Introducing IPageModelActivatorProvider

Fixes #5480

src/Microsoft.AspNetCore.Mvc.RazorPages/IPageModelActivatorProvider.cs

@@ -0,0 +1,27 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages
+{
+    /// <summary>
+    /// Provides methods to create a Razor page model.
+    /// </summary>
+    public interface IPageModelActivatorProvider
+    {
+        /// <summary>
+        /// Creates a Razor page model activator.
+        /// </summary>
+        /// <param name="descriptor">The <see cref="CompiledPageActionDescriptor"/>.</param>
+        /// <returns>The delegate used to activate the page model.</returns>
+        Func<PageContext, object> CreateActivator(CompiledPageActionDescriptor descriptor);
+
+        /// <summary>
+        /// Releases a Razor page model.
+        /// </summary>
+        /// <param name="descriptor">The <see cref="CompiledPageActionDescriptor"/>.</param>
+        /// <returns>The delegate used to dispose the activated page model.</returns>
+        Action<PageContext, object> CreateReleaser(CompiledPageActionDescriptor descriptor);
+    }
+}

src/Microsoft.AspNetCore.Mvc.RazorPages/IPageModelFactoryProvider.cs

@@ -0,0 +1,27 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages
+{
+    /// <summary>
+    /// Provides methods for creation and disposal of Razor page models.
+    /// </summary>
+    public interface IPageModelFactoryProvider
+    {
+        /// <summary>
+        /// Creates a factory for producing models for Razor pages given the specified <see cref="PageContext"/>.
+        /// </summary>
+        /// <param name="descriptor">The <see cref="CompiledPageActionDescriptor"/>.</param>
+        /// <returns>The Razor page model factory.</returns>
+        Func<PageContext, object> CreateModelFactory(CompiledPageActionDescriptor descriptor);
+
+        /// <summary>
+        /// Releases a Razor page model.
+        /// </summary>
+        /// <param name="descriptor">The <see cref="CompiledPageActionDescriptor"/>.</param>
+        /// <returns>The delegate used to release the created page model.</returns>
+        Action<PageContext, object> CreateModelDisposer(CompiledPageActionDescriptor descriptor);
+    }
+}

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/DefaultPageModelActivatorProvider.cs

@@ -0,0 +1,69 @@
+// 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.Reflection;
+using Microsoft.AspNetCore.Mvc.Internal;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
+{
+    /// <summary>
+    /// <see cref="IPageActivatorProvider"/> that uses type activation to create Pages.
+    /// </summary>
+    public class DefaultPageModelActivatorProvider : IPageModelActivatorProvider
+    {
+        private readonly Action<PageContext, object> _disposer = Dispose;
+
+        /// <inheritdoc />
+        public virtual Func<PageContext, object> CreateActivator(CompiledPageActionDescriptor actionDescriptor)
+        {
+            if (actionDescriptor == null)
+            {
+                throw new ArgumentNullException(nameof(actionDescriptor));
+            }
+
+            var modelTypeInfo = actionDescriptor.ModelTypeInfo?.AsType();
+            if (modelTypeInfo == null)
+            {
+                throw new ArgumentException(Resources.FormatPropertyOfTypeCannotBeNull(
+                    nameof(actionDescriptor.ModelTypeInfo),
+                    nameof(actionDescriptor)),
+                    nameof(actionDescriptor));
+            }
+
+            var factory = ActivatorUtilities.CreateFactory(modelTypeInfo, Type.EmptyTypes);
+            return (context) => factory(context.HttpContext.RequestServices, EmptyArray<object>.Instance);
+        }
+
+        public virtual Action<PageContext, object> CreateReleaser(CompiledPageActionDescriptor actionDescriptor)
+        {
+            if (actionDescriptor == null)
+            {
+                throw new ArgumentNullException(nameof(actionDescriptor));
+            }
+
+            if (typeof(IDisposable).GetTypeInfo().IsAssignableFrom(actionDescriptor.ModelTypeInfo))
+            {
+                return _disposer;
+            }
+
+            return null;
+        }
+
+        private static void Dispose(PageContext context, object page)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            if (page == null)
+            {
+                throw new ArgumentNullException(nameof(page));
+            }
+
+            ((IDisposable)page).Dispose();
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/DefaultPageModelFactoryProvider.cs

@@ -0,0 +1,70 @@
+// 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.Reflection;
+using Microsoft.Extensions.Internal;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
+{
+    public class DefaultPageModelFactoryProvider : IPageModelFactoryProvider
+    {
+        private static readonly Func<PropertyInfo, PropertyActivator<PageContext>> _createActivateInfo =
+            CreateActivateInfo;
+        private readonly IPageModelActivatorProvider _modelActivator;
+
+        public DefaultPageModelFactoryProvider(IPageModelActivatorProvider modelActivator)
+        {
+            _modelActivator = modelActivator;
+        }
+
+        public virtual Func<PageContext, object> CreateModelFactory(CompiledPageActionDescriptor descriptor)
+        {
+            if (descriptor == null)
+            {
+                throw new ArgumentNullException(nameof(descriptor));
+            }
+
+            if (descriptor.ModelTypeInfo == null)
+            {
+                return null;
+            }
+
+            var modelActivator = _modelActivator.CreateActivator(descriptor);
+            var propertyActivator = PropertyActivator<PageContext>.GetPropertiesToActivate(
+                    descriptor.ModelTypeInfo.AsType(),
+                    typeof(PageContextAttribute),
+                    _createActivateInfo,
+                    includeNonPublic: false);
+
+            return pageContext =>
+            {
+                var model = modelActivator(pageContext);
+                for (var i = 0; i < propertyActivator.Length; i++)
+                {
+                    propertyActivator[i].Activate(model, pageContext);
+                }
+
+                return model;
+            };
+        }
+
+        public virtual Action<PageContext, object> CreateModelDisposer(CompiledPageActionDescriptor descriptor)
+        {
+            if (descriptor == null)
+            {
+                throw new ArgumentNullException(nameof(descriptor));
+            }
+
+            if (descriptor.ModelTypeInfo == null)
+            {
+                return null;
+            }
+
+            return _modelActivator.CreateReleaser(descriptor);
+        }
+
+        private static PropertyActivator<PageContext> CreateActivateInfo(PropertyInfo property) =>
+            new PropertyActivator<PageContext>(property, pageContext => pageContext);
+    }
+}

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/PageActionInvokerProvider.cs

@@ -24,6 +24,7 @@ public class PageActionInvokerProvider : IActionInvokerProvider
         private const string ModelPropertyName = "Model";
         private readonly IPageLoader _loader;
         private readonly IPageFactoryProvider _pageFactoryProvider;
+        private readonly IPageModelFactoryProvider _modelFactoryProvider;
         private readonly IActionDescriptorCollectionProvider _collectionProvider;
         private readonly IFilterProvider[] _filterProviders;
         private readonly IReadOnlyList<IValueProviderFactory> _valueProviderFactories;
@@ -38,6 +39,7 @@ public class PageActionInvokerProvider : IActionInvokerProvider
         public PageActionInvokerProvider(
             IPageLoader loader,
             IPageFactoryProvider pageFactoryProvider,
+            IPageModelFactoryProvider modelFactoryProvider,
             IActionDescriptorCollectionProvider collectionProvider,
             IEnumerable<IFilterProvider> filterProviders,
             IEnumerable<IValueProviderFactory> valueProviderFactories,
@@ -49,8 +51,9 @@ public PageActionInvokerProvider(
             ILoggerFactory loggerFactory)
         {
             _loader = loader;
-            _collectionProvider = collectionProvider;
             _pageFactoryProvider = pageFactoryProvider;
+            _modelFactoryProvider = modelFactoryProvider;
+            _collectionProvider = collectionProvider;
             _filterProviders = filterProviders.ToArray();
             _valueProviderFactories = valueProviderFactories.ToArray();
             _modelMetadataProvider = modelMetadataProvider;
@@ -157,12 +160,23 @@ private PageActionInvokerCacheEntry CreateCacheEntry(
                 PageTypeInfo = compiledType,
             };
 
+            var pageFactory = _pageFactoryProvider.CreatePageFactory(compiledActionDescriptor);
+            var pageDisposer = _pageFactoryProvider.CreatePageDisposer(compiledActionDescriptor);
+
+            Func<PageContext, object> modelFactory = null;
+            Action<PageContext, object> modelReleaser = null;
+            if (modelType != null)
+            {
+                modelFactory = _modelFactoryProvider.CreateModelFactory(compiledActionDescriptor);
+                modelReleaser = _modelFactoryProvider.CreateModelDisposer(compiledActionDescriptor);
+            }
+
             return new PageActionInvokerCacheEntry(
                 compiledActionDescriptor,
-                _pageFactoryProvider.CreatePageFactory(compiledActionDescriptor),
-                _pageFactoryProvider.CreatePageDisposer(compiledActionDescriptor),
-                c => { throw new NotImplementedException(); },
-                (_, __) => { throw new NotImplementedException(); },
+                pageFactory,
+                pageDisposer,
+                modelFactory,
+                modelReleaser,
                 cachedFilters);
         }
 

src/Microsoft.AspNetCore.Mvc.RazorPages/PageContextAttribute.cs

@@ -0,0 +1,16 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages
+{
+    /// <summary>
+    /// Specifies that a Razor Page model property should be set with the current <see cref="PageContext"/> when creating
+    /// the model instance. The property must have a public set method.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+    public class PageContextAttribute : Attribute
+    {
+    }
+}