Added basic caching layer (#106)

Co-authored-by: Tom Whittington <[email protected]>
DFE-Digital · Jul 3, 2024 · da53160 · da53160
1 parent dc9458e
commit da53160
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Showing 8 changed files with 165 additions and 7 deletions.
diff --git a/src/Dfe.ContentSupport.Web/Extensions/WebApplicationBuilderExtensions.cs b/src/Dfe.ContentSupport.Web/Extensions/WebApplicationBuilderExtensions.cs
@@ -1,5 +1,6 @@
 using Dfe.ContentSupport.Web.Configuration;
 using Dfe.ContentSupport.Web.Http;
+using Dfe.ContentSupport.Web.Models.Mapped;
 using Dfe.ContentSupport.Web.Services;
 
 namespace Dfe.ContentSupport.Web.Extensions;
@@ -12,7 +13,8 @@ public static void InitDependencyInjection(this WebApplicationBuilder app)
         app.Configuration.GetSection("Contentful").Bind(contentfulOptions);
         app.Services.AddSingleton(contentfulOptions);
 
-
+        app.Services
+            .AddTransient<ICacheService<List<CsPage>>, CsPagesCacheService>();
         app.Services.AddTransient<IContentfulService, ContentfulService>();
         app.Services.AddTransient<IContentService, ContentService>();
 

diff --git a/src/Dfe.ContentSupport.Web/Services/ContentService.cs b/src/Dfe.ContentSupport.Web/Services/ContentService.cs
@@ -5,7 +5,8 @@
 
 namespace Dfe.ContentSupport.Web.Services;
 
-public class ContentService(IContentfulService contentfulService) : IContentService
+public class ContentService(IContentfulService contentfulService, ICacheService<List<CsPage>> cache)
+    : IContentService
 {
     public async Task<CsPage?> GetContent(string slug, bool isPreview = false)
     {
@@ -41,12 +42,22 @@ public async Task<List<CsPage>> GetCsPages()
         return pages.ToList();
     }
 
-    private async Task<List<CsPage>> GetContentSupportPages(
+    public async Task<List<CsPage>> GetContentSupportPages(
         string field, string value, bool isPreview)
     {
+        var key = $"{field}_{value}";
+        var fromCache = cache.GetFromCache(key);
+        if (fromCache is not null)
+        {
+            return fromCache;
+        }
+
         var builder = QueryBuilder<ContentSupportPage>.New.ContentTypeIs(nameof(ContentSupportPage))
             .FieldEquals($"fields.{field}", value);
         var result = await contentfulService.ContentfulClient(isPreview).Query(builder);
-        return result.Select(page => new CsPage(page)).ToList();
+        var pages = result.Select(page => new CsPage(page)).ToList();
+
+        cache.AddToCache(key, pages);
+        return pages;
     }
 }
diff --git a/src/Dfe.ContentSupport.Web/Services/CsPagesCacheService.cs b/src/Dfe.ContentSupport.Web/Services/CsPagesCacheService.cs
@@ -0,0 +1,26 @@
+using System.Diagnostics.CodeAnalysis;
+using Dfe.ContentSupport.Web.Models.Mapped;
+using Microsoft.Extensions.Caching.Memory;
+
+namespace Dfe.ContentSupport.Web.Services;
+
+[ExcludeFromCodeCoverage]
+public class CsPagesCacheService(IMemoryCache cache, IConfiguration configuration)
+    : ICacheService<List<CsPage>>
+{
+    private readonly int _cacheTimeOutMs = configuration.GetSection("CacheTimeOutMs").Get<int>();
+
+    public void AddToCache(string key, List<CsPage> item)
+    {
+        MemoryCacheEntryOptions options = new()
+        {
+            AbsoluteExpirationRelativeToNow = TimeSpan.FromMilliseconds(_cacheTimeOutMs)
+        };
+        cache.Set(key, item, options);
+    }
+
+    public List<CsPage>? GetFromCache(string key)
+    {
+        return cache.Get<List<CsPage>>(key);
+    }
+}
diff --git a/src/Dfe.ContentSupport.Web/Services/ICacheService.cs b/src/Dfe.ContentSupport.Web/Services/ICacheService.cs
@@ -0,0 +1,7 @@
+namespace Dfe.ContentSupport.Web.Services;
+
+public interface ICacheService<T>
+{
+    void AddToCache(string key,T item);
+    T? GetFromCache(string key);
+}
diff --git a/src/Dfe.ContentSupport.Web/Views/Shared/_BetaHeader.cshtml b/src/Dfe.ContentSupport.Web/Views/Shared/_BetaHeader.cshtml
@@ -3,7 +3,7 @@
         @* <govuk-phase-banner-tag>Beta</govuk-phase-banner-tag> *@
         <strong class="govuk-tag govuk-phase-banner__content__tag">Beta</strong>
         This is a new service - your
-        <a href="https://forms.office.com/e/Jk5PuNWvGe" class="govuk-link" target="_blank" rel="noopener">
+        <a href="" class="govuk-link" target="_blank" rel="noopener">
             feedback
         </a> will
         help us to improve it.

diff --git a/src/Dfe.ContentSupport.Web/appsettings.json b/src/Dfe.ContentSupport.Web/appsettings.json
@@ -1,4 +1,5 @@
 {
+  "CacheTimeOutMs": 30000,
   "Logging": {
     "LogLevel": {
       "Default": "Information",

diff --git a/tests/Dfe.ContentSupport.Web.Tests/Extensions/WebApplicationBuilderExtensionsTests.cs b/tests/Dfe.ContentSupport.Web.Tests/Extensions/WebApplicationBuilderExtensionsTests.cs
@@ -1,5 +1,6 @@
 using Dfe.ContentSupport.Web.Extensions;
 using Dfe.ContentSupport.Web.Http;
+using Dfe.ContentSupport.Web.Models.Mapped;
 using Microsoft.AspNetCore.Builder;
 
 namespace Dfe.ContentSupport.Web.Tests.Extensions;
@@ -16,7 +17,8 @@ public void Builder_Contains_Correct_Services()
         {
             typeof(IContentService),
             typeof(IContentfulService),
-            typeof(IHttpContentfulClient)
+            typeof(IHttpContentfulClient),
+            typeof(ICacheService<List<CsPage>>)
         };
         foreach (var type in types)
             builder.Services.Where(o => o.ServiceType == type).Should().ContainSingle();

diff --git a/tests/Dfe.ContentSupport.Web.Tests/Services/ContentServiceTests.cs b/tests/Dfe.ContentSupport.Web.Tests/Services/ContentServiceTests.cs
@@ -10,6 +10,7 @@ namespace Dfe.ContentSupport.Web.Tests.Services;
 public class ContentServiceTests
 {
     private readonly Mock<IHttpContentfulClient> _httpContentClientMock = new();
+    private readonly Mock<ICacheService<List<CsPage>>> _cacheMock = new();
 
 
     private readonly ContentfulCollection<ContentSupportPage> _response = new()
@@ -24,7 +25,7 @@ public class ContentServiceTests
 
     private ContentService GetService()
     {
-        return new ContentService(GetClient());
+        return new ContentService(GetClient(), _cacheMock.Object);
     }
 
     private IContentfulService GetClient()
@@ -104,4 +105,112 @@ public async void GetCsPages_Calls_Client_Once()
             Times.Once
         );
     }
+
+    [Fact]
+    public async void GetCsPages_Calls_Cache_Correct_Key()
+    {
+        const string expectedKey = "IsSitemap_true";
+        SetupResponse();
+        var sut = GetService();
+        await sut.GetCsPages();
+
+        _cacheMock.Verify(o => o.GetFromCache(expectedKey));
+    }
+
+
+    [Fact]
+    public async void GetContent_Calls_Cache_Correct_Key()
+    {
+        const string slug = "dummy-slug";
+        const string expectedKey = $"Slug_{slug}";
+        SetupResponse();
+        var sut = GetService();
+        await sut.GetContent(slug, It.IsAny<bool>());
+
+        _cacheMock.Verify(o => o.GetFromCache(expectedKey));
+    }
+
+    [Fact]
+    public async void GetCsPage_Calls_Cache_Correct_Key()
+    {
+        const string slug = "dummy-slug";
+        const string expectedKey = $"Slug_{slug}";
+        SetupResponse();
+        var sut = GetService();
+        await sut.GetContent(slug, It.IsAny<bool>());
+
+        _cacheMock.Verify(o => o.GetFromCache(expectedKey));
+    }
+
+    [Fact]
+    public async void GetContentSupportPages_Calls_Cache_Correct_Key()
+    {
+        const string field = "field";
+        const string value = "value";
+        SetupResponse();
+        var isPreview = It.IsAny<bool>();
+        const string expectedKey = $"{field}_{value}";
+        var sut = GetService();
+        await sut.GetContentSupportPages(field, value, isPreview);
+
+        _cacheMock.Verify(o => o.GetFromCache(expectedKey));
+    }
+
+    [Fact]
+    public async void GetContentSupportPages_GotCache_Returns_Cache()
+    {
+        var cacheValue = new List<CsPage> { It.IsAny<CsPage>() };
+
+        const string field = "field";
+        const string value = "value";
+        const string expectedKey = $"{field}_{value}";
+        var isPreview = It.IsAny<bool>();
+        _cacheMock.Setup(o => o.GetFromCache(expectedKey)).Returns(cacheValue);
+
+        var sut = GetService();
+        var result = await sut.GetContentSupportPages(field, value, isPreview);
+
+        result.Should().BeEquivalentTo(cacheValue);
+    }
+
+    [Fact]
+    public async void GetContentSupportPages_NotGotCache_Calls_Client()
+    {
+        List<CsPage>? cacheValue = null;
+
+        const string field = "field";
+        const string value = "value";
+        const string expectedKey = $"{field}_{value}";
+        SetupResponse();
+        var isPreview = It.IsAny<bool>();
+        _cacheMock.Setup(o => o.GetFromCache(expectedKey)).Returns(cacheValue);
+
+        var sut = GetService();
+        await sut.GetContentSupportPages(field, value, isPreview);
+
+        _httpContentClientMock.Verify(o =>
+                o.Query(
+                    It.IsAny<QueryBuilder<ContentSupportPage>>(),
+                    It.IsAny<CancellationToken>()),
+            Times.Once
+        );
+    }
+
+    [Fact]
+    public async void GetContentSupportPages_NotGotCache_AddsToCache()
+    {
+        List<CsPage>? cacheValue = null;
+
+        const string field = "field";
+        const string value = "value";
+        const string expectedKey = $"{field}_{value}";
+        SetupResponse();
+        var isPreview = It.IsAny<bool>();
+        _cacheMock.Setup(o => o.GetFromCache(expectedKey)).Returns(cacheValue);
+
+        var sut = GetService();
+        await sut.GetContentSupportPages(field, value, isPreview);
+
+        _cacheMock.Verify(o => o.AddToCache(expectedKey, It.IsAny<List<CsPage>>()), Times.Once);
+    }
 }