Reverse geocode using PHP

function getPostcode($lat, $lng) {
  $returnValue = NULL;
  $ch = curl_init();
  $url = "http://maps.googleapis.com/maps/api/geocode/json?latlng=${lat},${lng}&sensor=false";
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
  $result = curl_exec($ch);
  $json = json_decode($result, TRUE);

  if (isset($json['results'])) {
     foreach    ($json['results'] as $result) {
        foreach ($result['address_components'] as $address_component) {
          $types = $address_component['types'];
          if (in_array('postal_code', $types) && sizeof($types) == 1) {
             $returnValue = $address_component['short_name'];
          }
    }
     }
  }
  return $returnValue;
}

echo getPostcode(51.4691, -0.2963);