Azure Function for acquiring a token from Azure AD, and subsequently use this for auth towards Azure API Management

APIMFunction_02.csx

using System;
using System.Text;
using System.Net.Http;
using System.Net.Http.Headers;
using Newtonsoft.Json;
 
public static void Run(string input, TraceWriter log)
{
  log.Info($"C# manually triggered function called with input: {input}");

  var apimUrl = " https://contosio.azure-api.net/foo/messages";
  var content = "{\"on\":true, \"sat\":254, \"bri\":254, \"hue\":10000}";

  var AADToken = getToken().Result;

  HttpClient Client = new HttpClient();
  Client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", AADToken);
  Client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key","subKey");
  var foo = Client.PostAsync(apimUrl, new StringContent(content.ToString())).Result;
  log.Info($"result: {foo}");
}
 
public static async Task<string> getToken()
{
  var domain = "contoso.onmicrosoft.com";            
  var clientId = "id";
  var clientSecret = "secret";
  var resource = "app uri";

  HttpClient client = new HttpClient();

  string requestUrl = $"https://login.microsoftonline.com/{domain}/oauth2/token";

  string request_content = $"grant_type=client_credentials&resource={resource}&client_id={clientId}&client_secret={clientSecret}&scope=openid";

  HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, requestUrl);
  try
  {
    request.Content = new StringContent(request_content, Encoding.UTF8, "application/x-www-form-urlencoded");
  }
  catch (Exception x)
  {
    var msg = x.Message;                
  }
  HttpResponseMessage response = await client.SendAsync(request);

  string responseString = await response.Content.ReadAsStringAsync();

  GenericToken token = JsonConvert.DeserializeObject<GenericToken>(responseString);
  var at = token.access_token;
  return at;
}
 
internal class GenericToken
{
  public string token_type { get; set; }
  public string scope { get; set; }
  public string resource { get; set; }
  public string access_token { get; set; }
  public string refresh_token { get; set; }
  public string id_token { get; set; }
  public string expires_in { get; set; }
}