Get the raw request that is sent with HttpClient and HttpRequestMessage

Question

In my C# code running .NET 6 (Azure Function) I am sending an HttpRequestMessage using HttpClient. It doesn't work but it should work, so I want to get the raw request that I am sending, including the header, so I can compare with the documentation and see the differences.

In the past I have used Fiddler but it doesn't work for me now, probably because of some security settings on my laptop. So I am looking for a solution within the world of Visual Studio 2022 or .NET 6 where I can get the raw request out for troubleshooting purposes.

This question is not really about code, but here is my code anyway.

HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "https://myendpoint.com/rest/something");

var apiToken = "AOU9FrasdgasdfagtHJNV";
request.Headers.Add("Authorization", "Basic " + apiToken);

var message = new
{
    sender = "Hey",
    message = "Hello world",
    recipients = new[] { new { id = 12345678} }
};

request.Content = new StringContent(JsonSerializer.Serialize(message), Encoding.UTF8, "application/json");
request.Headers.Add("Accept", "application/json, text/javascript");
HttpResponseMessage response = await httpClient.SendAsync(request);

When SendAsync is invoked, I wish to know what exactly is sent, both header and content.

Answer 1

If you cannot use any proxy solution (like Fiddler) then I can see 2 options. One is described in comments in your question to use DelegatingHandler. You can read more about this in documentation. What is interesting is that HttpClient supports logging out of the box which is described in this section https://learn.microsoft.com/en-us/aspnet/core/fundamentals/http-requests?view=aspnetcore-6.0#logging of the article which describes DelegatingHandlers

If you are worried that something will manipulate the outgoing request then you can implement option 2. This is to create temporary asp.net core application with .UseHttpLogging() middleware plugged in into pipeline as described here https://learn.microsoft.com/en-us/aspnet/core/fundamentals/http-logging/?view=aspnetcore-6.0 That way you will know exactly how your request looks like from application which is being requested point of view. Now if you will point your azure function to you temporary app - you should see what gets send

Hope it helps