How to log in only once using Graph API?

I’m developing a small Windows form app to test Graph API functions. I have two functionalities in the application, user's log in and create a team. I created a class that contains a function for creating a GraphServiceClient. I call this function both when the users logs in and when I create a team. The problem is that the user login window is displayed both times, and I want that once the user logs in, to somehow save that GraphServiceClient instance so that the user does not have to double logs in. Here is the code:

public static class GraphManager
{
public static GraphServiceClient graphClient;
private static string[] scopes = new string[] { "user.read" };
public static string TokenForUser = null;
public static DateTimeOffset expiration;
private const string ClientId = "599ed98d-4356-4a96-ad37-04391e9c48dc";
private const string Tenant = "common"; // Alternatively "[Enter your tenant, as obtained from the Azure portal, e.g. kko365.onmicrosoft.com]"
private const string Authority = "https://login.microsoftonline.com/" + Tenant;
// The MSAL Public client app
private static IPublicClientApplication PublicClientApp;
private static string MSGraphURL = "https://graph.microsoft.com/beta/";
private static AuthenticationResult authResult;
public static GraphServiceClient GetGraphClient()
{
if(graphClient == null)
{
// Create Microsoft Graph client.
try
{
graphClient = new GraphServiceClient(
"https://graph.microsoft.com/v1.0",
new DelegateAuthenticationProvider(
async (requestMessage) =>
{
var token = await GetTokenForUserAsync();
requestMessage.Headers.Authorization = new AuthenticationHeaderValue("bearer", token);
// This header has been added to identify our sample in the Microsoft Graph service. If extracting this code for your project please remove.
requestMessage.Headers.Add("SampleID", "uwp-csharp-snippets-sample");
}));
return graphClient;
}
catch (Exception ex)
{
Debug.WriteLine("Could not create a graph client: " + ex.Message);
}
}
return graphClient;
}
public static async Task<string> GetTokenForUserAsync()
{
if (TokenForUser == null || expiration <= DateTimeOffset.UtcNow.AddMinutes(5))
{
PublicClientApp = PublicClientApplicationBuilder.Create(ClientId)
.WithAuthority(Authority)
.WithRedirectUri("https://login.microsoftonline.com/common/oauth2/nativeclient")
.WithLogging((level, message, containsPii) =>
{
Debug.WriteLine($"MSAL: {level} {message} ");
}, LogLevel.Warning, enablePiiLogging: false, enableDefaultPlatformLogging: true)
.Build();
// It's good practice to not do work on the UI thread, so use ConfigureAwait(false) whenever possible.
IEnumerable accounts = await PublicClientApp.GetAccountsAsync().ConfigureAwait(false);
IAccount firstAccount = accounts.FirstOrDefault();
try
{
authResult = await PublicClientApp.AcquireTokenSilent(scopes, firstAccount)
.ExecuteAsync();
}
catch (MsalUiRequiredException ex)
{
// A MsalUiRequiredException happened on AcquireTokenSilentAsync. This indicates you need to call AcquireTokenAsync to acquire a token
Debug.WriteLine($"MsalUiRequiredException: {ex.Message}");
authResult = await PublicClientApp.AcquireTokenInteractive(scopes)
.ExecuteAsync()
.ConfigureAwait(false);
}
TokenForUser = authResult.AccessToken;
}
return TokenForUser;
}
}
private async void button1_Click(object sender, EventArgs e)
{
GraphServiceClient graphClient = GraphManager.GetGraphClient();
User graphUser = await graphClient.Me.Request().GetAsync();
label2.Text = graphUser.DisplayName;
}
private async void button2_Click(object sender, EventArgs e)
{
GraphServiceClient graphClient = GraphManager.GetGraphClient();
var team = new Team
{
DisplayName = "Test1Test2",
Description = "My sample team's description.",
AdditionalData = new Dictionary<string, object>()
{
{"[email protected]", "https://graph.microsoft.com/beta/teamsTemplates('educationClass')" }
}
};
await graphClient.Teams.Request().AddAsync(team);
MessageBox.Show("Successfully created team!");
}

3 Replies

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Kiran Mohanty5y ago
Accepted answer
Every time when you are calling "GetGraphClient()", it is returning a new instance of "GraphServiceClient" . You should keep the Bearer token generated after login in client side (ex- local storage). Before calling graph API for second time, pass the token that was generated after login .
+1
Gordana Tasic5y ago
Thank you very much!
0
Mohsin Azam5y ago
https://www.c-sharpcorner.com/article/read-email-from-mailbox-folders-using-microsoft-graph-api/
+1