/** * This class is used to create JSONP requests. JSONP is a mechanism that allows for making * requests for data cross domain. JSONP is basically a `<script>` node with the source of the url executing * a function that was created by Ext.data.JsonP. Once the resource has loaded, the `<script>` node will be destroyed. * * If you have a request such as: * * Ext.data.JsonP.request({ * url : 'foo.php' * }); * * Ext.data.JsonP will create a `<script>` node in the `<head>` with the `src` attribute pointing to * `foo.php?callback=Ext.data.JsonP.callback1`. The `foo.php` script will have to detect the `callback` URL parameter * and return valid JavaScript: * * Ext.data.JsonP.callback1({"foo":"bar"}); * * A simple PHP example would look like: * * <?php * * $data = array('foo' => 'bar'); * * if (!empty($_REQUEST['callback'])) { * header('Content-Type: application/javascript'); * echo $_REQUEST['callback'] . '('; * } * * echo json_encode($data); * * if (!empty($_REQUEST['callback']) { * echo ');'; * } * * ?> * * More information is available <a href="http://en.wikipedia.org/wiki/JSONP">here</a>. You can also use <a href="http://www.jsonplint.com">JSONPLint</a> to test your JSONP. */Ext.define('Ext.data.JsonP', { singleton: true, /** * Number of requests done so far. * @private */ requestCount: 0, /** * Hash of pending requests. * @private */ requests: {}, /** * @property timeout * @type Number * A default timeout for any JsonP requests. If the request has not completed in this time the * failure callback will be fired. The timeout is in ms. Defaults to <tt>30000</tt>. */ timeout: 30000, /** * @property disableCaching * @type Boolean * True to add a unique cache-buster param to requests. Defaults to <tt>true</tt>. */ disableCaching: true, /** * @property disableCachingParam * @type String * Change the parameter which is sent went disabling caching through a cache buster. Defaults to <tt>'_dc'</tt>. */ disableCachingParam: '_dc', /** * @property callbackKey * @type String * Specifies the GET parameter that will be sent to the server containing the function name to be executed when * the request completes. Defaults to <tt>callback</tt>. Thus, a common request will be in the form of * url?callback=Ext.data.JsonP.callback1 */ callbackKey: 'callback', /** * Makes a JSONP request. * @param {Object} options An object which may contain the following properties. Note that options will * take priority over any defaults that are specified in the class. * @param {String} options.url The URL to request. * @param {Object} options.params (optional) An object containing a series of key value pairs that * will be sent along with the request. * @param {Number} options.timeout (optional) See {@link #timeout} * @param {String} options.callbackKey (optional) See {@link #callbackKey} * @param {String} options.callbackName (optional) The function name to use for this request. By * default this name will be auto-generated: Ext.data.JsonP.callback1, Ext.data.JsonP.callback2, etc. * Setting this option to "my_name" will force the function name to be Ext.data.JsonP.my_name. Use * this if you want deterministic behavior, but be careful - the callbackName should be different * in each JsonP request that you make. * @param {Boolean} options.disableCaching (optional) See {@link #disableCaching} * @param {String} options.disableCachingParam (optional) See {@link #disableCachingParam} * @param {Function} options.success (optional) A function to execute if the request succeeds. * @param {Function} options.failure (optional) A function to execute if the request fails. * @param {Function} options.callback (optional) A function to execute when the request completes, * whether it is a success or failure. * @param {Object} options.scope (optional) The scope in which to execute the callbacks: The "this" * object for the callback function. Defaults to the browser window. * * @return {Object} request An object containing the request details. */ request: function(options) { options = Ext.apply({}, options); //<debug> if (!options.url) { Ext.raise('A url must be specified for a JSONP request.'); } //</debug> var me = this, disableCaching = Ext.isDefined(options.disableCaching) ? options.disableCaching : me.disableCaching, cacheParam = options.disableCachingParam || me.disableCachingParam, id = ++me.requestCount, callbackName = options.callbackName || 'callback' + id, callbackKey = options.callbackKey || me.callbackKey, timeout = Ext.isDefined(options.timeout) ? options.timeout : me.timeout, params = Ext.apply({}, options.params), url = options.url, name = Ext.name, request, script; // Add cachebuster param unless it has already been done if (disableCaching && !params[cacheParam]) { params[cacheParam] = Ext.Date.now(); } options.params = params; params[callbackKey] = name + '.data.JsonP.' + callbackName; script = me.createScript(url, params, options); me.requests[id] = request = { url: url, params: params, script: script, id: id, scope: options.scope, success: options.success, failure: options.failure, callback: options.callback, callbackKey: callbackKey, callbackName: callbackName }; if (timeout > 0) { request.timeout = Ext.defer(me.handleTimeout, timeout, me, [request]); } me.setupErrorHandling(request); me[callbackName] = me.bindResponse(request); me.loadScript(request); return request; }, bindResponse: function (request) { var me = this; return function (result) { Ext.elevate(function () { me.handleResponse(result, request); }); }; }, /** * Abort a request. If the request parameter is not specified all open requests will * be aborted. * @param {Object/String} request (Optional) The request to abort */ abort: function(request){ var me = this, requests = me.requests, key; if (request) { if (!request.id) { request = requests[request]; } me.handleAbort(request); } else { for (key in requests) { if (requests.hasOwnProperty(key)) { me.abort(requests[key]); } } } }, /** * Sets up error handling for the script * @private * @param {Object} request The request */ setupErrorHandling: function(request){ request.script.onerror = Ext.bind(this.handleError, this, [request]); }, /** * Handles any aborts when loading the script * @private * @param {Object} request The request */ handleAbort: function(request){ request.errorType = 'abort'; this.handleResponse(null, request); }, /** * Handles any script errors when loading the script * @private * @param {Object} request The request */ handleError: function(request){ request.errorType = 'error'; this.handleResponse(null, request); }, /** * Cleans up anu script handling errors * @private * @param {Object} request The request */ cleanupErrorHandling: function(request){ request.script.onerror = null; }, /** * Handle any script timeouts * @private * @param {Object} request The request */ handleTimeout: function(request){ request.errorType = 'timeout'; this.handleResponse(null, request); }, /** * Handle a successful response * @private * @param {Object} result The result from the request * @param {Object} request The request */ handleResponse: function(result, request){ var success = true; Ext.undefer(request.timeout); delete this[request.callbackName]; delete this.requests[request.id]; this.cleanupErrorHandling(request); Ext.fly(request.script).destroy(); if (request.errorType) { success = false; Ext.callback(request.failure, request.scope, [request.errorType]); } else { Ext.callback(request.success, request.scope, [result]); } Ext.callback(request.callback, request.scope, [success, result, request.errorType]); }, /** * Create the script tag given the specified url, params and options. The options * parameter is passed to allow an override to access it. * @private * @param {String} url The url of the request * @param {Object} params Any extra params to be sent * @param {Object} options The object passed to {@link #request}. */ createScript: function(url, params, options) { var script = document.createElement('script'); script.setAttribute("src", Ext.urlAppend(url, Ext.Object.toQueryString(params))); script.setAttribute("async", true); script.setAttribute("type", "text/javascript"); return script; }, /** * Loads the script for the given request by appending it to the HEAD element. This is * its own method so that users can override it (as well as {@link #createScript}). * @private * @param request The request object. */ loadScript: function (request) { Ext.getHead().appendChild(request.script); }});