Using Google Maps to show the geographical location of your website's visitors
Part IV – Creating the XML
Now that we have all that data, we need to return it in a usable manner, so that we can parse it all and display it in the map. There are several ways to do that, but the best way is to use XML.
We could just echo out XML strings – this is a fairly simple XML document. We’ll go ahead and use the DOM-XML object in PHP 5 though, just to be clean.
So, first we need to create the document & root element:
$dom = new DOMDocument( '1.0', 'UTF-8' );
$rootElement = $dom->createElement("locations");
Then, attach the root element to the document:
$dom->appendChild($rootElement);
We want to show them on the map as a green pin, so we'll use the code from the previous page in here to add that one first:
mysql_connect( 'localhost', 'username', 'password' );
$db = mysql_select_db( 'db' );
$license_key = 'xxx';
$ipaddress = $_SERVER['REMOTE_ADDR'];
$sql = "SELECT *
FROM visitor_log
WHERE ip = '{$ipaddress}'";
$c = mysql_num_rows(mysql_query($sql));
if( $c > 0 ){
$info = mysql_fetch_array(mysql_query($sql));
$sql = "INSERT
INTO visitor_log
(ip,lat,lng,city,state,country)
VALUES('{$ipaddress}','{$info['lat']}','{$info['lng']}', '{$info['city']}', '{$info['state']}','{$info['country']}')";
} else{
$query = "http://maxmind.com:8010/f?l=" . $license_key . "&i=" . $ipaddress;
$url = parse_url($query);
$host = $url["host"];
$path = $url["path"] . "?" . $url["query"];
$timeout = 1;
$fp = fsockopen ($host, 8010, $errno, $errstr, $timeout)
or die('Can not open connection to server.');
if ($fp) {
fputs ($fp, "GET $path HTTP/1.0\nHost: " . $host . "\n\n");
while (!feof($fp)) {
$buf .= fgets($fp, 128);
}
$lines = split("\n", $buf);
$data = $lines[count($lines)-1];
fclose($fp);
} else {
# enter error handing code here
}
$dataArray = split( ",", $data );
$lat = $dataArray[4];
$lng = $dataArray[5];
$city = $dataArray[2];
$state = $dataArray[1];
$country = $dataArray[0];
$sql = "INSERT
INTO visitor_log
(ip,lat,lng,city,state,country)
VALUES ('{$ipaddress}','{$lat}','{$lng}','{$city}','{$state}','{$country}')";
}
mysql_query($sql);
$element = $dom->createElement( 'location' );
$element->setAttribute( 'lat', $lat );
$element->setAttribute( 'lng', $lng );
$text = $dom->createCDATASection( $city. ', ' . $state . ', ' . $country );
$element->appendChild( $text );
$rootElement->appendChild($element);
Now, query for the last 100 unique visits or so, except for the person viewing the page:
$sql = "SELECT *
FROM visitor_log
WHERE lat != {$lat} and lng != {$lng}
GROUP BY lat, lng
ORDER BY visit_date DESC
LIMIT 100";
$res = mysql_query($sql);
For each of them, we are going to create a new element with latitude, longitude, and the name of the city/state/country:
while($array = mysql_fetch_array($res)){
$lat = $array['lat'];
$lng = $array['lng'];
$location = $array['city'].', '.$array['state'].', '.$array['country'];
$element = $dom->createElement( 'location' );
$element->setAttribute( 'lat', $lat );
$element->setAttribute( 'lng', $lng );
$text = $dom->createCDATASection( $location );
$element->appendChild( $text );
$rootElement->appendChild($element);
}
And finally, return the XML:
And, that’s it!
It should return XML that looks something like this:
<locations>
<location lat="40.960701" lng="-111.928001">This is you!</location>
</locations>
We'll then use this XML to create our points on the map.
Part V – Setting up the map >>
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