SoapClient call returns 500 Internal Server Error

Question

I am trying to connect to an API using PHP and its built-in SoapClient. I have checked against the url I was given through the ill-formatted documents the client gave and $client->__getFunctions() returns a list of three functions. HelloWorld($name), which responds with Hello ~name~, shows me that I am communicating with the server through the SoapClient call and the URL is correct.

However, when I try to access one of the other methods that __getFunctions() gives me, even after copy/pasting the XML from the docs and putting in my own credentials, I am still being given an Internal Server Error faultstring and 500 as faultcode from the SoapFault object.

I am sure that it is my own XML string that is causing the issue but I cannot for the life of me figure out how. Reaching out to the API provider directly hasn't proven helpful. This is my first time dealing with Soap/Web Services so I am unsure of where to go from here.

I did wget http//xxx.xxx.xxx?wsdl and it returned me what looks like a valid XML response, the same one I get when I go directly to the url in the browser. What should I be looking into in order to solve this issue? All of the past API's I've dealt with have been JSON/RESTful so I feel out of my element trying to debug PHP errors.

Edit

I have slowly deleted parts of my method call and parts of my XML string, trying to trigger a different error or something in order to find what I need to fix. What I have found is that by not passing in my XML string, I get a valid response from the $client->FunctionCall(...). It's an "this isn't right" message but it's a message! In fact, passing that function ANYTHING for the xml parameter causes the 500 http faultcode/faultstring. Does this mean that my XMl is poorly formatted or does it mean that there is an issue on their end handling requests?

Second Edit

If I make my $client decleration as follows, I get the faultstring Could not connect to host

$opts = array(
    'ssl' => array('ciphers'=>'RC4-SHA')
  );
$client = new SoapClient($CREDS['orderingWSDL'], array (
"encoding"=>"ISO-8859-1",
'stream_context' => stream_context_create($opts),
  'exceptions'=>true,
));

I am getting more confused the longer I try to fix this.

Answer 1

Sometimes a 500 status coming from a SOAP service could be a SoapFault exception being thrown. To help your troubleshooting, you'll want to be able to inspect both your request XML, and the response XML.

Put your code in try/catch blocks, and use $client->__getLastRequest() and $client->__getLastResponse() to inspect the actual XML.

Example:

$client = new SoapClient('http//xxx.xxx.xxx?wsdl', array('soap_version'=>SOAP_1_1,'trace' => 1,'exceptions' => true));
try {
  $response = $client->someFunction();
  var_dump($response);
} catch (Exception $e)  {
  var_dump($e->getMessage());
  var_dump($client->__getLastRequest());
  var_dump($client->__getLastResponse());
}