library/Extlib/FileManager.php
static public function getMimeType($filePath, $default = 'application/octet-stream')
    {
        $mimeType = finfo_file(finfo_open(FILEINFO_MIME_TYPE), $filePath);
        if ($mimeType === false) {
            $mimeType = $default;
        }
        
        return $mimeType;
    }
static public function getMimeType($filePath, $default = 'application/octet-stream')
    {
        $mimeType = finfo_file(finfo_open(FILEINFO_MIME_TYPE), $filePath);
        if ($mimeType === false) {
            $mimeType = $default;
        }
        
        return $mimeType;
    }
Return mimetype for file

@param string $filePath
@param string $default
@return string