Support PerRequestLifetimeManager

Author: Cao Trong Thang

src/App_Start/UnityWebApiActivator.cs.pp

@@ -23,6 +23,9 @@
             var resolver = new UnityDependencyResolver(UnityConfig.Container);
 
             GlobalConfiguration.Configuration.DependencyResolver = resolver;
+
+            // Uncomment if you want to use PerRequestLifetimeManager
+            // Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility.RegisterModule(typeof(UnityPerRequestHttpModule));
         }
 
         /// <summary>

src/PerRequestLifetimeManager.cs

@@ -0,0 +1,53 @@
+using System;
+using Unity.Lifetime;
+
+namespace Unity.AspNet.WebApi
+{
+    public class PerRequestLifetimeManager : LifetimeManager,
+                                             IInstanceLifetimeManager,
+                                             IFactoryLifetimeManager,
+                                             ITypeLifetimeManager
+    {
+        private readonly object _lifetimeKey = new object();
+
+        /// <summary>
+        /// Retrieves a value from the backing store associated with this lifetime policy.
+        /// </summary>
+        /// <returns>The desired object, or null if no such object is currently stored.</returns>
+        public override object GetValue(ILifetimeContainer container = null)
+        {
+            return UnityPerRequestHttpModule.GetValue(_lifetimeKey);
+        }
+
+        /// <summary>
+        /// Stores the given value into the backing store for retrieval later.
+        /// </summary>
+        /// <param name="newValue">The object being stored.</param>
+        /// <param name="container"></param>
+        public override void SetValue(object newValue, ILifetimeContainer container = null)
+        {
+            UnityPerRequestHttpModule.SetValue(_lifetimeKey, newValue);
+        }
+
+        /// <summary>
+        /// Removes the given object from the backing store.
+        /// </summary>
+        public override void RemoveValue(ILifetimeContainer container = null)
+        {
+            var disposable = GetValue() as IDisposable;
+
+            disposable?.Dispose();
+
+            UnityPerRequestHttpModule.SetValue(_lifetimeKey, null);
+        }
+
+        /// <summary>
+        /// Creates clone
+        /// </summary>
+        /// <returns></returns>
+        protected override LifetimeManager OnCreateLifetimeManager()
+        {
+            return new PerRequestLifetimeManager();
+        }
+    }
+}

src/UnityPerRequestHttpModule.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Web;
+using Unity.Lifetime;
+
+namespace Unity.AspNet.WebApi
+{
+    public class UnityPerRequestHttpModule : IHttpModule
+    {
+        private static readonly object ModuleKey = new object();
+
+        internal static object GetValue(object lifetimeManagerKey)
+        {
+            var dict = GetDictionary(HttpContext.Current);
+
+            if (dict != null)
+            {
+                if (dict.TryGetValue(lifetimeManagerKey, out var obj))
+                {
+                    return obj;
+                }
+            }
+
+            return LifetimeManager.NoValue;
+        }
+
+        internal static void SetValue(object lifetimeManagerKey, object value)
+        {
+            var dict = GetDictionary(HttpContext.Current);
+
+            if (dict == null)
+            {
+                dict = new Dictionary<object, object>();
+
+                HttpContext.Current.Items[ModuleKey] = dict;
+            }
+
+            dict[lifetimeManagerKey] = value;
+        }
+
+        /// <summary>
+        /// Disposes the resources used by this module.
+        /// </summary>
+        public void Dispose()
+        {
+        }
+
+        /// <summary>
+        /// Initializes a module and prepares it to handle requests.
+        /// </summary>
+        /// <param name="context">An <see cref="HttpApplication"/> that provides access to the methods, properties,
+        /// and events common to all application objects within an ASP.NET application.</param>
+        public void Init(HttpApplication context)
+        {
+            (context ?? throw new ArgumentNullException(nameof(context))).EndRequest += OnEndRequest;
+        }
+
+        private void OnEndRequest(object sender, EventArgs e)
+        {
+            var app = (HttpApplication)sender;
+
+            var dict = GetDictionary(app.Context);
+
+            if (dict != null)
+            {
+                foreach (var disposable in dict.Values.OfType<IDisposable>())
+                {
+                    disposable.Dispose();
+                }
+            }
+        }
+
+        private static Dictionary<object, object> GetDictionary(HttpContext context)
+        {
+            if (context == null)
+            {
+                throw new InvalidOperationException(
+                    "The PerRequestLifetimeManager can only be used in the context of an HTTP request.Possible causes for this error are using the lifetime manager on a non-ASP.NET application, or using it in a thread that is not associated with the appropriate synchronization context.");
+            }
+
+            var dict = (Dictionary<object, object>)context.Items[ModuleKey];
+
+            return dict;
+        }
+    }
+}