1.下面的php代码附带了更多的蜘蛛标识
function isCrawler() {
echo $agent= strtolower($_SERVER['HTTP_USER_AGENT']);
if (!empty($agent)) {
$spiderSite= array(
"TencentTraveler",
"Baiduspider+",
"BaiduGame",
"Googlebot",
"msnbot",
"Sosospider+",
"Sogou web spider",
"ia_archiver",
"Yahoo! Slurp",
"YoudaoBot",
"Yahoo Slurp",
"MSNBot",
"Java (Often spam bot)",
"BaiDuSpider",
"Voila",
"Yandex bot",
"BSpider",
"twiceler",
"Sogou Spider",
"Speedy Spider",
"Google AdSense",
"Heritrix",
"Python-urllib",
"Alexa (IA Archiver)",
"Ask",
"Exabot",
"Custo",
"OutfoxBot/YodaoBot",
"yacy",
"SurveyBot",
"legs",
"lwp-trivial",
"Nutch",
"StackRambler",
"The web archive (IA Archiver)",
"Perl tool",
"MJ12bot",
"Netcraft",
"MSIECrawler",
"WGet tools",
"larbin",
"Fish search",
        );
foreach($spiderSite as $val) {
$str = strtolower($val);
if (strpos($agent, $str) !== false) {
return true;
            }
        }
    } else {
return false;
    }
}
if (isCrawler()){
echo "你好蜘蛛精！";
}
else{
echo "你不是蜘蛛精啊！";
}

2.使用PHP实现蜘蛛访问日志统计

$useragent = addslashes(strtolower($_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"]."\r\n");
fclose($fp);
     }


3.推荐的一种方法：php判断搜索引擎蜘蛛爬虫还是人为访问代码,摘自Discuz x3.2
function checkrobot($useragent=''){
static $kw_spiders = array('bot', 'crawl', 'spider' ,'slurp', 'sohu-search', 'lycos', 'robozilla');
static $kw_browsers = array('msie', 'netscape', 'opera', 'konqueror', 'mozilla');

$useragent = strtolower(empty($useragent) ? $_SERVER['HTTP_USER_AGENT'] : $useragent);
if(strpos($useragent, 'http://') === false && dstrpos($useragent, $kw_browsers)) return false;
if(dstrpos($useragent, $kw_spiders)) return true;
return false;
}
function dstrpos($string, $arr, $returnvalue = false) {
if(empty($string)) return false;
foreach((array)$arr as $v) {
if(strpos($string, $v) !== false) {
$return = $returnvalue ? $v : true;
return $return;
        }
    }
return false;
}
if(checkrobot()){
echo '机器人爬虫';
}else{
echo '人';
}