:
		//		Returns the value encoded in a form field as
		//		as a string or an array of strings. Disabled form elements
		//		and unchecked radio and checkboxes are skipped.	Multi-select
		//		elements are returned as an array of string values.
		var ret = null;
		var item = _d.byId(inputNode);
		if(item){
			var _in = item.name;
			var type = (item.type||"").toLowerCase();
			if(_in && type && !item.disabled){
				if(type == "radio" || type == "checkbox"){
					if(item.checked){ ret = item.value; }
				}else if(item.multiple){
					ret = [];
					_d.query("option", item).forEach(function(opt){
						if(opt.selected){
							ret.push(opt.value);
						}
					});
				}else{
					ret = item.value;
				}
			}
		}
		return ret; // Object
	};

	dojo.formToObject = function(/*DOMNode||String*/ formNode){
		// summary:
		//		Serialize a form node to a JavaScript object.
		// description:
		//		Returns the values encoded in an HTML form as
		//		string properties in an object which it then returns. Disabled form
		//		elements, buttons, and other non-value form elements are skipped.
		//		Multi-select elements are returned as an array of string values.
		//
		// example:
		//		This form:
		//		|	<form id="test_form">
		//		|		<input type="text" name="blah" value="blah">
		//		|		<input type="text" name="no_value" value="blah" disabled>
		//		|		<input type="button" name="no_value2" value="blah">
		//		|		<select type="select" multiple name="multi" size="5">
		//		|			<option value="blah">blah</option>
		//		|			<option value="thud" selected>thud</option>
		//		|			<option value="thonk" selected>thonk</option>
		//		|		</select>
		//		|	</form>
		//
		//		yields this object structure as the result of a call to
		//		formToObject():
		//
		//		|	{
		//		|		blah: "blah",
		//		|		multi: [
		//		|			"thud",
		//		|			"thonk"
		//		|		]
		//		|	};

		var ret = {};
		var exclude = "file|submit|image|reset|button|";
		_d.forEach(dojo.byId(formNode).elements, function(item){
			var _in = item.name;
			var type = (item.type||"").toLowerCase();
			if(_in && type && exclude.indexOf(type) == -1 && !item.disabled){
				setValue(ret, _in, _d.fieldToObject(item));
				if(type == "image"){
					ret[_in+".x"] = ret[_in+".y"] = ret[_in].x = ret[_in].y = 0;
				}
			}
		});
		return ret; // Object
	};

	dojo.objectToQuery = function(/*Object*/ map){
		//	summary:
		//		takes a name/value mapping object and returns a string representing
		//		a URL-encoded version of that object.
		//	example:
		//		this object:
		//
		//		|	{
		//		|		blah: "blah",
		//		|		multi: [
		//		|			"thud",
		//		|			"thonk"
		//		|		]
		//		|	};
		//
		//	yields the following query string:
		//
		//	|	"blah=blah&multi=thud&multi=thonk"

		// FIXME: need to implement encodeAscii!!
		var enc = encodeURIComponent;
		var pairs = [];
		var backstop = {};
		for(var name in map){
			var value = map[name];
			if(value != backstop[name]){
				var assign = enc(name) + "=";
				if(_d.isArray(value)){
					for(var i=0; i < value.length; i++){
						pairs.push(assign + enc(value[i]));
					}
				}else{
					pairs.push(assign + enc(value));
				}
			}
		}
		return pairs.join("&"); // String
	};

	dojo.formToQuery = function(/*DOMNode||String*/ formNode){
		// summary:
		//		Returns a URL-encoded string representing the form passed as either a
		//		node or string ID identifying the form to serialize
		return _d.objectToQuery(_d.formToObject(formNode)); // String
	};

	dojo.formToJson = function(/*DOMNode||String*/ formNode, /*Boolean?*/prettyPrint){
		// summary:
		//		Create a serialized JSON string from a form node or string
		//		ID identifying the form to serialize
		return _d.toJson(_d.formToObject(formNode), prettyPrint); // String
	};

	dojo.queryToObject = function(/*String*/ str){
		// summary:
		//		Create an object representing a de-serialized query section of a
		//		URL. Query keys with multiple values are returned in an array.
		//
		// example:
		//		This string:
		//
		//	|		"foo=bar&foo=baz&thinger=%20spaces%20=blah&zonk=blarg&"
		//
		//		results in this object structure:
		//
		//	|		{
		//	|			foo: [ "bar", "baz" ],
		//	|			thinger: " spaces =blah",
		//	|			zonk: "blarg"
		//	|		}
		//
		//		Note that spaces and other urlencoded entities are correctly
		//		handled.

		// FIXME: should we grab the URL string if we're not passed one?
		var ret = {};
		var qp = str.split("&");
		var dec = decodeURIComponent;
		_d.forEach(qp, function(item){
			if(item.length){
				var parts = item.split("=");
				var name = dec(parts.shift());
				var val = dec(parts.join("="));
				if(typeof ret[name] == "string"){ // inline'd type check
					ret[name] = [ret[name]];
				}

				if(_d.isArray(ret[name])){
					ret[name].push(val);
				}else{
					ret[name] = val;
				}
			}
		});
		return ret; // Object
	};

	// need to block async callbacks from snatching this thread as the result
	// of an async callback might call another sync XHR, this hangs khtml forever
	// must checked by watchInFlight()

	dojo._blockAsync = false;

	// MOW: remove dojo._contentHandlers alias in 2.0
	var handlers = _d._contentHandlers = dojo.contentHandlers = {
		// summary:
		//		A map of availble XHR transport handle types. Name matches the
		//		`handleAs` attribute passed to XHR calls.
		//
		// description:
		//		A map of availble XHR transport handle types. Name matches the
		//		`handleAs` attribute passed to XHR calls. Each contentHandler is
		//		called, passing the xhr object for manipulation. The return value
		//		from the contentHandler will be passed to the `load` or `handle`
		//		functions defined in the original xhr call.
		//
		// example:
		//		Creating a custom content-handler:
		//	|	dojo.contentHandlers.makeCaps = function(xhr){
		//	|		return xhr.responseText.toUpperCase();
		//	|	}
		//	|	// and later:
		//	|	dojo.xhrGet({
		//	|		url:"foo.txt",
		//	|		handleAs:"makeCaps",
		//	|		load: function(data){ /* data is a toUpper version of foo.txt */ }
		//	|	});

		text: function(xhr){
			// summary: A contentHandler which simply returns the plaintext response data
			return xhr.responseText;
		},
		json: function(xhr){
			// summary: A contentHandler which returns a JavaScript object created from the response data
			return _d.fromJson(xhr.responseText || null);
		},
		"json-comment-filtered": function(xhr){
			// summary: A contentHandler which expects comment-filtered JSON.
			// description:
			//		A contentHandler which expects comment-filtered JSON.
			//		the json-comment-filtered option was implemented to prevent
			//		"JavaScript Hijacking", but it is less secure than standard JSON. Use
			//		standard JSON instead. JSON prefixing can be used to subvert hijacking.
			//
			//		Will throw a notice suggesting to use application/json mimetype, as
			//		json-commenting can introduce security issues. To decrease the chances of hijacking,
			//		use the standard `json` contentHandler, and prefix your "JSON" with: {}&&
			//
			//		use djConfig.useCommentedJson = true to turn off the notice
			if(!dojo.config.useCommentedJson){
				console.warn("Consider using the standard mimetype:application/json."
					+ " json-commenting can introduce security issues. To"
					+ " decrease the chances of hijacking, use the standard the 'json' handler and"
					+ " prefix your json with: {}&&\n"
					+ "Use djConfig.useCommentedJson=true to turn off this message.");
			}

			var value = xhr.responseText;
			var cStartIdx = value.indexOf("\/*");
			var cEndIdx = value.lastIndexOf("*\/");
			if(cStartIdx == -1 || cEndIdx == -1){
				throw new Error("JSON was not comment filtered");
			}
			return _d.fromJson(value.substring(cStartIdx+2, cEndIdx));
		},
		javascript: function(xhr){
			// summary: A contentHandler which evaluates the response data, expecting it to be valid JavaScript

			// FIXME: try Moz and IE specific eval variants?
			return _d.eval(xhr.responseText);
		},
		xml: function(xhr){
			// summary: A contentHandler returning an XML Document parsed from the response data
			var result = xhr.responseXML;
						if(_d.isIE && (!result || !result.documentElement)){
				//WARNING: this branch used by the xml handling in dojo.io.iframe,
				//so be sure to test dojo.io.iframe if making changes below.
				var ms = function(n){ return "MSXML" + n + ".DOMDocument"; };
				var dp = ["Microsoft.XMLDOM", ms(6), ms(4), ms(3), ms(2)];
				_d.some(dp, function(p){
					try{
						var dom = new ActiveXObject(p);
						dom.async = false;
						dom.loadXML(xhr.responseText);
						result = dom;
					}catch(e){ return false; }
					return true;
				});
			}
						return result; // DOMDocument
		},
		"json-comment-optional": function(xhr){
			// summary: A contentHandler which checks the presence of comment-filtered JSON and
			//		alternates between the `json` and `json-comment-filtered` contentHandlers.
			if(xhr.responseText && /^[^{\[]*\/\*/.test(xhr.responseText)){
				return handlers["json-comment-filtered"](xhr);
			}else{
				return handlers["json"](xhr);
			}
		}
	};

	/*=====
	dojo.__IoArgs = function(){
		//	url: String
		//		URL to server endpoint.
		//	content: Object?
		//		Contains properties with string values. These
		//		properties will be serialized as name1=value2 and
		//		passed in the request.
		//	timeout: Integer?
		//		Milliseconds to wait for the response. If this time
		//		passes, the then error callbacks are called.
		//	form: DOMNode?
		//		DOM node for a form. Used to extract the form values
		//		and send to the server.
		//	preventCache: Boolean?
		//		Default is false. If true, then a
		//		"dojo.preventCache" parameter is sent in the request
		//		with a value that changes with each request
		//		(timestamp). Useful only with GET-type requests.
		//	handleAs: String?
		//		Acceptable values depend on the type of IO
		//		transport (see specific IO calls for more information).
		//	rawBody: String?
		// 		Sets the raw body for an HTTP request. If this is used, then the content
		// 		property is ignored. This is mostly useful for HTTP methods that have
		// 		a body to their requests, like PUT or POST. This property can be used instead
		// 		of postData and putData for dojo.rawXhrPost and dojo.rawXhrPut respectively.
		//	ioPublish: Boolean?
		//		Set this explicitly to false to prevent publishing of topics related to
		// 		IO operations. Otherwise, if djConfig.ioPublish is set to true, topics
		// 		will be published via dojo.publish for different phases of an IO operation.
		// 		See dojo.__IoPublish for a list of topics that are published.
		//	load: Function?
		//		This function will be
		//		called on a successful HTTP response code.
		//	error: Function?
		//		This function will
		//		be called when the request fails due to a network or server error, the url
		//		is invalid, etc. It will also be called if the load or handle callback throws an
		//		exception, unless djConfig.debugAtAllCosts is true.  This allows deployed applications
		//		to continue to run even when a logic error happens in the callback, while making
		//		it easier to troubleshoot while in debug mode.
		//	handle: Function?
		//		This function will
		//		be called at the end of every request, whether or not an error occurs.
		this.url = url;
		this.content = content;
		this.timeout = timeout;
		this.form = form;
		this.preventCache = preventCache;
		this.handleAs = handleAs;
		this.ioPublish = ioPublish;
		this.load = function(response, ioArgs){
			// ioArgs: dojo.__IoCallbackArgs
			//		Provides additional information about the request.
			// response: Object
			//		The response in the format as defined with handleAs.
		}
		this.error = function(response, ioArgs){
			// ioArgs: dojo.__IoCallbackArgs
			//		Provides additional information about the request.
			// response: Object
			//		The response in the format as defined with handleAs.
		}
		this.handle = function(loadOrError, response, ioArgs){
			// loadOrError: String
			//		Provides a string that tells you whether this function
			//		was called because of success (load) or failure (error).
			// response: Object
			//		The response in the format as defined with handleAs.
			// ioArgs: dojo.__IoCallbackArgs
			//		Provides additional information about the request.
		}
	}
	=====*/

	/*=====
	dojo.__IoCallbackArgs = function(args, xhr, url, query, handleAs, id, canDelete, json){
		//	args: Object
		//		the original object argument to the IO call.
		//	xhr: XMLHttpRequest
		//		For XMLHttpRequest calls only, the
		//		XMLHttpRequest object that was used for the
		//		request.
		//	url: String
		//		The final URL used for the call. Many times it
		//		will be different than the original args.url
		//		value.
		//	query: String
		//		For non-GET requests, the
		//		name1=value1&name2=value2 parameters sent up in
		//		the request.
		//	handleAs: String
		//		The final indicator on how the response will be
		//		handled.
		//	id: String
		//		For dojo.io.script calls only, the internal
		//		script ID used for the request.
		//	canDelete: Boolean
		//		For dojo.io.script calls only, indicates
		//		whether the script tag that represents the
		//		request can be deleted after callbacks have
		//		been called. Used internally to know when
		//		cleanup can happen on JSONP-type requests.
		//	json: Object
		//		For dojo.io.script calls only: holds the JSON
		//		response for JSONP-type requests. Used
		//		internally to hold on to the JSON responses.
		//		You should not need to access it directly --
		//		the same object should be passed to the success
		//		callbacks directly.
		this.args = args;
		this.xhr = xhr;
		this.url = url;
		this.query = query;
		this.handleAs = handleAs;
		this.id = id;
		this.canDelete = canDelete;
		this.json = json;
	}
	=====*/


	/*=====
	dojo.__IoPublish = function(){
		// 	summary:
		// 		This is a list of IO topics that can be published
		// 		if djConfig.ioPublish is set to true. IO topics can be
		// 		published for any Input/Output, network operation. So,
		// 		dojo.xhr, dojo.io.script and dojo.io.iframe can all
		// 		trigger these topics to be published.
		//	start: String
		//		"/dojo/io/start" is sent when there are no outstanding IO
		// 		requests, and a new IO request is started. No arguments
		// 		are passed with this topic.
		//	send: String
		//		"/dojo/io/send" is sent whenever a new IO request is started.
		// 		It passes the dojo.Deferred for the request with the topic.
		//	load: String
		//		"/dojo/io/load" is sent whenever an IO request has loaded
		// 		successfully. It passes the response and the dojo.Deferred
		// 		for the request with the topic.
		//	error: String
		//		"/dojo/io/error" is sent whenever an IO request has errored.
		// 		It passes the error and the dojo.Deferred
		// 		for the request with the topic.
		//	done: String
		//		"/dojo/io/done" is sent whenever an IO request has completed,
		// 		either by loading or by erroring. It passes the error and
		// 		the dojo.Deferred for the request with the topic.
		//	stop: String
		//		"/dojo/io/stop" is sent when all outstanding IO requests have
		// 		finished. No arguments are passed with this topic.
		this.start = "/dojo/io/start";
		this.send = "/dojo/io/send";
		this.load = "/dojo/io/load";
		this.error = "/dojo/io/error";
		this.done = "/dojo/io/done";
		this.stop = "/dojo/io/stop";
	}
	=====*/


	dojo._ioSetArgs = function(/*dojo.__IoArgs*/args,
			/*Function*/canceller,
			/*Function*/okHandler,
			/*Function*/errHandler){
		//	summary:
		//		sets up the Deferred and ioArgs property on the Deferred so it
		//		can be used in an io call.
		//	args:
		//		The args object passed into the public io call. Recognized properties on
		//		the args object are:
		//	canceller:
		//		The canceller function used for the Deferred object. The function
		//		will receive one argument, the Deferred object that is related to the
		//		canceller.
		//	okHandler:
		//		The first OK callback to be registered with Deferred. It has the opportunity
		//		to transform the OK response. It will receive one argument -- the Deferred
		//		object returned from this function.
		//	errHandler:
		//		The first error callback to be registered with Deferred. It has the opportunity
		//		to do cleanup on an error. It will receive two arguments: error (the
		//		Error object) and dfd, the Deferred object returned from this function.

		var ioArgs = {args: args, url: args.url};

		//Get values from form if requestd.
		var formObject = null;
		if(args.form){
			var form = _d.byId(args.form);
			//IE requires going through getAttributeNode instead of just getAttribute in some form cases,
			//so use it for all.  See #2844
			var actnNode = form.getAttributeNode("action");
			ioArgs.url = ioArgs.url || (actnNode ? actnNode.value : null);
			formObject = _d.formToObject(form);
		}

		// set up the query params
		var miArgs = [{}];
	
		if(formObject){
			// potentially over-ride url-provided params w/ form values
			miArgs.push(formObject);
		}
		if(args.content){
			// stuff in content over-rides what's set by form
			miArgs.push(args.content);
		}
		if(args.preventCache){
			miArgs.push({"dojo.preventCache": new Date().valueOf()});
		}
		ioArgs.query = _d.objectToQuery(_d.mixin.apply(null, miArgs));
	
		// .. and the real work of getting the deferred in order, etc.
		ioArgs.handleAs = args.handleAs || "text";
		var d = new _d.Deferred(canceller);
		d.addCallbacks(okHandler, function(error){
			return errHandler(error, d);
		});

		//Support specifying load, error and handle callback functions from the args.
		//For those callbacks, the "this" object will be the args object.
		//The callbacks will get the deferred result value as the
		//first argument and the ioArgs object as the second argument.
		var ld = args.load;
		if(ld && _d.isFunction(ld)){
			d.addCallback(function(value){
				return ld.call(args, value, ioArgs);
			});
		}
		var err = args.error;
		if(err && _d.isFunction(err)){
			d.addErrback(function(value){
				return err.call(args, value, ioArgs);
			});
		}
		var handle = args.handle;
		if(handle && _d.isFunction(handle)){
			d.addBoth(function(value){
				return handle.call(args, value, ioArgs);
			});
		}

		//Plug in topic publishing, if dojo.publish is loaded.
		if(cfg.ioPublish && _d.publish && ioArgs.args.ioPublish !== false){
			d.addCallbacks(
				function(res){
					_d.publish("/dojo/io/load", [d, res]);
					return res;
				},
				function(res){
					_d.publish("/dojo/io/error", [d, res]);
					return res;
				}
			);
			d.addBoth(function(res){
				_d.publish("/dojo/io/done", [d, res]);
				return res;
			});
		}

		d.ioArgs = ioArgs;
	
		// FIXME: need to wire up the xhr object's abort method to something
		// analagous in the Deferred
		return d;
	};

	var _deferredCancel = function(/*Deferred*/dfd){
		// summary: canceller function for dojo._ioSetArgs call.
		
		dfd.canceled = true;
		var xhr = dfd.ioArgs.xhr;
		var _at = typeof xhr.abort;
		if(_at == "function" || _at == "object" || _at == "unknown"){
			xhr.abort();
		}
		var err = dfd.ioArgs.error;
		if(!err){
			err = new Error("xhr cancelled");
			err.dojoType="cancel";
		}
		return err;
	};
	var _deferredOk = function(/*Deferred*/dfd){
		// summary: okHandler function for dojo._ioSetArgs call.

		var ret = handlers[dfd.ioArgs.handleAs](dfd.ioArgs.xhr);
		return ret === undefined ? null : ret;
	};
	var _deferError = function(/*Error*/error, /*Deferred*/dfd){
		// summary: errHandler function for dojo._ioSetArgs call.

		if(!dfd.ioArgs.args.failOk){
			console.error(error);
		}
		return error;
	};

	// avoid setting a timer per request. It degrades performance on IE
	// something fierece if we don't use unified loops.
	var _inFlightIntvl = null;
	var _inFlight = [];
	
	
	//Use a separate count for knowing if we are starting/stopping io calls.
	//Cannot use _inFlight.length since it can change at a different time than
	//when we want to do this kind of test. We only want to decrement the count
	//after a callback/errback has finished, since the callback/errback should be
	//considered as part of finishing a request.
	var _pubCount = 0;
	var _checkPubCount = function(dfd){
		if(_pubCount <= 0){
			_pubCount = 0;
			if(cfg.ioPublish && _d.publish && (!dfd || dfd && dfd.ioArgs.args.ioPublish !== false)){
				_d.publish("/dojo/io/stop");
			}
		}
	};

	var _watchInFlight = function(){
		//summary:
		//		internal method that checks each inflight XMLHttpRequest to see
		//		if it has completed or if the timeout situation applies.
		
		var now = (new Date()).getTime();
		// make sure sync calls stay thread safe, if this callback is called
		// during a sync call and this results in another sync call before the
		// first sync call ends the browser hangs
		if(!_d._blockAsync){
			// we need manual loop because we often modify _inFlight (and therefore 'i') while iterating
			// note: the second clause is an assigment on purpose, lint may complain
			for(var i = 0, tif; i < _inFlight.length && (tif = _inFlight[i]); i++){
				var dfd = tif.dfd;
				var func = function(){
					if(!dfd || dfd.canceled || !tif.validCheck(dfd)){
						_inFlight.splice(i--, 1);
						_pubCount -= 1;
					}else if(tif.ioCheck(dfd)){
						_inFlight.splice(i--, 1);
						tif.resHandle(dfd);
						_pubCount -= 1;
					}else if(dfd.startTime){
						//did we timeout?
						if(dfd.startTime + (dfd.ioArgs.args.timeout || 0) < now){
							_inFlight.splice(i--, 1);
							var err = new Error("timeout exceeded");
							err.dojoType = "timeout";
							dfd.errback(err);
							//Cancel the request so the io module can do appropriate cleanup.
							dfd.cancel();
							_pubCount -= 1;
						}
					}
				};
				if(dojo.config.debugAtAllCosts){
					func.call(this);
				}else{
					try{
						func.call(this);
					}catch(e){
						dfd.errback(e);
					}
				}
			}
		}

		_checkPubCount(dfd);

		if(!_inFlight.length){
			clearInterval(_inFlightIntvl);
			_inFlightIntvl = null;
			return;
		}
	};

	dojo._ioCancelAll = function(){
		//summary: Cancels all pending IO requests, regardless of IO type
		//(xhr, script, iframe).
		try{
			_d.forEach(_inFlight, function(i){
				try{
					i.dfd.cancel();
				}catch(e){/*squelch*/}
			});
		}catch(e){/*squelch*/}
	};

	//Automatically call cancel all io calls on unload
	//in IE for trac issue #2357.
		if(_d.isIE){
		_d.addOnWindowUnload(_d._ioCancelAll);
	}
	
	_d._ioNotifyStart = function(/*Deferred*/dfd){
		// summary:
		// 		If dojo.publish is available, publish topics
		// 		about the start of a request queue and/or the
		// 		the beginning of request.
		// description:
		// 		Used by IO transports. An IO transport should
		// 		call this method before making the network connection.
		if(cfg.ioPublish && _d.publish && dfd.ioArgs.args.ioPublish !== false){
			if(!_pubCount){
				_d.publish("/dojo/io/start");
			}
			_pubCount += 1;
			_d.publish("/dojo/io/send", [dfd]);
		}
	};

	_d._ioWatch = function(dfd, validCheck, ioCheck, resHandle){
		// summary:
		//		Watches the io request represented by dfd to see if it completes.
		// dfd: Deferred
		//		The Deferred object to watch.
		// validCheck: Function
		//		Function used to check if the IO request is still valid. Gets the dfd
		//		object as its only argument.
		// ioCheck: Function
		//		Function used to check if basic IO call worked. Gets the dfd
		//		object as its only argument.
		// resHandle: Function
		//		Function used to process response. Gets the dfd
		//		object as its only argument.
		var args = dfd.ioArgs.args;
		if(args.timeout){
			dfd.startTime = (new Date()).getTime();
		}
		
		_inFlight.push({dfd: dfd, validCheck: validCheck, ioCheck: ioCheck, resHandle: resHandle});
		if(!_inFlightIntvl){
			_inFlightIntvl = setInterval(_watchInFlight, 50);
		}
		// handle sync requests
		//A weakness: async calls in flight
		//could have their handlers called as part of the
		//_watchInFlight call, before the sync's callbacks
		// are called.
		if(args.sync){
			_watchInFlight();
		}
	};

	var _defaultContentType = "application/x-www-form-urlencoded";

	var _validCheck = function(/*Deferred*/dfd){
		return dfd.ioArgs.xhr.readyState; //boolean
	};
	var _ioCheck = function(/*Deferred*/dfd){
		return 4 == dfd.ioArgs.xhr.readyState; //boolean
	};
	var _resHandle = function(/*Deferred*/dfd){
		var xhr = dfd.ioArgs.xhr;
		if(_d._isDocumentOk(xhr)){
			dfd.callback(dfd);
		}else{
			var err = new Error("Unable to load " + dfd.ioArgs.url + " status:" + xhr.status);
			err.status = xhr.status;
			err.responseText = xhr.responseText;
			dfd.errback(err);
		}
	};

	dojo._ioAddQueryToUrl = function(/*dojo.__IoCallbackArgs*/ioArgs){
		//summary: Adds query params discovered by the io deferred construction to the URL.
		//Only use this for operations which are fundamentally GET-type operations.
		if(ioArgs.query.length){
			ioArgs.url += (ioArgs.url.indexOf("?") == -1 ? "?" : "&") + ioArgs.query;
			ioArgs.query = null;
		}
	};

	/*=====
	dojo.declare("dojo.__XhrArgs", dojo.__IoArgs, {
		constructor: function(){
			//	summary:
			//		In addition to the properties listed for the dojo._IoArgs type,
			//		the following properties are allowed for dojo.xhr* methods.
			//	handleAs: String?
			//		Acceptable values are: text (default), json, json-comment-optional,
			//		json-comment-filtered, javascript, xml. See `dojo.contentHandlers`
			//	sync: Boolean?
			//		false is default. Indicates whether the request should
			//		be a synchronous (blocking) request.
			//	headers: Object?
			//		Additional HTTP headers to send in the request.
			//	failOk: Boolean?
			//		false is default. Indicates whether a request should be
			//		allowed to fail (and therefore no console error message in
			//		the event of a failure)
			this.handleAs = handleAs;
			this.sync = sync;
			this.headers = headers;
			this.failOk = failOk;
		}
	});
	=====*/

	dojo.xhr = function(/*String*/ method, /*dojo.__XhrArgs*/ args, /*Boolean?*/ hasBody){
		//	summary:
		//		Sends an HTTP request with the given method.
		//	description:
		//		Sends an HTTP request with the given method.
		//		See also dojo.xhrGet(), xhrPost(), xhrPut() and dojo.xhrDelete() for shortcuts
		//		for those HTTP methods. There are also methods for "raw" PUT and POST methods
		//		via dojo.rawXhrPut() and dojo.rawXhrPost() respectively.
		//	method:
		//		HTTP method to be used, such as GET, POST, PUT, DELETE.  Should be uppercase.
		//	hasBody:
		//		If the request has an HTTP body, then pass true for hasBody.

		//Make the Deferred object for this xhr request.
		var dfd = _d._ioSetArgs(args, _deferredCancel, _deferredOk, _deferError);
		var ioArgs = dfd.ioArgs;

		//Pass the args to _xhrObj, to allow alternate XHR calls based specific calls, like
		//the one used for iframe proxies.
		var xhr = ioArgs.xhr = _d._xhrObj(ioArgs.args);
		//If XHR factory fails, cancel the deferred.
		if(!xhr){
			dfd.cancel();
			return dfd;
		}

		//Allow for specifying the HTTP body completely.
		if("postData" in args){
			ioArgs.query = args.postData;
		}else if("putData" in args){
			ioArgs.query = args.putData;
		}else if("rawBody" in args){
			ioArgs.query = args.rawBody;
		}else if((arguments.length > 2 && !hasBody) || "POST|PUT".indexOf(method.toUpperCase()) == -1){
			//Check for hasBody being passed. If no hasBody,
			//then only append query string if not a POST or PUT request.
			_d._ioAddQueryToUrl(ioArgs);
		}

		// IE 6 is a steaming pile. It won't let you call apply() on the native function (xhr.open).
		// workaround for IE6's apply() "issues"
		xhr.open(method, ioArgs.url, args.sync !== true, args.user || undefined, args.password || undefined);
		if(args.headers){
			for(var hdr in args.headers){
				if(hdr.toLowerCase() === "content-type" && !args.contentType){
					args.contentType = args.headers[hdr];
				}else if(args.headers[hdr]){
					//Only add header if it has a value. This allows for instnace, skipping
					//insertion of X-Requested-With by specifying empty value.
					xhr.setRequestHeader(hdr, args.headers[hdr]);
				}
			}
		}
		// FIXME: is this appropriate for all content types?
		xhr.setRequestHeader("Content-Type", args.contentType || _defaultContentType);
		if(!args.headers || !("X-Requested-With" in args.headers)){
			xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
		}
		// FIXME: set other headers here!
		_d._ioNotifyStart(dfd);
		if(dojo.config.debugAtAllCosts){
			xhr.send(ioArgs.query);
		}else{
			try{
				xhr.send(ioArgs.query);
			}catch(e){
				ioArgs.error = e;
				dfd.cancel();
			}
		}
		_d._ioWatch(dfd, _validCheck, _ioCheck, _resHandle);
		xhr = null;
		return dfd; // dojo.Deferred
	};

	dojo.xhrGet = function(/*dojo.__XhrArgs*/ args){
		//	summary:
		//		Sends an HTTP GET request to the server.
		return _d.xhr("GET", args); // dojo.Deferred
	};

	dojo.rawXhrPost = dojo.xhrPost = function(/*dojo.__XhrArgs*/ args){
		//	summary:
		//		Sends an HTTP POST request to the server. In addtion to the properties
		//		listed for the dojo.__XhrArgs type, the following property is allowed:
		//	postData:
		//		String. Send raw data in the body of the POST request.
		return _d.xhr("POST", args, true); // dojo.Deferred
	};

	dojo.rawXhrPut = dojo.xhrPut = function(/*dojo.__XhrArgs*/ args){
		//	summary:
		//		Sends an HTTP PUT request to the server. In addtion to the properties
		//		listed for the dojo.__XhrArgs type, the following property is allowed:
		//	putData:
		//		String. Send raw data in the body of the PUT request.
		return _d.xhr("PUT", args, true); // dojo.Deferred
	};

	dojo.xhrDelete = function(/*dojo.__XhrArgs*/ args){
		//	summary:
		//		Sends an HTTP DELETE request to the server.
		return _d.xhr("DELETE", args); //dojo.Deferred
	};

	/*
	dojo.wrapForm = function(formNode){
		//summary:
		//		A replacement for FormBind, but not implemented yet.

		// FIXME: need to think harder about what extensions to this we might
		// want. What should we allow folks to do w/ this? What events to
		// set/send?
		throw new Error("dojo.wrapForm not yet implemented");
	}
	*/
})();

}