SOAP API integration

helpppppppppppp!!!!
so i have a SOAP function and i want to integrate it to the checkout process
its a DHL function
how should i proceed ; im really lost
here's the function

<?php

class DhlRetoure
{
private $username = "xxx";
private $password = "xxx";
private $portalId = "xxx";
private $deliveryName = "xxx";
private $end_point = "https://amsel.dpwn.net/abholportal/gw/lp/SoapConnector";

public function getRetourePdf($surname, $familyname, $street, $streetNumber, $zip, $city)
{
$xmlRequest = $this->getRequestXml($surname, $familyname, $street, $streetNumber, $zip, $city);
$response = $this->curlSoapRequest($xmlRequest);
if($response){
$pdf = $this->getPdfFromResponse($response);
}
return $pdf;
}
public function displayPdf($pdf){
header("Content-type: application/pdf");
echo $pdf;
}

private function getRequestXml($surname, $familyname, $street, $streetNumber, $zip, $city)
{
$request =
"<?xml version='1.0' encoding='UTF-8' ?>
<soapenv:Envelope xmlns:soapenv='http://schemas.xmlsoap.org/soap/envelope/' xmlns:var='https://amsel.dpwn.net/abholportal/gw/lp/schema/1.0/var3bl'>
<soapenv:Header>
<wsse:Security soapenv:mustUnderstand='1' xmlns:wsse='http://docs.oasis-open.org/…/oasis-200401-wss-wssecurity-se…'>
<wsse:UsernameToken>
<wsse:Username>".$this->username."</wsse:Username>
<wsse:Password Type='http://docs.oasis-open.org/…/oasis-200401-wss-username-toke…'>
".$this->password."
</wsse:Password>
</wsse:UsernameToken>
</wsse:Security>
</soapenv:Header>
<soapenv:Body>
<var:BookLabelRequest
portalId='".$this->portalId."'
deliveryName='".$this->deliveryName."'
shipmentReference='Shipment Reference'
customerReference='Customer Reference'
labelFormat='PDF'
senderName1='$surname'
senderName2='$familyname'
senderCareOfName='CareofName'
senderContactPhone=''
senderStreet='$street'
senderStreetNumber='$streetNumber'
senderBoxNumber=''
senderPostalCode='$zip'
senderCity='$city' />
</soapenv:Body>
</soapenv:Envelope>";
return $request;
}

/**
* @param $soap_request
* @return mixed
*/
private function curlSoapRequest($xmlRequest)
{
$header = array(
"Content-type: text/xml;charset=\"utf-8\"",
"Accept: text/xml",
"Cache-Control: no-cache",
"Pragma: no-cache",
"Content-length: " . strlen($xmlRequest),
);

$soap_do = curl_init();
curl_setopt($soap_do, CURLOPT_URL, $this->end_point);
curl_setopt($soap_do, CURLOPT_CONNECTTIMEOUT, 10);
curl_setopt($soap_do, CURLOPT_TIMEOUT, 10);
curl_setopt($soap_do, CURLOPT_RETURNTRANSFER, true);
curl_setopt($soap_do, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($soap_do, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($soap_do, CURLOPT_POST, true);
curl_setopt($soap_do, CURLOPT_POSTFIELDS, $xmlRequest);
curl_setopt($soap_do, CURLOPT_HTTPHEADER, $header);
$response = curl_exec($soap_do);

if (!$response) {
$err = 'Curl error: ' . curl_error($soap_do);
}
else {
/* var_dump(htmlentities($response));*/
}
curl_close($soap_do);
return $response;
}

/**
* @param $response
* @return string
*/
private function getPdfFromResponse($response)
{
$xml = simplexml_load_string($response);
$ns = $xml->getNamespaces(true);
$soap = $xml->children($ns['env']);
$pdf = $soap->Body->children($ns['var3bl'])->BookLabelResponse->label;
$pdf = base64_decode($pdf);
return $pdf;
}
}

What you are looking for has already been developed with the composer version: https://github.com/tobihille/DHL-API-Sample . To return the PDF, read the issues tab comment here with the getManifest() method: https://github.com/Petschko/dhl-php-sdk/issues/50 . If you don't know how to do it, either create a new service request in the Commercial Support section of the forum or, since this request is about an API, send me a PM to implement this class as a custom job.