Provided a way to add data to ActionDescriptor from ApplicationModel.

- Added Properties to Action, Controller and Application model
 - Added relevant tests

src/Microsoft.AspNet.Mvc.Core/ApplicationModels/ActionModel.cs

@@ -21,6 +21,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             HttpMethods = new List<string>();
             Parameters = new List<ParameterModel>();
             RouteConstraints = new List<IRouteConstraintProvider>();
+            Properties = new Dictionary<object, object>();
         }
 
         public ActionModel([NotNull] ActionModel other)
@@ -36,6 +37,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             Attributes = new List<object>(other.Attributes);
             Filters = new List<IFilter>(other.Filters);
             HttpMethods = new List<string>(other.HttpMethods);
+            Properties = new Dictionary<object, object>(other.Properties);
 
             // Make a deep copy of other 'model' types.
             ApiExplorer = new ApiExplorerModel(other.ApiExplorer);
@@ -79,5 +81,15 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
         public IList<ParameterModel> Parameters { get; private set; }
 
         public IList<IRouteConstraintProvider> RouteConstraints { get; private set; }
+
+        /// <summary>
+        /// Gets a set of properties associated with the action.
+        /// These properties will be copied to <see cref="ActionDescriptor.Properties"/>.
+        /// </summary>
+        /// <remarks>
+        /// Entries will take precedence over entries with the same key in
+        /// <see cref="ApplicationModel.Properties"/> and <see cref="ControllerModel.Properties"/>.
+        /// </remarks>
+        public IDictionary<object, object> Properties { get; }
     }
 }

src/Microsoft.AspNet.Mvc.Core/ApplicationModels/ApplicationModel.cs

@@ -12,6 +12,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             ApiExplorer = new ApiExplorerModel();
             Controllers = new List<ControllerModel>();
             Filters = new List<IFilter>();
+            Properties = new Dictionary<object, object>();
         }
 
         /// <summary>
@@ -30,5 +31,11 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
         public IList<ControllerModel> Controllers { get; private set; }
 
         public IList<IFilter> Filters { get; private set; }
+
+        /// <summary>
+        /// Gets a set of properties associated with all actions.
+        /// These properties will be copied to <see cref="ActionDescriptor.Properties"/>.
+        /// </summary>
+        public IDictionary<object, object> Properties { get; }
     }
 }

src/Microsoft.AspNet.Mvc.Core/ApplicationModels/ControllerModel.cs

@@ -21,6 +21,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             ActionConstraints = new List<IActionConstraintMetadata>();
             Filters = new List<IFilter>();
             RouteConstraints = new List<IRouteConstraintProvider>();
+            Properties = new Dictionary<object, object>();
         }
 
         public ControllerModel([NotNull] ControllerModel other)
@@ -36,6 +37,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             Attributes = new List<object>(other.Attributes);
             Filters = new List<IFilter>(other.Filters);
             RouteConstraints = new List<IRouteConstraintProvider>(other.RouteConstraints);
+            Properties = new Dictionary<object, object>(other.Properties);
 
             // Make a deep copy of other 'model' types.
             Actions = new List<ActionModel>(other.Actions.Select(a => new ActionModel(a)));
@@ -73,5 +75,15 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
         public IList<IFilter> Filters { get; private set; }
 
         public IList<IRouteConstraintProvider> RouteConstraints { get; private set; }
+
+        /// <summary>
+        /// Gets a set of properties associated with the controller.
+        /// These properties will be copied to <see cref="ActionDescriptor.Properties"/>.
+        /// </summary>
+        /// <remarks>
+        /// Entries will take precedence over entries with the same key
+        /// in <see cref="ApplicationModel.Properties"/>.
+        /// </remarks>
+        public IDictionary<object, object> Properties { get; }
     }
 }

src/Microsoft.AspNet.Mvc.Core/ControllerActionDescriptorBuilder.cs

@@ -58,6 +58,7 @@ namespace Microsoft.AspNet.Mvc
 
                         AddApiExplorerInfo(actionDescriptor, application, controller, action);
                         AddRouteConstraints(removalConstraints, actionDescriptor, controller, action);
+                        AddProperties(actionDescriptor, action, controller, application);
 
                         if (IsAttributeRoutedAction(actionDescriptor))
                         {
@@ -329,6 +330,28 @@ namespace Microsoft.AspNet.Mvc
             }
         }
 
+        private static void AddProperties(
+            ControllerActionDescriptor actionDescriptor,
+            ActionModel action,
+            ControllerModel controller,
+            ApplicationModel application)
+        {
+            foreach (var item in application.Properties)
+            {
+                actionDescriptor.Properties[item.Key] = item.Value;
+            }
+
+            foreach (var item in controller.Properties)
+            {
+                actionDescriptor.Properties[item.Key] = item.Value;
+            }
+
+            foreach (var item in action.Properties)
+            {
+                actionDescriptor.Properties[item.Key] = item.Value;
+            }
+        }
+
         private static void AddActionFilters(
             ControllerActionDescriptor actionDescriptor,
             IEnumerable<IFilter> actionFilters,

src/Microsoft.AspNet.Mvc.Core/Logging/ActionModelValues.cs

@@ -33,6 +33,7 @@ namespace Microsoft.AspNet.Mvc.Logging
                 }
                 HttpMethods = inner.HttpMethods;
                 ActionConstraints = inner.ActionConstraints?.Select(a => new ActionConstraintValues(a))?.ToList();
+                Properties = new Dictionary<object, object>(inner.Properties);
             }
         }
 
@@ -86,6 +87,11 @@ namespace Microsoft.AspNet.Mvc.Logging
         /// </summary>
         public IList<ActionConstraintValues> ActionConstraints { get; }
 
+        /// <summary>
+        /// Gets the set of properties associated with the action <see cref="ActionModel.Properties"/>.
+        /// </summary>
+        public IDictionary<object, object> Properties { get; }
+
         public override string Format()
         {
             return LogFormatter.FormatStructure(this);

src/Microsoft.AspNet.Mvc.Core/Logging/ControllerModelValues.cs

@@ -29,6 +29,7 @@ namespace Microsoft.AspNet.Mvc.Logging
                     r => new RouteConstraintProviderValues(r)).ToList();
                 AttributeRoutes = inner.AttributeRoutes.Select(
                     a => new AttributeRouteModelValues(a)).ToList();
+                Properties = new Dictionary<object, object>(inner.Properties);
             }
         }
 
@@ -83,6 +84,11 @@ namespace Microsoft.AspNet.Mvc.Logging
         /// </summary>
         public List<AttributeRouteModelValues> AttributeRoutes { get; set; }
 
+        /// <summary>
+        /// Gets the set of properties associated with the controller <see cref="ControllerModel.Properties"/>.
+        /// </summary>
+        public IDictionary<object, object> Properties { get; }
+
         public override string Format()
         {
             return LogFormatter.FormatStructure(this);

test/Microsoft.AspNet.Mvc.Core.Test/ApplicationModel/ActionModelTest.cs

@@ -53,6 +53,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             action.Filters.Add(new AuthorizeAttribute());
             action.HttpMethods.Add("GET");
             action.RouteConstraints.Add(new AreaAttribute("Admin"));
+            action.Properties.Add(new KeyValuePair<object, object>("test key", "test value"));
 
             // Act
             var action2 = new ActionModel(action);
@@ -60,6 +61,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             // Assert
             foreach (var property in typeof(ActionModel).GetProperties())
             {
+                // Reflection is used to make sure the test fails when a new property is added.
                 if (property.Name.Equals("ApiExplorer") ||
                     property.Name.Equals("AttributeRouteModel") ||
                     property.Name.Equals("Parameters"))
@@ -78,6 +80,13 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
                     // Ensure non-default value
                     Assert.NotEmpty((IEnumerable<object>)value1);
                 }
+                else if (typeof(IDictionary<object, object>).IsAssignableFrom(property.PropertyType))
+                {
+                    Assert.Equal(value1, value2);
+
+                    // Ensure non-default value
+                    Assert.NotEmpty((IDictionary<object, object>)value1);
+                }
                 else if (property.PropertyType.IsValueType ||
                     Nullable.GetUnderlyingType(property.PropertyType) != null)
                 {

test/Microsoft.AspNet.Mvc.Core.Test/ApplicationModel/ControllerModelTest.cs

@@ -56,6 +56,7 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
             controller.ControllerName = "cool";
             controller.Filters.Add(new AuthorizeAttribute());
             controller.RouteConstraints.Add(new AreaAttribute("Admin"));
+            controller.Properties.Add(new KeyValuePair<object, object>("test key", "test value"));
 
             // Act
             var controller2 = new ControllerModel(controller);
@@ -81,6 +82,13 @@ namespace Microsoft.AspNet.Mvc.ApplicationModels
                     // Ensure non-default value
                     Assert.NotEmpty((IEnumerable<object>)value1);
                 }
+                else if (typeof(IDictionary<object, object>).IsAssignableFrom(property.PropertyType))
+                {
+                    Assert.Equal(value1, value2);
+
+                    // Ensure non-default value
+                    Assert.NotEmpty((IDictionary<object, object>)value1);
+                }
                 else if (property.PropertyType.IsValueType ||
                     Nullable.GetUnderlyingType(property.PropertyType) != null)
                 {

test/Microsoft.AspNet.Mvc.Core.Test/ControllerActionDescriptorBuilderTest.cs

@@ -0,0 +1,94 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Microsoft.AspNet.Mvc.ApplicationModels;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc
+{
+    public class ControllerActionDescriptorBuilderTest
+    {
+        [Fact]
+        public void Build_WithPropertiesSet_FromApplicationModel()
+        {
+            // Arrange
+            var applicationModel = new ApplicationModel();
+            applicationModel.Properties["test"] = "application";
+
+            var controller = new ControllerModel(typeof(TestController).GetTypeInfo(),
+                                                 new List<object>() { });
+            controller.Application = applicationModel;
+            applicationModel.Controllers.Add(controller);
+
+            var methodInfo = typeof(TestController).GetMethod("SomeAction");
+            var actionModel = new ActionModel(methodInfo, new List<object>() { });
+            actionModel.Controller = controller;
+            controller.Actions.Add(actionModel);
+
+            // Act
+            var descriptors = ControllerActionDescriptorBuilder.Build(applicationModel);
+
+            // Assert
+            Assert.Equal("application", descriptors.Single().Properties["test"]);
+        }
+
+        [Fact]
+        public void Build_WithPropertiesSet_ControllerOverwritesApplicationModel()
+        {
+            // Arrange
+            var applicationModel = new ApplicationModel();
+            applicationModel.Properties["test"] = "application";
+
+            var controller = new ControllerModel(typeof(TestController).GetTypeInfo(),
+                                                 new List<object>() { });
+            controller.Application = applicationModel;
+            controller.Properties["test"] = "controller";
+            applicationModel.Controllers.Add(controller);
+
+            var methodInfo = typeof(TestController).GetMethod("SomeAction");
+            var actionModel = new ActionModel(methodInfo, new List<object>() { });
+            actionModel.Controller = controller;
+            controller.Actions.Add(actionModel);
+
+            // Act
+            var descriptors = ControllerActionDescriptorBuilder.Build(applicationModel);
+
+            // Assert
+            Assert.Equal("controller", descriptors.Single().Properties["test"]);
+        }
+
+        [Fact]
+        public void Build_WithPropertiesSet_ActionOverwritesApplicationAndControllerModel()
+        {
+            // Arrange
+            var applicationModel = new ApplicationModel();
+            applicationModel.Properties["test"] = "application";
+
+            var controller = new ControllerModel(typeof(TestController).GetTypeInfo(),
+                                                 new List<object>() { });
+            controller.Application = applicationModel;
+            controller.Properties["test"] = "controller";
+            applicationModel.Controllers.Add(controller);
+
+            var methodInfo = typeof(TestController).GetMethod("SomeAction");
+            var actionModel = new ActionModel(methodInfo, new List<object>() { });
+            actionModel.Controller = controller;
+            actionModel.Properties["test"] = "action";
+            controller.Actions.Add(actionModel);
+
+            // Act
+            var descriptors = ControllerActionDescriptorBuilder.Build(applicationModel);
+
+            // Assert
+            Assert.Equal("action", descriptors.Single().Properties["test"]);
+        }
+
+        private class TestController
+        {
+            public void SomeAction() { }
+        }
+    }
+}

test/Microsoft.AspNet.Mvc.FunctionalTests/ApplicationModelTest.cs

@@ -64,7 +64,57 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
 
             var body = await response.Content.ReadAsStringAsync();
             Assert.Equal("CoolMetadata", body);
-
         }
+
+        [Fact]
+        public async Task ApplicationModel_AddPropertyToActionDescriptor_FromApplicationModel()
+        {
+            // Arrange
+            var server = TestServer.Create(_services, _app);
+            var client = server.CreateClient();
+
+            // Act
+            var response = await client.GetAsync("http://localhost/Home/GetCommonDescription");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
+            var body = await response.Content.ReadAsStringAsync();
+            Assert.Equal("Common Application Description", body);
+        }
+
+        [Fact]
+        public async Task ApplicationModel_AddPropertyToActionDescriptor_ControllerModelOverwritesCommonApplicationProperty()
+        {
+            // Arrange
+            var server = TestServer.Create(_services, _app);
+            var client = server.CreateClient();
+
+            // Act
+            var response = await client.GetAsync("http://localhost/ApplicationModel/GetControllerDescription");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
+            var body = await response.Content.ReadAsStringAsync();
+            Assert.Equal("Common Controller Description", body);
+        }
+
+        [Fact]
+        public async Task ApplicationModel_ProvidesMetadataToActionDescriptor_ActionModelOverwritesControllerModelProperty()
+        {
+            // Arrange
+            var server = TestServer.Create(_services, _app);
+            var client = server.CreateClient();
+
+            // Act
+            var response = await client.GetAsync("http://localhost/ApplicationModel/GetActionSpecificDescription");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
+            var body = await response.Content.ReadAsStringAsync();
+            Assert.Equal("Specific Action Description", body);
+       }
     }
 }

test/WebSites/ApplicationModelWebSite/Controllers/ApplicationModelController.cs

@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc;
+
+namespace ApplicationModelWebSite
+{
+    // This controller uses an reflected model attribute to add arbitrary data to controller and action model.
+    [ControllerDescription("Common Controller Description")]
+    public class ApplicationModelController : Controller
+    {
+        public string GetControllerDescription()
+        {
+            var actionDescriptor = (ControllerActionDescriptor)ActionContext.ActionDescriptor;
+            return actionDescriptor.Properties["description"].ToString();
+        }
+
+        [ActionDescription("Specific Action Description")]
+        public string GetActionSpecificDescription()
+        {
+            var actionDescriptor = (ControllerActionDescriptor)ActionContext.ActionDescriptor;
+            return actionDescriptor.Properties["description"].ToString();
+        }
+    }
+}

test/WebSites/ApplicationModelWebSite/Controllers/HomeController.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc;
+
+namespace ApplicationModelWebSite
+{
+    public class HomeController : Controller
+    {
+        public string GetCommonDescription()
+        {
+            var actionDescriptor = (ControllerActionDescriptor)ActionContext.ActionDescriptor;
+            return actionDescriptor.Properties["description"].ToString();
+        }
+    }
+}

test/WebSites/ApplicationModelWebSite/Conventions/ActionDescriptionAttribute.cs

@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNet.Mvc.ApplicationModels;
+
+
+namespace ApplicationModelWebSite
+{
+    public class ActionDescriptionAttribute : Attribute, IActionModelConvention
+    {
+        private object _value;
+
+        public ActionDescriptionAttribute(object value)
+        {
+            _value = value;
+        }
+
+        public void Apply(ActionModel model)
+        {
+            model.Properties["description"] = _value;
+        }
+    }
+}

test/WebSites/ApplicationModelWebSite/Conventions/ApplicationDescription.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc.ApplicationModels;
+
+
+namespace ApplicationModelWebSite
+{
+    public class ApplicationDescription : IApplicationModelConvention
+    {
+        private string _description;
+
+        public ApplicationDescription(string description)
+        {
+            _description = description;
+        }
+
+        public void Apply(ApplicationModel application)
+        {
+            application.Properties["description"] = _description;
+        }
+    }
+}

test/WebSites/ApplicationModelWebSite/Conventions/ControllerDescriptionAttribute.cs

@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNet.Mvc.ApplicationModels;
+
+
+namespace ApplicationModelWebSite
+{
+    public class ControllerDescriptionAttribute : Attribute, IControllerModelConvention
+    {
+        private object _value;
+
+        public ControllerDescriptionAttribute(object value)
+        {
+            _value = value;
+        }
+
+        public void Apply(ControllerModel model)
+        {
+            model.Properties["description"] = _value;
+        }
+    }
+}

test/WebSites/ApplicationModelWebSite/Startup.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.Mvc;
 using Microsoft.Framework.DependencyInjection;
 
 namespace ApplicationModelWebSite
@@ -15,6 +16,11 @@ namespace ApplicationModelWebSite
             app.UseServices(services =>
             {
                 services.AddMvc(configuration);
+
+                services.Configure<MvcOptions>(options =>
+                {
+                    options.ApplicationModelConventions.Add(new ApplicationDescription("Common Application Description"));
+                });
             });
 
             app.UseMvc(routes =>