How do you send a certificate with an HttpRequestMessage?

Question

Here I have an HttpRequestMessage, and I am trying to add a client certificate to it, but cannot seem to find how to do this. Has anyone out there done something like this?

HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, "myapi/?myParm=" + aParm);
//Want to add a certificate to request - a .p12 file in my project
myAPIResponse res = await SendAndReadAsAsync<myAPIResponse>(request, aCancelToken);

Answer 1

Here is an answer combining HttpClient with HttpRequestMessage.

The HttpRequestMessage holding the data and client handling how the data is sent.

WebRequestHandler handler = new WebRequestHandler();
X509Certificate certificate = GetMyX509Certificate();
handler.ClientCertificates.Add(certificate);
HttpClient client = new HttpClient(handler);
var request = new HttpRequestMessage (HttpMethod.Get, "myapi/?myParm=" + aParm);
HttpResponseMessage response = await client.SendAsync (request);
response.EnsureSuccessStatusCode();

Edit: Here is a link explaining the difference between WebRequestHandler, HttpClientHandler & HttpClient to understand which one you should use when: https://docs.microsoft.com/en-us/archive/blogs/henrikn/httpclient-httpclienthandler-and-webrequesthandler-explained