We have problems with file assets such as PDF files being cached and users don't clear their browser cache, etc etc, so they get the old version of the file. This is a frustrating problem, so I whipped up this small cache busting script to fix the issue. The script adds a random string to the end of the file url, which will help with the caching issue:
/**
* Busts the cache for file assets
*
* @param string url The url to add the random string to
*
* @version $Revision: 0.1
*/
function fileCacheBuster(url) {
// If we have already added, don’t do it again
if (url.indexOf(‘zscb=’) != -1) {
return url;
}
// Min and max
var mx = 99999999;
var mn = 1;
// Create the random number
var r = Math.floor(Math.random() * (mx - mn + 1)) + mn;
// Apply the random string
if (url.indexOf(’?’) != -1) {
return url+’&zscb=’+r;
} else {
return url+’?zscb=’+r;
}
}//end
The script can then be used like (using jQuery):
$("a[href*='.pdf'], a[href*='.doc'], a[href*='.xls'], a[href*='.ppt']").click(function() {
var url = $(this).attr('href');
$(this).attr('href', fileCacheBuster(url));
});