How to add headers to httpclient .NET 4.7.2

Question

How to add the below headers to httpclient .NET 4.7.2. and How to add this json to the body of a PUT request?

I did not create the server I put test to sensor the data its a third party plugin. Using the header setting and the Json body in Postman client app with the Postman Agent app this works. But it does not work when trying through C# I am getting Error: 400 Bad request.

Cache-Control -> no-cache
Postman-Token -> <calculated when request is sent>
Content-Type  -> application/json
Content-Length -> <calculated when request is sent>
Host -> <calculated when request is sent>
User-Agent -> Postman Runtime/7.29.0
Accept -> */*
Accept-Encoding -> gzip,deflate,br

Json:

{
    "objectPath": "/TestData1/TestData2/_C++TestData3/TestData6.TestData8:TestData15",
    "functionName": "Test_FuncCall",
    "generateTransaction": true
}

Code:

static void Main(string[] args)
{
    using (var client = new HttpClient())
    {
        JObject data = JObject.Parse(File.ReadAllText(@"D:\data.txt"));


        client.BaseAddress = new Uri("http://127.0.0.1:5555/");

        var content = new StringContent(data.ToString(), Encoding.UTF8, "application/json");


        var response = client.PutAsync("test1/test2/test3", content).Result;

        if (response.IsSuccessStatusCode)
        {
            Console.Write("Success");
        }
        else
            Console.Write("Error");
    }
    Console.ReadKey();
}

One step after break point then hover over response:

{StatusCode: 400, ReasonPhrase: '', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
  Access-Control-Allow-Origin: *
  Access-Control-Allow-Methods: PUT, POST, GET, OPTIONS
  Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
  Access-Control-Max-Age: 600
  keep-alive: timeout=15.000000
  Content-Length: 67
  Content-Type: application/json
}}

This Works:

Call:

  TestServer yyy = new TestServer();
            JObject data2 = JObject.Parse(File.ReadAllText(@"D:\data.txt"));
            yyy.SendRequest("http://127.0.0.1:5555/test1/test2/test3", "PUT", data2.ToString(), false);

function:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestURIString);
request.UserAgent = "Test App";
request.Method = method;

if (body != "")
{
     p_CurrentAPIRequest = body;
    request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), request);
}
else
    request.BeginGetResponse(new AsyncCallback(GetResponseCallback), request);

allDone.WaitOne();

Answer 1

The simplest way to get web request code from Postman is to use its Code feature.

And then select RestSharp from the dropdown,

Answer 2

You can use DefaultRequestHeaders.Add() method in the following way:

HttpClient = new HttpClient();
HttpClient.DefaultRequestHeaders.Add("ApiKey", key);
HttpClient.DefaultRequestHeaders.Add("Authorization", String.Format("Bearer {0}", token));