public function isRobot() {
        $agent= strtolower(isset($_SERVER['HTTP_USER_AGENT'])? $_SERVER['HTTP_USER_AGENT'] : '');
        if(!empty($agent)){
            $spiderSite= array(
                "spider",
                "TencentTraveler",
                "Baiduspider+",
                "BaiduGame",
                "Googlebot",
                "msnbot",
                "Sosospider+",
                "Sogou web spider",
                "ia_archiver",
                "Yahoo! Slurp",
                "YoudaoBot",
                "Yahoo Slurp",
                "MSNBot",
                "Java (Often spam bot)",
                "BaiDuSpider",
                "Voila",
                "Yandex bot",
                "BSpider",
                "twiceler",
                "Sogou Spider",
                "Speedy Spider",
                "Google AdSense",
                "Heritrix",
                "Python-urllib",
                "Alexa (IA Archiver)",
                "Ask",
                "Exabot",
                "Custo",
                "OutfoxBot/YodaoBot",
                "yacy",
                "SurveyBot",
                "legs",
                "lwp-trivial",
                "Nutch",
                "StackRambler",
                "The web archive (IA Archiver)",
                "Perl tool",
                "MJ12bot",
                "Netcraft",
                "MSIECrawler",
                "WGet tools",
                "larbin",
                "Fish search",
            );
            foreach($spiderSite as $val){
                $str = strtolower($val);
                if(strpos($agent, $str) !== false){
                	echo "是爬虫";
                    return 2;
                }else{
                	echo "不是爬虫";
                    return 1;
                }
            }
        }
    }