From 74615ceaa1a6106e8e73e187993504db59fa88ea Mon Sep 17 00:00:00 2001
From: Alastair Crabtree <alastair.crabtree@bbc.com>
Date: Sat, 28 Dec 2019 14:25:29 +0000
Subject: [PATCH] task: improve constructor resolution in aspnet core
 dependency injection

---
 .../LazyCacheServiceCollectionExtensions.cs   |  4 +-
 .../LazyCache.Ninject.UnitTests.csproj        |  8 +---
 LazyCache.UnitTests/AspNetCoreTests.cs        | 42 +++++++++++++++++++
 .../LazyCache.UnitTests.csproj                |  2 +
 4 files changed, 48 insertions(+), 8 deletions(-)
 create mode 100644 LazyCache.UnitTests/AspNetCoreTests.cs

diff --git a/LazyCache.AspNetCore/LazyCacheServiceCollectionExtensions.cs b/LazyCache.AspNetCore/LazyCacheServiceCollectionExtensions.cs
index 8739b3f..81df994 100644
--- a/LazyCache.AspNetCore/LazyCacheServiceCollectionExtensions.cs
+++ b/LazyCache.AspNetCore/LazyCacheServiceCollectionExtensions.cs
@@ -18,7 +18,9 @@ public static IServiceCollection AddLazyCache(this IServiceCollection services)
             services.TryAdd(ServiceDescriptor.Singleton<IMemoryCache, MemoryCache>());
             services.TryAdd(ServiceDescriptor.Singleton<ICacheProvider, MemoryCacheProvider>());
 
-            services.TryAdd(ServiceDescriptor.Singleton<IAppCache, CachingService>());
+            services.TryAdd(ServiceDescriptor.Singleton<IAppCache, CachingService>(serviceProvider => 
+                new CachingService(
+                    new Lazy<ICacheProvider>(serviceProvider.GetRequiredService<ICacheProvider>))));
 
             return services;
         }
diff --git a/LazyCache.Ninject.UnitTests/LazyCache.Ninject.UnitTests.csproj b/LazyCache.Ninject.UnitTests/LazyCache.Ninject.UnitTests.csproj
index 6426959..b7037ea 100644
--- a/LazyCache.Ninject.UnitTests/LazyCache.Ninject.UnitTests.csproj
+++ b/LazyCache.Ninject.UnitTests/LazyCache.Ninject.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.2</TargetFramework>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
 
     <IsPackable>false</IsPackable>
   </PropertyGroup>
@@ -16,10 +16,4 @@
     <ProjectReference Include="..\LazyCache.Ninject\LazyCache.Ninject.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Reference Include="Ninject">
-      <HintPath>C:\Users\Alastair\.nuget\packages\ninject\3.3.4\lib\netstandard2.0\Ninject.dll</HintPath>
-    </Reference>
-  </ItemGroup>
-
 </Project>
diff --git a/LazyCache.UnitTests/AspNetCoreTests.cs b/LazyCache.UnitTests/AspNetCoreTests.cs
new file mode 100644
index 0000000..deabd8c
--- /dev/null
+++ b/LazyCache.UnitTests/AspNetCoreTests.cs
@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Microsoft.Extensions.DependencyInjection;
+using NUnit.Framework;
+
+namespace LazyCache.UnitTests
+{
+    public class AspNetCoreTests
+    {
+        [Test]
+        public void CanResolveCacheFromServiceCollectionAsRequiredService()
+        {
+            var container = new ServiceCollection();
+            container.AddLazyCache();
+            var provider = container.BuildServiceProvider();
+
+            var cache = provider.GetRequiredService<IAppCache>();
+            var result = cache?.GetOrAdd("key", () => new object());
+
+            cache.Should().NotBeNull();
+            result.Should().NotBeNull();
+        }
+
+        [Test]
+        public void CanResolveCacheFromServiceCollectionAsService()
+        {
+            var container = new ServiceCollection();
+            container.AddLazyCache();
+            var provider = container.BuildServiceProvider();
+
+            var cache = provider.GetService<IAppCache>();
+            var result = cache?.GetOrAdd("key", () => new object());
+
+            cache.Should().NotBeNull();
+            result.Should().NotBeNull();
+        }
+    }
+}
diff --git a/LazyCache.UnitTests/LazyCache.UnitTests.csproj b/LazyCache.UnitTests/LazyCache.UnitTests.csproj
index b4eb31e..a7d9b4e 100644
--- a/LazyCache.UnitTests/LazyCache.UnitTests.csproj
+++ b/LazyCache.UnitTests/LazyCache.UnitTests.csproj
@@ -8,12 +8,14 @@
 
   <ItemGroup>
     <PackageReference Include="fluentassertions" Version="5.9.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.1.1" />
     <PackageReference Include="nunit" Version="3.12.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.15.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\LazyCache.AspNetCore\LazyCache.AspNetCore.csproj" />
     <ProjectReference Include="..\LazyCache\LazyCache.csproj" />
   </ItemGroup>