Use this library, preferrably with your templating engine of choice, to easily append a cache busting token string to your hyperlinked resource, such as a stylesheet or a javascript file.

Usage

$fileService = new FileService('/var/mysite/public/');
$tokenType = new ResourceSizeHashToken();

$queryStringBuster = new QueryStringBuster($tokenType, $fileService);

$queryStringBuster->modifyResourcePath('css/stylesheet.min.css');

Will output: css/stylesheet.min.css?token=... with a token generated based on file size hash, which will then change every time the file itself gets updated.