/**
* 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>
/* eslint-disable-next-line vars-on-top */
var me = this,
/* eslint-disable-next-line max-len */
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);
}
});