Version 3 Beta 1 - Complete re-write

CS/TokenCacheHelperEx.cs

@@ -0,0 +1,57 @@
+// Updated original code from
+// Added support for custom file location
+// https://docs.microsoft.com/en-us/azure/active-directory/develop/msal-net-token-cache-serialization#simple-token-cache-serialization-msal-only
+
+using System;
+using System.IO;
+using System.Security.Cryptography;
+using Microsoft.Identity.Client;
+
+public static class TokenCacheHelperEx
+{
+    public static void EnableSerialization(ITokenCache tokenCache, String fileName = @"%LOCALAPPDATA%\GraphPowerShellManager\MSALToken.bin")
+    {
+        tokenCache.SetBeforeAccess(BeforeAccessNotification);
+        tokenCache.SetAfterAccess(AfterAccessNotification);
+
+        CacheFilePath = Environment.ExpandEnvironmentVariables(fileName);
+    }
+
+    /// <summary>
+    /// Path to the token cache
+    /// </summary>
+
+    public static string CacheFilePath { get; private set;}
+
+    private static readonly object FileLock = new object();
+
+    private static void BeforeAccessNotification(TokenCacheNotificationArgs args)
+    {
+        lock (FileLock)
+        {
+            args.TokenCache.DeserializeMsalV3(File.Exists(CacheFilePath)
+                    ? ProtectedData.Unprotect(File.ReadAllBytes(CacheFilePath),
+                    null,
+                    DataProtectionScope.CurrentUser)
+                    : null);
+        }
+    }
+
+    private static void AfterAccessNotification(TokenCacheNotificationArgs args)
+    {
+        // if the access operation resulted in a cache update
+        if (args.HasStateChanged)
+        {
+            lock (FileLock)
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(CacheFilePath));
+                // reflect changes in the persistent store
+                File.WriteAllBytes(CacheFilePath,
+                                    ProtectedData.Protect(args.TokenCache.SerializeMsalV3(),
+                                                            null,
+                                                            DataProtectionScope.CurrentUser)
+                                    );
+            }
+        }
+    }
+}