Tweak CacheTagHelper sample to use a token provider service for

cache expiration.

Fixes #3573

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

@@ -7,6 +7,7 @@ using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Reflection;
+using System.Text;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Testing;
 using Xunit;
@@ -445,17 +446,19 @@ Products: Book1, Book2 (1)";
             Assert.Equal(expected2, response2.Trim(), ignoreLineEndingDifferences: true);
 
             // Act - 3
-            // Trigger an expiration
+            // Trigger an expiration of the nested content.
-            var response3 = await Client.PostAsync("/categories/update-products", new StringContent(string.Empty));
+            var content = @"[{ productName: ""Music Systems"" },{ productName: ""Televisions"" }]";
-            response3.EnsureSuccessStatusCode();
+            var requestMessage = new HttpRequestMessage(HttpMethod.Post, "/categories/Electronics");
+            requestMessage.Content = new StringContent(content, Encoding.UTF8, "application/json");
+            (await Client.SendAsync(requestMessage)).EnsureSuccessStatusCode();
 
-            var response4 = await Client.GetStringAsync("/categories/Electronics?correlationId=3");
+            var response3 = await Client.GetStringAsync("/categories/Electronics?correlationId=3");
 
             // Assert - 3
             var expected3 =
 @"Category: Electronics
-Products: Laptops (3)";
+Products: Music Systems, Televisions (3)";
-            Assert.Equal(expected3, response4.Trim(), ignoreLineEndingDifferences: true);
+            Assert.Equal(expected3, response3.Trim(), ignoreLineEndingDifferences: true);
         }
 
         [Fact]

test/WebSites/HtmlGenerationWebSite/Components/ProductsViewComponent.cs

@@ -1,36 +0,0 @@
-// 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 Microsoft.AspNet.Mvc;
-using Microsoft.Extensions.Caching.Memory;
-using Microsoft.Extensions.Primitives;
-
-namespace HtmlGenerationWebSite.Components
-{
-    public class ProductsViewComponent : ViewComponent
-    {
-        public ProductsViewComponent(ProductsService productsService, IMemoryCache cache)
-        {
-            ProductsService = productsService;
-            Cache = cache;
-        }
-
-        private ProductsService ProductsService { get; }
-
-        public IMemoryCache Cache { get; }
-
-        public IViewComponentResult Invoke(string category)
-        {
-            string products;
-            if (!Cache.TryGetValue(category, out products))
-            {
-                IChangeToken changeToken;
-                products = ProductsService.GetProducts(category, out changeToken);
-                Cache.Set(category, products, new MemoryCacheEntryOptions().AddExpirationToken(changeToken));
-            }
-
-            ViewData["Products"] = products;
-            return View();
-        }
-    }
-}

test/WebSites/HtmlGenerationWebSite/Controllers/Catalog_CacheTagHelperController.cs

@@ -1,7 +1,9 @@
 // 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.Collections.Generic;
 using System.Security.Claims;
+using HtmlGenerationWebSite.Models;
 using Microsoft.AspNet.Mvc;
 
 namespace HtmlGenerationWebSite.Controllers
@@ -71,10 +73,14 @@ namespace HtmlGenerationWebSite.Controllers
             return View();
         }
 
-        [HttpPost("/categories/update-products")]
+        [HttpPost("/categories/{category}")]
-        public void UpdateCategories([FromServices] ProductsService productsService)
+        public IActionResult UpdateProducts(
+            [FromServices] ProductsService productService,
+            string category,
+            [FromBody] List<Product> products)
         {
-            productsService.UpdateProducts();
+            productService.UpdateProducts(category, products);
+            return Ok();
         }
 
         [HttpGet("/catalog/GetDealPercentage/{dealPercentage}")]

test/WebSites/HtmlGenerationWebSite/ISignalTokenProviderService.cs

@@ -0,0 +1,14 @@
+// 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 Microsoft.Extensions.Primitives;
+
+namespace HtmlGenerationWebSite
+{
+    public interface ISignalTokenProviderService<TKey>
+    {
+        IChangeToken GetToken(object key);
+
+        void SignalToken(object key);
+    }
+}

test/WebSites/HtmlGenerationWebSite/ProductsService.cs

@@ -1,33 +1,59 @@
 // 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.Threading;
+using System.Collections.Generic;
-using Microsoft.Extensions.Primitives;
+using System.Linq;
+using HtmlGenerationWebSite.Models;
+using Microsoft.Extensions.Caching.Memory;
 
 namespace HtmlGenerationWebSite
 {
     public class ProductsService
     {
-        private readonly CancellationTokenSource _tokenSource = new CancellationTokenSource();
+        private readonly IMemoryCache _memoryCache;
-
+        private readonly ISignalTokenProviderService<Product> _tokenProviderService;
-        public string GetProducts(string category, out IChangeToken changeToken)
+        private readonly Dictionary<string, Product[]> _products = new Dictionary<string, Product[]>
         {
-            var token = _tokenSource.IsCancellationRequested ?
+            ["Books"] = new[]
-                CancellationToken.None : _tokenSource.Token;
-            changeToken = new CancellationChangeToken(token);
-            if (category == "Books")
             {
-                return "Book1, Book2";
+                new Product { ProductName = "Book1" },
-            }
+                new Product { ProductName = "Book2" }
-            else
+            },
+            ["Electronics"] = new[]
             {
-                return "Laptops";
+                new Product { ProductName = "Laptops" }
             }
+        };
+
+        public ProductsService(
+            IMemoryCache memoryCache,
+            ISignalTokenProviderService<Product> tokenProviderService)
+        {
+            _memoryCache = memoryCache;
+            _tokenProviderService = tokenProviderService;
         }
 
-        public void UpdateProducts()
+        public IEnumerable<string> GetProductNames(string category)
         {
-            _tokenSource.Cancel();
+            IEnumerable<Product> products;
+            var key = typeof(ProductsService).FullName;
+            if (!_memoryCache.TryGetValue(key, out products))
+            {
+                var changeToken = _tokenProviderService.GetToken(key);
+                products = _memoryCache.Set<IEnumerable<Product>>(
+                    key,
+                    _products[category],
+                    new MemoryCacheEntryOptions().AddExpirationToken(changeToken));
+            }
+
+            return products.Select(p => p.ProductName);
+        }
+
+        public void UpdateProducts(string category, IEnumerable<Product> products)
+        {
+            _products[category] = products.ToArray();
+            var key = typeof(ProductsService).FullName;
+            _tokenProviderService.SignalToken(key);
         }
     }
 }

test/WebSites/HtmlGenerationWebSite/SignalTokenProviderService.cs

@@ -0,0 +1,49 @@
+// 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.Collections.Concurrent;
+using System.Threading;
+using Microsoft.Extensions.Primitives;
+
+namespace HtmlGenerationWebSite
+{
+    public class SignalTokenProviderService<TKey> : ISignalTokenProviderService<TKey>
+    {
+        private readonly ConcurrentDictionary<object, ChangeTokenInfo> _changeTokens
+            = new ConcurrentDictionary<object, ChangeTokenInfo>();
+
+        public IChangeToken GetToken(object key)
+        {
+            return _changeTokens.GetOrAdd(
+                key,
+                _ =>
+                {
+                    var cancellationTokenSource = new CancellationTokenSource();
+                    var changeToken = new CancellationChangeToken(cancellationTokenSource.Token);
+                    return new ChangeTokenInfo(changeToken, cancellationTokenSource);
+                }).ChangeToken;
+        }
+
+        public void SignalToken(object key)
+        {
+            ChangeTokenInfo changeTokenInfo;
+            if (_changeTokens.TryRemove(key, out changeTokenInfo))
+            {
+                changeTokenInfo.TokenSource.Cancel();
+            }
+        }
+
+        private class ChangeTokenInfo
+        {
+            public ChangeTokenInfo(IChangeToken changeToken, CancellationTokenSource tokenSource)
+            {
+                ChangeToken = changeToken;
+                TokenSource = tokenSource;
+            }
+
+            public IChangeToken ChangeToken { get; }
+
+            public CancellationTokenSource TokenSource { get; }
+        }
+    }
+}

test/WebSites/HtmlGenerationWebSite/Startup.cs

@@ -16,6 +16,7 @@ namespace HtmlGenerationWebSite
             // null which is interpreted as true unless element includes an action attribute.
             services.AddMvc().InitializeTagHelper<FormTagHelper>((helper, _) => helper.Antiforgery = false);
 
+            services.AddSingleton(typeof(ISignalTokenProviderService<>), typeof(SignalTokenProviderService<>));
             services.AddSingleton<ProductsService>();
         }
 

test/WebSites/HtmlGenerationWebSite/Views/Catalog_CacheTagHelper/ListCategories.cshtml

@@ -1,4 +1,5 @@
-<cache vary-by-route="category">
+@inject HtmlGenerationWebSite.ProductsService ProductsService
+<cache vary-by-route="category">
 Category: @ViewBag.Category
-<cache>@Component.Invoke("Products", ViewBag.Category)</cache>
+<cache>Products: @string.Join(", ", ProductsService.GetProductNames(ViewBag.Category)) (@ViewBag.CorrelationId)</cache>
 </cache>

test/WebSites/HtmlGenerationWebSite/Views/Shared/Components/Products/Default.cshtml

@@ -1 +0,0 @@
-Products: @ViewBag.Products (@ViewBag.CorrelationId)