Is this a valid SOAP response content-type?

Question

I am attempting to consume a third party WebService in Visual Studio 2008 and am getting a unique response back from the server. This return has two content-type tags.

HTTP/1.0 200 OK  
Server: SMBDK_1/2.3.0  
Date: Thu, 09 Aug 2012 18:59:14 GMT  
Connection: close  
Content-Length: 670  
Content-Type: text/html; charset=ISO-8859-1  
Content-Type: text/xml  
Expires: Thu, 09 Aug 2012 18:59:14 GMT  
Last-Modified: Thu, 09 Aug 2012 18:59:14 GMT  

Is this a common and valid SOAP response or an oddity?

Answer 1

I can't comment on how common it is, but it is not valid (although it fails validity at the HTTP level rather than the SOAP level).

Since we have two content-types:

From http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 :

Multiple message-header fields with the same field-name MAY be present in a message if and only if the entire field-value for that header field is defined as a comma-separated list [ie, #(values)].

So let us look at the content-type header:

From http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.17 :

  Content-Type = "Content-Type" ":" media-type 

and then we expand media-type :

  media-type = type "/" subtype *( ";" parameter ) type = token subtype = token 

That isn't a comma-separated list.