Lift Framework example source code file (connection.js)
The Lift Framework connection.js source code
/*
Copyright (c) 2008, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
version: 2.6.0
*/
/**
* 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:[
'Microsoft.XMLHTTP',
'MSXML2.XMLHTTP.3.0',
'MSXML2.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 The default header used for POST transactions.
* @property _default_post_header
* @private
* @static
* @type boolean
*/
_default_post_header:'application/x-www-form-urlencoded; charset=UTF-8',
/**
* @description The default header used for transactions involving the
* use of HTML forms.
* @property _default_form_header
* @private
* @static
* @type boolean
*/
_default_form_header:'application/x-www-form-urlencoded',
/**
* @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.nodeName.toLowerCase() == 'input' && (obj.type && obj.type.toLowerCase() == '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);
},
/**
* @description Member to override the default POST header.
* @method setDefaultPostHeader
* @public
* @static
* @param {boolean} b Set and use default header - true or false .
* @return void
*/
setDefaultPostHeader:function(b)
{
if(typeof b == 'string'){
this._default_post_header = b;
}
else if(typeof b == 'boolean'){
this._use_default_post_header = b;
}
},
/**
* @description Member to override the default transaction header..
* @method setDefaultXhrHeader
* @public
* @static
* @param {boolean} b Set and use default header - true or false .
* @return void
*/
setDefaultXhrHeader:function(b)
{
if(typeof b == 'string'){
this._default_xhr_header = b;
}
else{
this._use_default_xhr_header = b;
}
},
/**
* @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;
}
},
/**
* @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 };
}
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 };
break;
}
catch(e2){}
}
}
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();
var args = (callback && callback.argument)?callback.argument:null;
if(!o){
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 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;
}
}
if(method.toUpperCase() == 'GET' && (callback && callback.cache === false)){
// If callback.cache is defined and set to false, a
// timestamp value will be added to the querystring.
uri += ((uri.indexOf('?') == -1)?'?':'&') + "rnd=" + new Date().valueOf().toString();
}
o.conn.open(method, uri, true);
// 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);
}
}
//If the transaction method is POST and the POST header value is set to true
//or a custom value, initalize the Content-Type header to this value.
if((method.toUpperCase() === 'POST' && this._use_default_post_header) && this._isFormSubmit === false){
this.initHeader('Content-Type', this._default_post_header);
}
//Initialize all default and custom HTTP headers,
if(this._has_default_headers || this._has_http_headers){
this.setHeader(o);
}
this.handleReadyState(o, callback);
o.conn.send(postData || '');
// Reset the HTML form data and state properties as
// soon as the data are submitted.
if(this._isFormSubmit === true){
this.resetFormState();
}
// Fire global custom event -- startEvent
this.startEvent.fire(o, args);
if(o.startEvent){
// Fire transaction custom event -- startEvent
o.startEvent.fire(o, args);
}
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)
{
var prop;
// Enumerate through callback.customevents members and bind/subscribe
// events that match in the _customEvents table.
for(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);
// Subscribe the custom event
o[this._customEvents[prop][0]].subscribe(callback.customevents[prop]);
}
}
},
/**
* @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;
var args = (callback && callback.argument)?callback.argument:null;
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, args);
if(o.completeEvent){
// Fire transaction custom event -- completeEvent
o.completeEvent.fire(o, args);
}
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)
{
var httpStatus, responseObject;
var args = (callback && callback.argument)?callback.argument:null;
try
{
if(o.conn.status !== undefined && o.conn.status !== 0){
httpStatus = o.conn.status;
}
else{
httpStatus = 13030;
}
}
catch(e){
// 13030 is a custom code to indicate the condition -- in Mozilla/FF --
// when the XHR 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, args);
if(callback && callback.success){
if(!callback.scope){
callback.success(responseObject);
}
else{
// If a scope property is defined, the callback will be fired from
// the context of the object.
callback.success.apply(callback.scope, [responseObject]);
}
}
// 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, args, (isAbort?isAbort:false));
if(callback && callback.failure){
if(!callback.scope){
callback.failure(responseObject);
}
else{
callback.failure.apply(callback.scope, [responseObject]);
}
}
break;
default:
responseObject = this.createResponseObject(o, args);
if(callback && callback.failure){
if(!callback.scope){
callback.failure(responseObject);
}
else{
callback.failure.apply(callback.scope, [responseObject]);
}
}
}
// 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(callbackArg){
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;
headerObj[label] = value;
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)
{
var prop;
if(this._has_default_headers){
for(prop in this._default_headers){
if(YAHOO.lang.hasOwnProperty(this._default_headers, prop)){
o.conn.setRequestHeader(prop, this._default_headers[prop]);
}
}
}
if(this._has_http_headers){
for(prop in this._http_headers){
if(YAHOO.lang.hasOwnProperty(this._http_headers, prop)){
o.conn.setRequestHeader(prop, this._http_headers[prop]);
}
}
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)
{
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{
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;
}
else{
data[item++] = oName + oValue;
}
hasSubmit = true;
}
break;
default:
data[item++] = oName + oValue;
}
}
}
this._isFormSubmit = true;
this._sFormData = data.join('&');
this.initHeader('Content-Type', this._default_form_header);
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(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);
},
/**
* @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 = [],
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}
*/
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,
uploadEncoding = 'multipart/form-data',
io = document.getElementById(frameId),
oConn = this,
args = (callback && callback.argument)?callback.argument:null,
oElements,i,prop,obj;
// 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(YAHOO.env.ua.ie){
// 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.
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, 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);
}
else{
callback.upload.apply(callback.scope, [obj]);
}
}
// Fire global custom event -- uploadEvent
oConn.uploadEvent.fire(obj);
if(o.uploadEvent){
// Fire transaction custom event -- uploadEvent
o.uploadEvent.fire(obj);
}
YAHOO.util.Event.removeListener(io, "load", uploadCallback);
setTimeout(
function(){
document.body.removeChild(io);
oConn.releaseObject(o);
}, 100);
};
// Bind the onload handler to the iframe to detect the file upload response.
YAHOO.util.Event.addListener(io, "load", uploadCallback);
},
/**
* @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;
var args = (callback && callback.argument)?callback.argument:null;
if(o && 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 && o.isUpload === true){
var frameId = 'yuiIO' + o.tId;
var io = document.getElementById(frameId);
if(io){
// Remove all listeners on the iframe prior to
// its destruction.
YAHOO.util.Event.removeListener(io, "load");
// Destroy the iframe facilitating the transaction.
document.body.removeChild(io);
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, args);
if(o.abortEvent){
// Fire transaction custom event -- abortEvent
o.abortEvent.fire(o, args);
}
this.handleTransactionResponse(o, callback, true);
}
return abortStatus;
},
/**
* @description Determines 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)
{
if(o && o.conn){
//dereference the XHR instance.
o.conn = null;
//dereference the connection object.
o = null;
}
}
};
YAHOO.register("connection", YAHOO.util.Connect, {version: "2.6.0", build: "1321"});
Other Lift Framework examples (source code examples)Here is a short list of links related to this Lift Framework connection.js source code file: |
The search page
Other Lift Framework source code examples at this package level
Click here to learn more about this project
