#282 Add filter attribute for publishing ModelReceived and ModelPrep…

…ared events

src/Presentation/Nop.Web.Framework/Controllers/BaseController.cs

@@ -28,6 +28,7 @@ namespace Nop.Web.Framework.Controllers
     /// <summary>
     /// Base controller
     /// </summary>
+    [PublishModelEvents]
     [SignOutFromExternalAuthentication]
     [ValidatePassword]
     [SaveIpAddress]

src/Presentation/Nop.Web.Framework/Events/EventPublisherExtensions.cs

@@ -4,15 +4,30 @@
 
 namespace Nop.Web.Framework.Events
 {
+    /// <summary>
+    /// Represents event publisher extensions
+    /// </summary>
     public static class EventPublisherExtensions
     {
+        /// <summary>
+        /// Publish ModelPrepared event
+        /// </summary>
+        /// <typeparam name="T">Type of the model</typeparam>
+        /// <param name="eventPublisher">Event publisher</param>
+        /// <param name="model">Model</param>
         public static void ModelPrepared<T>(this IEventPublisher eventPublisher, T model) where T : BaseNopModel
         {
             eventPublisher.Publish(new ModelPrepared<T>(model));
         }
 
-        public static void ModelReceived<T>(this IEventPublisher eventPublisher, T model,
-            ModelStateDictionary modelState) where T : BaseNopModel
+        /// <summary>
+        /// Publish ModelReceived event
+        /// </summary>
+        /// <typeparam name="T">Type of the model</typeparam>
+        /// <param name="eventPublisher">Event publisher</param>
+        /// <param name="model">Model</param>
+        /// <param name="modelState">Model state</param>
+        public static void ModelReceived<T>(this IEventPublisher eventPublisher, T model, ModelStateDictionary modelState) where T : BaseNopModel
         {
             eventPublisher.Publish(new ModelReceived<T>(model, modelState));
         }

src/Presentation/Nop.Web.Framework/Events/ModelPrepared.cs

@@ -1,18 +1,29 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Nop.Web.Framework.Mvc.Models;
+using Nop.Web.Framework.Mvc.Models;
 
 namespace Nop.Web.Framework.Events
 {
+    /// <summary>
+    /// Represents an event that occurs after the model is prepared for view
+    /// </summary>
+    /// <typeparam name="T">Type of the model</typeparam>
     public class ModelPrepared<T> where T : BaseNopModel
     {
+        #region Ctor
+
         public ModelPrepared(T model)
         {
             this.Model = model;
         }
+
+        #endregion
+
+        #region Properties
+
+        /// <summary>
+        /// Gets a model
+        /// </summary>
         public T Model { get; private set; }
+
+        #endregion
     }
 }

src/Presentation/Nop.Web.Framework/Events/ModelReceived.cs

@@ -1,22 +1,36 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc.ModelBinding;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Nop.Web.Framework.Mvc.Models;
 
 namespace Nop.Web.Framework.Events
 {
+    /// <summary>
+    /// Represents an event that occurs after the model is receved from the view
+    /// </summary>
+    /// <typeparam name="T">Type of the model</typeparam>
     public class ModelReceived<T> where T : BaseNopModel
     {
+        #region Ctor
+
         public ModelReceived(T model, ModelStateDictionary modelState)
         {
             this.Model = model;
             this.ModelState = modelState;
         }
 
+        #endregion
+
+        #region Properties
+
+        /// <summary>
+        /// Gets a model
+        /// </summary>
         public T Model { get; private set; }
+
+        /// <summary>
+        /// Gets a model state
+        /// </summary>
         public ModelStateDictionary ModelState { get; private set; }
+
+        #endregion
     }
 }

src/Presentation/Nop.Web.Framework/Mvc/Filters/PublishModelEventsAttribute.cs

@@ -0,0 +1,148 @@
+using System;
+using System.Linq;
+using System.Net;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Nop.Services.Events;
+using Nop.Web.Framework.Events;
+using Nop.Web.Framework.Mvc.Models;
+
+namespace Nop.Web.Framework.Mvc.Filters
+{
+    /// <summary>
+    /// Represents filter attribute that publish ModelReceived event before the action executes, after model binding is complete
+    /// and publish ModelPrepared event after the action executes, before the action result
+    /// </summary>
+    public class PublishModelEventsAttribute : TypeFilterAttribute
+    {
+        #region Fields
+
+        private readonly bool _ignoreFilter;
+
+        #endregion
+
+        #region Ctor
+
+        /// <summary>
+        /// Create instance of the filter attribute
+        /// </summary>
+        /// <param name="ignore">Whether to ignore the execution of filter actions</param>
+        public PublishModelEventsAttribute(bool ignore = false) : base(typeof(PublishModelEventsFilter))
+        {
+            this._ignoreFilter = ignore;
+            this.Arguments = new object[] { ignore };
+        }
+
+        #endregion
+
+        #region Properties
+
+        /// <summary>
+        /// Gets a value indicating whether to ignore the execution of filter actions
+        /// </summary>
+        public bool IgnoreFilter => _ignoreFilter;
+
+        #endregion
+
+        #region Nested filter
+
+        /// <summary>
+        /// Represents filter that publish ModelReceived event before the action executes, after model binding is complete
+        /// and publish ModelPrepared event after the action executes, before the action result
+        /// </summary>
+        private class PublishModelEventsFilter : IActionFilter
+        {
+            #region Fields
+
+            private readonly bool _ignoreFilter;
+            private readonly IEventPublisher _eventPublisher;
+
+            #endregion
+
+            #region Ctor
+
+            public PublishModelEventsFilter(bool ignoreFilter,
+                IEventPublisher eventPublisher)
+            {
+                this._ignoreFilter = ignoreFilter;
+                this._eventPublisher = eventPublisher;
+            }
+
+            #endregion
+
+            #region Methods
+
+            /// <summary>
+            /// Called before the action executes, after model binding is complete
+            /// </summary>
+            /// <param name="context">A context for action filters</param>
+            public void OnActionExecuting(ActionExecutingContext context)
+            {
+                if (context == null)
+                    throw new ArgumentNullException(nameof(context));
+
+                //check whether this filter has been overridden for the Action
+                var actionFilter = context.ActionDescriptor.FilterDescriptors
+                    .Where(filterDescriptor => filterDescriptor.Scope == FilterScope.Action)
+                    .Select(filterDescriptor => filterDescriptor.Filter).OfType<PublishModelEventsAttribute>().FirstOrDefault();
+
+                //whether to ignore this filter
+                if (actionFilter?.IgnoreFilter ?? _ignoreFilter)
+                    return;
+
+                if (context.HttpContext.Request == null)
+                    return;
+
+                //only in POST requests
+                if (!context.HttpContext.Request.Method.Equals(WebRequestMethods.Http.Post, StringComparison.InvariantCultureIgnoreCase))
+                    return;
+
+                //model received event
+                foreach (var model in context.ActionArguments.Values.OfType<BaseNopModel>())
+                {
+                    //we publish the ModelReceived event for all models as the BaseNopModel, 
+                    //so you need to implement IConsumer<ModelReceived<BaseNopModel>> interface to handle this event
+                    _eventPublisher.ModelReceived(model, context.ModelState);
+                }
+            }
+
+            /// <summary>
+            /// Called after the action executes, before the action result
+            /// </summary>
+            /// <param name="context">A context for action filters</param>
+            public void OnActionExecuted(ActionExecutedContext context)
+            {
+                if (context == null)
+                    throw new ArgumentNullException(nameof(context));
+
+                //check whether this filter has been overridden for the Action
+                var actionFilter = context.ActionDescriptor.FilterDescriptors
+                    .Where(filterDescriptor => filterDescriptor.Scope == FilterScope.Action)
+                    .Select(filterDescriptor => filterDescriptor.Filter).OfType<PublishModelEventsAttribute>().FirstOrDefault();
+
+                //whether to ignore this filter
+                if (actionFilter?.IgnoreFilter ?? _ignoreFilter)
+                    return;
+
+                if (context.HttpContext.Request == null)
+                    return;
+
+                //only in GET requests
+                if (!context.HttpContext.Request.Method.Equals(WebRequestMethods.Http.Get, StringComparison.InvariantCultureIgnoreCase))
+                    return;
+
+                //model prepared event
+                if (context.Controller is Controller controller && controller.ViewData.Model is BaseNopModel model)
+                {
+                    //we publish the ModelPrepared event for all models as the BaseNopModel, 
+                    //so you need to implement IConsumer<ModelPrepared<BaseNopModel>> interface to handle this event
+                    _eventPublisher.ModelPrepared(model);
+                }
+            }
+
+            #endregion
+        }
+
+        #endregion
+    }
+}