使用IP判斷訪問用戶是在哪個城市的PHP代碼

function detect_city($ip) {


    $default = 'UNKNOWN';

    $curlopt_useragent = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6 (.NET CLR 3.5.30729)';

    $url = 'http://ipinfodb.com/ip_locator.php?ip=' . urlencode($ip);
    $ch = curl_init();

    $curl_opt = array(
        CURLOPT_FOLLOWLOCATION  => 1,
        CURLOPT_HEADER      => 0,
        CURLOPT_RETURNTRANSFER  => 1,
        CURLOPT_USERAGENT   => $curlopt_useragent,
        CURLOPT_URL       => $url,
        CURLOPT_TIMEOUT         => 1,
        CURLOPT_REFERER         => 'http://' . $_SERVER['HTTP_HOST'],
    );

    curl_setopt_array($ch, $curl_opt);

    $content = curl_exec($ch);

    if (!is_null($curl_info)) {
        $curl_info = curl_getinfo($ch);
    }

    curl_close($ch);

    if ( preg_match('{<li>City : ([^<]*)</li>}i', $content, $regs) )  {
        $city = $regs[1];
    }
    if ( preg_match('{<li>State/Province : ([^<]*)</li>}i', $content, $regs) )  {
        $state = $regs[1];
    }

    if( $city!='' && $state!='' ){
      $location = $city . ', ' . $state;
      return $location;
    }else{
      return $default; 
    }

}</pre> 



 用法： 
<?php
$ip = $_SERVER['REMOTE_ADDR'];
$city = detect_city($ip);
echo $city;
?>