Why returns 500 when I tested SOAP API in apex code?

Question

I got OK when I was testing Marketing Cloud SOAP API with SoapUI tool.

So then I tried to send http request in apex, but I got 500 result: Status=Internal Server Error, StatusCode=500

The code is following:

Http http = new Http();
HttpRequest req = new HttpRequest();
req.setEndpoint('https://webservice.s7.exacttarget.com/Service.asmx');
req.setMethod('POST');

String eBody = '';
eBody += '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">';
eBody += '<soapenv:Header>';
eBody += '<wsse:Security soapenv:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">';
eBody += '<wsse:UsernameToken wsu:Id="UsernameToken-32259181" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">';
eBody += '<wsse:Username>xxxx</wsse:Username>';
eBody += '<wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">xxxx</wsse:Password>';
eBody += '</wsse:UsernameToken>';
eBody += '</wsse:Security>';
eBody += '</soapenv:Header>';
eBody += '<soapenv:Body>';
eBody += '<RetrieveRequestMsg xmlns="http://exacttarget.com/wsdl/partnerAPI">';
eBody += '<RetrieveRequest>';
eBody += '<ObjectType>Email</ObjectType>';
eBody += '<Properties>Name</Properties>';
eBody += '<Properties>Subject</Properties>';
eBody += '<Properties>HTMLBody</Properties>';
eBody += '</RetrieveRequest>';
eBody += '</RetrieveRequestMsg>';
eBody += '</soapenv:Body>';
eBody += '</soapenv:Envelope>';

req.setBody(eBody);
HttpResponse res = http.send(req);

// Log the XML content
System.debug('qqqq res.getBody=' + res.getBody());

Answer 1

I`m pleased to share the answer when I successfully resolved the issue.

We need to clarify the soap action and put it in to the header information when we are going to access ExactTarget SOAP API, like as:

req.setHeader('SOAPAction', 'Retrieve');

AND IF the content type is xml, then we will add additional header information:

req.setHeader('Content-Type', 'text/xml;charset=UTF-8');

And then, I got the correct content from the response message.