At one point in recent history, VB.Net was one of the most popular development languages around. In fact, there are many legacy applications written in VB.Net and even still, VB.Net is still in the top 10 languages ( source: https://www.techworm.net/2018/02/popular-programming-languages-2018-according-tiobe-pypl.html ). I will show a simple console application using VB.Net to authenticate using MSAL.Net
Of course, the first step, as in everything Azure, starts with setting up an app registration to use for Authentication. For this demonstration, I created a single tenant app registration with the following Redirect URI configured ( urn:ietf:wg:oauth:2.0:oob ):
There is nothing else special about this app registration.
Now, for the code. To start with, you must install the Microsoft.Identity.Client from the Nuget package manager. I will present to you sample VB.Net code that performs authentication synchronously, then asynchronously.
Imports Microsoft.Identity.Client
Module Module1
Private _accessToken As String = String.Empty
Private Const client_id As String = "{client_id}" '<-- enter the client_id guid here
Private Const tenant_id As String = "{tenant_id}" '<-- enter either your tenant id here
Private authority As String = $"https://login.microsoftonline.com/{tenant_id}"
Private scopes As New List(Of String)
Sub Main()
scopes.Add($"{client_id}/.default")
Console.WriteLine("Starting Synchronous Sample...")
SyncSample()
Console.WriteLine($"{Environment.NewLine}End Synchronous Sample...{Environment.NewLine}Start Asynchronous Sample...")
AsyncSample()
Console.WriteLine($"{Environment.NewLine}End Asynchronous Sample.{Environment.NewLine}Press any key to close...")
Console.ReadKey()
End Sub
#Region "Synchronous Code"
Private Sub SyncSample()
If Login() Then
Console.WriteLine(_accessToken)
Else
Console.WriteLine("Not Authorized")
End If
End Sub
Private Function Login() As Boolean
Dim publicClientApp As IPublicClientApplication
publicClientApp = PublicClientApplicationBuilder.Create(client_id).WithAuthority(authority).Build()
Dim accounts As IEnumerable(Of IAccount) = publicClientApp.GetAccountsAsync().Result()
Dim firstAccount As IAccount = accounts.FirstOrDefault()
Dim authResult As AuthenticationResult
Try
authResult = publicClientApp.AcquireTokenSilent(scopes, firstAccount).ExecuteAsync().Result()
Catch e As MsalUiRequiredException
Try
authResult = publicClientApp.AcquireTokenInteractive(scopes).ExecuteAsync().Result()
Catch ex As Exception
'user cancelled
Return False
End Try
Catch ex As Exception
Console.WriteLine($"Auth Exception: {ex.Message}")
Return False
End Try
_accessToken = authResult.AccessToken
Return True
End Function
#End Region
#Region "Asynchronous Code"
Private Sub AsyncSample()
Dim task As Task(Of Boolean) = LoginTask()
If task.Result() Then
Console.WriteLine(_accessToken)
Else
Console.WriteLine("Not Authorized")
End If
End Sub
Private Async Function LoginTask() As Task(Of Boolean)
Dim publicClientApp As IPublicClientApplication
publicClientApp = PublicClientApplicationBuilder.Create(client_id).WithAuthority(authority).Build()
Dim accounts As IEnumerable(Of IAccount) = Await publicClientApp.GetAccountsAsync()
Dim firstAccount As IAccount = accounts.FirstOrDefault()
Dim authResult As AuthenticationResult
Dim tryInteractive As Boolean = False
Try
authResult = Await publicClientApp.AcquireTokenSilent(scopes, firstAccount).ExecuteAsync()
_accessToken = authResult.AccessToken
Catch e As MsalUiRequiredException
tryInteractive = True
End Try
If tryInteractive Then
Try
authResult = Await publicClientApp.AcquireTokenInteractive(scopes).ExecuteAsync()
_accessToken = authResult.AccessToken
Catch ex As Exception
Return False
End Try
End If
Return _accessToken <> String.Empty
End Function
#End Region
End Module
Although there are quite a few differences from our C# samples, we can still leverage MSAL in our VB.Net code as well with some minor changes.
UPDATE: 06/18/2020
To clear up some confusion about the redirect URI, please try selecting the default MSAL redirect from the portal that is created when you create the app registration and after selecting that by clicking the checkbox, click the save button:
Then, modify your code to add the .WithRedirectUri parameter like so:
publicClientApp = PublicClientApplicationBuilder.Create(client_id).WithAuthority(authority).WithRedirectUri(“msal28a00d08-ba05-4015-a269-9d0546e850b9://auth”).Build()
The redirect URI I had in this post, I obtained to see what the default was sent during authentication by running fiddler, in an attempt to make this more universal for everyone, which apparently isn’t the case š
