DIF DIF - 2 months ago 21x
C# Question

Does RestSharp overwrite manually set Content-Type?

I'm creating a RestSharp.RestRequest via:

RestRequest request = new RestRequest();
request.Method = Method.POST;
request.Resource = "/rest-uri";

request.AddHeader("Content-Type", "application/someContentType");

string xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>" + Environment.NewLine +
"<register-request">" + Environment.NewLine +
" <name=\"someName\"/>" + Environment.NewLine +

request.AddParameter("text/xml", registerSinkRequest, ParameterType.RequestBody);

(The Content-Type is manually set to

In debug-mode it also shows

But executing the RestRequest returns an
415 Media Not Supported
-Error and WireShark shows that the Media-Type is set to
(like set in the AddParameter-Method).

Why is RestSharp showing a different Content-Type then WireShark? And how can I prevent the Content-Type to be changed (if it is)?


svick's comment is right. Set the content type in the first parameter of AddParameter() and you can leave out the AddHeader() call.

While that's the 'right' answer, I'll explain why it has a confusing method for doing this that's not exactly obvious.

The intended way to accomplish this is to use AddBody() along with RestRequest.RequestFormat. An example:

var client = new RestClient();
// client.XmlSerializer = new XmlSerializer(); // default
// client.XmlSerializer = new SuperXmlSerializer(); // can override with any implementaiton of ISerializer

var request = new RestRequest();
request.RequestFormat = DataFormat.Xml;

The serialization of objectToSerialize is based on the registered XmlSerializer. If you use RequestFormat = DataFormat.Json, then the RestClient.JsonSerializer is used. Implementations of ISerializer (which you can use to override the default serialization) declare their own Content-Types which is what gets passed through the janky AddParameter() overload you're using.

AddParameter(contentType, content, ParameterType.RequestBody) was never meant to be called directly. It was added as a workaround to pass though data from AddBody() but then other things became dependent on it so it stuck around. It was a terrible decision in hindsight but it's too late to change it in the 1xx version line. If I ever build another version I'll make this more obvious.