Provide a better error message when invoking a non-existant hub method (#2768)

src/Microsoft.AspNetCore.SignalR.Core/Internal/DefaultHubDispatcher.cs

@@ -136,7 +136,7 @@ namespace Microsoft.AspNetCore.SignalR.Internal
         {
             if (!_methods.TryGetValue(methodName, out var descriptor))
             {
-                return Type.EmptyTypes;
+                throw new HubException("Method does not exist.");
             }
             return descriptor.ParameterTypes;
         }

src/Microsoft.AspNetCore.SignalR.Protocols.MessagePack/Protocol/MessagePackHubProtocol.cs

@@ -157,10 +157,10 @@ namespace Microsoft.AspNetCore.SignalR.Protocol
             }
 
             var target = ReadString(input, ref offset, "target");
-            var parameterTypes = binder.GetParameterTypes(target);
 
             try
             {
+                var parameterTypes = binder.GetParameterTypes(target);
                 var arguments = BindArguments(input, ref offset, parameterTypes, resolver);
                 return ApplyHeaders(headers, new InvocationMessage(invocationId, target, arguments));
             }
@@ -175,10 +175,10 @@ namespace Microsoft.AspNetCore.SignalR.Protocol
             var headers = ReadHeaders(input, ref offset);
             var invocationId = ReadInvocationId(input, ref offset);
             var target = ReadString(input, ref offset, "target");
-            var parameterTypes = binder.GetParameterTypes(target);
 
             try
             {
+                var parameterTypes = binder.GetParameterTypes(target);
                 var arguments = BindArguments(input, ref offset, parameterTypes, resolver);
                 return ApplyHeaders(headers, new StreamInvocationMessage(invocationId, target, arguments));
             }

test/Microsoft.AspNetCore.SignalR.Client.FunctionalTests/HubConnectionTests.cs

@@ -464,7 +464,7 @@ namespace Microsoft.AspNetCore.SignalR.Client.FunctionalTests
             bool ExpectedErrors(WriteContext writeContext)
             {
                 return writeContext.LoggerName == DefaultHubDispatcherLoggerName &&
-                       writeContext.EventId.Name == "UnknownHubMethod";
+                       writeContext.EventId.Name == "FailedInvokingHubMethod";
             }
 
             var hubProtocol = HubProtocols[hubProtocolName];
@@ -476,7 +476,40 @@ namespace Microsoft.AspNetCore.SignalR.Client.FunctionalTests
                     await connection.StartAsync().OrTimeout();
 
                     var ex = await Assert.ThrowsAsync<HubException>(() => connection.InvokeAsync("!@#$%")).OrTimeout();
-                    Assert.Equal("Unknown hub method '!@#$%'", ex.Message);
+                    Assert.Equal("Failed to invoke '!@#$%' due to an error on the server. HubException: Method does not exist.", ex.Message);
+                }
+                catch (Exception ex)
+                {
+                    loggerFactory.CreateLogger<HubConnectionTests>().LogError(ex, "{ExceptionType} from test", ex.GetType().FullName);
+                    throw;
+                }
+                finally
+                {
+                    await connection.DisposeAsync().OrTimeout();
+                }
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(HubProtocolsAndTransportsAndHubPaths))]
+        public async Task ServerThrowsHubExceptionIfHubMethodCannotBeResolvedAndArgumentsPassedIn(string hubProtocolName, HttpTransportType transportType, string hubPath)
+        {
+            bool ExpectedErrors(WriteContext writeContext)
+            {
+                return writeContext.LoggerName == DefaultHubDispatcherLoggerName &&
+                       writeContext.EventId.Name == "FailedInvokingHubMethod";
+            }
+
+            var hubProtocol = HubProtocols[hubProtocolName];
+            using (StartVerifiableLog(out var loggerFactory, $"{nameof(ServerThrowsHubExceptionIfHubMethodCannotBeResolvedAndArgumentsPassedIn)}_{hubProtocol.Name}_{transportType}_{hubPath.TrimStart('/')}", expectedErrorsFilter: ExpectedErrors))
+            {
+                var connection = CreateHubConnection(hubPath, transportType, hubProtocol, loggerFactory);
+                try
+                {
+                    await connection.StartAsync().OrTimeout();
+
+                    var ex = await Assert.ThrowsAsync<HubException>(() => connection.InvokeAsync("!@#$%", 10, "test")).OrTimeout();
+                    Assert.Equal("Failed to invoke '!@#$%' due to an error on the server. HubException: Method does not exist.", ex.Message);
                 }
                 catch (Exception ex)
                 {
@@ -563,7 +596,7 @@ namespace Microsoft.AspNetCore.SignalR.Client.FunctionalTests
             bool ExpectedErrors(WriteContext writeContext)
             {
                 return writeContext.LoggerName == DefaultHubDispatcherLoggerName &&
-                       writeContext.EventId.Name == "UnknownHubMethod";
+                       writeContext.EventId.Name == "FailedInvokingHubMethod";
             }
 
             var hubProtocol = HubProtocols[hubProtocolName];
@@ -576,7 +609,7 @@ namespace Microsoft.AspNetCore.SignalR.Client.FunctionalTests
 
                     var channel = await connection.StreamAsChannelAsync<int>("!@#$%");
                     var ex = await Assert.ThrowsAsync<HubException>(() => channel.ReadAllAsync().OrTimeout());
-                    Assert.Equal("Unknown hub method '!@#$%'", ex.Message);
+                    Assert.Equal("Failed to invoke '!@#$%' due to an error on the server. HubException: Method does not exist.", ex.Message);
                 }
                 catch (Exception ex)
                 {

test/Microsoft.AspNetCore.SignalR.Tests/HubConnectionHandlerTests.cs

@@ -799,7 +799,7 @@ namespace Microsoft.AspNetCore.SignalR.Tests
 
                 var result = await client.InvokeAsync(nameof(MethodHub.OnDisconnectedAsync)).OrTimeout();
 
-                Assert.Equal("Unknown hub method 'OnDisconnectedAsync'", result.Error);
+                Assert.Equal("Failed to invoke 'OnDisconnectedAsync' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 // kill the connection
                 client.Dispose();
@@ -837,7 +837,7 @@ namespace Microsoft.AspNetCore.SignalR.Tests
 
                 var result = await client.InvokeAsync(nameof(MethodHub.StaticMethod)).OrTimeout();
 
-                Assert.Equal("Unknown hub method 'StaticMethod'", result.Error);
+                Assert.Equal("Failed to invoke 'StaticMethod' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 // kill the connection
                 client.Dispose();
@@ -858,16 +858,16 @@ namespace Microsoft.AspNetCore.SignalR.Tests
                 var connectionHandlerTask = await client.ConnectAsync(connectionHandler);
 
                 var result = await client.InvokeAsync(nameof(MethodHub.ToString)).OrTimeout();
-                Assert.Equal("Unknown hub method 'ToString'", result.Error);
+                Assert.Equal("Failed to invoke 'ToString' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 result = await client.InvokeAsync(nameof(MethodHub.GetHashCode)).OrTimeout();
-                Assert.Equal("Unknown hub method 'GetHashCode'", result.Error);
+                Assert.Equal("Failed to invoke 'GetHashCode' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 result = await client.InvokeAsync(nameof(MethodHub.Equals)).OrTimeout();
-                Assert.Equal("Unknown hub method 'Equals'", result.Error);
+                Assert.Equal("Failed to invoke 'Equals' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 result = await client.InvokeAsync(nameof(MethodHub.ReferenceEquals)).OrTimeout();
-                Assert.Equal("Unknown hub method 'ReferenceEquals'", result.Error);
+                Assert.Equal("Failed to invoke 'ReferenceEquals' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 // kill the connection
                 client.Dispose();
@@ -889,7 +889,7 @@ namespace Microsoft.AspNetCore.SignalR.Tests
 
                 var result = await client.InvokeAsync(nameof(MethodHub.Dispose)).OrTimeout();
 
-                Assert.Equal("Unknown hub method 'Dispose'", result.Error);
+                Assert.Equal("Failed to invoke 'Dispose' due to an error on the server. HubException: Method does not exist.", result.Error);
 
                 // kill the connection
                 client.Dispose();