Added LinuxChix theme

[moodle-linuxchix.git] / lib / yui / connection / connection-debug.js

/*
Copyright (c) 2007, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
version: 2.3.0
*/
/**
 * The Connection Manager provides a simplified interface to the XMLHttpRequest
 * object.  It handles cross-browser instantiantion of XMLHttpRequest, negotiates the
 * interactive states and server response, returning the results to a pre-defined
 * callback you create.
 *
 * @namespace YAHOO.util
 * @module connection
 * @requires yahoo
 * @requires event
 */

/**
 * The Connection Manager singleton provides methods for creating and managing
 * asynchronous transactions.
 *
 * @class Connect
 */

YAHOO.util.Connect =
{
  /**
   * @description Array of MSFT ActiveX ids for XMLHttpRequest.
   * @property _msxml_progid
   * @private
   * @static
   * @type array
   */
        _msxml_progid:[
                'MSXML2.XMLHTTP.3.0',
                'MSXML2.XMLHTTP',
                'Microsoft.XMLHTTP'
                ],

  /**
   * @description Object literal of HTTP header(s)
   * @property _http_header
   * @private
   * @static
   * @type object
   */
        _http_headers:{},

  /**
   * @description Determines if HTTP headers are set.
   * @property _has_http_headers
   * @private
   * @static
   * @type boolean
   */
        _has_http_headers:false,

 /**
  * @description Determines if a default header of
  * Content-Type of 'application/x-www-form-urlencoded'
  * will be added to any client HTTP headers sent for POST
  * transactions.
  * @property _use_default_post_header
  * @private
  * @static
  * @type boolean
  */
    _use_default_post_header:true,

 /**
  * @description Determines if a default header of
  * Content-Type of 'application/x-www-form-urlencoded'
  * will be added to client HTTP headers sent for POST
  * transactions.
  * @property _default_post_header
  * @private
  * @static
  * @type boolean
  */
    _default_post_header:'application/x-www-form-urlencoded; charset=UTF-8',

 /**
  * @description Determines if a default header of
  * 'X-Requested-With: XMLHttpRequest'
  * will be added to each transaction.
  * @property _use_default_xhr_header
  * @private
  * @static
  * @type boolean
  */
    _use_default_xhr_header:true,

 /**
  * @description The default header value for the label
  * "X-Requested-With".  This is sent with each
  * transaction, by default, to identify the
  * request as being made by YUI Connection Manager.
  * @property _default_xhr_header
  * @private
  * @static
  * @type boolean
  */
    _default_xhr_header:'XMLHttpRequest',

 /**
  * @description Determines if custom, default headers
  * are set for each transaction.
  * @property _has_default_header
  * @private
  * @static
  * @type boolean
  */
    _has_default_headers:true,

 /**
  * @description Determines if custom, default headers
  * are set for each transaction.
  * @property _has_default_header
  * @private
  * @static
  * @type boolean
  */
    _default_headers:{},

 /**
  * @description Property modified by setForm() to determine if the data
  * should be submitted as an HTML form.
  * @property _isFormSubmit
  * @private
  * @static
  * @type boolean
  */
    _isFormSubmit:false,

 /**
  * @description Property modified by setForm() to determine if a file(s)
  * upload is expected.
  * @property _isFileUpload
  * @private
  * @static
  * @type boolean
  */
    _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
  */
    _formNode:null,

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

 /**
  * @description Collection of polling references to the polling mechanism in handleReadyState.
  * @property _poll
  * @private
  * @static
  * @type object
  */
    _poll:{},

 /**
  * @description Queue of timeout values for each transaction callback with a defined timeout value.
  * @property _timeOut
  * @private
  * @static
  * @type object
  */
    _timeOut:{},

  /**
   * @description The polling frequency, in milliseconds, for HandleReadyState.
   * when attempting to determine a transaction's XHR readyState.
   * The default is 50 milliseconds.
   * @property _polling_interval
   * @private
   * @static
   * @type int
   */
     _polling_interval:50,

  /**
   * @description A transaction counter that increments the transaction id for each transaction.
   * @property _transaction_id
   * @private
   * @static
   * @type int
   */
     _transaction_id:0,

  /**
   * @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
   */
         _submitElementValue:null,

  /**
   * @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
   */
         _hasSubmitListener:(function()
         {
                if(YAHOO.util.Event){
                        YAHOO.util.Event.addListener(
                                document,
                                'click',
                                function(e){
                                        var obj = YAHOO.util.Event.getTarget(e);
                                        if(obj.type == 'submit'){
                                                YAHOO.util.Connect._submitElementValue = encodeURIComponent(obj.name) + "=" + encodeURIComponent(obj.value);
                                        }
                                });
                        return true;
            }
            return false;
         })(),

  /**
   * @description Custom event that fires at the start of a transaction
   * @property startEvent
   * @private
   * @static
   * @type CustomEvent
   */
        startEvent: new YAHOO.util.CustomEvent('start'),

  /**
   * @description Custom event that fires when a transaction response has completed.
   * @property completeEvent
   * @private
   * @static
   * @type CustomEvent
   */
        completeEvent: new YAHOO.util.CustomEvent('complete'),

  /**
   * @description Custom event that fires when handleTransactionResponse() determines a
   * response in the HTTP 2xx range.
   * @property successEvent
   * @private
   * @static
   * @type CustomEvent
   */
        successEvent: new YAHOO.util.CustomEvent('success'),

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

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

  /**
   * @description Custom event that fires when a transaction is successfully aborted.
   * @property abortEvent
   * @private
   * @static
   * @type CustomEvent
   */
        abortEvent: new YAHOO.util.CustomEvent('abort'),

  /**
   * @description A reference table that maps callback custom events members to its specific
   * event name.
   * @property _customEvents
   * @private
   * @static
   * @type object
   */
        _customEvents:
        {
                onStart:['startEvent', 'start'],
                onComplete:['completeEvent', 'complete'],
                onSuccess:['successEvent', 'success'],
                onFailure:['failureEvent', 'failure'],
                onUpload:['uploadEvent', 'upload'],
                onAbort:['abortEvent', 'abort']
        },

  /**
   * @description Member to add an ActiveX id to the existing xml_progid array.
   * In the event(unlikely) a new ActiveX id is introduced, it can be added
   * without internal code modifications.
   * @method setProgId
   * @public
   * @static
   * @param {string} id The ActiveX id to be added to initialize the XHR object.
   * @return void
   */
        setProgId:function(id)
        {
                this._msxml_progid.unshift(id);
                YAHOO.log('ActiveX Program Id  ' + id + ' added to _msxml_progid.', 'info', 'Connection');
        },

  /**
   * @description Member to enable or disable the default POST header.
   * @method setDefaultPostHeader
   * @public
   * @static
   * @param {boolean} b Set and use default header - true or false .
   * @return void
   */
        setDefaultPostHeader:function(b)
        {
                this._use_default_post_header = b;
                YAHOO.log('Use default POST header set to  ' + b, 'info', 'Connection');
        },

  /**
   * @description Member to enable or disable the default POST header.
   * @method setDefaultXhrHeader
   * @public
   * @static
   * @param {boolean} b Set and use default header - true or false .
   * @return void
   */
        setDefaultXhrHeader:function(b)
        {
                this._use_default_xhr_header = b;
                YAHOO.log('Use default transaction header set to  ' + b, 'info', 'Connection');
        },

  /**
   * @description Member to modify the default polling interval.
   * @method setPollingInterval
   * @public
   * @static
   * @param {int} i The polling interval in milliseconds.
   * @return void
   */
        setPollingInterval:function(i)
        {
                if(typeof i == 'number' && isFinite(i)){
                        this._polling_interval = i;
                        YAHOO.log('Default polling interval set to ' + i +'ms', 'info', 'Connection');
                }
        },

  /**
   * @description Instantiates a XMLHttpRequest object and returns an object with two properties:
   * the XMLHttpRequest instance and the transaction id.
   * @method createXhrObject
   * @private
   * @static
   * @param {int} transactionId Property containing the transaction id for this transaction.
   * @return object
   */
        createXhrObject:function(transactionId)
        {
                var obj,http;
                try
                {
                        // Instantiates XMLHttpRequest in non-IE browsers and assigns to http.
                        http = new XMLHttpRequest();
                        //  Object literal with http and tId properties
                        obj = { conn:http, tId:transactionId };
                        YAHOO.log('XHR object created for transaction ' + transactionId, 'info', 'Connection');
                }
                catch(e)
                {
                        for(var i=0; i<this._msxml_progid.length; ++i){
                                try
                                {
                                        // Instantiates XMLHttpRequest for IE and assign to http.
                                        http = new ActiveXObject(this._msxml_progid[i]);
                                        //  Object literal with conn and tId properties
                                        obj = { conn:http, tId:transactionId };
                                        YAHOO.log('ActiveX XHR object created for transaction ' + transactionId, 'info', 'Connection');
                                        break;
                                }
                                catch(e){}
                        }
                }
                finally
                {
                        return obj;
                }
        },

  /**
   * @description This method is called by asyncRequest to create a
   * valid connection object for the transaction.  It also passes a
   * transaction id and increments the transaction id counter.
   * @method getConnectionObject
   * @private
   * @static
   * @return {object}
   */
        getConnectionObject:function(isFileUpload)
        {
                var o;
                var tId = this._transaction_id;

                try
                {
                        if(!isFileUpload){
                                o = this.createXhrObject(tId);
                        }
                        else{
                                o = {};
                                o.tId = tId;
                                o.isUpload = true;
                        }

                        if(o){
                                this._transaction_id++;
                        }
                }
                catch(e){}
                finally
                {
                        return o;
                }
        },

  /**
   * @description Method for initiating an asynchronous request via the XHR object.
   * @method asyncRequest
   * @public
   * @static
   * @param {string} method HTTP transaction method
   * @param {string} uri Fully qualified path of resource
   * @param {callback} callback User-defined callback function or object
   * @param {string} postData POST body
   * @return {object} Returns the connection object
   */
        asyncRequest:function(method, uri, callback, postData)
        {
                var o = (this._isFileUpload)?this.getConnectionObject(true):this.getConnectionObject();

                if(!o){
                        YAHOO.log('Unable to create connection object.', 'error', 'Connection');
                        return null;
                }
                else{

                        // Intialize any transaction-specific custom events, if provided.
                        if(callback && callback.customevents){
                                this.initCustomEvents(o, callback);
                        }

                        if(this._isFormSubmit){
                                if(this._isFileUpload){
                                        this.uploadFile(o, callback, uri, postData);
                                        return o;
                                }

                                // If the specified HTTP method is GET, setForm() will return an
                                // encoded string that is concatenated to the uri to
                                // create a querystring.
                                if(method.toUpperCase() == 'GET'){
                                        if(this._sFormData.length !== 0){
                                                // If the URI already contains a querystring, append an ampersand
                                                // and then concatenate _sFormData to the URI.
                                                uri += ((uri.indexOf('?') == -1)?'?':'&') + this._sFormData;
                                        }
                                        else{
                                                uri += "?" + this._sFormData;
                                        }
                                }
                                else if(method.toUpperCase() == 'POST'){
                                        // If POST data exist in addition to the HTML form data,
                                        // it will be concatenated to the form data.
                                        postData = postData?this._sFormData + "&" + postData:this._sFormData;
                                }
                        }

                        o.conn.open(method, uri, true);
                        //this.processTransactionHeaders(o);

                        // Each transaction will automatically include a custom header of
                        // "X-Requested-With: XMLHttpRequest" to identify the request as
                        // having originated from Connection Manager.
                        if(this._use_default_xhr_header){
                                if(!this._default_headers['X-Requested-With']){
                                        this.initHeader('X-Requested-With', this._default_xhr_header, true);
                                        YAHOO.log('Initialize transaction header X-Request-Header to XMLHttpRequest.', 'info', 'Connection');
                                }
                        }

                        if(this._isFormSubmit || (postData && this._use_default_post_header)){
                                this.initHeader('Content-Type', this._default_post_header);
                                YAHOO.log('Initialize header Content-Type to application/x-www-form-urlencoded for POST transaction.', 'info', 'Connection');
                                if(this._isFormSubmit){
                                        this.resetFormState();
                                }
                        }

                        if(this._has_default_headers || this._has_http_headers){
                                this.setHeader(o);
                        }

                        this.handleReadyState(o, callback);
                        o.conn.send(postData || null);

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

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

                        return o;
                }
        },

  /**
   * @description This method creates and subscribes custom events,
   * specific to each transaction
   * @method initCustomEvents
   * @private
   * @static
   * @param {object} o The connection object
   * @param {callback} callback The user-defined callback object
   * @return {void}
   */
        initCustomEvents:function(o, callback)
        {
                // Enumerate through callback.customevents members and bind/subscribe
                // events that match in the _customEvents table.
                for(var prop in callback.customevents){
                        if(this._customEvents[prop][0]){
                                // Create the custom event
                                o[this._customEvents[prop][0]] = new YAHOO.util.CustomEvent(this._customEvents[prop][1], (callback.scope)?callback.scope:null);
                                YAHOO.log('Transaction-specific Custom Event ' + o[this._customEvents[prop][1]] + ' created.', 'info', 'Connection');

                                // Subscribe the custom event
                                o[this._customEvents[prop][0]].subscribe(callback.customevents[prop]);
                                YAHOO.log('Transaction-specific Custom Event ' + o[this._customEvents[prop][1]] + ' subscribed.', 'info', 'Connection');
                        }
                }
        },

  /**
   * @description This method serves as a timer that polls the XHR object's readyState
   * property during a transaction, instead of binding a callback to the
   * onreadystatechange event.  Upon readyState 4, handleTransactionResponse
   * will process the response, and the timer will be cleared.
   * @method handleReadyState
   * @private
   * @static
   * @param {object} o The connection object
   * @param {callback} callback The user-defined callback object
   * @return {void}
   */

    handleReadyState:function(o, callback)

    {
                var oConn = this;

                if(callback && callback.timeout){
                        this._timeOut[o.tId] = window.setTimeout(function(){ oConn.abort(o, callback, true); }, callback.timeout);
                }

                this._poll[o.tId] = window.setInterval(
                        function(){
                                if(o.conn && o.conn.readyState === 4){

                                        // Clear the polling interval for the transaction
                                        // and remove the reference from _poll.
                                        window.clearInterval(oConn._poll[o.tId]);
                                        delete oConn._poll[o.tId];

                                        if(callback && callback.timeout){
                                                window.clearTimeout(oConn._timeOut[o.tId]);
                                                delete oConn._timeOut[o.tId];
                                        }

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

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

                                        oConn.handleTransactionResponse(o, callback);
                                }
                        }
                ,this._polling_interval);
    },

  /**
   * @description This method attempts to interpret the server response and
   * determine whether the transaction was successful, or if an error or
   * exception was encountered.
   * @method handleTransactionResponse
   * @private
   * @static
   * @param {object} o The connection object
   * @param {object} callback The user-defined callback object
   * @param {boolean} isAbort Determines if the transaction was terminated via abort().
   * @return {void}
   */
    handleTransactionResponse:function(o, callback, isAbort)
    {
                // If no valid callback is provided, then do not process any callback handling.
                if(!callback){
                        this.releaseObject(o);
                        YAHOO.log('No callback object to process. Transaction complete.', 'info', 'Connection');
                        return;
                }

                var httpStatus, responseObject;

                try
                {
                        if(o.conn.status !== undefined && o.conn.status !== 0){
                                httpStatus = o.conn.status;
                        }
                        else{
                                httpStatus = 13030;
                        }
                }
                catch(e){

                         // 13030 is the custom code to indicate the condition -- in Mozilla/FF --
                         // when the o object's status and statusText properties are
                         // unavailable, and a query attempt throws an exception.
                        httpStatus = 13030;
                }

                if(httpStatus >= 200 && httpStatus < 300 || httpStatus === 1223){
                        responseObject = this.createResponseObject(o, callback.argument);
                        if(callback.success){
                                if(!callback.scope){
                                        callback.success(responseObject);
                                        YAHOO.log('Success callback. HTTP code is ' + httpStatus, 'info', 'Connection');
                                }
                                else{
                                        // If a scope property is defined, the callback will be fired from
                                        // the context of the object.
                                        callback.success.apply(callback.scope, [responseObject]);
                                        YAHOO.log('Success callback with scope. HTTP code is ' + httpStatus, 'info', 'Connection');
                                }
                        }

                        // Fire global custom event -- successEvent
                        this.successEvent.fire(responseObject);

                        if(o.successEvent){
                                // Fire transaction custom event -- successEvent
                                o.successEvent.fire(responseObject);
                        }
                }
                else{
                        switch(httpStatus){
                                // The following cases are wininet.dll error codes that may be encountered.
                                case 12002: // Server timeout
                                case 12029: // 12029 to 12031 correspond to dropped connections.
                                case 12030:
                                case 12031:
                                case 12152: // Connection closed by server.
                                case 13030: // See above comments for variable status.
                                        responseObject = this.createExceptionObject(o.tId, callback.argument, (isAbort?isAbort:false));
                                        if(callback.failure){
                                                if(!callback.scope){
                                                        callback.failure(responseObject);
                                                        YAHOO.log('Failure callback. Exception detected. Status code is ' + httpStatus, 'warn', 'Connection');
                                                }
                                                else{
                                                        callback.failure.apply(callback.scope, [responseObject]);
                                                        YAHOO.log('Failure callback with scope. Exception detected. Status code is ' + httpStatus, 'warn', 'Connection');
                                                }
                                        }
                                        break;
                                default:
                                        responseObject = this.createResponseObject(o, callback.argument);
                                        if(callback.failure){
                                                if(!callback.scope){
                                                        callback.failure(responseObject);
                                                        YAHOO.log('Failure callback. HTTP status code is ' + httpStatus, 'warn', 'Connection');
                                                }
                                                else{
                                                        callback.failure.apply(callback.scope, [responseObject]);
                                                        YAHOO.log('Failure callback with scope. HTTP status code is ' + httpStatus, 'warn', 'Connection');
                                                }
                                        }
                        }

                        // Fire global custom event -- failureEvent
                        this.failureEvent.fire(responseObject);

                        if(o.failureEvent){
                                // Fire transaction custom event -- failureEvent
                                o.failureEvent.fire(responseObject);
                        }

                }

                this.releaseObject(o);
                responseObject = null;
    },

  /**
   * @description This method evaluates the server response, creates and returns the results via
   * its properties.  Success and failure cases will differ in the response
   * object's property values.
   * @method createResponseObject
   * @private
   * @static
   * @param {object} o The connection object
   * @param {callbackArg} callbackArg The user-defined argument or arguments to be passed to the callback
   * @return {object}
   */
    createResponseObject:function(o, callbackArg)
    {
                var obj = {};
                var headerObj = {};

                try
                {
                        var headerStr = o.conn.getAllResponseHeaders();
                        var header = headerStr.split('\n');
                        for(var i=0; i<header.length; i++){
                                var delimitPos = header[i].indexOf(':');
                                if(delimitPos != -1){
                                        headerObj[header[i].substring(0,delimitPos)] = header[i].substring(delimitPos+2);
                                }
                        }
                }
                catch(e){}

                obj.tId = o.tId;
                // Normalize IE's response to HTTP 204 when Win error 1223.
                obj.status = (o.conn.status == 1223)?204:o.conn.status;
                // Normalize IE's statusText to "No Content" instead of "Unknown".
                obj.statusText = (o.conn.status == 1223)?"No Content":o.conn.statusText;
                obj.getResponseHeader = headerObj;
                obj.getAllResponseHeaders = headerStr;
                obj.responseText = o.conn.responseText;
                obj.responseXML = o.conn.responseXML;

                if(typeof callbackArg !== undefined){
                        obj.argument = callbackArg;
                }

                return obj;
    },

  /**
   * @description If a transaction cannot be completed due to dropped or closed connections,
   * there may be not be enough information to build a full response object.
   * The failure callback will be fired and this specific condition can be identified
   * by a status property value of 0.
   *
   * If an abort was successful, the status property will report a value of -1.
   *
   * @method createExceptionObject
   * @private
   * @static
   * @param {int} tId The Transaction Id
   * @param {callbackArg} callbackArg The user-defined argument or arguments to be passed to the callback
   * @param {boolean} isAbort Determines if the exception case is caused by a transaction abort
   * @return {object}
   */
    createExceptionObject:function(tId, callbackArg, isAbort)
    {
                var COMM_CODE = 0;
                var COMM_ERROR = 'communication failure';
                var ABORT_CODE = -1;
                var ABORT_ERROR = 'transaction aborted';

                var obj = {};

                obj.tId = tId;
                if(isAbort){
                        obj.status = ABORT_CODE;
                        obj.statusText = ABORT_ERROR;
                }
                else{
                        obj.status = COMM_CODE;
                        obj.statusText = COMM_ERROR;
                }

                if(callbackArg){
                        obj.argument = callbackArg;
                }

                return obj;
    },

  /**
   * @description Method that initializes the custom HTTP headers for the each transaction.
   * @method initHeader
   * @public
   * @static
   * @param {string} label The HTTP header label
   * @param {string} value The HTTP header value
   * @param {string} isDefault Determines if the specific header is a default header
   * automatically sent with each transaction.
   * @return {void}
   */
        initHeader:function(label,value,isDefault)
        {
                var headerObj = (isDefault)?this._default_headers:this._http_headers;

                if(headerObj[label] === undefined){
                        headerObj[label] = value;
                }
                else{
                        // Concatenate multiple values, comma-delimited,
                        // for the same header label,
                        headerObj[label] =  value + "," + headerObj[label];
                }

                if(isDefault){
                        this._has_default_headers = true;
                }
                else{
                        this._has_http_headers = true;
                }
        },


  /**
   * @description Accessor that sets the HTTP headers for each transaction.
   * @method setHeader
   * @private
   * @static
   * @param {object} o The connection object for the transaction.
   * @return {void}
   */
        setHeader:function(o)
        {
                if(this._has_default_headers){
                        for(var prop in this._default_headers){
                                if(YAHOO.lang.hasOwnProperty(this._default_headers, prop)){
                                        o.conn.setRequestHeader(prop, this._default_headers[prop]);
                                        YAHOO.log('Default HTTP header ' + prop + ' set with value of ' + this._default_headers[prop], 'info', 'Connection');
                                }
                        }
                }

                if(this._has_http_headers){
                        for(var prop in this._http_headers){
                                if(YAHOO.lang.hasOwnProperty(this._http_headers, prop)){
                                        o.conn.setRequestHeader(prop, this._http_headers[prop]);
                                        YAHOO.log('HTTP header ' + prop + ' set with value of ' + this._http_headers[prop], 'info', 'Connection');
                                }
                        }
                        delete this._http_headers;

                        this._http_headers = {};
                        this._has_http_headers = false;
                }
        },

  /**
   * @description Resets the default HTTP headers object
   * @method resetDefaultHeaders
   * @public
   * @static
   * @return {void}
   */
        resetDefaultHeaders:function(){
                delete this._default_headers;
                this._default_headers = {};
                this._has_default_headers = 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..
   */
        setForm:function(formId, isUpload, secureUri)
        {
                this.resetFormState();
                var oForm;
                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.
                        var io = this.createFrame(secureUri?secureUri:null);
                        // Set form reference and file upload properties to true.
                        this._isFormSubmit = true;
                        this._isFileUpload = true;
                        this._formNode = oForm;

                        return;

                }

                var oElement, oName, oValue, oDisabled;
                var hasSubmit = false;

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

                        // Do not submit fields that are disabled or
                        // do not have a name attribute value.
                        if(!oDisabled && oName)
                        {
                                switch(oElement.type)
                                {
                                        case 'select-one':
                                        case 'select-multiple':
                                                for(var j=0; j<oElement.options.length; j++){
                                                        if(oElement.options[j].selected){
                                                                if(window.ActiveXObject){
                                                                        this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oElement.options[j].attributes['value'].specified?oElement.options[j].value:oElement.options[j].text) + '&';
                                                                }
                                                                else{
                                                                        this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oElement.options[j].hasAttribute('value')?oElement.options[j].value:oElement.options[j].text) + '&';
                                                                }
                                                        }
                                                }
                                                break;
                                        case 'radio':
                                        case 'checkbox':
                                                if(oElement.checked){
                                                        this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(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){
                                                                this._sFormData += this._submitElementValue + '&';
                                                        }
                                                        else{
                                                                this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
                                                        }

                                                        hasSubmit = true;
                                                }
                                                break;
                                        default:
                                                this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
                                }
                        }
                }

                this._isFormSubmit = true;
                this._sFormData = this._sFormData.substr(0, this._sFormData.length - 1);

                YAHOO.log('Form initialized for transaction. HTML form POST message is: ' + this._sFormData, '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}
   */
        resetFormState:function(){
                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}
   */
        createFrame:function(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;
                var io;
                if(window.ActiveXObject){
                        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 if(typeof secureURI == 'string'){
                                // Deprecated
                                io.src = secureUri;
                        }
                }
                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.
   */
        appendPostData:function(postData)
        {
                var formElements = [];
                var postMessage = postData.split('&');
                for(var i=0; i < postMessage.length; i++){
                        var delimitPos = postMessage[i].indexOf('=');
                        if(delimitPos != -1){
                                formElements[i] = document.createElement('input');
                                formElements[i].type = 'hidden';
                                formElements[i].name = postMessage[i].substring(0,delimitPos);
                                formElements[i].value = 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}
   */
        uploadFile:function(o, callback, uri, postData){

                // Each iframe has an id prefix of "yuiIO" followed
                // by the unique transaction id.
                var frameId = 'yuiIO' + o.tId;
                var uploadEncoding = 'multipart/form-data';
                var io = document.getElementById(frameId);
                var oConn = this;

                // Track original HTML form attribute values.
                var 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(this._formNode.encoding){
                        // 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){
                        var oElements = this.appendPostData(postData);
                }

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

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

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

                // 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(var i=0; i < oElements.length; i++){
                                this._formNode.removeChild(oElements[i]);
                        }
                }

                // Restore HTML form attributes to their original
                // values prior to file upload.
                for(var 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.
                var 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);

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

                        var obj = {};
                        obj.tId = o.tId;
                        obj.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 -- completeEvent
                        oConn.uploadEvent.fire(obj);

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

                        if(YAHOO.util.Event){
                                YAHOO.util.Event.removeListener(io, "load", uploadCallback);
                        }
                        else if(window.detachEvent){
                                io.detachEvent('onload', uploadCallback);
                        }
                        else{
                                io.removeEventListener('load', uploadCallback, false);
                        }
                        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.
                if(YAHOO.util.Event){
                        YAHOO.util.Event.addListener(io, "load", uploadCallback);
                }
                else if(window.attachEvent){
                        io.attachEvent('onload', uploadCallback);
                }
                else{
                        io.addEventListener('load', uploadCallback, false);
                }
        },

  /**
   * @description Method to terminate a transaction, if it has not reached readyState 4.
   * @method abort
   * @public
   * @static
   * @param {object} o The connection object returned by asyncRequest.
   * @param {object} callback  User-defined callback object.
   * @param {string} isTimeout boolean to indicate if abort resulted from a callback timeout.
   * @return {boolean}
   */
        abort:function(o, callback, isTimeout)
        {
                var abortStatus;

                if(o.conn){
                        if(this.isCallInProgress(o)){
                                // Issue abort request
                                o.conn.abort();

                                window.clearInterval(this._poll[o.tId]);
                                delete this._poll[o.tId];

                                if(isTimeout){
                                        window.clearTimeout(this._timeOut[o.tId]);
                                        delete this._timeOut[o.tId];
                                }

                                abortStatus = true;
                        }
                }
                else if(o.isUpload === true){
                        var frameId = 'yuiIO' + o.tId;
                        var io = document.getElementById(frameId);

                        if(io){
                                // Destroy the iframe facilitating the transaction.
                                document.body.removeChild(io);
                                YAHOO.log('File upload iframe destroyed. Id is:' + frameId, 'info', 'Connection');

                                if(isTimeout){
                                        window.clearTimeout(this._timeOut[o.tId]);
                                        delete this._timeOut[o.tId];
                                }

                                abortStatus = true;
                        }
                }
                else{
                        abortStatus = false;
                }

                if(abortStatus === true){
                        // Fire global custom event -- abortEvent
                        this.abortEvent.fire(o);

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

                        this.handleTransactionResponse(o, callback, true);
                        YAHOO.log('Transaction ' + o.tId + ' aborted.', 'info', 'Connection');
                }
                else{
                        YAHOO.log('Transaction ' + o.tId + ' abort call failed.  Connection object no longer exists.', 'warn', 'Connection');
                }

                return abortStatus;
        },

  /**
   * Public method to check if the transaction is still being processed.
   *
   * @method isCallInProgress
   * @public
   * @static
   * @param {object} o The connection object returned by asyncRequest
   * @return {boolean}
   */
        isCallInProgress:function(o)
        {
                // if the XHR object assigned to the transaction has not been dereferenced,
                // then check its readyState status.  Otherwise, return false.
                if(o && o.conn){
                        return o.conn.readyState !== 4 && o.conn.readyState !== 0;
                }
                else if(o && o.isUpload === true){
                        var frameId = 'yuiIO' + o.tId;
                        return document.getElementById(frameId)?true:false;
                }
                else{
                        return false;
                }
        },

  /**
   * @description Dereference the XHR instance and the connection object after the transaction is completed.
   * @method releaseObject
   * @private
   * @static
   * @param {object} o The connection object
   * @return {void}
   */
        releaseObject:function(o)
        {
                //dereference the XHR instance.
                if(o.conn){
                        o.conn = null;
                }
                YAHOO.log('Connection object for transaction ' + o.tId + ' destroyed.', 'info', 'Connection');
                //dereference the connection object.
                o = null;
        }
};

YAHOO.register("connection", YAHOO.util.Connect, {version: "2.3.0", build: "442"});