From 32ef3eb35522f1f3bf1c90a82c9656cc4ffe57fe Mon Sep 17 00:00:00 2001
From: Mikael Mengistu <mikaelm12@users.noreply.github.com>
Date: Tue, 8 Aug 2017 17:39:09 -0700
Subject: [PATCH] Hub<T> (#689)

---
 build/dependencies.props                      |   1 +
 samples/SocketsSample/Hubs/HubTChat.cs        |  56 +++++
 samples/SocketsSample/Startup.cs              |   1 +
 samples/SocketsSample/wwwroot/index.html      |   6 +
 src/Microsoft.AspNetCore.SignalR/Hub`T.cs     |  23 ++
 .../IHubClients`T.cs                          |  20 ++
 .../Microsoft.AspNetCore.SignalR.csproj       |   1 +
 .../TypedClientBuilder.cs                     | 227 ++++++++++++++++++
 .../TypedHubClients.cs                        |  32 +++
 .../HubEndpointTests.cs                       |  83 +++++++
 10 files changed, 450 insertions(+)
 create mode 100644 samples/SocketsSample/Hubs/HubTChat.cs
 create mode 100644 src/Microsoft.AspNetCore.SignalR/Hub`T.cs
 create mode 100644 src/Microsoft.AspNetCore.SignalR/IHubClients`T.cs
 create mode 100644 src/Microsoft.AspNetCore.SignalR/TypedClientBuilder.cs
 create mode 100644 src/Microsoft.AspNetCore.SignalR/TypedHubClients.cs

diff --git a/build/dependencies.props b/build/dependencies.props
index ba251f86df..e9ecbf69e3 100644
--- a/build/dependencies.props
+++ b/build/dependencies.props
@@ -16,6 +16,7 @@
     <XunitVersion>2.3.0-beta2-*</XunitVersion>
     <RxVersion>3.1.1</RxVersion>
     <MsgPackVersion>0.9.0-beta2</MsgPackVersion>
+    <SystemReflectionEmitVersion>4.3.0</SystemReflectionEmitVersion>
     <!--
       TODO remove in next update of xunit
       Prevent bug in xunit.analyzer from failing the build.
diff --git a/samples/SocketsSample/Hubs/HubTChat.cs b/samples/SocketsSample/Hubs/HubTChat.cs
new file mode 100644
index 0000000000..c96b3867e4
--- /dev/null
+++ b/samples/SocketsSample/Hubs/HubTChat.cs
@@ -0,0 +1,56 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.SignalR;
+
+namespace SocketsSample.Hubs
+{
+    public class HubTChat : Hub<IChatClient>
+    {
+        public override async Task OnConnectedAsync()
+        {
+            await Clients.All.Send($"{Context.ConnectionId} joined");
+        }
+
+        public override async Task OnDisconnectedAsync(Exception ex)
+        {
+            await Clients.All.Send($"{Context.ConnectionId} left");
+        }
+
+        public Task Send(string message)
+        {
+            return Clients.All.Send($"{Context.ConnectionId}: {message}");
+        }
+
+        public Task SendToGroup(string groupName, string message)
+        {
+            return Clients.Group(groupName).Send($"{Context.ConnectionId}@{groupName}: {message}");
+        }
+
+        public async Task JoinGroup(string groupName)
+        {
+            await Groups.AddAsync(Context.ConnectionId, groupName);
+
+            await Clients.Group(groupName).Send($"{Context.ConnectionId} joined {groupName}");
+        }
+
+        public async Task LeaveGroup(string groupName)
+        {
+            await Groups.RemoveAsync(Context.ConnectionId, groupName);
+
+            await Clients.Group(groupName).Send($"{Context.ConnectionId} left {groupName}");
+        }
+
+        public Task Echo(string message)
+        {
+            return Clients.Client(Context.ConnectionId).Send($"{Context.ConnectionId}: {message}");
+        }
+    }
+
+    public interface IChatClient
+    {
+        Task Send(string message);
+    }
+}
diff --git a/samples/SocketsSample/Startup.cs b/samples/SocketsSample/Startup.cs
index 4b3b90715a..6c68af5414 100644
--- a/samples/SocketsSample/Startup.cs
+++ b/samples/SocketsSample/Startup.cs
@@ -50,6 +50,7 @@ namespace SocketsSample
                 routes.MapHub<DynamicChat>("dynamic");
                 routes.MapHub<Chat>("default");
                 routes.MapHub<Streaming>("streaming");
+                routes.MapHub<HubTChat>("hubT");
             });
 
             app.UseSockets(routes =>
diff --git a/samples/SocketsSample/wwwroot/index.html b/samples/SocketsSample/wwwroot/index.html
index 9c45d8c636..d9d0c9209f 100644
--- a/samples/SocketsSample/wwwroot/index.html
+++ b/samples/SocketsSample/wwwroot/index.html
@@ -24,6 +24,12 @@
         <li><a href="hubs.html?transport=ServerSentEvents&hubType=dynamic">Server Sent Events</a></li>
         <li><a href="hubs.html?transport=WebSockets&hubType=dynamic">Web Sockets</a></li>
     </ul>
+    <h1>ASP.NET Core SignalR (Hub&lt;T&gt;)</h1>
+    <ul>
+        <li><a href="hubs.html?transport=LongPolling&hubType=hubT">Long polling</a></li>
+        <li><a href="hubs.html?transport=ServerSentEvents&hubType=hubT">Server Sent Events</a></li>
+        <li><a href="hubs.html?transport=WebSockets&hubType=hubT">Web Sockets</a></li>
+    </ul>
     <h1>ASP.NET Core SignalR (Streaming)</h1>
     <ul>
         <li><a href="streaming.html?transport=LongPolling">Long polling</a></li>
diff --git a/src/Microsoft.AspNetCore.SignalR/Hub`T.cs b/src/Microsoft.AspNetCore.SignalR/Hub`T.cs
new file mode 100644
index 0000000000..c7583cb29d
--- /dev/null
+++ b/src/Microsoft.AspNetCore.SignalR/Hub`T.cs
@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.SignalR
+{
+    public class Hub<T> : Hub where T : class
+    {
+        private IHubClients<T> _clients;
+
+        public new IHubClients<T> Clients
+        {
+            get
+            {
+                if (_clients == null)
+                {
+                    _clients = new TypedHubClients<T>(base.Clients);
+                }
+                return _clients;
+            }
+            set { _clients = value; }
+        }
+    }
+}
diff --git a/src/Microsoft.AspNetCore.SignalR/IHubClients`T.cs b/src/Microsoft.AspNetCore.SignalR/IHubClients`T.cs
new file mode 100644
index 0000000000..637e0da43d
--- /dev/null
+++ b/src/Microsoft.AspNetCore.SignalR/IHubClients`T.cs
@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Microsoft.AspNetCore.SignalR
+{
+    public interface IHubClients<T>
+    {
+        T All { get; }
+
+        T Client(string connectionId);
+
+        T Group(string groupName);
+
+        T User(string userId);
+    }
+}
diff --git a/src/Microsoft.AspNetCore.SignalR/Microsoft.AspNetCore.SignalR.csproj b/src/Microsoft.AspNetCore.SignalR/Microsoft.AspNetCore.SignalR.csproj
index eb316c5cea..8875a9b7de 100644
--- a/src/Microsoft.AspNetCore.SignalR/Microsoft.AspNetCore.SignalR.csproj
+++ b/src/Microsoft.AspNetCore.SignalR/Microsoft.AspNetCore.SignalR.csproj
@@ -19,6 +19,7 @@
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.ClosedGenericMatcher.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
     <PackageReference Include="Microsoft.Extensions.ObjectMethodExecutor.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
+    <PackageReference Include="System.Reflection.Emit" Version="$(SystemReflectionEmitVersion)" />
     <PackageReference Include="Newtonsoft.Json" Version="$(JsonNetVersion)" />
   </ItemGroup>
 
diff --git a/src/Microsoft.AspNetCore.SignalR/TypedClientBuilder.cs b/src/Microsoft.AspNetCore.SignalR/TypedClientBuilder.cs
new file mode 100644
index 0000000000..594ea6b42a
--- /dev/null
+++ b/src/Microsoft.AspNetCore.SignalR/TypedClientBuilder.cs
@@ -0,0 +1,227 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Reflection;
+using System.Reflection.Emit;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.SignalR
+{
+    internal static class TypedClientBuilder<T>
+    {
+        private const string ClientModuleName = "Microsoft.AspNetCore.SignalR.TypedClientBuilder";
+
+        // There is one static instance of _builder per T
+        private static Lazy<Func<IClientProxy, T>> _builder = new Lazy<Func<IClientProxy, T>>(() => GenerateClientBuilder());
+
+        public static T Build(IClientProxy proxy)
+        {
+            return _builder.Value(proxy);
+        }
+
+        public static void Validate()
+        {
+            // The following will throw if T is not a valid type
+            _  = _builder.Value;
+        }
+
+        private static Func<IClientProxy, T> GenerateClientBuilder()
+        {
+            VerifyInterface(typeof(T));
+
+            var assemblyName = new AssemblyName(ClientModuleName);
+            var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
+            var moduleBuilder = assemblyBuilder.DefineDynamicModule(ClientModuleName);
+            var clientType = GenerateInterfaceImplementation(moduleBuilder);
+
+            return proxy => (T)Activator.CreateInstance(clientType, proxy);
+        }
+
+        private static Type GenerateInterfaceImplementation(ModuleBuilder moduleBuilder)
+        {
+            var type = moduleBuilder.DefineType(
+                ClientModuleName + "." + typeof(T).Name + "Impl",
+                TypeAttributes.Public,
+                typeof(Object),
+                new[] { typeof(T) });
+
+            var proxyField = type.DefineField("_proxy", typeof(IClientProxy), FieldAttributes.Private);
+
+            BuildConstructor(type, proxyField);
+
+            foreach (var method in GetAllInterfaceMethods(typeof(T)))
+            {
+                BuildMethod(type, method, proxyField);
+            }
+
+            return type.CreateTypeInfo();
+        }
+
+        private static IEnumerable<MethodInfo> GetAllInterfaceMethods(Type interfaceType)
+        {
+            foreach (var parent in interfaceType.GetInterfaces())
+            {
+                foreach (var parentMethod in GetAllInterfaceMethods(parent))
+                {
+                    yield return parentMethod;
+                }
+            }
+
+            foreach (var method in interfaceType.GetMethods())
+            {
+                yield return method;
+            }
+        }
+
+        private static void BuildConstructor(TypeBuilder type, FieldInfo proxyField)
+        {
+            var method = type.DefineMethod(".ctor", System.Reflection.MethodAttributes.Public | System.Reflection.MethodAttributes.HideBySig);
+
+            var ctor = typeof(object).GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
+                null, new Type[] { }, null);
+
+            method.SetReturnType(typeof(void));
+            method.SetParameters(typeof(IClientProxy));
+
+            var generator = method.GetILGenerator();
+
+            // Call object constructor
+            generator.Emit(OpCodes.Ldarg_0);
+            generator.Emit(OpCodes.Call, ctor);
+
+            // Assign constructor argument to the proxyField
+            generator.Emit(OpCodes.Ldarg_0); // type
+            generator.Emit(OpCodes.Ldarg_1); // type proxyfield
+            generator.Emit(OpCodes.Stfld, proxyField); // type.proxyField = proxyField
+            generator.Emit(OpCodes.Ret);
+        }
+
+        private static void BuildMethod(TypeBuilder type, MethodInfo interfaceMethodInfo, FieldInfo proxyField)
+        {
+            var methodAttributes =
+                  MethodAttributes.Public
+                | MethodAttributes.Virtual
+                | MethodAttributes.Final
+                | MethodAttributes.HideBySig
+                | MethodAttributes.NewSlot;
+
+            ParameterInfo[] parameters = interfaceMethodInfo.GetParameters();
+            Type[] paramTypes = parameters.Select(param => param.ParameterType).ToArray();
+
+            var methodBuilder = type.DefineMethod(interfaceMethodInfo.Name, methodAttributes);
+
+            var invokeMethod = typeof(IClientProxy).GetMethod(
+                "InvokeAsync", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null,
+                new Type[] { typeof(string), typeof(object[]) }, null);
+
+            methodBuilder.SetReturnType(interfaceMethodInfo.ReturnType);
+            methodBuilder.SetParameters(paramTypes);
+
+            // Sets the number of generic type parameters
+            var genericTypeNames =
+                paramTypes.Where(p => p.IsGenericParameter).Select(p => p.Name).Distinct().ToArray();
+
+            if (genericTypeNames.Any())
+            {
+                methodBuilder.DefineGenericParameters(genericTypeNames);
+            }
+
+            var generator = methodBuilder.GetILGenerator();
+
+            // Declare local variable to store the arguments to IClientProxy.InvokeAsync
+            generator.DeclareLocal(typeof(object[]));
+
+            // Get IClientProxy
+            generator.Emit(OpCodes.Ldarg_0);
+            generator.Emit(OpCodes.Ldfld, proxyField);
+
+            // The first argument to IClientProxy.InvokeAsync is this method's name
+            generator.Emit(OpCodes.Ldstr, interfaceMethodInfo.Name);
+
+            // Create an new object array to hold all the parameters to this method
+            generator.Emit(OpCodes.Ldc_I4, parameters.Length); // Stack: 
+            generator.Emit(OpCodes.Newarr, typeof(object)); // allocate object array
+            generator.Emit(OpCodes.Stloc_0);
+
+            // Store each parameter in the object array
+            for (int i = 0; i < paramTypes.Length; i++)
+            {
+                generator.Emit(OpCodes.Ldloc_0); // Object array loaded
+                generator.Emit(OpCodes.Ldc_I4, i); 
+                generator.Emit(OpCodes.Ldarg, i + 1); // i + 1 
+                generator.Emit(OpCodes.Box, paramTypes[i]);
+                generator.Emit(OpCodes.Stelem_Ref);
+            }
+
+            // Call InvokeAsync
+            generator.Emit(OpCodes.Ldloc_0);
+            generator.Emit(OpCodes.Callvirt, invokeMethod);
+
+            if (interfaceMethodInfo.ReturnType == typeof(void))
+            {
+                // void return
+                generator.Emit(OpCodes.Pop);
+            }
+
+            generator.Emit(OpCodes.Ret); // Return 
+        }
+
+        private static void VerifyInterface(Type interfaceType)
+        {
+            if (!interfaceType.IsInterface)
+            {
+                throw new InvalidOperationException("Type must be an interface.");
+            }
+
+            if (interfaceType.GetProperties().Length != 0)
+            {
+                throw new InvalidOperationException("Type must not contain properties.");
+            }
+
+            if (interfaceType.GetEvents().Length != 0)
+            {
+                throw new InvalidOperationException("Type can not contain events.");
+            }
+
+            foreach (var method in interfaceType.GetMethods())
+            {
+                VerifyMethod(interfaceType, method);
+            }
+
+            foreach (var parent in interfaceType.GetInterfaces())
+            {
+                VerifyInterface(parent);
+            }
+        }
+
+        private static void VerifyMethod(Type interfaceType, MethodInfo interfaceMethod)
+        {
+            if (interfaceMethod.ReturnType != typeof(void) && interfaceMethod.ReturnType != typeof(Task))
+            {
+                throw new InvalidOperationException("Method must return Void or Task.");
+            }
+
+            foreach (var parameter in interfaceMethod.GetParameters())
+            {
+                VerifyParameter(interfaceType, interfaceMethod, parameter);
+            }
+        }
+
+        private static void VerifyParameter(Type interfaceType, MethodInfo interfaceMethod, ParameterInfo parameter)
+        {
+            if (parameter.IsOut)
+            {
+                throw new InvalidOperationException("Method must not take out parameters.");
+            }
+
+            if (parameter.ParameterType.IsByRef)
+            {
+                throw new InvalidOperationException("Method must not take reference parameters.");
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Microsoft.AspNetCore.SignalR/TypedHubClients.cs b/src/Microsoft.AspNetCore.SignalR/TypedHubClients.cs
new file mode 100644
index 0000000000..db835ff951
--- /dev/null
+++ b/src/Microsoft.AspNetCore.SignalR/TypedHubClients.cs
@@ -0,0 +1,32 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.SignalR
+{
+    internal class TypedHubClients<T> : IHubClients<T>
+    {
+        private IHubClients hubClients;
+
+        public TypedHubClients(IHubClients dynamicContext)
+        {
+            hubClients = dynamicContext;
+        }
+
+        public T All => TypedClientBuilder<T>.Build(hubClients.All);
+
+        public T Client(string connectionId)
+        {
+            return TypedClientBuilder<T>.Build(hubClients.Client(connectionId));
+        }
+
+        public T Group(string groupName)
+        {
+            return TypedClientBuilder<T>.Build(hubClients.Group(groupName));
+        }
+
+        public T User(string userId)
+        {
+            return TypedClientBuilder<T>.Build(hubClients.User(userId));
+        }
+    }
+}
diff --git a/test/Microsoft.AspNetCore.SignalR.Tests/HubEndpointTests.cs b/test/Microsoft.AspNetCore.SignalR.Tests/HubEndpointTests.cs
index 61ecf3a363..992da47016 100644
--- a/test/Microsoft.AspNetCore.SignalR.Tests/HubEndpointTests.cs
+++ b/test/Microsoft.AspNetCore.SignalR.Tests/HubEndpointTests.cs
@@ -605,6 +605,38 @@ namespace Microsoft.AspNetCore.SignalR.Tests
             }
         }
 
+        [Fact]
+        public async Task DelayedSendTest()
+        {
+            var serviceProvider = CreateServiceProvider();
+
+            dynamic endPoint = serviceProvider.GetService(GetEndPointType(typeof(HubT)));
+
+            using (var firstClient = new TestClient())
+            using (var secondClient = new TestClient())
+            {
+                Task firstEndPointTask = endPoint.OnConnectedAsync(firstClient.Connection);
+                Task secondEndPointTask = endPoint.OnConnectedAsync(secondClient.Connection);
+
+                await Task.WhenAll(firstClient.Connected, secondClient.Connected).OrTimeout();
+
+                await firstClient.SendInvocationAsync("DelayedSend", secondClient.Connection.ConnectionId, "test").OrTimeout();
+
+                // check that 'secondConnection' has received the group send
+                var hubMessage = await secondClient.Read().OrTimeout();
+                var invocation = Assert.IsType<InvocationMessage>(hubMessage);
+                Assert.Equal("Send", invocation.Target);
+                Assert.Equal(1, invocation.Arguments.Length);
+                Assert.Equal("test", invocation.Arguments[0]);
+
+                // kill the connections
+                firstClient.Dispose();
+                secondClient.Dispose();
+
+                await Task.WhenAll(firstEndPointTask, secondEndPointTask).OrTimeout();
+            }
+        }
+
         [Theory]
         [InlineData(nameof(StreamingHub.CounterChannel))]
         [InlineData(nameof(StreamingHub.CounterObservable))]
@@ -732,6 +764,7 @@ namespace Microsoft.AspNetCore.SignalR.Tests
         {
             yield return new Type[] { typeof(DynamicTestHub) };
             yield return new Type[] { typeof(MethodHub) };
+            yield return new Type[] { typeof(HubT) };
         }
 
         private static Type GetEndPointType(Type hubType)
@@ -797,6 +830,56 @@ namespace Microsoft.AspNetCore.SignalR.Tests
             }
         }
 
+        public interface Test
+        {
+            Task Send(string message);
+            Task Broadcast(string message);
+        }
+
+        public class HubT : Hub<Test>
+        {
+            public override Task OnConnectedAsync()
+            {
+                var tcs = (TaskCompletionSource<bool>)Context.Connection.Metadata["ConnectedTask"];
+                tcs?.TrySetResult(true);
+                return base.OnConnectedAsync();
+            }
+
+            public string Echo(string data)
+            {
+                return data;
+            }
+
+            public Task ClientSendMethod(string userId, string message)
+            {
+                return Clients.User(userId).Send(message);
+            }
+
+            public Task ConnectionSendMethod(string connectionId, string message)
+            {
+                return Clients.Client(connectionId).Send(message);
+            }
+            public Task DelayedSend(string connectionId, string message)
+            {
+                Task.Delay(100);
+                return Clients.Client(connectionId).Send(message);
+            }
+            public Task GroupAddMethod(string groupName)
+            {
+                return Groups.AddAsync(Context.ConnectionId, groupName);
+            }
+
+            public Task GroupSendMethod(string groupName, string message)
+            {
+                return Clients.Group(groupName).Send(message);
+            }
+
+            public Task BroadcastMethod(string message)
+            {
+                return Clients.All.Broadcast(message);
+            }
+        }
+
         public class StreamingHub : TestHub
         {
             public IObservable<string> CounterObservable(int count)