get_file_mimetype.php

<?php

/**
 * get file mimetype
 *
 * Tries to get mime data of the file.
 *
 * @param str $filepath
 * @return str mime-type of the given file, or false if nothing found
 */
function get_file_mimetype( $filepath )
{
    if( !file_exists($filepath) )
    {
        return false;
    }
    
    if( function_exists("mime_content_type") )
    {
        // if mime_content_type exists use it.
        $m = mime_content_type($filepath);
    }
    else if( function_exists('finfo_open') )
    {
        // if php5.3 or Pecl installed use it
        $finfo = finfo_open(FILEINFO_MIME);
        $m = finfo_file($finfo, $filepath);
        finfo_close($finfo);
    }
    else
    {
        
        // if nothing left try shell
        if( strstr($_SERVER['SERVER_SOFTWARE'], "Windows") )
        {
            # Nothing to do on windows
            # anyway, blank mime display most files correctly especially images.
            return false;
        }
        elseif( strstr($_SERVER['SERVER_SOFTWARE'], "Macintosh") )
        {
            # Correct output on macs
            $m = trim( exec('file -b --mime '.escapeshellarg($filepath)) );
        }
        else
        {
            # Regular unix systems
            $m = trim( exec('file -bi '.escapeshellarg($filepath)) );
        }
        
    }
    return $m;
}