silverstripe-framework/javascript/jquery-ondemand/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.
*
* Requires jQuery 1.5 ($.Deferred support)
*
* CAUTION: Relies on customization of the 'beforeSend' callback in jQuery.ajaxSetup()
*
* @author Ingo Schommer (ingo at silverstripe dot com)
* @author Sam Minnee (sam at silverstripe dot com)
*/
(function($){
var decodePath = function(str) {
return str.replace(/%2C/g,',').replace(/\&/g, '&').replace(/^\s+|\s+$/g, '');
};
$.extend({
// loaded files list - to protect against loading existed file again (by PGA)
_ondemand_loaded_list : null,
/**
* Returns true if the given CSS or JS script has already been loaded
*/
isItemLoaded : function(scriptUrl) {
var self = this, src;
if(this._ondemand_loaded_list === null) {
this._ondemand_loaded_list = {};
$('script').each(function() {
src = $(this).attr('src');
if(src) self._ondemand_loaded_list[src] = 1;
});
$('link[rel="stylesheet"]').each(function() {
src = $(this).attr('href');
if(src) self._ondemand_loaded_list[src] = 1;
});
}
return (this._ondemand_loaded_list[decodePath(scriptUrl)] !== undefined);
},
requireCss : function(styleUrl, media){
if(!media) media = 'all';
// Don't double up on loading scripts
if($.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, xhr) {
var self = this, processDfd = new $.Deferred();
// CSS
if(xhr.getResponseHeader && xhr.getResponseHeader('X-Include-CSS')) {
var cssIncludes = xhr.getResponseHeader('X-Include-CSS').split(',');
for(var i=0;i<cssIncludes.length;i++) {
// Syntax: "URL:##:media"
if(cssIncludes[i].match(/^(.*):##:(.*)$/)) {
$.requireCss(decodePath(RegExp.$1), RegExp.$2);
// Syntax: "URL"
} else {
$.requireCss(decodePath(cssIncludes[i]));
}
}
}
// JavaScript
var newJsIncludes = [];
if(xhr.getResponseHeader && xhr.getResponseHeader('X-Include-JS')) {
var jsIncludes = xhr.getResponseHeader('X-Include-JS').split(',');
for(var i=0;i<jsIncludes.length;i++) {
var jsIncludePath = decodePath(jsIncludes[i]);
if(!$.isItemLoaded(jsIncludePath)) {
newJsIncludes.push(jsIncludePath);
}
}
}
// 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 {
processDfd.resolve(xml, status, xhr);
}
}
if(newJsIncludes.length) {
getScriptQueue();
} else {
// If there aren't any new includes, then we can just call the callbacks ourselves
processDfd.resolve(xml, status, xhr);
}
return processDfd.promise();
}
});
$.ajaxSetup({
// beforeSend is the only place to access the XHR object before success handlers are added
beforeSend: function(jqXHR, s) {
// Avoid recursion in ajax callbacks caused by getScript(), by not parsing
// ondemand headers for 'script' datatypes
if(s.dataType == 'script') return;
var dfd = new $.Deferred();
// Register our own success handler (assumes no handlers are already registered)
// 'success' is an alias for 'done', which is executed by the built-in deferred instance in $.ajax()
jqXHR.success(function(success, statusText, jXHR) {
$.processOnDemandHeaders(success, statusText, jXHR).done(function() {
dfd.resolveWith(s.context || this, [success, statusText, jXHR]);
});
});
// Reroute all external success hanlders through our own deferred.
// Not overloading fail() as no event can cause the original request to fail.
jqXHR.success = function(callback) {
dfd.done(callback);
}
}
});
})(jQuery);