source: trunk/admin/inc/ckeditor/_source/plugins/ajax/plugin.js@ 428

/*
Copyright (c) 2003-2011, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

/**
 * @fileOverview Defines the {@link CKEDITOR.ajax} object, which holds ajax methods for
 *              data loading.
 */

(function()
{
        CKEDITOR.plugins.add( 'ajax',
                {
                        requires : [ 'xml' ]
                });

        /**
         * Ajax methods for data loading.
         * @namespace
         * @example
         */
        CKEDITOR.ajax = (function()
        {
                var createXMLHttpRequest = function()
                {
                        // In IE, using the native XMLHttpRequest for local files may throw
                        // "Access is Denied" errors.
                        if ( !CKEDITOR.env.ie || location.protocol != 'file:' )
                                try { return new XMLHttpRequest(); } catch(e) {}

                        try { return new ActiveXObject( 'Msxml2.XMLHTTP' ); } catch (e) {}
                        try { return new ActiveXObject( 'Microsoft.XMLHTTP' ); } catch (e) {}

                        return null;
                };

                var checkStatus = function( xhr )
                {
                        // HTTP Status Codes:
                        //       2xx : Success
                        //       304 : Not Modified
                        //         0 : Returned when running locally (file://)
                        //      1223 : IE may change 204 to 1223 (see http://dev.jquery.com/ticket/1450)

                        return ( xhr.readyState == 4 &&
                                        (       ( xhr.status >= 200 && xhr.status < 300 ) ||
                                                xhr.status == 304 ||
                                                xhr.status === 0 ||
                                                xhr.status == 1223 ) );
                };

                var getResponseText = function( xhr )
                {
                        if ( checkStatus( xhr ) )
                                return xhr.responseText;
                        return null;
                };

                var getResponseXml = function( xhr )
                {
                        if ( checkStatus( xhr ) )
                        {
                                var xml = xhr.responseXML;
                                return new CKEDITOR.xml( xml && xml.firstChild ? xml : xhr.responseText );
                        }
                        return null;
                };

                var load = function( url, callback, getResponseFn )
                {
                        var async = !!callback;

                        var xhr = createXMLHttpRequest();

                        if ( !xhr )
                                return null;

                        xhr.open( 'GET', url, async );

                        if ( async )
                        {
                                // TODO: perform leak checks on this closure.
                                /** @ignore */
                                xhr.onreadystatechange = function()
                                {
                                        if ( xhr.readyState == 4 )
                                        {
                                                callback( getResponseFn( xhr ) );
                                                xhr = null;
                                        }
                                };
                        }

                        xhr.send(null);

                        return async ? '' : getResponseFn( xhr );
                };

                return  /** @lends CKEDITOR.ajax */ {

                        /**
                         * Loads data from an URL as plain text.
                         * @param {String} url The URL from which load data.
                         * @param {Function} [callback] A callback function to be called on
                         *              data load. If not provided, the data will be loaded
                         *              synchronously.
                         * @returns {String} The loaded data. For asynchronous requests, an
                         *              empty string. For invalid requests, null.
                         * @example
                         * // Load data synchronously.
                         * var data = CKEDITOR.ajax.load( 'somedata.txt' );
                         * alert( data );
                         * @example
                         * // Load data asynchronously.
                         * var data = CKEDITOR.ajax.load( 'somedata.txt', function( data )
                         *     {
                         *         alert( data );
                         *     } );
                         */
                        load : function( url, callback )
                        {
                                return load( url, callback, getResponseText );
                        },

                        /**
                         * Loads data from an URL as XML.
                         * @param {String} url The URL from which load data.
                         * @param {Function} [callback] A callback function to be called on
                         *              data load. If not provided, the data will be loaded
                         *              synchronously.
                         * @returns {CKEDITOR.xml} An XML object holding the loaded data. For asynchronous requests, an
                         *              empty string. For invalid requests, null.
                         * @example
                         * // Load XML synchronously.
                         * var xml = CKEDITOR.ajax.loadXml( 'somedata.xml' );
                         * alert( xml.getInnerXml( '//' ) );
                         * @example
                         * // Load XML asynchronously.
                         * var data = CKEDITOR.ajax.loadXml( 'somedata.xml', function( xml )
                         *     {
                         *         alert( xml.getInnerXml( '//' ) );
                         *     } );
                         */
                        loadXml : function( url, callback )
                        {
                                return load( url, callback, getResponseXml );
                        }
                };
        })();

})();