private function _displayFile()
 {
     $registry = Zend_Registry::getInstance();
     // Print the contents of the file
     $file = $registry->configuration->testcase->dir . '/' . $this->getRequest()->getParam(2);
     if ($stream = fopen($file, 'r')) {
         // Disable layout
         $layout = Zend_Layout::getMvcInstance();
         $layout->disableLayout();
         /// @todo: output headers and file information
         $mm = new MimeMagic();
         /// @todo: fix in mimemagic instead
         header('Content-type: ' . $mm->get(realpath($file)));
         echo stream_get_contents($stream);
         fclose($stream);
     } else {
         throw new Exception("Attempted to view a non-existing file \"{$file}\".");
     }
 }
<?php

/*$file = realpath('C:\\xampp\\htdocs\\apache_pb2.gif');
echo $file.' mime is "'.mime_content_type($file).'"';*/
$filename = realpath('class_vars_for_RDI.php');
$filename = realpath('../../apache_pb2.gif');
$mimefile = 'C:\\xampp\\htdocs\\wtf2\\library\\mime\\magic';
/*
$handle = finfo_open(FILEINFO_MIME,'C:/xampp/php/extras/magic');
var_dump($handle);
$mime_type = finfo_file($handle,$file); 
echo $mime_type;
*/
/*
$finfo = new finfo(FILEINFO_MIME, $mimefile); 

if (!$finfo) {
    echo "Opening fileinfo database failed";
    exit();
}

// get mime-type for a specific file 
echo $finfo->file($filename);
*/
require_once 'C:\\xampp\\htdocs\\wtf2\\library\\mime\\MimeMagic.class.php';
$mm = new MimeMagic();
echo $mm->get($filename);