Sk8erPeter - function is_real_agent()

/**
 * is_real_agent() - Check if user agent given as a parameter is a search robot or a "real" visitor (list is absolutely incomplete :-) )
 * Original source (code modified below): http://neo22s.com/function-to-check-if-visitor-is-a-bot/
 * @param string $HTTP_USER_AGENT - böngésző ($_SERVER['HTTP_USER_AGENT'])
 * @return bool is_real_agent - is it a "real" visitor?
 */
function is_real_agent( $HTTP_USER_AGENT ){
    $unreal_agent_list = array(
        "W3C_Validator", // not a search robot, but isn't a "real" visitor
        "blahblahblahblahblah" // modify as you wish
    );
    $botlist = array(
        "Googlebot", "Feedfetcher-Google", "Mediapartners-Google",
        "Teoma", "alexa", "froogle", "Gigabot", "inktomi",
        "looksmart", "URL_Spider_SQL", "Firefly", "NationalDirectory",
        "Ask Jeeves", "TECNOSEEK", "InfoSeek", "WebFindBot", "girafabot",
        "crawler", "www.galaxy.com", "Scooter", "Slurp",
        "msnbot", "appie", "FAST", "WebBug", "Spade", "ZyBorg", "rabaz",
        "Baiduspider", "TechnoratiSnoop", "Rankivabot",
        "Sogou web spider", "WebAlta Crawler","TweetmemeBot",
        "Butterfly","Twitturls", "Me.dium", "Twiceler"
    );

    foreach($unreal_agent_list as $unreal_agent){
        if(stripos($HTTP_USER_AGENT, $unreal_agent)!==false){
            return false;    // Is not real
        }
    }

    foreach($botlist as $bot){
        if(stripos($HTTP_USER_AGENT, $bot)!==false){
            return false;    // Is a bot
        }
    }

    return true;    // Not a bot
}


/// ............
// using the function below:

// if user agent header is set, we can check if it's a search robot or a real (e.g. human :D) visitor
if( !empty($_SERVER['HTTP_USER_AGENT']) ) {
    $HTTP_USER_AGENT = $_SERVER['HTTP_USER_AGENT'];
    if(false == is_real_agent($HTTP_USER_AGENT)){
        $real_visitor = 'false';
    }
}