Bearer token authentication failed on asp.net - asp.net

Question

i am trying to make a GET request on a web api. I build the client side. The problem seems to be on the authentication with bearer token. I've already seen a lot of posts but nothing worked.
Here is my code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
namespace AuthUsingBearerToken
{
class Program
{
static void Main(string[] args)
{
RunClient();
Console.ReadLine();
}
static void RunClient()
{
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("uri");//address of web api
client.DefaultRequestHeaders.Accept.Clear();//removes all entries from system.net.http.headers...
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));//adds an entry to system in json format
//First Method i tried
//client.DefaultRequestHeaders.Accept.Add(new AuthenticationHeaderValue("Bearer ", "token from web api));
//Second method
// var token = "token from web api";
// client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
//Third Method
//client.DefaultRequestHeaders.Add("Authorization", "Bearer " + token);
GetPatient(client, "1").Wait();
}
}
public static async Task GetPatient(HttpClient client, string id)
{
try
{
HttpResponseMessage response = await client.GetAsync(""+id);
response.EnsureSuccessStatusCode();
Patient patient = await response.Content.ReadAsAsync<Patient>();
Console.WriteLine("Id: {0}\tName: {1}", patient.id, patient.patient_name);
}
catch (HttpRequestException e)
{
Console.WriteLine("{0}", e.Message);
throw;
}
}
}
My problem is this:
How can i make a Bearer with token authentication?
Or is it somethimg else that i do not do correctly?
Thank you!

Answer 1

You will need to POST a valid request to your web api authorization endpoint (eg. "\token") with the following http body key value pairs : username, password, client_id and grant_type=password. (make sure to follow the Content-Type of your request's header)
for that use await client.PostAsync("token", content);
if the authorization succeeded, you will receive a response with access_token in it. You could use a Token object to deserialize to (ApiToken = await JsonConvert.DeserializeObject<Token>(response.Content.ReadAsStringAsync());
Add that token in your header of any subsequent request that need to be authenticated : Authorization : Bearer {acces_token_value}
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", ApiToken.ToString());
There is a lot of resources on that topic, the most interesting for me was :
http://bitoftech.net/2014/06/01/token-based-authentication-asp-net-web-api-2-owin-asp-net-identity/