Using PHP to implement spider access log statistics_PHP tutorial

$useragent = addslashes(strtolower($_SERVER['HTTP_USER_AGENT']));

 if (strpos($useragent, 'googlebot')!== false){$bot = 'Google';}
 elseif (strpos($useragent,'mediapartners-google') !== false){$bot = 'Google Adsense';}
 elseif (strpos($useragent,'baiduspider') !== false){$bot = 'Baidu';}
 elseif (strpos($useragent,'sogou spider') !== false){$bot = 'Sogou';}
 elseif (strpos($useragent,'sogou web') !== false){$bot = 'Sogou web';}
 elseif (strpos($useragent,'sosospider') !== false){$bot = 'SOSO';}
 elseif (strpos($useragent,'360spider') !== false){$bot = '360Spider';}
 elseif (strpos($useragent,'yahoo') !== false){$bot = 'Yahoo';}
 elseif (strpos($useragent,'msn') !== false){$bot = 'MSN';}
 elseif (strpos($useragent,'msnbot') !== false){$bot = 'msnbot';}
 elseif (strpos($useragent,'sohu') !== false){$bot = 'Sohu';}
 elseif (strpos($useragent,'yodaoBot') !== false){$bot = 'Yodao';}
 elseif (strpos($useragent,'twiceler') !== false){$bot = 'Twiceler';}
 elseif (strpos($useragent,'ia_archiver') !== false){$bot = 'Alexa_';}
 elseif (strpos($useragent,'iaarchiver') !== false){$bot = 'Alexa';}
 elseif (strpos($useragent,'slurp') !== false){$bot = '雅虎';}
 elseif (strpos($useragent,'bot') !== false){$bot = '其它蜘蛛';}
 if(isset($bot)){
     $fp = @fopen('bot.txt','a');
     fwrite($fp,date('Y-m-d H:i:s')."t".$_SERVER["REMOTE_ADDR"]."t".$bot."t".'http://'.$_SERVER['SERVER_NAME'].$_SERVER["REQUEST_URI"]."rn");
     fclose($fp);
 }