Restore IISServerSetupFilter server type check

2 files changed, 27 insertions, 0 deletions

diff --git a/src/Servers/IIS/IIS/src/Core/IISServerSetupFilter.cs b/src/Servers/IIS/IIS/src/Core/IISServerSetupFilter.cs
new file mode 100644
index 0000000000..97a0f0e3b4
--- /dev/null
+++ b/src/Servers/IIS/IIS/src/Core/IISServerSetupFilter.cs
@@ -0,0 +1,26 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.Server;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Microsoft.AspNetCore.Server.IIS.Core;
+
+internal sealed class IISServerSetupFilter : IStartupFilter
+{
+    public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
+    {
+        return app =>
+        {
+            var server = app.ApplicationServices.GetService<IServer>();
+            if (server?.GetType() != typeof(IISHttpServer))
+            {
+                throw new InvalidOperationException("Application is running inside IIS process but is not configured to use IIS server.");
+            }
+
+            next(app);
+        };
+    }
+}
diff --git a/src/Servers/IIS/IIS/src/WebHostBuilderIISExtensions.cs b/src/Servers/IIS/IIS/src/WebHostBuilderIISExtensions.cs
index bb6be412e3..302f1af5a6 100644
--- a/src/Servers/IIS/IIS/src/WebHostBuilderIISExtensions.cs
+++ b/src/Servers/IIS/IIS/src/WebHostBuilderIISExtensions.cs
@@ -37,6 +37,7 @@ public static class WebHostBuilderIISExtensions
                     services.AddSingleton(new IISNativeApplication(new NativeSafeHandle(iisConfigData.pNativeApplication)));
                     services.AddSingleton<IServer, IISHttpServer>();
                     services.AddTransient<IISServerAuthenticationHandlerInternal>();
+                    services.AddSingleton<IStartupFilter, IISServerSetupFilter>();
                     services.AddAuthenticationCore();
                     services.AddSingleton<IServerIntegratedAuth>(_ => new ServerIntegratedAuth()
                     {