/*
Copyright (c) 2006, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
*/
/**
* 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
*/
/**
* 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_header:{},
/**
* @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 any client HTTP headers sent for POST
* transactions.
* @property _default_post_header
* @private
* @static
* @type boolean
*/
_default_post_header:'application/x-www-form-urlencoded',
/**
* @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 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 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;
},
/**
* @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(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()
{
var o;
var tId = this._transaction_id;
try
{
o = this.createXhrObject(tId);
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.getConnectionObject();
if(!o){
return null;
}
else{
if(this._isFormSubmit){
if(this._isFileUpload){
this.uploadFile(o.tId, callback, uri, postData);
this.releaseObject(o);
return;
}
//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 == '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 == '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);
if(this._isFormSubmit || (postData && this._use_default_post_header)){
this.initHeader('Content-Type', this._default_post_header);
if(this._isFormSubmit){
this.resetFormState();
}
}
if(this._has_http_headers){
this.setHeader(o);
}
this.handleReadyState(o, callback);
o.conn.send(postData || null);
return o;
}
},
/**
* @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){
window.clearInterval(oConn._poll[o.tId]);
delete oConn._poll[o.tId];
if(callback && callback.timeout){
delete oConn._timeOut[o.tId];
}
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 sser-defined callback object
* @param {boolean} isAbort Determines if the transaction was aborted.
* @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);
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){
try
{
responseObject = this.createResponseObject(o, callback.argument);
if(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]);
}
}
}
catch(e){}
}
else{
try
{
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);
}
else{
callback.failure.apply(callback.scope, [responseObject]);
}
}
break;
default:
responseObject = this.createResponseObject(o, callback.argument);
if(callback.failure){
if(!callback.scope){
callback.failure(responseObject);
}
else{
callback.failure.apply(callback.scope, [responseObject]);
}
}
}
}
catch(e){}
}
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;
obj.status = o.conn.status;
obj.statusText = 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 Public method that stores the custom HTTP headers for each transaction.
* @method initHeader
* @public
* @static
* @param {string} label The HTTP header label
* @param {string} value The HTTP header value
* @return {void}
*/
initHeader:function(label,value)
{
if(this._http_header[label] === undefined){
this._http_header[label] = value;
}
else{
// Concatenate multiple values, comma-delimited,
// for the same header label,
this._http_header[label] = value + "," + this._http_header[label];
}
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)
{
for(var prop in this._http_header){
if(this._http_header.hasOwnProperty(prop)){
o.conn.setRequestHeader(prop, this._http_header[prop]);
}
}
delete this._http_header;
this._http_header = {};
this._has_http_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 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 {string} optional boolean to indicate SSL environment.
* @param {string || boolean} optional qualified path of iframe resource for SSL in IE.
* @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 but 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;
}
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){
this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
hasSubmit = true;
}
break;
default:
this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
break;
}
}
}
this._isFormSubmit = true;
this._sFormData = this._sFormData.substr(0, this._sFormData.length - 1);
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} secureUri 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;
if(window.ActiveXObject){
var 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{
var 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 = [];
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, including files/attachments, to the
* iframe created in createFrame.
* @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.
* @return {void}
*/
uploadFile:function(id, callback, uri, postData){
// Each iframe has an id prefix of "yuiIO" followed
// by the unique transaction id.
var frameId = 'yuiIO' + id;
var io = document.getElementById(frameId);
// Initialize the HTML form properties in case they are
// not defined in the HTML form.
this._formNode.action = uri;
this._formNode.method = 'POST';
this._formNode.target = frameId;
if(this._formNode.encoding){
// IE does not respect property enctype for HTML forms.
// Instead use property encoding.
this._formNode.encoding = 'multipart/form-data';
}
else{
this._formNode.enctype = 'multipart/form-data';
}
if(postData){
var oElements = this.appendPostData(postData);
}
this._formNode.submit();
if(oElements && oElements.length > 0){
try
{
for(var i=0; i < oElements.length; i++){
this._formNode.removeChild(oElements[i]);
}
}
catch(e){}
}
// Reset HTML form status 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()
{
var obj = {};
obj.tId = id;
obj.argument = callback.argument;
try
{
obj.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
obj.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
}
catch(e){}
if(callback.upload){
if(!callback.scope){
callback.upload(obj);
}
else{
callback.upload.apply(callback.scope, [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); }, 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 was a timeout.
* @return {boolean}
*/
abort:function(o, callback, isTimeout)
{
if(this.isCallInProgress(o)){
o.conn.abort();
window.clearInterval(this._poll[o.tId]);
delete this._poll[o.tId];
if(isTimeout){
delete this._timeOut[o.tId];
}
this.handleTransactionResponse(o, callback, true);
return true;
}
else{
return false;
}
},
/**
* 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.conn){
return o.conn.readyState != 4 && o.conn.readyState != 0;
}
else{
//The XHR object has been destroyed.
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.
o.conn = null;
//dereference the connection object.
o = null;
}
};