Included async interception and fix the bug with multiple in…

src/Foil.Logging/Foil.Logging.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Library</OutputType>
+        <PackageVersion>1.0.0</PackageVersion>
+        <TargetFrameworks>netstandard1.6;netstandard2.0</TargetFrameworks>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Castle.Core" Version="4.3.1" />
+        <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
+        <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="1.1.1" />
+        <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="1.1.2" />
+    </ItemGroup>
+
+</Project>

src/Foil.Logging/InvocationExtensions.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Linq;
+using Castle.DynamicProxy;
+using Newtonsoft.Json;
+
+namespace Foil.Logging
+{
+    public static class InvocationExtensions
+    {
+        public static string FormatArguments(this IInvocation invocation)
+        {
+            if (invocation == null) throw new ArgumentNullException(nameof(invocation));
+
+            var arguments = invocation.Arguments;
+            if (!arguments.Any())
+                return string.Empty;
+
+
+            var serializedArguments = arguments
+                .Select((a, index) => $"Arg[{index}]: {a.ToJsonOrDefault()}")
+                .ToList();
+            return string.Join(Environment.NewLine, serializedArguments);
+
+        }
+
+        private static string ToJsonOrDefault(this object obj)
+        {
+            if (obj == null) throw new ArgumentNullException(nameof(obj));
+            try
+            {
+                return JsonConvert.SerializeObject(obj);
+            }
+            catch
+            {
+                return "Error in serializing argument to json";
+            }
+        }
+    }
+}

src/Foil.Logging/LoggingInterceptor.cs

@@ -0,0 +1,33 @@
+using System;
+using Castle.DynamicProxy;
+using Microsoft.Extensions.Logging;
+
+namespace Foil.Logging
+{
+    public sealed class LoggingInterceptor : IInterceptor
+    {
+        private readonly ILogger<LoggingInterceptor> _logger;
+
+        public LoggingInterceptor(ILogger<LoggingInterceptor> logger)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+        }
+
+        public void Intercept(IInvocation invocation)
+        {
+            _logger.LogInformation($"Executing Method: {invocation.Method.Name}");
+
+            LogInvocationInfo(invocation);
+
+            invocation.Proceed();
+
+            _logger.LogInformation($"Executed Method: {invocation.Method.Name}");
+        }
+
+        private void LogInvocationInfo(IInvocation invocation)
+        {
+            if (_logger.IsEnabled(LogLevel.Trace))
+                _logger.LogTrace(invocation.FormatArguments());
+        }
+    }
+}

src/Foil.Sample/Foil.Sample.csproj

@@ -1,14 +1,18 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <OutputType>Exe</OutputType>
-        <TargetFramework>netcoreapp1.1</TargetFramework>
+        <TargetFrameworks>netcoreapp1.1;netcoreapp2.0</TargetFrameworks>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="Castle.Core" Version="4.1.1"/>
-        <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="1.1.1"/>
-        <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="1.1.1"/>
+        <PackageReference Include="Castle.Core" Version="4.3.1" />
+        <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="1.1.1" />
+        <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="1.1.1" />
+        <PackageReference Include="Microsoft.Extensions.Logging" Version="1.1.1" />
+        <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="1.1.1" />
+        <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="1.1.1" />
     </ItemGroup>
     <ItemGroup>
-        <ProjectReference Include="..\Foil\Foil.csproj"/>
+        <ProjectReference Include="..\Foil.Logging\Foil.Logging.csproj" />
+        <ProjectReference Include="..\Foil\Foil.csproj" />
     </ItemGroup>
 </Project>

src/Foil.Sample/Program.cs

@@ -1,6 +1,8 @@
-using Foil.Sample.Interceptors;
+using Foil.Logging;
+using Foil.Sample.Interceptors;
 using Foil.Sample.Services;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
 
 namespace Foil.Sample
 {
@@ -10,12 +12,16 @@ static void Main(string[] args)
         {
             var services = new ServiceCollection();
 
-            services.AddTransientWithInterception<ISampleService, SampleService>(m => m.InterceptBy<LogInterceptor>());
+            services.AddLogging();
+            services.AddTransientWithInterception<ISampleService, SampleService>(m => m.InterceptBy<LoggingInterceptor>().ThenBy<LogInterceptor>());
 
             var provider = services.BuildServiceProvider();
+            var loggingFactory = provider.GetRequiredService<ILoggerFactory>();
+            loggingFactory.AddConsole(LogLevel.Trace);
 
             var service = provider.GetRequiredService<ISampleService>();
-            service.Call();
+
+            service.Call("Dear User");
         }
     }
 }

src/Foil.Sample/Services/ISampleService.cs

@@ -2,6 +2,6 @@
 {
     public interface ISampleService
     {
-        void Call();
+        void Call(string sample);
     }
 }

src/Foil.Sample/Services/SampleService.cs

@@ -4,9 +4,9 @@ namespace Foil.Sample.Services
 {
     public class SampleService : ISampleService
     {
-        public virtual void Call()
+        public virtual void Call(string sample)
         {
-            Console.WriteLine("Hello Sample");
+            Console.WriteLine($"Hello {sample}");
         }
     }
 }

src/Foil.UnitTests/Foil.UnitTests.csproj

@@ -1,16 +1,16 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netcoreapp1.1</TargetFramework>
+    <TargetFrameworks>netcoreapp1.1;netcoreapp2.0</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
-      <PackageReference Include="FluentAssertions" Version="4.19.4"/>
-      <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="1.1.2"/>
-      <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0"/>
-      <PackageReference Include="NSubstitute" Version="2.0.3"/>
-      <PackageReference Include="xunit" Version="2.2.0"/>
-      <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0"/>
+      <PackageReference Include="FluentAssertions" Version="5.4.2" />
+      <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="1.1.2" />
+      <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
+      <PackageReference Include="NSubstitute" Version="3.1.0" />
+      <PackageReference Include="xunit" Version="2.2.0" />
+      <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
   </ItemGroup>
   <ItemGroup>
-      <ProjectReference Include="..\Foil\Foil.csproj"/>
+      <ProjectReference Include="..\Foil\Foil.csproj" />
   </ItemGroup>
 </Project>

src/Foil.sln

@@ -9,6 +9,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Foil.UnitTests", "Foil.Unit
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Foil.Sample", "Foil.Sample\Foil.Sample.csproj", "{3AD6C03C-F18A-4F95-9575-FC4B32D83F40}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Foil.Logging", "Foil.Logging\Foil.Logging.csproj", "{22710EAF-09BE-495D-A7EF-23F262ACF80A}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -27,6 +29,10 @@ Global
 		{3AD6C03C-F18A-4F95-9575-FC4B32D83F40}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{3AD6C03C-F18A-4F95-9575-FC4B32D83F40}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{3AD6C03C-F18A-4F95-9575-FC4B32D83F40}.Release|Any CPU.Build.0 = Release|Any CPU
+		{22710EAF-09BE-495D-A7EF-23F262ACF80A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{22710EAF-09BE-495D-A7EF-23F262ACF80A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{22710EAF-09BE-495D-A7EF-23F262ACF80A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{22710EAF-09BE-495D-A7EF-23F262ACF80A}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/Foil/AsyncInterceptor.cs

@@ -0,0 +1,173 @@
+using System;
+using System.Collections.Concurrent;
+using System.Reflection;
+using System.Threading.Tasks;
+using Castle.DynamicProxy;
+
+namespace Foil
+{
+    public abstract class AsyncInterceptor : IInterceptor
+    {
+        private static readonly MethodInfo InterceptSynchronousMethodInfo =
+            typeof(AsyncInterceptor)
+                .GetMethod(nameof(InterceptSynchronousResult), BindingFlags.Static | BindingFlags.NonPublic);
+
+        private static readonly ConcurrentDictionary<Type, GenericSynchronousHandler> GenericSynchronousHandlers =
+            new ConcurrentDictionary<Type, GenericSynchronousHandler>
+            {
+                [typeof(void)] = InterceptSynchronousVoid
+            };
+
+        private static readonly MethodInfo HandleAsyncMethodInfo =
+            typeof(AsyncInterceptor)
+                .GetMethod(nameof(HandleAsyncWithResult), BindingFlags.Static | BindingFlags.NonPublic);
+
+        private static readonly ConcurrentDictionary<Type, GenericAsyncHandler> GenericAsyncHandlers =
+            new ConcurrentDictionary<Type, GenericAsyncHandler>();
+
+        public void Intercept(IInvocation invocation)
+        {
+            var methodType = GetMethodType(invocation.Method.ReturnType);
+
+            switch (methodType)
+            {
+                case MethodType.AsyncAction:
+                    InterceptAsynchronous(invocation);
+                    return;
+                case MethodType.AsyncFunction:
+                    GetHandler(invocation.Method.ReturnType).Invoke(invocation, this);
+                    return;
+                default:
+                    InterceptSynchronous(invocation);
+                    return;
+            }
+        }
+
+        private static MethodType GetMethodType(Type returnType)
+        {
+            if (returnType == typeof(void) || !typeof(Task).IsAssignableFrom(returnType))
+                return MethodType.Synchronous;
+
+            return returnType.GetTypeInfo().IsGenericType ? MethodType.AsyncFunction : MethodType.AsyncAction;
+        }
+
+        private static GenericAsyncHandler GetHandler(Type returnType)
+        {
+            var handler = GenericAsyncHandlers.GetOrAdd(returnType, CreateHandlerAsync);
+            return handler;
+        }
+
+        private static void HandleAsyncWithResult<TResult>(IInvocation invocation,
+            AsyncInterceptor asyncInterceptor)
+        {
+            asyncInterceptor.InterceptAsynchronous<TResult>(invocation);
+        }
+
+        public void InterceptSynchronous(IInvocation invocation)
+        {
+            var returnType = invocation.Method.ReturnType;
+            var handler = GenericSynchronousHandlers.GetOrAdd(returnType, CreateHandlerForSync);
+            handler(this, invocation);
+        }
+
+        private static GenericSynchronousHandler CreateHandlerForSync(Type returnType)
+        {
+            var method = InterceptSynchronousMethodInfo.MakeGenericMethod(returnType);
+            return (GenericSynchronousHandler) method.CreateDelegate(typeof(GenericSynchronousHandler));
+        }
+
+        private static GenericAsyncHandler CreateHandlerAsync(Type returnType)
+        {
+            var taskReturnType = returnType.GetGenericArguments()[0];
+            var method = HandleAsyncMethodInfo.MakeGenericMethod(taskReturnType);
+            return (GenericAsyncHandler) method.CreateDelegate(typeof(GenericAsyncHandler));
+        }
+
+        public void InterceptAsynchronous(IInvocation invocation)
+        {
+            invocation.ReturnValue = InterceptAsync(invocation, ProceedAsynchronous);
+        }
+
+        public void InterceptAsynchronous<TResult>(IInvocation invocation)
+        {
+            invocation.ReturnValue = InterceptAsync(invocation, ProceedAsynchronous<TResult>);
+        }
+
+        protected abstract Task InterceptAsync(IInvocation invocation, Func<IInvocation, Task> proceed);
+
+        protected abstract Task<TResult> InterceptAsync<TResult>(
+            IInvocation invocation,
+            Func<IInvocation, Task<TResult>> proceed);
+
+        private static void InterceptSynchronousVoid(AsyncInterceptor me, IInvocation invocation)
+        {
+            var task = me.InterceptAsync(invocation, ProceedSynchronous);
+
+            if (!task.IsCompleted) Task.Run(() => task).Wait();
+
+            if (task.IsFaulted) throw task.Exception.InnerException;
+        }
+
+        private static void InterceptSynchronousResult<TResult>(AsyncInterceptor me, IInvocation invocation)
+        {
+            Task task = me.InterceptAsync(invocation, ProceedSynchronous<TResult>);
+
+            if (!task.IsCompleted) Task.Run(() => task).Wait();
+
+            if (task.IsFaulted) throw task.Exception.InnerException;
+        }
+
+        private static Task ProceedSynchronous(IInvocation invocation)
+        {
+            try
+            {
+                invocation.Proceed();
+                return Task.CompletedTask;
+            }
+            catch (Exception e)
+            {
+                return Task.FromException(e);
+            }
+        }
+
+        private static Task<TResult> ProceedSynchronous<TResult>(IInvocation invocation)
+        {
+            try
+            {
+                invocation.Proceed();
+                return Task.FromResult((TResult) invocation.ReturnValue);
+            }
+            catch (Exception e)
+            {
+                return Task.FromException<TResult>(e);
+            }
+        }
+
+        private static async Task ProceedAsynchronous(IInvocation invocation)
+        {
+            invocation.Proceed();
+            var originalReturnValue = (Task) invocation.ReturnValue;
+            await originalReturnValue.ConfigureAwait(false);
+        }
+
+        private static async Task<TResult> ProceedAsynchronous<TResult>(IInvocation invocation)
+        {
+            invocation.Proceed();
+            var originalReturnValue = (Task<TResult>) invocation.ReturnValue;
+
+            var result = await originalReturnValue.ConfigureAwait(false);
+            return result;
+        }
+
+        private delegate void GenericSynchronousHandler(AsyncInterceptor me, IInvocation invocation);
+
+        private delegate void GenericAsyncHandler(IInvocation invocation, AsyncInterceptor asyncInterceptor);
+
+        private enum MethodType
+        {
+            Synchronous,
+            AsyncAction,
+            AsyncFunction
+        }
+    }
+}