php判断来访者是否是搜索引擎的蜘蛛

我们可以通过HTTP_USER_AGENT来判断是否是蜘蛛，搜索引擎的蜘蛛都有自己的独特标志，下面列取了一部分。

function is_crawler() { 
    $userAgent = strtolower($_SERVER['HTTP_USER_AGENT']); 
    $spiders = array( 
        'Googlebot', // Google 爬虫 
        'Baiduspider', // 百度爬虫 
        'Yahoo! Slurp', // 雅虎爬虫 
        'YodaoBot', // 有道爬虫 
        'msnbot' // Bing爬虫 
        // 更多爬虫关键字 
    ); 
    foreach ($spiders as $spider) { 
        $spider = strtolower($spider); 
        if (strpos($userAgent, $spider) !== false) { 
            return true; 
        } 
    } 
    return false; 
} 

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！"; 
}