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