php_do_post_request.php

function do_post_request($url, $data, $optional_headers = null) {
    $params = array('http' => array(
    	'method' => 'POST',
		'content' => $data
		));
    
	if ($optional_headers !== null) {
		$params['http']['header'] = $optional_headers;
	}
	$ctx = stream_context_create($params);
	$stream = @fopen($url, 'rb', false, $ctx);
	if (!$stream) {
        if(isset($php_errormsg) && preg_match("/401/", $php_errormsg)) header("HTTP/1.1 401 Authentication failed");
        else header("HTTP/1.1 403 Forbidden");
		die();
	}
	$response = @stream_get_contents($stream);
    fclose($stream);
	if ($response === false || empty($response)) {
		throw new Exception("Problem reading data from $url");
	}
	return $response;
}