XTE 3.0 Token in PHP from scratch

The documentation provided for the ProStores XTE (XML Transaction Engine) authentication scheme is pretty thorough, so I will assume that you are familiar with the variables, and how to receive them into your application. That being said, here is a way to create an XTE 3.0 token using PHP.

$entry_url = {$_GET variable};
$app_id = {$_GET variable or hardcoded};
$secret = {$_GET variable or hardcoded};
$timestamp = time();

$entry_url_pre_sig = "$secret&appid=$app_id&ts=$timestamp";
$entry_url_sig = md5($entry_url_pre_sig);

$complete_entry_url = "$entry_url/getInfo?appid=$app_id" . "&ts=$timestamp" . "&sig=$entry_url_sig";

$result = http_post_send($complete_entry_url, 80, '', 'text/xml', '');        
$responseXML = str_replace('®', "", $result['body']); 
$tree = GetXMLTree($responseXML);

$xml_api = $tree["XTE"][0]["RESPONSE"][0]["XMLAPI"][0]["VALUE"];
$rest_api_non_secure = $tree["XTE"][0]["RESPONSE"][0]["RESTAPINONSECURE"][0]["VALUE"];

$api_ticket = $_GET['ticket'];

$get_token_pre_sig = "$secret&appid=$app_id&ts=$timestamp&ticket=$api_ticket";
$get_token_sig = md5($get_token_pre_sig);

$complete_token_url = $rest_api_non_secure . "auth/getToken?appid=$app_id" . "&ts=$timestamp" . "&ticket=$api_ticket" . "&sig=$get_token_sig";

$token_result = http_post_send($complete_token_url, 80, '', 'text/xml', '');        
$responseXML = str_replace('®', "", $token_result['body']); 
$tree = GetXMLTree($responseXML);

$token = $tree["XTE"][0]["RESPONSE"][0]["TOKEN"][0]["VALUE"];

echo "Your sweet token = $token ";

/*  These facilitate the transmission of data to the xte, and parsing the data into a nice array */

function http_post_send($url, $port, $body, $content_type, $cookie) {
	$url = ereg_replace("^http://", "", $url);
	$host = substr($url, 0, strpos($url, "/"));
	$uri = strstr($url, "/");
	$header = http_post_header($uri, $host, strlen($body), $content_type, $cookie);
	$socket = fsockopen($host, $port, $errno, $errstr);
	fputs($socket, $header.$body);
	$ret = array("header" => array(), "body" => "");
	$reading_header = true;
	$status = array("unread_bytes" => 1);
	while ($status["unread_bytes"] != 0){
		$chunk = fgets($socket);
		$status = socket_get_status($socket);
		if($reading_header){
			if ($chunk == "\r\n"){
				$reading_header = false;
			}
			else{
				$ret["header"][] = $chunk;
			}
		} 
		else{
			$ret["body"] .= $chunk;
		}
	}
	
	while ($more = fgets($socket)){
		$ret["body"] .= $more;
	}
	
	fclose($socket);
	return $ret;
}

function http_post_header($uri, $host, $content_length, $content_type, $cookie) {
	$h  = "POST $uri HTTP/1.0\n";
	$h .= "Host: $host\n";
	$h .= "User-Agent: Mozilla/4.0 [en] (Windows NT 5.0; U)\n";
	$h .= "Accept: */*\n";
	$h .= "Accept-Language: en-us\n";
	$h .= "Accept-Encoding: gzip, deflate\n";
	$h .= "Connection: Keep-Alive\n";
	$h .= "Content-Type: $content_type\n";
	$h .= "Content-Length: $content_length\n";
	$h .= "\n";
	return $h;
}

function GetXMLTree($data) { 
	$parser = xml_parser_create('ISO-8859-1');
	xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, 1); 
	xml_parse_into_struct($parser, $data, $vals, $index); 
	xml_parser_free($parser); 
	
	$tree = array(); 
	$i = 0; 
	$tree[$vals[$i]['tag']][] = GetChildren($vals, $i); 
	return $tree; 
} 


function GetChildren($vals, &$i){ 
	$children = array();
	if(isset($vals[$i]['value'])){ 
		$children['VALUE'] = $vals[$i]['value']; 
	}
	while(++$i < count($vals)){ 
		switch ($vals[$i]['type']){ 
			case 'cdata': 
				if(isset($children['VALUE'])){
					$children['VALUE'] .= $vals[$i]['value'];
				}
				else{
					$children['VALUE'] = $vals[$i]['value'];
				}
				break;
			case 'complete': 
				if(isset($vals[$i]['attributes'])) {
					$children[$vals[$i]['tag']][]['ATTRIBUTES'] = $vals[$i]['attributes'];
					$index = count($children[$vals[$i]['tag']])-1;
				
					if(isset($vals[$i]['value'])){ 
						$children[$vals[$i]['tag']][$index]['VALUE'] = $vals[$i]['value'];
					}
					else{
						$children[$vals[$i]['tag']][$index]['VALUE'] = '';
					} 
				} 
				else{
					if(isset($vals[$i]['value'])){ 
						$children[$vals[$i]['tag']][]['VALUE'] = $vals[$i]['value'];
					} 
					else{
						$children[$vals[$i]['tag']][]['VALUE'] = '';
					} 
				}
				break; 
			case 'open': 
				if(isset($vals[$i]['attributes'])){
					$children[$vals[$i]['tag']][]['ATTRIBUTES'] = $vals[$i]['attributes'];
					$index = count($children[$vals[$i]['tag']])-1;
					$children[$vals[$i]['tag']][$index] = array_merge($children[$vals[$i]['tag']][$index],GetChildren($vals, $i));
				} 
				else{
					$children[$vals[$i]['tag']][] = GetChildren($vals, $i);
				}
				break; 
			case 'close': 
				return $children; 
		} 
	} 
}