Headless communcation to Dynamics CRM using application user

d365-app-user-poc.cs

        /// <summary>
        /// Headless communication to dynamics CRM using application user.
        /// More information at : http://www.wrapcode.com/server-authentication-dynamics-crm/
        /// This is just a sample code, there are way better ways to achieve the same. Did not want to spend much time on code snippet.
        /// </summary>
        public static async Task HeadlessAuthenticationPOC()
        {
            var clientCreds = new ClientCredential("{AZURE_AD_APP_ID}", "{AZURE_AD_APP_SECRET}");
            AuthenticationResult authResult = null;
                
            // Call sample API
            try
            {
                authResult = await authContext.AcquireTokenAsync("https://{{TENANT}}.crm4.dynamics.com", clientCreds);
                // Add the access token to the authorization header of the request.
                if(authResult == null)
                        return;
                
                httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", authResult.AccessToken);
                HttpResponseMessage response = await httpClient.GetAsync("https://{{TENANT}}.crm4.dynamics.com/api/data/v8.1/contacts?$top=1");
                if (response.IsSuccessStatusCode)
                {
                    // Read the response and output it to the console.
                    string s = await response.Content.ReadAsStringAsync();
                }
                else
                {
                    Console.WriteLine("Failed to retrieve contact \nError:  {0}\n", response.ReasonPhrase);
                }
            }
            catch (Exception ex)
            {
              _logger.Fatal(ex);
            }
           

        }