silverstripe-framework/javascript/core/jquery.ondemand.js

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/**
* On-demand JavaScript handler
* Based on http://plugins.jquery.com/files/issues/jquery.ondemand.js_.txt
* and heavily modified to integrate with SilverStripe and prototype.js.
* Adds capabilities for custom X-Include-CSS and X-Include-JS HTTP headers
* to request loading of externals alongside an ajax response.
*
* IMPORTANT: This plugin monkeypatches the jQuery.ajax() method.
*/
(function($){
$.extend({
// loaded files list - to protect against loading existed file again (by PGA)
_ondemand_loaded_list : null,
// Added by SRM: Initialise the loaded_list with the scripts included on first load
initialiseItemLoadedList : function() {
if(this.loaded_list == null) {
$this = this;
$this.loaded_list = {};
$('script').each(function() {
if($(this).attr('src')) $this.loaded_list[ $(this).attr('src') ] = 1;
});
$('link[rel="stylesheet"]').each(function() {
if($(this).attr('href')) $this.loaded_list[ $(this).attr('href') ] = 1;
});
}
},
/**
* Returns true if the given CSS or JS script has already been loaded
*/
isItemLoaded : function(scriptUrl) {
var self = this;
if(this._ondemand_loaded_list == null) {
this._ondemand_loaded_list = {};
$('script').each(function() {
if($(this).attr('src')) self._ondemand_loaded_list[ $(this).attr('src') ] = 1;
});
$('link[rel="stylesheet"]').each(function() {
if($(this).attr('href')) self._ondemand_loaded_list[ $(this).attr('href') ] = 1;
});
}
return (this._ondemand_loaded_list[scriptUrl] != undefined);
},
requireCss : function(styleUrl, media){
if(media == null) media = 'all';
// Don't double up on loading scripts
if($.isItemLoaded(styleUrl)) return;
if(document.createStyleSheet){
var ss = document.createStyleSheet(styleUrl);
ss.media = media;
} else {
var styleTag = document.createElement('link');
$(styleTag).attr({
href : styleUrl,
type : 'text/css',
media : media,
rel : 'stylesheet'
}).appendTo($('head').get(0));
}
this._ondemand_loaded_list[styleUrl] = 1;
},
/**
* Process the X-Include-CSS and X-Include-JS headers provided by the Requirements class
*/
processOnDemandHeaders: function(xml, status, _ondemandComplete) {
var self = this;
// CSS
if(xml.getResponseHeader('X-Include-CSS')) {
var cssIncludes = xml.getResponseHeader('X-Include-CSS').split(',');
for(var i=0;i<cssIncludes.length;i++) {
// Syntax: "URL:##:media"
if(cssIncludes[i].match(/^(.*):##:(.*)$/)) {
$.requireCss(RegExp.$1, RegExp.$2);
// Syntax: "URL"
} else {
$.requireCss(cssIncludes[i]);
}
}
}
// JavaScript
var newJsIncludes = [];
if(xml.getResponseHeader('X-Include-JS')) {
var jsIncludes = xml.getResponseHeader('X-Include-JS').split(',');
for(var i=0;i<jsIncludes.length;i++) {
if(!$.isItemLoaded(jsIncludes[i])) {
newJsIncludes.push(jsIncludes[i]);
}
}
}
// We make an array of the includes that are actually new, and attach the callback to the last one
// They are placed in a queue and will be included in order. This means that the callback will
// be able to execute script in the new includes (such as a livequery update)
var getScriptQueue = function() {
if(newJsIncludes.length) {
var newJsInclude = newJsIncludes.shift();
// emulates getScript() with addtl. setting
$.ajax({
dataType: 'script',
url: newJsInclude,
success: function() {
self._ondemand_loaded_list[newJsInclude] = 1;
getScriptQueue();
},
cache: false,
// jQuery seems to override the XHR objects if used in async mode
async: false
});
} else {
_ondemandComplete(xml, status);
}
}
if(newJsIncludes.length) {
getScriptQueue();
} else {
// If there aren't any new includes, then we can just call the callbacks ourselves
_ondemandComplete(xml, status);
}
}
});
/**
* Ajax requests are amended to look for X-Include-JS and X-Include-CSS headers
*/
_originalAjax = $.ajax;
$.ajax = function(s) {
// Avoid recursion in ajax callbacks caused by getScript(), by not parsing
// ondemand headers for 'script' datatypes
if(s.dataType == 'script') return _originalAjax(s);
var _complete = s.complete;
var _success = s.success;
var _dataType = s.dataType;
// This replaces the usual ajax success & complete handlers. They are called after any on demand JS is loaded.
var _ondemandComplete = function(xml, status) {
var status = $.httpSuccess(xml) ? 'success' : 'error';
if(status == 'success') {
var data = jQuery.httpData(xml, _dataType);
if(_success) _success(data, status);
}
if(_complete) _complete(xml, status);
}
// We remove the success handler and take care of calling it outselves within _ondemandComplete
s.success = null;
s.complete = function(xml, status) {
$.processOnDemandHeaders(xml, status, _ondemandComplete);
}
return _originalAjax(s);
}
})(jQuery);
/**
* This is the on-demand handler used by our patched version of prototype.
* once we get rid of all uses of prototype, we can remove this
*/
function prototypeOnDemandHandler(xml, status, callback) {
jQuery.processOnDemandHeaders(xml, status, callback);
}