How to reuse an interactive session (CreateWithInteractiveLogin)

[tiagoduarte]

I have a small C# console application that connects to SharePoint Online using CreateWithInteractiveLogin.
I try to reuse the session inside my code so that only one prompt is presented during the entire script execution, and it all works well.
However, everytime the script finishes and I run it again for the first time, there will be a prompt.

Similar scripts (pnp powershell, graph poweshell) tend to store the credentials for some time and avoid promts at least within minutes or hours of a previous prompt.

Is there a way to cache the credentials somehow so that they are reusable between uses of the console application?

I suppose that there must be a way, either using a different method other than CreateWithInteractiveLogin, or by tweaking some of CreateWithInteractiveLogin's parameters.

Thanks.

Update
It seems that tokenCacheCallback can maybe be used for this

AuthManager = PnP.Framework.AuthenticationManager.CreateWithInteractiveLogin(
APP_ID,
null,
TENANT_ID,
PnP.Framework.AzureEnvironment.Production,
tokenCacheCallback: (tokenCache) =>
{
// 1. Add logic here to load existing cache from a file
// 2. Add logic here to save updated cache back to the file
// Refer to MSAL documentation for "Cross-platform token cache serialization"
}
);

[tiagoduarte]

ok I managed to implement this.

method call:

AuthManager = PnP.Framework.AuthenticationManager.CreateWithInteractiveLogin(
APP_ID,
null,
TENANT_ID,
PnP.Framework.AzureEnvironment.Production,
tokenCacheCallback: (tokenCache) =>
{
TokenCacheHelper.EnableSerialization(tokenCache);
}
);

token helper class:

using Microsoft.Identity.Client;
using System.IO;

public static class TokenCacheHelper
{
    private static readonly object FileLock = new object();
    private static string CacheFilePath = "msal_token_cache.bin";

    public static void EnableSerialization(ITokenCache tokenCache)
    {
        tokenCache.SetBeforeAccess(BeforeAccessNotification);
        tokenCache.SetAfterAccess(AfterAccessNotification);
    }

    private static void BeforeAccessNotification(TokenCacheNotificationArgs args)
    {
        lock (FileLock)
        {
            if (File.Exists(CacheFilePath))
            {
                byte[] data = File.ReadAllBytes(CacheFilePath);
                args.TokenCache.DeserializeMsalV3(data);
            }
        }
    }

    private static void AfterAccessNotification(TokenCacheNotificationArgs args)
    {
        // Only write if cache changed
        if (args.HasStateChanged)
        {
            lock (FileLock)
            {
                byte[] data = args.TokenCache.SerializeMsalV3();
                File.WriteAllBytes(CacheFilePath, data);
            }
        }
    }
}