• Create a console application add Newtonsoft and Active Directory Authentication Library. Or we can add the below Helper Sample Code package which will add the above libraries.

• Add reference to System.Net.Http

• Register the app

https://nishantrana.wordpress.com/2016/11/13/register-a-dynamics-365-app-with-azure-active-directory/

• Sample Code

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using Microsoft.IdentityModel.Clients.ActiveDirectory;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace Dynamics365ConsoleApp
{
internal class Program
{
// username and password
private const string UserName = "sapnarana@nishant365.onmicrosoft.com";
private const string Password = "mypassword";
// Crm Url
private const string Resource = "https://nishant365.crm8.dynamics.com";
// Application's Client Id
private const string ClientId = "d08b641c-2dc8-4f33-8a57-b1573da88a22";
// Redirct Uri specified during registration of application
private const string RedirectUri = "http://localhost";
// Authroiztion Endpoint
private const string Authority = "https://login.windows.net/nishant365.onmicrosoft.com";

private static AuthenticationResult _authResult;

private static void Main(string[] args)
{
// without prompt
var authContext = new AuthenticationContext(Authority, false);
var credentials = new UserCredential(UserName, Password);
_authResult = authContext.AcquireToken(Resource, ClientId, credentials);

// with prompt
AuthenticationContext authContext = new AuthenticationContext(authority);
authResult = authContext.AcquireToken(resource, clientId, new Uri(redirectUri));

Task.WaitAll(Task.Run(async () => await GetFullNameSystemUsers()));
}

private static async Task GetFullNameSystemUsers()
{
var httpClient = new HttpClient
{
BaseAddress = new Uri(Resource),
Timeout = new TimeSpan(0, 2, 0)
};
httpClient.DefaultRequestHeaders.Add("OData-MaxVersion", "4.0");
httpClient.DefaultRequestHeaders.Add("OData-Version", "4.0");
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer",
_authResult.AccessToken);

var retrieveResponse =
await httpClient.GetAsync("api/data/v8.1/systemusers?$select=fullname");
if (retrieveResponse.IsSuccessStatusCode)
{
var jRetrieveResponse =
JObject.Parse(retrieveResponse.Content.ReadAsStringAsync().Result);

dynamic systemUserObject = JsonConvert.DeserializeObject(jRetrieveResponse.ToString());

foreach (var data in systemUserObject.value)
Console.Write(data.fullname.Value);
}
}
}
}

For in depth understanding please refer the following post

https://debajmecrm.com/2016/02/23/understanding-in-depth-cross-origin-resource-sharing-cors-in-dynamics-crm-2016/

Hope it helps..

• Sign in to Microsoft Azure Management Portal or Sign up for a free trial. The account should be in the same Office 365 tenant where we would like to register the app. (or link existing Azure Subscription not in same tenant as CRM)

https://manage.windowsazure.com/

• Inside Azure Management Portal select Azure Active Directory

• Select App registrations and click Add

• Provide required details for the App and click Create

• Select the App created to get the required details

• To give permission to App to access Dynamics CRM, click on Required Permissions in API Access section

• Click on Add

• Select Dynamics CRM Online

We’d get the notifications.

• Along with Client id we would also need Authorization Endpoint, when we develop App.

Hope it helps..