root/releases/0.6/_files/icon.php

<?php

// Icon script

// Run includes
require_once(dirname(dirname(__FILE__))."/includes.php");

// Initialise functions for user details, icon management and profile management
run("userdetails:init");
run("profile:init");
run("files:init");

// If an ID number for the file has been specified ...
$id = optional_param('id',0,PARAM_INT);
if (!empty($id)) {
    // ... and the file exists ...
    if ($file = get_record('files','ident',$id)) {
        if (run("users:access_level_check",$file->access) == true) {
            // Send 304s where possible, rather than spitting out the file each time
            $if_modified_since = preg_replace('/;.*$/', '', $_SERVER['HTTP_IF_MODIFIED_SINCE']);
            
            $tstamp = filemtime($CFG->dataroot. $file->location);
            $lm = gmdate("D, d M Y H:i:s", $tstamp) . " GMT";
            
            if ($if_modified_since == $lm) {
                header("{$_SERVER['SERVER_PROTOCOL']} 304 Not Modified");
                exit;
            }
            
            // Send last-modified header to enable if-modified-since requests
            if ($tstamp < time()) {
                header("Last-Modified: " . $lm);
            }
            
            // Then output some appropriate headers and send the file data!
            require_once($CFG->dirroot.'/lib/filelib.php');
            $mimetype = mimeinfo('type',$file->originalname);
            if ($mimetype == "image/jpeg" || $mimetype == "image/png") {
                $icon = url . "units/phpthumb/phpThumb.php?w=90&src=" . urlencode($CFG->dataroot . $file->location);
                $mimetype = "image/jpeg";
            } else {
                $mimetype = "image/png";
                $icon = path . "_files/file.png";
            }
            
            // "Cache-Control: private" to allow a user's browser to cache the file, but not a shared proxy
            // Also to override PHP's default "DON'T EVER CACHE THIS EVER" header
            header("Cache-Control: private");
            
            header("Content-type: $mimetype");
            readfile($icon);
            
        }
    }
}

?>