3 * Copyright(c) 2006-2010 Ext JS, Inc.
5 * http://www.extjs.com/license
8 * @class Ext.data.ScriptTagProxy
9 * @extends Ext.data.DataProxy
10 * An implementation of Ext.data.DataProxy that reads a data object from a URL which may be in a domain
11 * other than the originating domain of the running page.<br>
13 * <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
14 * of the running page, you must use this class, rather than HttpProxy.</b><br>
16 * The content passed back from a server resource requested by a ScriptTagProxy <b>must</b> be executable JavaScript
17 * source code because it is used as the source inside a <script> tag.<br>
19 * In order for the browser to process the returned data, the server must wrap the data object
20 * with a call to a callback function, the name of which is passed as a parameter by the ScriptTagProxy.
21 * Below is a Java example for a servlet which returns data for either a ScriptTagProxy, or an HttpProxy
22 * depending on whether the callback name was passed:
25 boolean scriptTag = false;
26 String cb = request.getParameter("callback");
29 response.setContentType("text/javascript");
31 response.setContentType("application/x-json");
33 Writer out = response.getWriter();
37 out.print(dataBlock.toJsonString());
42 * <p>Below is a PHP example to do the same thing:</p><pre><code>
43 $callback = $_REQUEST['callback'];
45 // Create the output object.
46 $output = array('a' => 'Apple', 'b' => 'Banana');
50 header('Content-Type: text/javascript');
51 echo $callback . '(' . json_encode($output) . ');';
53 header('Content-Type: application/x-json');
54 echo json_encode($output);
57 * <p>Below is the ASP.Net code to do the same thing:</p><pre><code>
58 String jsonString = "{success: true}";
59 String cb = Request.Params.Get("callback");
60 String responseString = "";
61 if (!String.IsNullOrEmpty(cb)) {
62 responseString = cb + "(" + jsonString + ")";
64 responseString = jsonString;
66 Response.Write(responseString);
70 * @param {Object} config A configuration object.
72 Ext.data.ScriptTagProxy = function(config){
73 Ext.apply(this, config);
75 Ext.data.ScriptTagProxy.superclass.constructor.call(this, config);
77 this.head = document.getElementsByTagName("head")[0];
80 * @event loadexception
81 * <b>Deprecated</b> in favor of 'exception' event.
82 * Fires if an exception occurs in the Proxy during data loading. This event can be fired for one of two reasons:
83 * <ul><li><b>The load call timed out.</b> This means the load callback did not execute within the time limit
84 * specified by {@link #timeout}. In this case, this event will be raised and the
85 * fourth parameter (read error) will be null.</li>
86 * <li><b>The load succeeded but the reader could not read the response.</b> This means the server returned
87 * data, but the configured Reader threw an error while reading the data. In this case, this event will be
88 * raised and the caught error will be passed along as the fourth parameter of this event.</li></ul>
89 * Note that this event is also relayed through {@link Ext.data.Store}, so you can listen for it directly
90 * on any Store instance.
91 * @param {Object} this
92 * @param {Object} options The loading options that were specified (see {@link #load} for details). If the load
93 * call timed out, this parameter will be null.
94 * @param {Object} arg The callback's arg object passed to the {@link #load} function
95 * @param {Error} e The JavaScript Error object caught if the configured Reader could not read the data.
96 * If the remote request returns success: false, this parameter will be null.
100 Ext.data.ScriptTagProxy.TRANS_ID = 1000;
102 Ext.extend(Ext.data.ScriptTagProxy, Ext.data.DataProxy, {
104 * @cfg {String} url The URL from which to request the data object.
107 * @cfg {Number} timeout (optional) The number of milliseconds to wait for a response. Defaults to 30 seconds.
111 * @cfg {String} callbackParam (Optional) The name of the parameter to pass to the server which tells
112 * the server the name of the callback function set up by the load call to process the returned data object.
113 * Defaults to "callback".<p>The server-side processing must read this parameter value, and generate
114 * javascript output which calls this named function passing the data object as its only parameter.
116 callbackParam : "callback",
118 * @cfg {Boolean} nocache (optional) Defaults to true. Disable caching by adding a unique parameter
119 * name to the request.
124 * HttpProxy implementation of DataProxy#doRequest
125 * @param {String} action
126 * @param {Ext.data.Record/Ext.data.Record[]} rs If action is <tt>read</tt>, rs will be null
127 * @param {Object} params An object containing properties which are to be used as HTTP parameters
128 * for the request to the remote server.
129 * @param {Ext.data.DataReader} reader The Reader object which converts the data
130 * object into a block of Ext.data.Records.
131 * @param {Function} callback The function into which to pass the block of Ext.data.Records.
132 * The function must be passed <ul>
133 * <li>The Record block object</li>
134 * <li>The "arg" argument from the load function</li>
135 * <li>A boolean success indicator</li>
137 * @param {Object} scope The scope (<code>this</code> reference) in which the callback function is executed. Defaults to the browser window.
138 * @param {Object} arg An optional argument which is passed to the callback as its second parameter.
140 doRequest : function(action, rs, params, reader, callback, scope, arg) {
141 var p = Ext.urlEncode(Ext.apply(params, this.extraParams));
143 var url = this.buildUrl(action, rs);
145 throw new Ext.data.Api.Error('invalid-url', url);
147 url = Ext.urlAppend(url, p);
150 url = Ext.urlAppend(url, '_dc=' + (new Date().getTime()));
152 var transId = ++Ext.data.ScriptTagProxy.TRANS_ID;
156 cb : "stcCallback"+transId,
157 scriptId : "stcScript"+transId,
165 window[trans.cb] = this.createCallback(action, rs, trans);
166 url += String.format("&{0}={1}", this.callbackParam, trans.cb);
167 if(this.autoAbort !== false){
171 trans.timeoutId = this.handleFailure.defer(this.timeout, this, [trans]);
173 var script = document.createElement("script");
174 script.setAttribute("src", url);
175 script.setAttribute("type", "text/javascript");
176 script.setAttribute("id", trans.scriptId);
177 this.head.appendChild(script);
182 // @private createCallback
183 createCallback : function(action, rs, trans) {
185 return function(res) {
187 self.destroyTrans(trans, true);
188 if (action === Ext.data.Api.actions.read) {
189 self.onRead.call(self, action, trans, res);
191 self.onWrite.call(self, action, trans, res, rs);
196 * Callback for read actions
197 * @param {String} action [Ext.data.Api.actions.create|read|update|destroy]
198 * @param {Object} trans The request transaction object
199 * @param {Object} res The server response
202 onRead : function(action, trans, res) {
205 result = trans.reader.readRecords(res);
207 // @deprecated: fire loadexception
208 this.fireEvent("loadexception", this, trans, res, e);
210 this.fireEvent('exception', this, 'response', action, trans, res, e);
211 trans.callback.call(trans.scope||window, null, trans.arg, false);
214 if (result.success === false) {
215 // @deprecated: fire old loadexception for backwards-compat.
216 this.fireEvent('loadexception', this, trans, res);
218 this.fireEvent('exception', this, 'remote', action, trans, res, null);
220 this.fireEvent("load", this, res, trans.arg);
222 trans.callback.call(trans.scope||window, result, trans.arg, result.success);
225 * Callback for write actions
226 * @param {String} action [Ext.data.Api.actions.create|read|update|destroy]
227 * @param {Object} trans The request transaction object
228 * @param {Object} res The server response
231 onWrite : function(action, trans, response, rs) {
232 var reader = trans.reader;
234 // though we already have a response object here in STP, run through readResponse to catch any meta-data exceptions.
235 var res = reader.readResponse(action, response);
237 this.fireEvent('exception', this, 'response', action, trans, res, e);
238 trans.callback.call(trans.scope||window, null, res, false);
241 if(!res.success === true){
242 this.fireEvent('exception', this, 'remote', action, trans, res, rs);
243 trans.callback.call(trans.scope||window, null, res, false);
246 this.fireEvent("write", this, action, res.data, res, rs, trans.arg );
247 trans.callback.call(trans.scope||window, res.data, res, true);
251 isLoading : function(){
252 return this.trans ? true : false;
256 * Abort the current server request.
259 if(this.isLoading()){
260 this.destroyTrans(this.trans);
265 destroyTrans : function(trans, isLoaded){
266 this.head.removeChild(document.getElementById(trans.scriptId));
267 clearTimeout(trans.timeoutId);
269 window[trans.cb] = undefined;
271 delete window[trans.cb];
274 // if hasn't been loaded, wait for load to remove it to prevent script error
275 window[trans.cb] = function(){
276 window[trans.cb] = undefined;
278 delete window[trans.cb];
285 handleFailure : function(trans){
287 this.destroyTrans(trans, false);
288 if (trans.action === Ext.data.Api.actions.read) {
289 // @deprecated firing loadexception
290 this.fireEvent("loadexception", this, null, trans.arg);
293 this.fireEvent('exception', this, 'response', trans.action, {
297 trans.callback.call(trans.scope||window, null, trans.arg, false);
303 Ext.data.ScriptTagProxy.superclass.destroy.call(this);