From b145b505acfe687b3d6aa7e86f3aa42876da161b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20Gether=20S=C3=B8rensen?= <mso@delegate.dk>
Date: Thu, 5 Jun 2025 19:53:48 +0200
Subject: [PATCH] Add Microsoft.Extensions.Caching.Memory and
 Microsoft.Extensions.DependencyInjection packages for improved caching and
 dependency management

---
 .../DataverseConnection.csproj                |  2 ++
 .../ServiceCollectionExtensions.cs            | 29 ++++++++++++++++++-
 DataverseWhoAmI/DataverseWhoAmI.csproj        |  1 +
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/DataverseConnection/DataverseConnection.csproj b/DataverseConnection/DataverseConnection.csproj
index 90410b6..1cc72da 100644
--- a/DataverseConnection/DataverseConnection.csproj
+++ b/DataverseConnection/DataverseConnection.csproj
@@ -14,6 +14,8 @@
   <ItemGroup>
     <PackageReference Include="Azure.Identity" Version="1.13.2" />
     <PackageReference Include="Microsoft.PowerPlatform.Dataverse.Client" Version="1.2.7" />
+    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
   </ItemGroup>
 
 </Project>
diff --git a/DataverseConnection/ServiceCollectionExtensions.cs b/DataverseConnection/ServiceCollectionExtensions.cs
index 68226d2..27c6666 100644
--- a/DataverseConnection/ServiceCollectionExtensions.cs
+++ b/DataverseConnection/ServiceCollectionExtensions.cs
@@ -5,6 +5,7 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.PowerPlatform.Dataverse.Client;
 using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Caching.Memory;
 
 namespace DataverseConnection
 {
@@ -40,6 +41,9 @@ public static IServiceCollection AddDataverse(this IServiceCollection services,
             var options = new DataverseOptions();
             configureOptions?.Invoke(options);
 
+            // Ensure MemoryCache is registered
+            services.AddMemoryCache();
+
             services.AddSingleton(sp =>
             {
                 // Determine DataverseUrl: options first, then configuration
@@ -56,11 +60,34 @@ public static IServiceCollection AddDataverse(this IServiceCollection services,
                 var credential = options.TokenCredential ?? new DefaultAzureCredential();
                 var resource = $"{new Uri(dataverseUrl).GetLeftPart(UriPartial.Authority)}/.default";
 
+                var memoryCache = sp.GetRequiredService<IMemoryCache>();
+
                 // Token provider function for ServiceClient
                 async Task<string> TokenProvider(string url)
                 {
-                    var tokenRequestContext = new TokenRequestContext(new[] { resource });
+                    var cacheKey = $"dataverse_token_{resource}";
+                    if (memoryCache.TryGetValue<string>(cacheKey, out var cachedToken) && cachedToken != null)
+                        return cachedToken;
+
+                    var tokenRequestContext = new TokenRequestContext([resource]);
                     var token = await credential.GetTokenAsync(tokenRequestContext, default);
+
+                    // Set expiration 5 minutes before actual expiry, but never in the past
+                    var expiresOn = token.ExpiresOn.UtcDateTime;
+                    var now = DateTime.UtcNow;
+                    var expiration = expiresOn - TimeSpan.FromMinutes(5);
+                    if (expiration <= now)
+                    {
+                        // If token lifetime is less than 5 minutes, expire 1 minute before, or immediately if needed
+                        expiration = expiresOn > now.AddMinutes(1) ? expiresOn - TimeSpan.FromMinutes(1) : now.AddSeconds(10);
+                    }
+
+                    var cacheEntryOptions = new MemoryCacheEntryOptions
+                    {
+                        AbsoluteExpiration = expiration
+                    };
+                    memoryCache.Set(cacheKey, token.Token, cacheEntryOptions);
+
                     return token.Token;
                 }
 
diff --git a/DataverseWhoAmI/DataverseWhoAmI.csproj b/DataverseWhoAmI/DataverseWhoAmI.csproj
index a4de6c7..2e903d9 100644
--- a/DataverseWhoAmI/DataverseWhoAmI.csproj
+++ b/DataverseWhoAmI/DataverseWhoAmI.csproj
@@ -22,6 +22,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration" Version="8.0.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="8.0.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
   </ItemGroup>
   <ItemGroup>
     <None Update="appsettings.json">