PHP : detect bot

gistfile1

<?php
public function isBot() {
  $bots = array(
  	'googlebot', 
  	'adsbot-google', 
  	'feedfetcher-google',
  	'yahoo', 
  	'lycos', 
  	'bloglines subscriber', 
  	'dumbot', 
  	'sosoimagespider', 
  	'qihoobot', 
  	'fast-webcrawler', 
  	'superdownloads spiderman', 
  	'linkwalker', 
  	'msnbot', 
  	'aspseek', 
  	'webalta crawler', 
  	'youdaobot', 
  	'scooter', 
  	'gigabot', 
  	'charlotte', 
  	'estyle', 
  	'aciorobot', 
  	'geonabot', 
  	'msnbot-media', 
  	'baidu', 
  	'cococrawler', 
  	'google', 
  	'charlotte t', 
  	'yahoo! slurp china', 
  	'sogou web spider', 
  	'yodaobot', 
  	'msrbot', 
  	'abachobot', 
  	'sogou head spider', 
  	'altavista', 
  	'idbot', 
  	'sosospider', 
  	'yahoo! slurp', 
  	'java vm', 
  	'dotbot', 
  	'litefinder', 
  	'yeti', 
  	'rambler', 
  	'scrubby', 
  	'baiduspider', 
  	'accoona'
  );

  foreach($bots as $bot) {
    if (strpos(strtolower($_SERVER['HTTP_USER_AGENT']), trim($bot)) !== false) {
      return true;
    }
  }
  return false;
}