Add ValueTupleServiceProvider and update samples to show usage of Val…

…ueTuple contexts and more advanced scenarios around cache eviction/update

samples/Samples/Controllers/PostsController.cs

@@ -3,6 +3,7 @@
 using System.Threading.Tasks;
 using Magneto;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Caching.Memory;
 using Samples.Domain;
 using Samples.Models;
@@ -14,10 +15,7 @@ public class PostsController : Controller
 	{
 		readonly IMagneto _magneto;
 
-		public PostsController(IMagneto magneto)
-		{
-			_magneto = magneto;
-		}
+		public PostsController(IMagneto magneto) => _magneto = magneto;
 
 		[HttpGet("")]
 		public async Task<IActionResult> Index()
@@ -33,16 +31,34 @@ public async Task<IActionResult> Index(int id)
 			var postComments = await _magneto.QueryAsync(new CommentsByPostId { PostId = id });
 			return View("Post", new PostViewModel { Post = post, Comments = postComments });
 		}
+
+		[HttpPost("{id:int}")]
+		public async Task<IActionResult> Post(Post model)
+		{
+			var postById = new PostById { Id = model.Id };
+			var post = await _magneto.QueryAsync(postById);
+			post.Body = model.Body;
+			await _magneto.CommandAsync(new SavePost { Post = post });
+			// When using a distributed cache, we should either evict or update the entry, since we know it to be stale now
+			await _magneto.UpdateCachedResultAsync(postById);
+			//await _magneto.EvictCachedResultAsync(postById);
+
+			return RedirectToAction(nameof(Index), new { post.Id });
+		}
 	}
 
 	public class AllPosts : AsyncQuery<JsonPlaceHolderHttpClient, Post[]>
 	{
-		public override Task<Post[]> ExecuteAsync(JsonPlaceHolderHttpClient context, CancellationToken cancellationToken = default) => context.GetAsync<Post[]>("/posts", cancellationToken);
+		protected override Task<Post[]> QueryAsync(JsonPlaceHolderHttpClient context, CancellationToken cancellationToken = default) => context.GetAsync<Post[]>("/posts", cancellationToken);
 	}
 
-	public class PostById : AsyncQuery<JsonPlaceHolderHttpClient, Post>
+	public class PostById : AsyncCachedQuery<JsonPlaceHolderHttpClient, DistributedCacheEntryOptions, Post>
 	{
-		public override Task<Post> ExecuteAsync(JsonPlaceHolderHttpClient context, CancellationToken cancellationToken = default) => context.GetAsync<Post>($"/posts/{Id}", cancellationToken);
+		protected override void ConfigureCache(ICacheConfig cacheConfig) => cacheConfig.VaryBy(Id);
+
+		protected override DistributedCacheEntryOptions GetCacheEntryOptions(JsonPlaceHolderHttpClient context) => new DistributedCacheEntryOptions().SetAbsoluteExpiration(TimeSpan.FromSeconds(30));
+
+		protected override Task<Post> QueryAsync(JsonPlaceHolderHttpClient context, CancellationToken cancellationToken = default) => context.GetAsync<Post>($"/posts/{Id}", cancellationToken);
 
 		public int Id { get; set; }
 	}
@@ -57,4 +73,11 @@ public class CommentsByPostId : AsyncCachedQuery<JsonPlaceHolderHttpClient, Memo
 
 		public int PostId { get; set; }
 	}
+
+	public class SavePost : AsyncCommand<JsonPlaceHolderHttpClient>
+	{
+		public override Task ExecuteAsync(JsonPlaceHolderHttpClient context, CancellationToken cancellationToken = default) => context.PostAsync($"/posts/{Post.Id}", Post, cancellationToken);
+
+		public Post Post { get; set; }
+	}
 }

samples/Samples/Controllers/UsersController.cs

@@ -1,4 +1,3 @@
-using System;
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -8,8 +7,8 @@
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.FileProviders;
+using Microsoft.Extensions.Logging;
 using Newtonsoft.Json;
-using Newtonsoft.Json.Serialization;
 using Samples.Domain;
 using Samples.Models;
 
@@ -62,26 +61,26 @@ public class UserById : AsyncTransformedCachedQuery<JsonPlaceHolderHttpClient, D
 
 		protected override Task<User[]> QueryAsync(JsonPlaceHolderHttpClient context, CancellationToken cancellationToken = default) => User.AllUsersAsync(context, cancellationToken);
 
-		protected override Task<User> TransformCachedResultAsync(User[] cachedResult, CancellationToken cancellationToken = default) => Task.FromResult(cachedResult.Single(x => x.Id == Id));
+		protected override Task<User> TransformCachedResultAsync(User[] cachedResult, CancellationToken cancellationToken = default) => Task.FromResult(cachedResult.SingleOrDefault(x => x.Id == Id));
 
 		public int Id { get; set; }
 	}
 
-	public class AlbumsByUserId : SyncTransformedCachedQuery<IFileProvider, MemoryCacheEntryOptions, Album[], Album[]>
+	public class AlbumsByUserId : SyncTransformedCachedQuery<(IFileProvider, ILogger<AlbumsByUserId>), MemoryCacheEntryOptions, Album[], Album[]>
 	{
-		const string Filename = "albums.json";
-
-		protected override MemoryCacheEntryOptions GetCacheEntryOptions(IFileProvider context) =>
-			new MemoryCacheEntryOptions()
-				.AddExpirationToken(context.Watch(Filename))
-				.RegisterPostEvictionCallback((echoKey, value, reason, state) =>
-				{
-					Console.WriteLine($"{echoKey} : {value} was evicted due to {reason}");
-				});
+		protected override MemoryCacheEntryOptions GetCacheEntryOptions((IFileProvider, ILogger<AlbumsByUserId>) context)
+		{
+			var (fileProvider, logger) = context;
+			return new MemoryCacheEntryOptions()
+				.AddExpirationToken(fileProvider.Watch(Album.AllAlbumsFilename))
+				.RegisterPostEvictionCallback((key, value, reason, state) =>
+					logger.LogInformation($"{key} : {value} was evicted due to {reason}"));
+		}
 
-		protected override Album[] Query(IFileProvider context)
+		protected override Album[] Query((IFileProvider, ILogger<AlbumsByUserId>) context)
 		{
-			using (var streamReader = new StreamReader(context.GetFileInfo(Filename).CreateReadStream()))
+			var (fileProvider, _) = context;
+			using (var streamReader = new StreamReader(fileProvider.GetFileInfo(Album.AllAlbumsFilename).CreateReadStream()))
 			{
 				var json = streamReader.ReadToEnd();
 				return JsonConvert.DeserializeObject<Album[]>(json);
@@ -93,15 +92,14 @@ protected override Album[] Query(IFileProvider context)
 		public int UserId { get; set; }
 	}
 
-	public class SaveAlbum : SyncCommand<IFileProvider>
+	public class SaveAlbum : SyncCommand<(IFileProvider, JsonSerializerSettings)>
 	{
-		const string Filename = "albums.json";
-
-		public override void Execute(IFileProvider context)
+		public override void Execute((IFileProvider, JsonSerializerSettings) context)
 		{
-			lock (context)
+			var (fileProvider, jsonSerializerSettings) = context;
+			lock (fileProvider)
 			{
-				var fileInfo = context.GetFileInfo(Filename);
+				var fileInfo = fileProvider.GetFileInfo(Album.AllAlbumsFilename);
 				Album[] albums;
 				using (var streamReader = new StreamReader(fileInfo.CreateReadStream()))
 				{
@@ -110,7 +108,7 @@ public override void Execute(IFileProvider context)
 					Album.Id = existingAlbums.Max(x => x.Id) + 1;
 					albums = existingAlbums.Concat(new[] { Album }).ToArray();
 				}
-				File.WriteAllText(fileInfo.PhysicalPath, JsonConvert.SerializeObject(albums, Formatting.Indented, new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
+				File.WriteAllText(fileInfo.PhysicalPath, JsonConvert.SerializeObject(albums, jsonSerializerSettings));
 			}
 		}
 

samples/Samples/Domain/Entities.cs

@@ -19,6 +19,8 @@ public class Album
 		public int UserId { get; set; }
 		public int Id { get; set; }
 		public string Title { get; set; }
+
+		public const string AllAlbumsFilename = "albums.json";
 	}
 
 	public class Comment

samples/Samples/Domain/JsonPlaceHolderHttpClient.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
@@ -20,5 +21,8 @@ public async Task<T> GetAsync<T>(string requestUri, CancellationToken cancellati
 			var response = await _httpClient.GetAsync(requestUri, cancellationToken);
 			return await response.Content.ReadAsAsync<T>(cancellationToken);
 		}
+
+		public Task<HttpResponseMessage> PostAsync<T>(string requestUri, T data, CancellationToken cancellationToken = default) =>
+			Task.FromResult(new HttpResponseMessage(HttpStatusCode.NoContent));
 	}
 }

samples/Samples/Program.cs

@@ -5,10 +5,7 @@ namespace Samples
 {
 	public sealed class Program
 	{
-		public static void Main(string[] args)
-		{
-			CreateWebHostBuilder(args).Build().Run();
-		}
+		public static void Main(string[] args) => CreateWebHostBuilder(args).Build().Run();
 
 		public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
 			WebHost.CreateDefaultBuilder(args)

samples/Samples/Properties/launchSettings.json

@@ -3,7 +3,7 @@
 		"windowsAuthentication": false,
 		"anonymousAuthentication": true,
 		"iisExpress": {
-			"applicationUrl": "http://localhost:49808/",
+			"applicationUrl": "http://localhost:47808/",
 			"sslPort": 0
 		}
 	},
@@ -21,7 +21,7 @@
 			"environmentVariables": {
 				"ASPNETCORE_ENVIRONMENT": "Development"
 			},
-			"applicationUrl": "http://localhost:49809"
+			"applicationUrl": "http://localhost:47809"
 		}
 	}
 }

samples/Samples/Startup.cs

@@ -10,6 +10,8 @@
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
 using Polly;
 using Samples.Domain;
 using Samples.Infrastructure;
@@ -18,26 +20,20 @@ namespace Samples
 {
 	public class Startup
 	{
-		public Startup(IHostingEnvironment env)
+		public Startup(IHostingEnvironment environment, IConfiguration configuration)
 		{
-			Environment = env;
+			Environment = environment;
+			Configuration = configuration;
 			InitializeAlbums();
-			var builder = new ConfigurationBuilder()
-				.SetBasePath(env.ContentRootPath)
-				.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
-				.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
-				.AddEnvironmentVariables();
-			Configuration = builder.Build();
 		}
 
 		void InitializeAlbums()
 		{
-			const string filename = "albums.json";
-			using (var streamReader = new StreamReader(Environment.ContentRootFileProvider.GetFileInfo(filename).CreateReadStream()))
-				File.WriteAllText(Path.Combine(Environment.WebRootPath, filename), streamReader.ReadToEnd());
+			using (var streamReader = new StreamReader(Environment.ContentRootFileProvider.GetFileInfo(Album.AllAlbumsFilename).CreateReadStream()))
+				File.WriteAllText(Path.Combine(Environment.WebRootPath, Album.AllAlbumsFilename), streamReader.ReadToEnd());
 		}
 
-		public IConfigurationRoot Configuration { get; }
+		public IConfiguration Configuration { get; }
 
 		protected IHostingEnvironment Environment { get; }
 
@@ -57,10 +53,15 @@ public void ConfigureServices(IServiceCollection services)
 			// Here we add a decorator object which performs exception logging and timing telemetry for all our Magneto operations.
 			services.AddSingleton<IDecorator, ApplicationInsightsDecorator>();
 
-			// Here we add the two context objects with which our queries and commands are executed.
+			// Here we add the three context objects with which our queries and commands are executed. The first two are actually
+			// used together in a ValueTuple and are resolved as such by a special wrapper around IServiceProvider.
 			services.AddSingleton(Environment.WebRootFileProvider);
-			services
-				.AddHttpClient<JsonPlaceHolderHttpClient>()
+			services.AddSingleton(new JsonSerializerSettings
+			{
+				ContractResolver = new CamelCasePropertyNamesContractResolver(),
+				Formatting = Formatting.Indented
+			});
+			services.AddHttpClient<JsonPlaceHolderHttpClient>()
 				.AddHttpMessageHandler(() => new EnsureSuccessHandler())
 				.AddTransientHttpErrorPolicy(x => x.WaitAndRetryAsync(new[]
 				{
@@ -78,9 +79,9 @@ public void ConfigureServices(IServiceCollection services)
 			services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
 		}
 
-		public static void Configure(IApplicationBuilder app, IHostingEnvironment env)
+		public void Configure(IApplicationBuilder app)
 		{
-			if (env.IsDevelopment())
+			if (Environment.IsDevelopment())
 			{
 				app.UseDeveloperExceptionPage();
 			}

samples/Samples/Views/Posts/Post.cshtml

@@ -5,7 +5,10 @@
 }
 
 <h3>@Model.Post.Title</h3>
-<div>@Model.Post.Body</div>
+<form asp-action="Post" asp-route-id="@Model.Post.Id">
+	<textarea name="Body" type="input">@Model.Post.Body</textarea>
+	<button>Update</button>
+</form>
 <h4>Comments</h4>
 <ul class="list-unstyled">
 	@foreach (var comment in Model.Comments)
@@ -15,4 +18,4 @@
 			<i class="info small">@comment.Name <a href="mailto:@comment.Email">@comment.Email</a></i>
 		</li>
 	}
-</ul>
+</ul>

src/Magneto.Microsoft/Magneto.Microsoft.csproj

@@ -17,7 +17,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="Microsoft.Extensions.Caching.Abstractions" Version="2.0.0" />
-		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta-63102-01" PrivateAssets="All" />
+		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-19367-01" PrivateAssets="All" />
 		<PackageReference Include="MinVer" Version="1.1.0" PrivateAssets="All" />
 		<PackageReference Include="Newtonsoft.Json" Version="9.0.1" />
 	</ItemGroup>

src/Magneto/Magneto.cs

@@ -1,16 +1,29 @@
-using System;
+using System;
 using System.Threading;
 using System.Threading.Tasks;
+#if NETSTANDARD
+using Code.Extensions.ValueTuple.ServiceProvider;
+#endif
 using Magneto.Core;
 
 namespace Magneto
 {
+#if NETSTANDARD
 	/// <summary>
 	/// The main entry point for consumers to execute queries and commands using context retrieved from the given <see cref="IServiceProvider"/>.
-	/// If using an IoC container, it's highly recommended that this be registered as a scoped service
-	/// so that the injected <see cref="IServiceProvider"/> is scoped appropriately.
+	/// If using an IoC container, it's highly recommended that this be registered as a scoped service so that the injected <see cref="IServiceProvider"/>
+	/// is scoped appropriately. A special wrapper is used for the <see cref="IServiceProvider"/> which can resolve instances of <see cref="ValueTuple"/>
+	/// having up to 8 items by resolving each item from the wrapped <see cref="IServiceProvider"/>.
 	/// </summary>
 	public class Magneto : IMagneto
+#else
+	/// <summary>
+	/// The main entry point for consumers to execute queries and commands using context retrieved from the given <see cref="IServiceProvider"/>.
+	/// If using an IoC container, it's highly recommended that this be registered as a scoped service so that the injected <see cref="IServiceProvider"/>
+	/// is scoped appropriately.
+	/// </summary>
+	public class Magneto : IMagneto
+#endif
 	{
 		/// <summary>
 		/// Creates a new instance of <see cref="Magneto"/>.
@@ -22,6 +35,9 @@ public Magneto(IServiceProvider serviceProvider)
 		{
 			ServiceProvider = serviceProvider ?? throw new ArgumentNullException(nameof(serviceProvider));
 			Mediary = ServiceProvider.GetService<IMediary>() ?? new Mediary(ServiceProvider);
+#if NETSTANDARD
+			ServiceProvider = new ValueTupleServiceProvider(ServiceProvider);
+#endif
 		}
 
 		/// <summary>

src/Magneto/Magneto.csproj

@@ -15,7 +15,8 @@
 	<ItemGroup>
 		<PackageReference Include="Code.Extensions.Generic.QuasiEquals" Version="1.0.0" PrivateAssets="All" />
 		<PackageReference Include="Code.Extensions.Object.Flatten" Version="1.0.3" PrivateAssets="All" />
-		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta-63102-01" PrivateAssets="All" />
+		<PackageReference Condition="'$(TargetFramework)' == 'netstandard2.0'" Include="Code.Extensions.ValueTuple.ServiceProvider" Version="1.0.0" PrivateAssets="All" />
+		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-19367-01" PrivateAssets="All" />
 		<PackageReference Include="MinVer" Version="1.1.0" PrivateAssets="All" />
 	</ItemGroup>
 

src/Magneto/Query.cs

@@ -6,25 +6,32 @@ namespace Magneto
 {
 	/// <summary>
 	/// <para>A base class for synchronous queries.</para>
-	/// <para>Implementors must override <see cref="Execute"/> in order to define how the query is executed.</para>
+	/// <para>Implementors must override <see cref="Query"/> in order to define how the query is executed.</para>
 	/// </summary>
 	/// <typeparam name="TContext">The type of context with which the query is executed.</typeparam>
 	/// <typeparam name="TResult">The type of the query result.</typeparam>
 	public abstract class SyncQuery<TContext, TResult> : Operation, ISyncQuery<TContext, TResult>
 	{
 		/// <inheritdoc cref="ISyncQuery{TContext,TResult}.Execute"/>
-		public abstract TResult Execute(TContext context);
+		public TResult Execute(TContext context) => Query(context);
+
+		/// <inheritdoc cref="ISyncQuery{TContext,TResult}.Execute"/>
+		protected abstract TResult Query(TContext context);
 	}
 
 	/// <summary>
 	/// <para>A base class for asynchronous queries.</para>
-	/// <para>Implementors must override <see cref="ExecuteAsync"/> in order to define how the query is executed.</para>
+	/// <para>Implementors must override <see cref="QueryAsync"/> in order to define how the query is executed.</para>
 	/// </summary>
 	/// <typeparam name="TContext">The type of context with which the query is executed.</typeparam>
 	/// <typeparam name="TResult">The type of the query result.</typeparam>
 	public abstract class AsyncQuery<TContext, TResult> : Operation, IAsyncQuery<TContext, TResult>
 	{
 		/// <inheritdoc cref="IAsyncQuery{TContext,TResult}.ExecuteAsync"/>
-		public abstract Task<TResult> ExecuteAsync(TContext context, CancellationToken cancellationToken = default);
+		public Task<TResult> ExecuteAsync(TContext context, CancellationToken cancellationToken = default) =>
+			QueryAsync(context, cancellationToken);
+
+		/// <inheritdoc cref="IAsyncQuery{TContext,TResult}.ExecuteAsync"/>
+		protected abstract Task<TResult> QueryAsync(TContext context, CancellationToken cancellationToken = default);
 	}
 }