Pretty Link Robot detection

prettylinkrobotdetector.php

<?php
  function is_robot(&$click,&$browsecap,$header='')
  {
    global $prli_utils, $prli_click, $prli_options;
    $ua_string = trim(urldecode($click->browser));
    $btype = trim($click->btype);

    // Yah, if the whole user agent string is missing -- wtf?
    if(empty($ua_string))
      return 1;

    // If we're doing extended tracking and the Browser type
    // was unidentifiable then it's most likely a bot
    if( isset($prli_options->extended_tracking) and
        $prli_options->extended_tracking == 'extended' and
        empty($btype) )
      return 1;

    // Some bots actually say they're bots right up front let's get rid of them asap
    if(preg_match("#(bot|Bot|spider|Spider|crawl|Crawl)#",$ua_string))
      return 1;

    $crawler = $browsecap['crawler'];

    // If php_browsecap tells us its a bot, let's believe him
    if($crawler == 1)
      return 1;

    return 0;
  }
?>