PHP soap client

soap.php

<?php
class UserCredentials {
	public $Username;
	public $Password;
	
	public function __construct( $username, $password ) {
		$this->Username = $username;
		$this->Password = $password;
	}
}

class Document {
	private $instance;
	
	public function __construct(string $version = '1.0') {
		$document = $this->instance = 
					new DomDocument( $version );
		
		$document->preserveWhiteSpace = false;
		$document->formatOutput = true;
	}
	
	public function parse( string $document ): String {
		$this->instance->loadXML( $document );
		return $this->instance->saveXML();
	}
}


$accountId	= "";
$document	= new Document;

$options	= [
	'features' => SOAP_SINGLE_ELEMENT_ARRAYS,
	'exceptions' => false,
	'trace' => 1
];

// Create the SoapClient instance
$url    = "https://mws.envisionrx.com/rxfunctions.asmx?WSDL";
$client = new SoapClient( $url, $options );

// Create the header
$args	= [];

$client->__setSoapHeaders([
	new SoapHeader(
		"http://mws.envisionrx.com",
		"UserCredentials",
		new UserCredentials( "Username", "Password" ), 
		false)
]);

// Call SOAP service
$response = $client
	->GetBrandEquivalentByGenericNDC();

printf( "SOAP request:\n" );
printf( "%s\n", $document->parse( $client->__getLastRequest()));

var_dump( $response );