From bfc6edc1dde18f4acc825ccfb397cdfebd99de31 Mon Sep 17 00:00:00 2001
From: Suha Can <Suha.Can@microsoft.com>
Date: Mon, 10 May 2010 13:35:07 -0700
Subject: [PATCH] - An autofac events module for dynamic proxy creation when an
 interface of type IEventHandler is resolved through DI. - Intercept method on
 the proxy calls Notify on the event-bus with appropriate conversion of event
 name and parameters.

--HG--
branch : dev
---
 src/Orchard/Events/EventsInterceptor.cs       | 23 ++++++++++
 src/Orchard/Events/EventsModule.cs            | 10 +++++
 .../Events/EventsRegistrationSource.cs        | 43 +++++++++++++++++++
 src/Orchard/Events/IEventHandler.cs           |  4 ++
 src/Orchard/Orchard.Framework.csproj          |  4 ++
 5 files changed, 84 insertions(+)
 create mode 100644 src/Orchard/Events/EventsInterceptor.cs
 create mode 100644 src/Orchard/Events/EventsModule.cs
 create mode 100644 src/Orchard/Events/EventsRegistrationSource.cs
 create mode 100644 src/Orchard/Events/IEventHandler.cs

diff --git a/src/Orchard/Events/EventsInterceptor.cs b/src/Orchard/Events/EventsInterceptor.cs
new file mode 100644
index 000000000..0c71265fe
--- /dev/null
+++ b/src/Orchard/Events/EventsInterceptor.cs
@@ -0,0 +1,23 @@
+using System.Linq;
+using Castle.Core.Interceptor;
+
+namespace Orchard.Events {
+    public class EventsInterceptor : IInterceptor {
+        private readonly IEventBus _eventBus;
+
+        public EventsInterceptor(IEventBus eventBus) {
+            _eventBus = eventBus;
+        }
+
+        public void Intercept(IInvocation invocation) {
+            var interfaceName = invocation.Method.DeclaringType.Name;
+            var methodName = invocation.Method.Name;
+
+            var data = invocation.Method.GetParameters()
+                .Select((parameter, index) => new { parameter.Name, Value = invocation.Arguments[index] })
+                .ToDictionary(kv => kv.Name, kv => kv.Value.ToString());
+
+            _eventBus.Notify(interfaceName + "_" + methodName, data);
+        }
+    }
+}
diff --git a/src/Orchard/Events/EventsModule.cs b/src/Orchard/Events/EventsModule.cs
new file mode 100644
index 000000000..2aa10ef52
--- /dev/null
+++ b/src/Orchard/Events/EventsModule.cs
@@ -0,0 +1,10 @@
+using Autofac;
+
+namespace Orchard.Events {
+    public class EventsModule : Module {
+        protected override void Load(ContainerBuilder builder) {
+            builder.RegisterSource(new EventsRegistrationSource());
+            base.Load(builder);
+        }
+    }
+}
diff --git a/src/Orchard/Events/EventsRegistrationSource.cs b/src/Orchard/Events/EventsRegistrationSource.cs
new file mode 100644
index 000000000..e39d7fe51
--- /dev/null
+++ b/src/Orchard/Events/EventsRegistrationSource.cs
@@ -0,0 +1,43 @@
+using System;
+using System.Collections.Generic;
+using Autofac;
+using Autofac.Builder;
+using Autofac.Core;
+using Castle.Core.Interceptor;
+using Castle.DynamicProxy;
+
+namespace Orchard.Events {
+    public class EventsRegistrationSource : IRegistrationSource {
+        private readonly DefaultProxyBuilder _proxyBuilder;
+
+        public EventsRegistrationSource() {
+            _proxyBuilder = new DefaultProxyBuilder();
+        }
+
+        public IEnumerable<IComponentRegistration> RegistrationsFor(Service service, Func<Service, IEnumerable<IComponentRegistration>> registrationAccessor) {
+            var serviceWithType = service as IServiceWithType;
+            if (serviceWithType == null)
+                yield break;
+
+            var serviceType = serviceWithType.ServiceType;
+            if (!serviceType.IsInterface || !typeof(IEventHandler).IsAssignableFrom(serviceType))
+                yield break;
+
+            var interfaceProxyType = _proxyBuilder.CreateInterfaceProxyTypeWithoutTarget(
+                serviceType,
+                new Type[0],
+                ProxyGenerationOptions.Default);
+
+
+            var rb = RegistrationBuilder
+                .ForDelegate((ctx, parameters) => {
+                    var interceptors = new IInterceptor[] { new EventsInterceptor(ctx.Resolve<IEventBus>()) };
+                    var args = new object[] { interceptors, null };
+                    return Activator.CreateInstance(interfaceProxyType, args);
+                })
+                .As(service);
+
+            yield return rb.CreateRegistration();
+        }
+    }
+} 
\ No newline at end of file
diff --git a/src/Orchard/Events/IEventHandler.cs b/src/Orchard/Events/IEventHandler.cs
new file mode 100644
index 000000000..b40f7ae9a
--- /dev/null
+++ b/src/Orchard/Events/IEventHandler.cs
@@ -0,0 +1,4 @@
+namespace Orchard.Events {
+    public interface IEventHandler {
+    }
+}
diff --git a/src/Orchard/Orchard.Framework.csproj b/src/Orchard/Orchard.Framework.csproj
index 9beecc61b..0a8653d58 100644
--- a/src/Orchard/Orchard.Framework.csproj
+++ b/src/Orchard/Orchard.Framework.csproj
@@ -181,6 +181,9 @@
     <Compile Include="Environment\Configuration\ShellSettings.cs" />
     <Compile Include="Environment\StandaloneEnvironment.cs" />
     <Compile Include="Events\DefaultOrchardEventBus.cs" />
+    <Compile Include="Events\EventsInterceptor.cs" />
+    <Compile Include="Events\EventsModule.cs" />
+    <Compile Include="Events\EventsRegistrationSource.cs" />
     <Compile Include="Events\IEventBus.cs" />
     <Compile Include="Events\IEventBusHandler.cs" />
     <Compile Include="Environment\Extensions\Folders\AreaFolders.cs" />
@@ -190,6 +193,7 @@
     <Compile Include="Environment\Extensions\Models\Feature.cs" />
     <Compile Include="Environment\Extensions\Models\FeatureDescriptor.cs" />
     <Compile Include="Environment\Extensions\OrchardFeatureAttribute.cs" />
+    <Compile Include="Events\IEventHandler.cs" />
     <Compile Include="Modules\IModule.cs" />
     <Compile Include="Modules\IModuleFeature.cs" />
     <Compile Include="Modules\IModuleService.cs" />