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connection  2.8.2r1

Yahoo! UI Library > connection > connectionx.js (source view)
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/**
  * @for Connect
  */
(function(){
	var YCM = YAHOO.util.Connect,
		YE = YAHOO.util.Event;
   /**
	* @description Property modified by setForm() to determine if the data
	* should be submitted as an HTML form.
	* @property _isFormSubmit
	* @private
	* @static
	* @type boolean
	*/
	YCM._isFormSubmit = false;

   /**
	* @description Property modified by setForm() to determine if a file(s)
	* upload is expected.
	* @property _isFileUpload
	* @private
	* @static
	* @type boolean
	*/
	YCM._isFileUpload = false;

   /**
	* @description Property modified by setForm() to set a reference to the HTML
	* form node if the desired action is file upload.
	* @property _formNode
	* @private
	* @static
	* @type object
	*/
	YCM._formNode = null;

   /**
	* @description Property modified by setForm() to set the HTML form data
	* for each transaction.
	* @property _sFormData
	* @private
	* @static
	* @type string
	*/
	YCM._sFormData = null;

   /**
	* @description Tracks the name-value pair of the "clicked" submit button if multiple submit
	* buttons are present in an HTML form; and, if YAHOO.util.Event is available.
	* @property _submitElementValue
	* @private
	* @static
	* @type string
	*/
	YCM._submitElementValue = null;

   /**
    * @description Custom event that fires when handleTransactionResponse() determines a
    * response in the HTTP 4xx/5xx range.
    * @property failureEvent
    * @private
    * @static
    * @type CustomEvent
    */
	YCM.uploadEvent = new YAHOO.util.CustomEvent('upload'),

   /**
	* @description Determines whether YAHOO.util.Event is available and returns true or false.
	* If true, an event listener is bound at the document level to trap click events that
	* resolve to a target type of "Submit".  This listener will enable setForm() to determine
	* the clicked "Submit" value in a multi-Submit button, HTML form.
	* @property _hasSubmitListener
	* @private
	* @static
	*/
	YCM._hasSubmitListener = function() {
		if(YE){
			YE.addListener(
				document,
				'click',
				function(e){
					var obj = YE.getTarget(e),
						name = obj.nodeName.toLowerCase();

					if((name === 'input' || name === 'button') && (obj.type && obj.type.toLowerCase() == 'submit')){
						YCM._submitElementValue = encodeURIComponent(obj.name) + "=" + encodeURIComponent(obj.value);
					}
				});
			return true;
		}
		return false;
	}();

  /**
   * @description This method assembles the form label and value pairs and
   * constructs an encoded string.
   * asyncRequest() will automatically initialize the transaction with a
   * a HTTP header Content-Type of application/x-www-form-urlencoded.
   * @method setForm
   * @public
   * @static
   * @param {string || object} form id or name attribute, or form object.
   * @param {boolean} optional enable file upload.
   * @param {boolean} optional enable file upload over SSL in IE only.
   * @return {string} string of the HTML form field name and value pairs..
   */
	function _setForm(formId, isUpload, secureUri)
	{
		var oForm, oElement, oName, oValue, oDisabled,
			hasSubmit = false,
			data = [], item = 0,
			i,len,j,jlen,opt;

		this.resetFormState();

		if(typeof formId == 'string'){
			// Determine if the argument is a form id or a form name.
			// Note form name usage is deprecated by supported
			// here for legacy reasons.
			oForm = (document.getElementById(formId) || document.forms[formId]);
		}
		else if(typeof formId == 'object'){
			// Treat argument as an HTML form object.
			oForm = formId;
		}
		else{
			YAHOO.log('Unable to create form object ' + formId, 'warn', 'Connection');
			return;
		}

		// If the isUpload argument is true, setForm will call createFrame to initialize
		// an iframe as the form target.
		//
		// The argument secureURI is also required by IE in SSL environments
		// where the secureURI string is a fully qualified HTTP path, used to set the source
		// of the iframe, to a stub resource in the same domain.
		if(isUpload){

			// Create iframe in preparation for file upload.
			this.createFrame(secureUri?secureUri:null);

			// Set form reference and file upload properties to true.
			this._isFormSubmit = true;
			this._isFileUpload = true;
			this._formNode = oForm;

			return;
		}

		// Iterate over the form elements collection to construct the
		// label-value pairs.
		for (i=0,len=oForm.elements.length; i<len; ++i){
			oElement  = oForm.elements[i];
			oDisabled = oElement.disabled;
			oName     = oElement.name;

			// Do not submit fields that are disabled or
			// do not have a name attribute value.
			if(!oDisabled && oName)
			{
				oName  = encodeURIComponent(oName)+'=';
				oValue = encodeURIComponent(oElement.value);

				switch(oElement.type)
				{
					// Safari, Opera, FF all default opt.value from .text if
					// value attribute not specified in markup
					case 'select-one':
						if (oElement.selectedIndex > -1) {
							opt = oElement.options[oElement.selectedIndex];
							data[item++] = oName + encodeURIComponent(
								(opt.attributes.value && opt.attributes.value.specified) ? opt.value : opt.text);
						}
						break;
					case 'select-multiple':
						if (oElement.selectedIndex > -1) {
							for(j=oElement.selectedIndex, jlen=oElement.options.length; j<jlen; ++j){
								opt = oElement.options[j];
								if (opt.selected) {
									data[item++] = oName + encodeURIComponent(
										(opt.attributes.value && opt.attributes.value.specified) ? opt.value : opt.text);
								}
							}
						}
						break;
					case 'radio':
					case 'checkbox':
						if(oElement.checked){
							data[item++] = oName + oValue;
						}
						break;
					case 'file':
						// stub case as XMLHttpRequest will only send the file path as a string.
					case undefined:
						// stub case for fieldset element which returns undefined.
					case 'reset':
						// stub case for input type reset button.
					case 'button':
						// stub case for input type button elements.
						break;
					case 'submit':
						if(hasSubmit === false){
							if(this._hasSubmitListener && this._submitElementValue){
								data[item++] = this._submitElementValue;
							}
							hasSubmit = true;
						}
						break;
					default:
						data[item++] = oName + oValue;
				}
			}
		}

		this._isFormSubmit = true;
		this._sFormData = data.join('&');

		YAHOO.log('Form initialized for transaction. HTML form POST message is: ' + this._sFormData, 'info', 'Connection');

		this.initHeader('Content-Type', this._default_form_header);
		YAHOO.log('Initialize header Content-Type to application/x-www-form-urlencoded for setForm() transaction.', 'info', 'Connection');

		return this._sFormData;
	}

   /**
    * @description Resets HTML form properties when an HTML form or HTML form
    * with file upload transaction is sent.
    * @method resetFormState
    * @private
    * @static
    * @return {void}
    */
	function _resetFormState(){
		this._isFormSubmit = false;
		this._isFileUpload = false;
		this._formNode = null;
		this._sFormData = "";
	}


   /**
    * @description Creates an iframe to be used for form file uploads.  It is remove from the
    * document upon completion of the upload transaction.
    * @method createFrame
    * @private
    * @static
    * @param {string} optional qualified path of iframe resource for SSL in IE.
    * @return {void}
    */
	function _createFrame(secureUri){

		// IE does not allow the setting of id and name attributes as object
		// properties via createElement().  A different iframe creation
		// pattern is required for IE.
		var frameId = 'yuiIO' + this._transaction_id,
			io;
		if(YAHOO.env.ua.ie){
			io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');

			// IE will throw a security exception in an SSL environment if the
			// iframe source is undefined.
			if(typeof secureUri == 'boolean'){
				io.src = 'javascript:false';
			}
		}
		else{
			io = document.createElement('iframe');
			io.id = frameId;
			io.name = frameId;
		}

		io.style.position = 'absolute';
		io.style.top = '-1000px';
		io.style.left = '-1000px';

		document.body.appendChild(io);
		YAHOO.log('File upload iframe created. Id is:' + frameId, 'info', 'Connection');
	}

   /**
    * @description Parses the POST data and creates hidden form elements
    * for each key-value, and appends them to the HTML form object.
    * @method appendPostData
    * @private
    * @static
    * @param {string} postData The HTTP POST data
    * @return {array} formElements Collection of hidden fields.
    */
	function _appendPostData(postData){
		var formElements = [],
			postMessage = postData.split('&'),
			i, delimitPos;

		for(i=0; i < postMessage.length; i++){
			delimitPos = postMessage[i].indexOf('=');
			if(delimitPos != -1){
				formElements[i] = document.createElement('input');
				formElements[i].type = 'hidden';
				formElements[i].name = decodeURIComponent(postMessage[i].substring(0,delimitPos));
				formElements[i].value = decodeURIComponent(postMessage[i].substring(delimitPos+1));
				this._formNode.appendChild(formElements[i]);
			}
		}

		return formElements;
	}

   /**
    * @description Uploads HTML form, inclusive of files/attachments, using the
    * iframe created in createFrame to facilitate the transaction.
    * @method uploadFile
    * @private
    * @static
    * @param {int} id The transaction id.
    * @param {object} callback User-defined callback object.
    * @param {string} uri Fully qualified path of resource.
    * @param {string} postData POST data to be submitted in addition to HTML form.
    * @return {void}
    */
	function _uploadFile(o, callback, uri, postData){
		// Each iframe has an id prefix of "yuiIO" followed
		// by the unique transaction id.
		var frameId = 'yuiIO' + o.tId,
		    uploadEncoding = 'multipart/form-data',
		    io = document.getElementById(frameId),
		    ie8 = (document.documentMode && document.documentMode === 8) ? true : false,
		    oConn = this,
			args = (callback && callback.argument)?callback.argument:null,
            oElements,i,prop,obj, rawFormAttributes, uploadCallback;

		// Track original HTML form attribute values.
		rawFormAttributes = {
			action:this._formNode.getAttribute('action'),
			method:this._formNode.getAttribute('method'),
			target:this._formNode.getAttribute('target')
		};

		// Initialize the HTML form properties in case they are
		// not defined in the HTML form.
		this._formNode.setAttribute('action', uri);
		this._formNode.setAttribute('method', 'POST');
		this._formNode.setAttribute('target', frameId);

		if(YAHOO.env.ua.ie && !ie8){
			// IE does not respect property enctype for HTML forms.
			// Instead it uses the property - "encoding".
			this._formNode.setAttribute('encoding', uploadEncoding);
		}
		else{
			this._formNode.setAttribute('enctype', uploadEncoding);
		}

		if(postData){
			oElements = this.appendPostData(postData);
		}

		// Start file upload.
		this._formNode.submit();

		// Fire global custom event -- startEvent
		this.startEvent.fire(o, args);

		if(o.startEvent){
			// Fire transaction custom event -- startEvent
			o.startEvent.fire(o, args);
		}

		// Start polling if a callback is present and the timeout
		// property has been defined.
		if(callback && callback.timeout){
			this._timeOut[o.tId] = window.setTimeout(function(){ oConn.abort(o, callback, true); }, callback.timeout);
		}

		// Remove HTML elements created by appendPostData
		if(oElements && oElements.length > 0){
			for(i=0; i < oElements.length; i++){
				this._formNode.removeChild(oElements[i]);
			}
		}

		// Restore HTML form attributes to their original
		// values prior to file upload.
		for(prop in rawFormAttributes){
			if(YAHOO.lang.hasOwnProperty(rawFormAttributes, prop)){
				if(rawFormAttributes[prop]){
					this._formNode.setAttribute(prop, rawFormAttributes[prop]);
				}
				else{
					this._formNode.removeAttribute(prop);
				}
			}
		}

		// Reset HTML form state properties.
		this.resetFormState();

		// Create the upload callback handler that fires when the iframe
		// receives the load event.  Subsequently, the event handler is detached
		// and the iframe removed from the document.
		uploadCallback = function() {
			if(callback && callback.timeout){
				window.clearTimeout(oConn._timeOut[o.tId]);
				delete oConn._timeOut[o.tId];
			}

			// Fire global custom event -- completeEvent
			oConn.completeEvent.fire(o, args);

			if(o.completeEvent){
				// Fire transaction custom event -- completeEvent
				o.completeEvent.fire(o, args);
			}

			obj = {
			    tId : o.tId,
			    argument : callback.argument
            };

			try
			{
				// responseText and responseXML will be populated with the same data from the iframe.
				// Since the HTTP headers cannot be read from the iframe
				obj.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:io.contentWindow.document.documentElement.textContent;
				obj.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
			}
			catch(e){}

			if(callback && callback.upload){
				if(!callback.scope){
					callback.upload(obj);
					YAHOO.log('Upload callback.', 'info', 'Connection');
				}
				else{
					callback.upload.apply(callback.scope, [obj]);
					YAHOO.log('Upload callback with scope.', 'info', 'Connection');
				}
			}

			// Fire global custom event -- uploadEvent
			oConn.uploadEvent.fire(obj);

			if(o.uploadEvent){
				// Fire transaction custom event -- uploadEvent
				o.uploadEvent.fire(obj);
			}

			YE.removeListener(io, "load", uploadCallback);

			setTimeout(
				function(){
					document.body.removeChild(io);
					oConn.releaseObject(o);
					YAHOO.log('File upload iframe destroyed. Id is:' + frameId, 'info', 'Connection');
				}, 100);
		};

		// Bind the onload handler to the iframe to detect the file upload response.
		YE.addListener(io, "load", uploadCallback);
	}

	YCM.setForm = _setForm;
	YCM.resetFormState = _resetFormState;
	YCM.createFrame = _createFrame;
	YCM.appendPostData = _appendPostData;
	YCM.uploadFile = _uploadFile;
})();

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