Detect location by IP address (I get a blank page. Why?) - php

Question

Here is an useful code snippet to detect the location of a specific IP address. The function below takes one IP address as a parameter, and returns the location of the IP address. If no location is found, UNKNOWN is returned.
But I get a blank page. Why?
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;
}
}

Answer 1

You probably get a blank page because there is an error in your script and PHP is not configured to display errors, which is the case on most online webspaces. Try to enable error display by adding this to a .htaccess file in the same directory:
php_flag display_errors on
php_value error_reporting 7

Answer 2

This line:
if (!is_null($curl_info)) {
$curl_info = curl_getinfo($ch);
}
The $curl_info does not exist and cannot be by seeing your parameters and the rest code above. Instead, comment the if out and you should be fine (tested on my IP address):
// if (!is_null($curl_info)) {
$curl_info = curl_getinfo($ch);
// }

Answer 3

Hope this helps :)
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;
}
}