Let’s we are building a dynamic photo gallery in flash using ActionsScript 3.0. The data is originally placed in a MySQL database, and through a web application written in PHP, the user is allowed to upload files to the gallery or delete existing files. Flash is used as a front-end in order to achieve better results for visual effects. When the user makes changes to the gallery, the PHP application updates the XML file located on the webserver with the new data. When accesing the page containing the flash galley, the user should see the updated gallery, but instead he sees the old one. The reason is that the browser loads the XML file from it’s cache and not the webserver. Not even a refresh won’t solve this problem on most browsers.

The solution is a small trick used by programmers to fool the browser into thinking it is always loading a different file, by adding an extra parameter (with a ramndom value)  to the URL of the file that is beeing loaded. So, even if the file name itself is the same, the URL changes on every request.

The changes must be made on the portion of the code where the XML file is requested throught ActionScript.

myIdentifier=Math.round(Math.random()*10000);
xmlData.load("gallery.xml?uid="+myIdentifier);

Simple as that!