Merge pull request #322 from ServiceComposer/set-action-result

MVC action results support

docs/README.md

@@ -14,6 +14,10 @@ ServiceComposer can be added to existing or new ASP.NET Core projects, or it can
 
 When handling composition requests it possible to leverage the power of ASP.Net Model Binding to bind incoming forms, bodies, query string parameters, or route data to strongly typed C# models. For more information on model binding refer to the [Model Binding](model-binding.md) section.
 
+### ASP.Net MVC Action results
+
+MVC Action results support allow composition handlers to set custom response results for specific scenarios, like for example, handling bad requests or validation error thoat would nornmally require throwing an exception. For more information on action results refer to the [MVC Action results](action-results.md) section.
+
 ## Authentication and Authorization
 
 By virtue of leveraging ASP.NET Core 3.x Endpoints ServiceComposer automatically supports authentication and authorization metadata attributes to express authentication and authorization requirements on routes. For more information refer to the [Authentication and Authorization](authentication-authorization.md) section

docs/README.source.md

@@ -7,6 +7,10 @@ ServiceComposer can be added to existing or new ASP.NET Core projects, or it can
 
 When handling composition requests it possible to leverage the power of ASP.Net Model Binding to bind incoming forms, bodies, query string parameters, or route data to strongly typed C# models. For more information on model binding refer to the [Model Binding](model-binding.source.md) section.
 
+### ASP.Net MVC Action results
+
+MVC Action results support allow composition handlers to set custom response results for specific scenarios, like for example, handling bad requests or validation error thoat would nornmally require throwing an exception. For more information on action results refer to the [MVC Action results](action-results.source.md) section.
+
 ## Authentication and Authorization
 
 By virtue of leveraging ASP.NET Core 3.x Endpoints ServiceComposer automatically supports authentication and authorization metadata attributes to express authentication and authorization requirements on routes. For more information refer to the [Authentication and Authorization](authentication-authorization.source.md) section

docs/action-results.md

@@ -0,0 +1,52 @@
+<!--
+GENERATED FILE - DO NOT EDIT
+This file was generated by [MarkdownSnippets](https://github.com/SimonCropp/MarkdownSnippets).
+Source File: /docs/action-results.source.md
+To change this file edit the source file and then run MarkdownSnippets.
+-->
+
+# ASP.Net MVC Action results
+
+MVC Action results support allow composition handlers to set custom response results for specific scenarios, like for example, handling bad requests or validation error thoat would nornmally require throwing an exception. Setting a custom action result is done by using the `SetActionResult()` `HttpRequest` extension method:
+
+<!-- snippet: net-core-3x-action-results -->
+<a id='snippet-net-core-3x-action-results'></a>
+```cs
+public class UseSetActionResultHandler : ICompositionRequestsHandler
+{
+ [HttpGet("/product/{id}")]
+ public Task Handle(HttpRequest request)
+ {
+ var id = request.RouteValues["id"];
+
+ //validate the id format
+
+ var problems = new ValidationProblemDetails(new Dictionary<string, string[]>()
+ {
+ { "Id", new []{ "The supplied id does not respect the identifier format." } }
+ });
+ var result = new BadRequestObjectResult(problems);
+
+ request.SetActionResult(result);
+
+ return Task.CompletedTask;
+ }
+}
+```
+<sup><a href='/src/Snippets.NetCore3x/ActionResult/UseSetActionResultHandler.cs#L10-L31' title='Snippet source file'>snippet source</a> | <a href='#snippet-net-core-3x-action-results' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->
+
+Using MVC action results require enabling output formatters support:
+
+<!-- snippet: net-core-3x-action-results-required-config -->
+<a id='snippet-net-core-3x-action-results-required-config'></a>
+```cs
+services.AddViewModelComposition(options =>
+{
+ options.ResponseSerialization.UseOutputFormatters = true;
+});
+```
+<sup><a href='/src/Snippets.NetCore3x/ActionResult/UseSetActionResultHandler.cs#L37-L42' title='Snippet source file'>snippet source</a> | <a href='#snippet-net-core-3x-action-results-required-config' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->
+
+Note: ServiceComposer supports only one action result per request. If two or more composition handlers try to set action results, only the frst one will succeed and subsequent requests will be ignored.

docs/action-results.source.md

@@ -0,0 +1,11 @@
+# ASP.Net MVC Action results
+
+MVC Action results support allow composition handlers to set custom response results for specific scenarios, like for example, handling bad requests or validation error thoat would nornmally require throwing an exception. Setting a custom action result is done by using the `SetActionResult()` `HttpRequest` extension method:
+
+snippet: net-core-3x-action-results
+
+Using MVC action results require enabling output formatters support:
+
+snippet: net-core-3x-action-results-required-config
+
+Note: ServiceComposer supports only one action result per request. If two or more composition handlers try to set action results, only the frst one will succeed and subsequent requests will be ignored.

src/ServiceComposer.AspNetCore.Endpoints.Tests/When_setting_action_result.cs

@@ -0,0 +1,129 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.DependencyInjection;
+using Newtonsoft.Json.Linq;
+using ServiceComposer.AspNetCore.Testing;
+using Xunit;
+
+namespace ServiceComposer.AspNetCore.Endpoints.Tests
+{
+ public class When_setting_action_result
+ {
+ const string expectedError = "I'm not sure I like the Id property value";
+
+ class TestGetIntegerHandler : ICompositionRequestsHandler
+ {
+ class Model
+ {
+ [FromRoute]public int id { get; set; }
+ }
+
+ [HttpGet("/sample/{id}")]
+ public async Task Handle(HttpRequest request)
+ {
+ var model = await request.Bind<Model>();
+
+ var problems = new ValidationProblemDetails(new Dictionary<string, string[]>() 
+ {
+ { "Id", new []{ expectedError } }
+ });
+ var result = new BadRequestObjectResult(problems);
+
+ request.SetActionResult(result);
+ }
+ }
+
+ class TestGetStringHandler : ICompositionRequestsHandler
+ {
+ [HttpGet("/sample/{id}")]
+ public Task Handle(HttpRequest request)
+ {
+ var vm = request.GetComposedResponseModel();
+ vm.AString = "sample";
+ return Task.CompletedTask;
+ }
+ }
+
+ [Fact]
+ public async Task Returns_expected_bad_request_using_output_formatters()
+ {
+ // Arrange
+ var client = new SelfContainedWebApplicationFactoryWithWebHost<Dummy>
+ (
+ configureServices: services =>
+ {
+ services.AddViewModelComposition(options =>
+ {
+ options.AssemblyScanner.Disable();
+ options.RegisterCompositionHandler<TestGetStringHandler>();
+ options.RegisterCompositionHandler<TestGetIntegerHandler>();
+ options.ResponseSerialization.UseOutputFormatters = true;
+ });
+ services.AddRouting();
+ services.AddControllers()
+ .AddNewtonsoftJson();
+ },
+ configure: app =>
+ {
+ app.UseRouting();
+ app.UseEndpoints(builder => builder.MapCompositionHandlers());
+ }
+ ).CreateClient();
+
+ // Act
+ var response = await client.GetAsync("/sample/1");
+
+ // Assert
+ Assert.False(response.IsSuccessStatusCode);
+ Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+
+ var responseString = await response.Content.ReadAsStringAsync();
+ dynamic responseObj = JObject.Parse(responseString);
+
+ dynamic errors = responseObj.errors;
+ var idErrors = (JArray)errors["Id"];
+
+ var error = idErrors[0].Value<string>();
+
+ Assert.Equal(expectedError, error);
+ }
+
+ [Fact]
+ public async Task Throws_if_output_formatters_are_not_enabled()
+ {
+ await Assert.ThrowsAsync<NotSupportedException>(async () => 
+ {
+ // Arrange
+ var client = new SelfContainedWebApplicationFactoryWithWebHost<Dummy>
+ (
+ configureServices: services =>
+ {
+ services.AddViewModelComposition(options =>
+ {
+ options.AssemblyScanner.Disable();
+ options.RegisterCompositionHandler<TestGetStringHandler>();
+ options.RegisterCompositionHandler<TestGetIntegerHandler>();
+ options.ResponseSerialization.UseOutputFormatters = false;
+ });
+ services.AddRouting();
+ services.AddControllers()
+ .AddNewtonsoftJson();
+ },
+ configure: app =>
+ {
+ app.UseRouting();
+ app.UseEndpoints(builder => builder.MapCompositionHandlers());
+ }
+ ).CreateClient();
+
+ // Act
+ var response = await client.GetAsync("/sample/1");
+ });
+ }
+ }
+}

src/ServiceComposer.AspNetCore.Tests/API/NET5_0/APIApprovals.Approve_API.approved.txt

@@ -69,6 +69,7 @@ namespace ServiceComposer.AspNetCore
  public static T GetComposedResponseModel<T>(this Microsoft.AspNetCore.Http.HttpRequest request)
  where T : class { }
  public static ServiceComposer.AspNetCore.ICompositionContext GetCompositionContext(this Microsoft.AspNetCore.Http.HttpRequest request) { }
+ public static void SetActionResult(this Microsoft.AspNetCore.Http.HttpRequest request, Microsoft.AspNetCore.Mvc.ActionResult actionResult) { }
  }
  public static class HttpRequestModelBinderExtension
  {

src/ServiceComposer.AspNetCore.Tests/API/NETCOREAPP3_1/APIApprovals.Approve_API.approved.txt

@@ -69,6 +69,7 @@ namespace ServiceComposer.AspNetCore
  public static T GetComposedResponseModel<T>(this Microsoft.AspNetCore.Http.HttpRequest request)
  where T : class { }
  public static ServiceComposer.AspNetCore.ICompositionContext GetCompositionContext(this Microsoft.AspNetCore.Http.HttpRequest request) { }
+ public static void SetActionResult(this Microsoft.AspNetCore.Http.HttpRequest request, Microsoft.AspNetCore.Mvc.ActionResult actionResult) { }
  }
  public static class HttpRequestModelBinderExtension
  {

src/ServiceComposer.AspNetCore/CompositionEndpointBuilder.cs

@@ -48,55 +48,28 @@ public CompositionEndpointBuilder(RoutePattern routePattern, Type[] componentsTy
  var viewModel = await CompositionHandler.HandleComposableRequest(context, componentsTypes);
  if (viewModel != null)
  {
- if (useOutputFormatters)
+ var containsActionResult = context.Items.ContainsKey(HttpRequestExtensions.ComposedActionResultKey);
+ if(!useOutputFormatters && containsActionResult)
  {
- OutputFormatterSelector formatterSelector;
- IHttpResponseStreamWriterFactory writerFactory;
- IOptions<MvcOptions> options;
- try
- {
- formatterSelector = context.RequestServices.GetRequiredService<OutputFormatterSelector>();
- writerFactory = context.RequestServices.GetRequiredService<IHttpResponseStreamWriterFactory>();
- options = context.RequestServices.GetRequiredService<IOptions<MvcOptions>>();
- }
- catch (InvalidOperationException e)
- {
- throw new InvalidOperationException("Unable to resolve one of the services required to support output formatting. " +
- "Make sure the application is configured to use MVC services by calling either " +
- $"services.{nameof(MvcServiceCollectionExtensions.AddControllers)}(), or " +
- $"services.{nameof(MvcServiceCollectionExtensions.AddControllersWithViews)}(), or " +
- $"services.{nameof(MvcServiceCollectionExtensions.AddMvc)}(), or " +
- $"services.{nameof(MvcServiceCollectionExtensions.AddRazorPages)}().", e);
- }
-
- var outputFormatterWriteContext = new OutputFormatterWriteContext(context, writerFactory.CreateWriter, viewModel.GetType(), viewModel);
+ throw new NotSupportedException($"Setting an action results requires output formatters supports. " +
+ $"Enable output formatters by setting to true the {nameof(ResponseSerializationOptions.UseOutputFormatters)} " +
+ $"configuration property in the {nameof(ResponseSerializationOptions)} options.");
+ }
 
- if (!context.Request.Headers.TryGetValue(HeaderNames.Accept, out var accept))
+ if (useOutputFormatters)
+ {
+ if (containsActionResult)
  {
- accept = MediaTypeNames.Application.Json;
+ await context.ExecuteResultAsync(context.Items[HttpRequestExtensions.ComposedActionResultKey] as IActionResult);
  }
-
- var mediaTypes = new MediaTypeCollection
- {
- accept
- };
-
- //TODO: log list of configured formatters
- var selectedFormatter = formatterSelector.SelectFormatter(
- outputFormatterWriteContext,
- options.Value.OutputFormatters, mediaTypes);
- if (selectedFormatter == null)
+ else
  {
- //TODO: log
- context.Response.StatusCode = StatusCodes.Status406NotAcceptable;
- return;
+ await context.WriteModelAsync(viewModel);
  }
-
- await selectedFormatter.WriteAsync(outputFormatterWriteContext);
  }
  else
  {
- var json = (string) JsonConvert.SerializeObject(viewModel, GetSettings(context));
+ var json = (string)JsonConvert.SerializeObject(viewModel, GetSettings(context));
  context.Response.ContentType = "application/json; charset=utf-8";
  await context.Response.WriteAsync(json);
  }

src/ServiceComposer.AspNetCore/HttpContextActionResultExtensions.cs

@@ -0,0 +1,45 @@
+#if NETCOREAPP3_1 || NET5_0
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Routing;
+using System;
+using System.Threading.Tasks;
+
+namespace ServiceComposer.AspNetCore
+{
+ static class HttpContextActionResultExtensions
+ {
+ private static readonly RouteData EmptyRouteData = new RouteData();
+
+ private static readonly ActionDescriptor EmptyActionDescriptor = new ActionDescriptor();
+
+ /// <summary>
+ /// Write a model to the response.
+ /// </summary>
+ public static Task WriteModelAsync<TModel>(this HttpContext context, TModel model)
+ {
+ var result = new ObjectResult(model)
+ {
+ DeclaredType = typeof(TModel)
+ };
+
+ return context.ExecuteResultAsync(result);
+ }
+
+ /// <summary>
+ /// Write any action result to the response.
+ /// </summary>
+ public static Task ExecuteResultAsync(this HttpContext context, IActionResult result)
+ {
+ if (context == null) throw new ArgumentNullException(nameof(context));
+ if (result == null) throw new ArgumentNullException(nameof(result));
+
+ var routeData = context.GetRouteData() ?? EmptyRouteData;
+ var actionContext = new ActionContext(context, routeData, EmptyActionDescriptor);
+
+ return result.ExecuteResultAsync(actionContext);
+ }
+ }
+}
+#endif

src/ServiceComposer.AspNetCore/HttpRequestExtensions.cs

@@ -2,20 +2,21 @@
 
 using System;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
 
 namespace ServiceComposer.AspNetCore
 {
  public static class HttpRequestExtensions
  {
  internal static readonly string ComposedResponseModelKey = "composed-response-model";
  internal static readonly string CompositionContextKey = "composition-context";
+ internal static readonly string ComposedActionResultKey = "composed-action-result";
 
  public static dynamic GetComposedResponseModel(this HttpRequest request)
  {
  return request.HttpContext.Items[ComposedResponseModelKey];
  }
 
-#if NETCOREAPP3_1 || NET5_0
  public static T GetComposedResponseModel<T>(this HttpRequest request) where T : class
  {
  var vm = request.HttpContext.Items[ComposedResponseModelKey];
@@ -29,7 +30,14 @@ public static T GetComposedResponseModel<T>(this HttpRequest request) where T :
  $"and that the created view model is of type {typeof(T).Name}.";
  throw new InvalidCastException(message);
  }
-#endif
+
+ public static void SetActionResult(this HttpRequest request, ActionResult actionResult)
+ {
+ if (!request.HttpContext.Items.ContainsKey(HttpRequestExtensions.ComposedActionResultKey))
+ {
+ request.HttpContext.Items.Add(HttpRequestExtensions.ComposedActionResultKey, actionResult);
+ }
+ }
 
  internal static void SetViewModel(this HttpRequest request, dynamic viewModel)
  {