From 964173f27758f3be72bf8c3b1aea7db54e8f507f Mon Sep 17 00:00:00 2001
From: Steve Smith <steve@kentsmiths.com>
Date: Wed, 18 Oct 2017 13:18:25 -0400
Subject: [PATCH] Using Base Specification Class (#56)

* Ardalis/upgrade1 (#44)

* Upgrading to netcore 2.0
Updating repository to support async options and refactoring to use it.

* Starting work on tracking customer orders feature.

* Cleaning up some bugs
Working on basket view component implementation

* Fixing up styles, especially for basket in header.

* Adding Order Features (#47)

* Working on order model binding from checkout page - WIP

* Small layout tweaks (#43)

* Updating quantities implemented.

* Fixed basket widget count

* Order History (#49)

* working on creating and viewing orders.
* Working on wiring up listing of orders
* List orders page works as expected. Needed to support ThenInclude scenarios. Currently using strings.

* Remove non-icon basket link from header
Add comments to EF query logic

* Refactoring to use base specification type

* minor cleanup
---
 .../Interfaces/ISpecification.cs              |  1 -
 .../Specifications/BaseSpecification.cs       | 27 +++++++++++++++++
 .../BasketWithItemsSpecification.cs           | 29 +++----------------
 .../CatalogFilterSpecification.cs             | 28 +++---------------
 .../CustomerOrdersWithItemsSpecification.cs   | 27 ++---------------
 src/Infrastructure/Data/EfRepository.cs       |  9 ++++++
 src/Web/Views/Shared/_Layout.cshtml           |  2 --
 7 files changed, 47 insertions(+), 76 deletions(-)
 create mode 100644 src/ApplicationCore/Specifications/BaseSpecification.cs

diff --git a/src/ApplicationCore/Interfaces/ISpecification.cs b/src/ApplicationCore/Interfaces/ISpecification.cs
index 5b1173486..f9a216712 100644
--- a/src/ApplicationCore/Interfaces/ISpecification.cs
+++ b/src/ApplicationCore/Interfaces/ISpecification.cs
@@ -9,6 +9,5 @@ public interface ISpecification<T>
         Expression<Func<T, bool>> Criteria { get; }
         List<Expression<Func<T, object>>> Includes { get; }
         List<string> IncludeStrings { get; }
-        void AddInclude(Expression<Func<T, object>> includeExpression);
     }
 }
diff --git a/src/ApplicationCore/Specifications/BaseSpecification.cs b/src/ApplicationCore/Specifications/BaseSpecification.cs
new file mode 100644
index 000000000..e39a86d6f
--- /dev/null
+++ b/src/ApplicationCore/Specifications/BaseSpecification.cs
@@ -0,0 +1,27 @@
+using ApplicationCore.Interfaces;
+using System;
+using System.Linq.Expressions;
+using System.Collections.Generic;
+
+namespace ApplicationCore.Specifications
+{
+    public abstract class BaseSpecification<T> : ISpecification<T>
+    {
+        public BaseSpecification(Expression<Func<T, bool>> criteria)
+        {
+            Criteria = criteria;
+        }
+        public Expression<Func<T, bool>> Criteria { get; }
+        public List<Expression<Func<T, object>>> Includes { get; } = new List<Expression<Func<T, object>>>();
+        public List<string> IncludeStrings { get; } = new List<string>();
+
+        protected virtual void AddInclude(Expression<Func<T, object>> includeExpression)
+        {
+            Includes.Add(includeExpression);
+        }
+        protected virtual void AddInclude(string includeString)
+        {
+            IncludeStrings.Add(includeString);
+        }
+    }
+}
diff --git a/src/ApplicationCore/Specifications/BasketWithItemsSpecification.cs b/src/ApplicationCore/Specifications/BasketWithItemsSpecification.cs
index a44fb7766..5608dc6a0 100644
--- a/src/ApplicationCore/Specifications/BasketWithItemsSpecification.cs
+++ b/src/ApplicationCore/Specifications/BasketWithItemsSpecification.cs
@@ -1,39 +1,18 @@
-using ApplicationCore.Interfaces;
-using Microsoft.eShopWeb.ApplicationCore.Entities;
-using System;
-using System.Linq.Expressions;
-using System.Collections.Generic;
-using ApplicationCore.Entities.OrderAggregate;
+using Microsoft.eShopWeb.ApplicationCore.Entities;
 
 namespace ApplicationCore.Specifications
 {
-    public class BasketWithItemsSpecification : ISpecification<Basket>
+    public class BasketWithItemsSpecification : BaseSpecification<Basket>
     {
         public BasketWithItemsSpecification(int basketId)
+            :base(b => b.Id == basketId)
         {
-            BasketId = basketId;
             AddInclude(b => b.Items);
         }
         public BasketWithItemsSpecification(string buyerId)
+            :base(b => b.BuyerId == buyerId)
         {
-            BuyerId = buyerId;
             AddInclude(b => b.Items);
         }
-
-        public int? BasketId { get; }
-        public string BuyerId { get; }
-
-        public Expression<Func<Basket, bool>> Criteria => b =>
-            (BasketId.HasValue && b.Id == BasketId.Value)
-            || (BuyerId != null && b.BuyerId == BuyerId);
-
-        public List<Expression<Func<Basket, object>>> Includes { get; } = new List<Expression<Func<Basket, object>>>();
-
-        public List<string> IncludeStrings { get; } = new List<string>();
-
-        public void AddInclude(Expression<Func<Basket, object>> includeExpression)
-        {
-            Includes.Add(includeExpression);
-        }
     }
 }
diff --git a/src/ApplicationCore/Specifications/CatalogFilterSpecification.cs b/src/ApplicationCore/Specifications/CatalogFilterSpecification.cs
index 54e1f8628..efcba8c5d 100644
--- a/src/ApplicationCore/Specifications/CatalogFilterSpecification.cs
+++ b/src/ApplicationCore/Specifications/CatalogFilterSpecification.cs
@@ -1,34 +1,14 @@
-using ApplicationCore.Interfaces;
-using Microsoft.eShopWeb.ApplicationCore.Entities;
-using System;
-using System.Linq.Expressions;
-using System.Collections.Generic;
+using Microsoft.eShopWeb.ApplicationCore.Entities;
 
 namespace ApplicationCore.Specifications
 {
 
-    public class CatalogFilterSpecification : ISpecification<CatalogItem>
+    public class CatalogFilterSpecification : BaseSpecification<CatalogItem>
     {
         public CatalogFilterSpecification(int? brandId, int? typeId)
+            : base(i => (!brandId.HasValue || i.CatalogBrandId == brandId) &&
+                (!typeId.HasValue || i.CatalogTypeId == typeId))
         {
-            BrandId = brandId;
-            TypeId = typeId;
-        }
-
-        public int? BrandId { get; }
-        public int? TypeId { get; }
-
-        public Expression<Func<CatalogItem, bool>> Criteria => 
-            i => (!BrandId.HasValue || i.CatalogBrandId == BrandId) && 
-                (!TypeId.HasValue || i.CatalogTypeId == TypeId);
-
-        public List<Expression<Func<CatalogItem, object>>> Includes { get; }  = new List<Expression<Func<CatalogItem, object>>>();
-
-        public List<string> IncludeStrings { get; } = new List<string>();
-
-        public void AddInclude(Expression<Func<CatalogItem, object>> includeExpression)
-        {
-            Includes.Add(includeExpression);
         }
     }
 }
diff --git a/src/ApplicationCore/Specifications/CustomerOrdersWithItemsSpecification.cs b/src/ApplicationCore/Specifications/CustomerOrdersWithItemsSpecification.cs
index abfa9b658..df234c418 100644
--- a/src/ApplicationCore/Specifications/CustomerOrdersWithItemsSpecification.cs
+++ b/src/ApplicationCore/Specifications/CustomerOrdersWithItemsSpecification.cs
@@ -1,35 +1,14 @@
-using ApplicationCore.Interfaces;
-using System;
-using System.Linq.Expressions;
-using System.Collections.Generic;
-using ApplicationCore.Entities.OrderAggregate;
+using ApplicationCore.Entities.OrderAggregate;
 
 namespace ApplicationCore.Specifications
 {
-    public class CustomerOrdersWithItemsSpecification : ISpecification<Order>
+    public class CustomerOrdersWithItemsSpecification : BaseSpecification<Order>
     {
-        private readonly string _buyerId;
-
         public CustomerOrdersWithItemsSpecification(string buyerId)
+            : base(o => o.BuyerId == buyerId)
         {
-            _buyerId = buyerId;
             AddInclude(o => o.OrderItems);
             AddInclude("OrderItems.ItemOrdered");
         }
-
-        public Expression<Func<Order, bool>> Criteria => o => o.BuyerId == _buyerId;
-
-        public List<Expression<Func<Order, object>>> Includes { get; } = new List<Expression<Func<Order, object>>>();
-        public List<string> IncludeStrings { get; } = new List<string>();
-
-        public void AddInclude(Expression<Func<Order, object>> includeExpression)
-        {
-            Includes.Add(includeExpression);
-        }
-
-        public void AddInclude(string includeString)
-        {
-            IncludeStrings.Add(includeString);
-        }
     }
 }
diff --git a/src/Infrastructure/Data/EfRepository.cs b/src/Infrastructure/Data/EfRepository.cs
index cdc84fa44..b0cecfa10 100644
--- a/src/Infrastructure/Data/EfRepository.cs
+++ b/src/Infrastructure/Data/EfRepository.cs
@@ -43,25 +43,34 @@ public async Task<List<T>> ListAllAsync()
 
         public IEnumerable<T> List(ISpecification<T> spec)
         {
+            // fetch a Queryable that includes all expression-based includes
             var queryableResultWithIncludes = spec.Includes
                 .Aggregate(_dbContext.Set<T>().AsQueryable(),
                     (current, include) => current.Include(include));
+
+            // modify the IQueryable to include any string-based include statements
             var secondaryResult = spec.IncludeStrings
                 .Aggregate(queryableResultWithIncludes,
                     (current, include) => current.Include(include));
+
+            // return the result of the query using the specification's criteria expression
             return secondaryResult
                             .Where(spec.Criteria)
                             .AsEnumerable();
         }
         public async Task<List<T>> ListAsync(ISpecification<T> spec)
         {
+            // fetch a Queryable that includes all expression-based includes
             var queryableResultWithIncludes = spec.Includes
                 .Aggregate(_dbContext.Set<T>().AsQueryable(),
                     (current, include) => current.Include(include));
+
+            // modify the IQueryable to include any string-based include statements
             var secondaryResult = spec.IncludeStrings
                 .Aggregate(queryableResultWithIncludes,
                     (current, include) => current.Include(include));
 
+            // return the result of the query using the specification's criteria expression
             return await secondaryResult
                             .Where(spec.Criteria)
                             .ToListAsync();
diff --git a/src/Web/Views/Shared/_Layout.cshtml b/src/Web/Views/Shared/_Layout.cshtml
index 998deb2c4..8803d103c 100644
--- a/src/Web/Views/Shared/_Layout.cshtml
+++ b/src/Web/Views/Shared/_Layout.cshtml
@@ -33,8 +33,6 @@
 					</a>
 				</section>
 				@await Html.PartialAsync("_LoginPartial")
-				<section class="col-lg-1 col-md-3 col-xs-6"><a asp-controller="Basket" asp-action="Index">Basket</a></section>
-
 			</article>
 		</div>
 	</header>