azure directory service implementation w/ config

src/Core/Utilities/AzureAuthenticationProvider.cs

@@ -0,0 +1,33 @@
+using Bit.Core.Services;
+using Microsoft.Graph;
+using Microsoft.IdentityModel.Clients.ActiveDirectory;
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace Bit.Core.Utilities
+{
+    public class AzureAuthenticationProvider : IAuthenticationProvider
+    {
+        public async Task AuthenticateRequestAsync(HttpRequestMessage request)
+        {
+            if(SettingsService.Instance.Server?.Azure == null)
+            {
+                throw new ApplicationException("No server configuration.");
+            }
+
+            var authContext = new AuthenticationContext(
+                $"https://login.windows.net/{SettingsService.Instance.Server.Azure.Tenant}/oauth2/token");
+            var creds = new ClientCredential(SettingsService.Instance.Server.Azure.Id,
+                SettingsService.Instance.Server.Azure.Secret.DecryptToString());
+            var authResult = await authContext.AcquireTokenAsync("https://graph.microsoft.com/", creds);
+            request.Headers.Add("Authorization", $"Bearer {authResult.AccessToken}");
+        }
+
+        // ref: https://github.com/AzureAD/azure-activedirectory-library-for-dotnet/issues/511
+        private static void SomeMethodToLinkPlatform()
+        {
+            var creds = new UserPasswordCredential("user", "pass");
+        }
+    }
+}