Snippets

Detect location by IP

Here is an useful code snippet to detect the location of a specific IP. The function below takes one IP as a parameter, and returns the location of the IP. If no location is found, UNKNOWN is returned.

function detect_city($ip) {

        $default = 'UNKNOWN';

        if (!is_string($ip) || strlen($ip) < 1 || $ip == '127.0.0.1' || $ip == 'localhost')
            $ip = '8.8.8.8';

        $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;
        }

    }

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  • http://codeseekah.com Gennady

    Oooh, nice one if you don’t have access to your own database or for very quick prototying. Couple of problems for production use: heavily relying on this ipinfodb website. Tomorrow they might add a captcha, change their markup (the regexp will break), or completely fail as a site and shut down. There are no guarantees, you may end up getting a call at 3 AM because the IP2Location system you developed is down. Problem two: no caching. Get an IPv4/6 database, it isn’t usually too large, lookups will be much faster, guaranteed and reliable.

    • http://artatm.com Rocky

      What do you mean by your second point “no caching”? And also where to get the IPv4/6 db?

    • http://pagesofinterest.net/ Michael Robinson

      I’ve used GeoIP for this many times: http://www.maxmind.com/app/geolitecity

      PHP/Apache integration is available.

  • http://www.amazon.com/gp/aw/d/B0084AKY18/ Al Jensen

    Awesome!