php写的关于静态页面的蜘蛛爬行记录的代码

<?php
      $useragent = addslashes(strtolower($_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($useragent,'yahoo') !== false){$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["HTTP_X_REWRITE_URL"]."rn");
     fclose($fp);
     }
     $file=".".$_SERVER[HTTP_X_REWRITE_URL];
     $f_head=substr($file,-5);
     if($f_head==".html")
     {
         if(file_exists($file))
        {
           echo file_get_contents($file);
         }else
         {
          
         header('HTTP/1.1 404 Not Found');
        header("status: 404 Not Found");

         echo "该页面无法找到";
        }
   }
    else
     {
        header('HTTP/1.1 404 Not Found');
        header("status: 404 Not Found");
         echo "该页面无法找到";  
    }
?>

[ISAPI_Rewrite]

 # 3600 = 1 hour
 CacheClockRate 3600
 
 RepeatLimit 32
 
 # Protect httpd.ini and httpd.parse.errors files
 # from accessing through HTTP
 RewriteRule /index.html /index.php
 RewriteRule ^/article/(.*) /bot.php [L]
 RewriteRule ^/list/(.*) /bot.php [L]