/*!
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* Ext JS Library 3.1.0
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* Copyright(c) 2006-2009 Ext JS, LLC
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* licensing@extjs.com
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* http://www.extjs.com/license
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*/
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/**
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* @class Ext.data.ScriptTagProxy
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* @extends Ext.data.DataProxy
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* An implementation of Ext.data.DataProxy that reads a data object from a URL which may be in a domain
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* other than the originating domain of the running page.<br>
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* <p>
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* <b>Note that if you are retrieving data from a page that is in a domain that is NOT the same as the originating domain
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* of the running page, you must use this class, rather than HttpProxy.</b><br>
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* <p>
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* The content passed back from a server resource requested by a ScriptTagProxy <b>must</b> be executable JavaScript
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* source code because it is used as the source inside a <script> tag.<br>
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* <p>
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* In order for the browser to process the returned data, the server must wrap the data object
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* with a call to a callback function, the name of which is passed as a parameter by the ScriptTagProxy.
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* Below is a Java example for a servlet which returns data for either a ScriptTagProxy, or an HttpProxy
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* depending on whether the callback name was passed:
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* <p>
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* <pre><code>
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boolean scriptTag = false;
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String cb = request.getParameter("callback");
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if (cb != null) {
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scriptTag = true;
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response.setContentType("text/javascript");
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} else {
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response.setContentType("application/x-json");
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}
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Writer out = response.getWriter();
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if (scriptTag) {
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out.write(cb + "(");
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}
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out.print(dataBlock.toJsonString());
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if (scriptTag) {
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out.write(");");
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}
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</code></pre>
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* <p>Below is a PHP example to do the same thing:</p><pre><code>
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$callback = $_REQUEST['callback'];
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// Create the output object.
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$output = array('a' => 'Apple', 'b' => 'Banana');
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//start output
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if ($callback) {
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header('Content-Type: text/javascript');
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echo $callback . '(' . json_encode($output) . ');';
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} else {
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header('Content-Type: application/x-json');
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echo json_encode($output);
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}
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</code></pre>
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*
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* @constructor
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* @param {Object} config A configuration object.
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*/
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Ext.data.ScriptTagProxy = function(config){
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Ext.apply(this, config);
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Ext.data.ScriptTagProxy.superclass.constructor.call(this, config);
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this.head = document.getElementsByTagName("head")[0];
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/**
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* @event loadexception
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* <b>Deprecated</b> in favor of 'exception' event.
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* Fires if an exception occurs in the Proxy during data loading. This event can be fired for one of two reasons:
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* <ul><li><b>The load call timed out.</b> This means the load callback did not execute within the time limit
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* specified by {@link #timeout}. In this case, this event will be raised and the
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* fourth parameter (read error) will be null.</li>
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* <li><b>The load succeeded but the reader could not read the response.</b> This means the server returned
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* data, but the configured Reader threw an error while reading the data. In this case, this event will be
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* raised and the caught error will be passed along as the fourth parameter of this event.</li></ul>
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* Note that this event is also relayed through {@link Ext.data.Store}, so you can listen for it directly
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* on any Store instance.
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* @param {Object} this
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* @param {Object} options The loading options that were specified (see {@link #load} for details). If the load
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* call timed out, this parameter will be null.
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* @param {Object} arg The callback's arg object passed to the {@link #load} function
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* @param {Error} e The JavaScript Error object caught if the configured Reader could not read the data.
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* If the remote request returns success: false, this parameter will be null.
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*/
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};
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Ext.data.ScriptTagProxy.TRANS_ID = 1000;
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Ext.extend(Ext.data.ScriptTagProxy, Ext.data.DataProxy, {
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/**
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* @cfg {String} url The URL from which to request the data object.
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*/
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/**
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* @cfg {Number} timeout (optional) The number of milliseconds to wait for a response. Defaults to 30 seconds.
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*/
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timeout : 30000,
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/**
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* @cfg {String} callbackParam (Optional) The name of the parameter to pass to the server which tells
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* the server the name of the callback function set up by the load call to process the returned data object.
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* Defaults to "callback".<p>The server-side processing must read this parameter value, and generate
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* javascript output which calls this named function passing the data object as its only parameter.
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*/
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callbackParam : "callback",
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/**
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* @cfg {Boolean} nocache (optional) Defaults to true. Disable caching by adding a unique parameter
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* name to the request.
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*/
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nocache : true,
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/**
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* HttpProxy implementation of DataProxy#doRequest
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* @param {String} action
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* @param {Ext.data.Record/Ext.data.Record[]} rs If action is <tt>read</tt>, rs will be null
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* @param {Object} params An object containing properties which are to be used as HTTP parameters
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* for the request to the remote server.
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* @param {Ext.data.DataReader} reader The Reader object which converts the data
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* object into a block of Ext.data.Records.
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* @param {Function} callback The function into which to pass the block of Ext.data.Records.
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* The function must be passed <ul>
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* <li>The Record block object</li>
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* <li>The "arg" argument from the load function</li>
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* <li>A boolean success indicator</li>
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* </ul>
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* @param {Object} scope The scope (<code>this</code> reference) in which the callback function is executed. Defaults to the browser window.
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* @param {Object} arg An optional argument which is passed to the callback as its second parameter.
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*/
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doRequest : function(action, rs, params, reader, callback, scope, arg) {
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var p = Ext.urlEncode(Ext.apply(params, this.extraParams));
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var url = this.buildUrl(action, rs);
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if (!url) {
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throw new Ext.data.Api.Error('invalid-url', url);
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}
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url = Ext.urlAppend(url, p);
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if(this.nocache){
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url = Ext.urlAppend(url, '_dc=' + (new Date().getTime()));
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}
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var transId = ++Ext.data.ScriptTagProxy.TRANS_ID;
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var trans = {
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id : transId,
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action: action,
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cb : "stcCallback"+transId,
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scriptId : "stcScript"+transId,
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params : params,
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arg : arg,
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url : url,
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callback : callback,
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scope : scope,
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reader : reader
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};
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window[trans.cb] = this.createCallback(action, rs, trans);
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url += String.format("&{0}={1}", this.callbackParam, trans.cb);
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if(this.autoAbort !== false){
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this.abort();
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}
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trans.timeoutId = this.handleFailure.defer(this.timeout, this, [trans]);
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var script = document.createElement("script");
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script.setAttribute("src", url);
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script.setAttribute("type", "text/javascript");
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script.setAttribute("id", trans.scriptId);
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this.head.appendChild(script);
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this.trans = trans;
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},
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// @private createCallback
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createCallback : function(action, rs, trans) {
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var self = this;
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return function(res) {
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self.trans = false;
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self.destroyTrans(trans, true);
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if (action === Ext.data.Api.actions.read) {
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self.onRead.call(self, action, trans, res);
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} else {
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self.onWrite.call(self, action, trans, res, rs);
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}
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};
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},
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/**
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* Callback for read actions
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* @param {String} action [Ext.data.Api.actions.create|read|update|destroy]
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* @param {Object} trans The request transaction object
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* @param {Object} res The server response
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* @protected
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*/
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onRead : function(action, trans, res) {
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var result;
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try {
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result = trans.reader.readRecords(res);
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}catch(e){
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// @deprecated: fire loadexception
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this.fireEvent("loadexception", this, trans, res, e);
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this.fireEvent('exception', this, 'response', action, trans, res, e);
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trans.callback.call(trans.scope||window, null, trans.arg, false);
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return;
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}
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if (result.success === false) {
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// @deprecated: fire old loadexception for backwards-compat.
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this.fireEvent('loadexception', this, trans, res);
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this.fireEvent('exception', this, 'remote', action, trans, res, null);
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} else {
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this.fireEvent("load", this, res, trans.arg);
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}
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trans.callback.call(trans.scope||window, result, trans.arg, result.success);
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},
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/**
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* Callback for write actions
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* @param {String} action [Ext.data.Api.actions.create|read|update|destroy]
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* @param {Object} trans The request transaction object
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* @param {Object} res The server response
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* @protected
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*/
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onWrite : function(action, trans, response, rs) {
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var reader = trans.reader;
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try {
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// though we already have a response object here in STP, run through readResponse to catch any meta-data exceptions.
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var res = reader.readResponse(action, response);
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} catch (e) {
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this.fireEvent('exception', this, 'response', action, trans, res, e);
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trans.callback.call(trans.scope||window, null, res, false);
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return;
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}
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if(!res.success === true){
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this.fireEvent('exception', this, 'remote', action, trans, res, rs);
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trans.callback.call(trans.scope||window, null, res, false);
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return;
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}
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this.fireEvent("write", this, action, res.data, res, rs, trans.arg );
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trans.callback.call(trans.scope||window, res.data, res, true);
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},
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// private
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isLoading : function(){
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return this.trans ? true : false;
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},
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/**
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* Abort the current server request.
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*/
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abort : function(){
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if(this.isLoading()){
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this.destroyTrans(this.trans);
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}
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},
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// private
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destroyTrans : function(trans, isLoaded){
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this.head.removeChild(document.getElementById(trans.scriptId));
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clearTimeout(trans.timeoutId);
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if(isLoaded){
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window[trans.cb] = undefined;
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try{
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delete window[trans.cb];
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}catch(e){}
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}else{
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// if hasn't been loaded, wait for load to remove it to prevent script error
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window[trans.cb] = function(){
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window[trans.cb] = undefined;
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try{
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delete window[trans.cb];
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}catch(e){}
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};
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}
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},
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// private
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handleFailure : function(trans){
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this.trans = false;
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this.destroyTrans(trans, false);
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if (trans.action === Ext.data.Api.actions.read) {
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// @deprecated firing loadexception
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this.fireEvent("loadexception", this, null, trans.arg);
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}
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this.fireEvent('exception', this, 'response', trans.action, {
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response: null,
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options: trans.arg
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});
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trans.callback.call(trans.scope||window, null, trans.arg, false);
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},
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// inherit docs
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destroy: function(){
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this.abort();
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Ext.data.ScriptTagProxy.superclass.destroy.call(this);
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}
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});
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