Throw better exceptions when invalid actor interfaces are used.

src/Dapr.Actors/Client/ActorProxyFactory.cs

@@ -1,4 +1,4 @@
-// ------------------------------------------------------------------------
+// ------------------------------------------------------------------------
 // Copyright 2021 The Dapr Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -14,6 +14,7 @@
 namespace Dapr.Actors.Client
 {
     using System;
+    using System.Globalization;
     using System.Net.Http;
     using Dapr.Actors.Builder;
     using Dapr.Actors.Communication;
@@ -77,6 +78,16 @@ public ActorProxy Create(ActorId actorId, string actorType, ActorProxyOptions op
         /// <inheritdoc/>
         public object CreateActorProxy(ActorId actorId, Type actorInterfaceType, string actorType, ActorProxyOptions options = null)
         {
+            if (!actorInterfaceType.IsAssignableFrom(actorInterfaceType))
+            {
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, "The actor interface type '{0}' must implement IActor.", actorInterfaceType), nameof(actorInterfaceType));
+            }
+
+            if (!actorInterfaceType.IsVisible)
+            {
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, "The actor interface type '{0}' must be public.", actorInterfaceType), nameof(actorInterfaceType));
+            }
+
             options ??= this.DefaultOptions;
 
             var daprInteractor = new DaprHttpInteractor(this.handler, options.HttpEndpoint, options.DaprApiToken, options.RequestTimeout);

test/Dapr.Actors.Test/ActorProxyTests.cs

@@ -1,4 +1,4 @@
-// ------------------------------------------------------------------------
+// ------------------------------------------------------------------------
 // Copyright 2021 The Dapr Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -119,5 +119,41 @@ public void SetActorProxyFactoryDefaultOptions_ToNull_ThrowsArgumentNullExceptio
 
             action.Should().Throw<ArgumentNullException>();
         }
+
+        public interface INonActor
+        {
+        }
+
+        [Fact]
+        public void CreateActorProxyForNonActorInterfaces()
+        {
+            var factory = new ActorProxyFactory();
+
+            var actorId = new ActorId("abc");
+
+            Assert.Throws<ArgumentException>(() => factory.CreateActorProxy(actorId, typeof(INonActor), "NonActor"));
+        }
+
+        internal interface IInternalActor : IActor
+        {
+        }
+
+        internal interface IInternalActor2 : IInternalActor
+        {
+        }
+
+        [Fact]
+        public void CreateActorProxyForNonPublicActorInterfaces()
+        {
+            var factory = new ActorProxyFactory();
+
+            var actorId = new ActorId("abc");
+
+            Assert.Throws<ArgumentException>(() => factory.CreateActorProxy<IInternalActor>(actorId, "InternalActor"));
+            Assert.Throws<ArgumentException>(() => factory.CreateActorProxy<IInternalActor2>(actorId, "InternalActor2"));
+
+            Assert.Throws<ArgumentException>(() => factory.CreateActorProxy(actorId, typeof(IInternalActor), "InternalActor"));
+            Assert.Throws<ArgumentException>(() => factory.CreateActorProxy(actorId, typeof(IInternalActor2), "InternalActor2"));
+        }
     }
 }