You can use CURL in php like this:
$ch = curl_init( $url );
$data_string = " ";
curl_setopt( $ch, CURLOPT_POSTFIELDS, $data_string );
curl_setopt( $ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));
curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
$result = curl_exec($ch);
curl_close($ch);
return $result;
and empty data string doesn't make sense in post request, but i've checked it with empty data string and it works quiet well.