Merge branch 'improvement/ErrorController-static-files' into develop

Customer error pages for HTTP status codes are intended to provide a friendly experience for human audiences. This requires additional processing and bandwidth, however, as the `ErrorController` must find the appropriate `Topic`, generate the corresponding view model, execute the view, and return the markup. That's a lot of overhead for content that _doesn't_ have a human audience. Most notably, web resources—such as scripts, style sheets, images, fonts, &c.—that return a 404 error won't typically be seen by human audiences, outside of developers, since the errors are swallowed by the browser, or simply result in loss of functionality (such as a broken image). In these cases, it doesn't make sense to process and deliver a custom HTTP error.

To facilitate this, this update introduces a new `includeStaticFiles` parameter to both the `UseTopicErrors()` extension method as well as the `ErrorController`'s `HttpAsync()` action. This isn't the only way to configure a route to the error controller, but it's the one that exposes custom control over how it behaves, and will be the preferred option for customers requiring that level of flexibility. This is an optional parameter, and defaults to `true`—meaning static files will return the normal error page experience. While that's an intuitive default, however, we expect most implementers will want to disable this default, and thus the `Host` boilerplate code has been updated to include this configuration option.

This satisfies Feature #101.

Author: JeremyCaney

OnTopic.AspNetCore.Mvc.Host/Program.cs

@@ -53,8 +53,8 @@
 /*------------------------------------------------------------------------------------------------------------------------------
 | Configure: Error Pages
 \-----------------------------------------------------------------------------------------------------------------------------*/
-if (!app.Environment.IsDevelopment()) {
   app.UseStatusCodePagesWithReExecute("/Error/{0}/");
+if (!app.Environment.IsDevelopment()) {
   app.UseExceptionHandler("/Error/500/");
   // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
   app.UseHsts();
@@ -77,7 +77,7 @@
 app.MapDefaultAreaControllerRoute();                            // {area:exists}/{controller}/{action=Index}/{id?}
 app.MapTopicAreaRoute();                                        // {area:exists}/{**path}
 
-app.MapTopicErrors(rootTopic: "Error");                         // Error/{statusCode}
+app.MapTopicErrors(includeStaticFiles: false);                  // Error/{statusCode}
 app.MapDefaultControllerRoute();                                // {controller=Home}/{action=Index}/{id?}
 app.MapTopicRoute(rootTopic: "Web");                            // Web/{**path}
 app.MapTopicRoute(rootTopic: "Error");                          // Error/{**path}

OnTopic.AspNetCore.Mvc.IntegrationTests.Host/Startup.cs

@@ -95,7 +95,7 @@ public static void Configure(IApplicationBuilder app) {
       | Configure: MVC
       \-----------------------------------------------------------------------------------------------------------------------*/
       app.UseEndpoints(endpoints => {
-        endpoints.MapTopicErrors();
+        endpoints.MapTopicErrors(includeStaticFiles: false);
         endpoints.MapDefaultAreaControllerRoute();
         endpoints.MapDefaultControllerRoute();
         endpoints.MapImplicitAreaControllerRoute();

OnTopic.AspNetCore.Mvc.IntegrationTests/ServiceCollectionExtensionsTests.cs

@@ -96,6 +96,7 @@ public async Task MapTopicSitemap_RespondsToRequest() {
     [InlineData("/MissingPage/", HttpStatusCode.NotFound, "400")]
     [InlineData("/Web/MissingPage/", HttpStatusCode.NotFound, "400")]
     [InlineData("/Web/Container/", HttpStatusCode.Forbidden, "400")]
+    [InlineData("/Scripts/ECMAScript.js", HttpStatusCode.NotFound, "The resource requested could not found.")]
     public async Task UseStatusCodePages_ReturnsExpectedStatusCode(string path, HttpStatusCode statusCode, string expectedContent) {
 
       var client                = _factory.CreateClient();
@@ -104,7 +105,6 @@ public async Task UseStatusCodePages_ReturnsExpectedStatusCode(string path, Http
       var actualContent         = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
 
       Assert.Equal(statusCode, response.StatusCode);
-      Assert.Equal("text/html; charset=utf-8", response.Content.Headers.ContentType?.ToString());
       Assert.Equal(expectedContent, actualContent);
 
     }

OnTopic.AspNetCore.Mvc/Controllers/ErrorController.cs

@@ -4,6 +4,7 @@
 | Project       Topics Library
 \=============================================================================================================================*/
 using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Diagnostics;
 using OnTopic.Mapping;
 
 namespace OnTopic.AspNetCore.Mvc.Controllers {
@@ -48,7 +49,17 @@ ITopicMappingService topicMappingService
     ///   content available.
     /// </summary>
     /// <returns>A view associated with the requested current <paramref name="statusCode"/>.</returns>
-    public async virtual Task<IActionResult> HttpAsync([FromRoute(Name="id")] int statusCode) {
+    public async virtual Task<IActionResult> HttpAsync([FromRoute(Name="id")] int statusCode, bool includeStaticFiles = true) {
+
+      /*------------------------------------------------------------------------------------------------------------------------
+      | Bypass for resources
+      \-----------------------------------------------------------------------------------------------------------------------*/
+      if (!includeStaticFiles) {
+        var feature             = HttpContext.Features.Get<IStatusCodeReExecuteFeature>();
+        if (feature?.OriginalPath.Contains('.', StringComparison.Ordinal)?? false) {
+          return Content("The resource requested could not found.");
+        }
+      }
 
       /*------------------------------------------------------------------------------------------------------------------------
       | Identify base path

OnTopic.AspNetCore.Mvc/README.md

@@ -187,7 +187,7 @@ public class Startup {
   public void Configure(IApplicationBuilder app, IWebHostEnvironment env) {
     app.UseEndpoints(endpoints => {
       endpoints.MapTopicErrors();                        // Error/{errorCode}
-      endpoints.MapTopicErrors("Errors");                // Errors/{errorCode}
+      endpoints.MapTopicErrors("Errors", false);         // Errors/{errorCode}; disables includeStaticFiles
       endpoints.MapDefaultControllerRoute();             // Error/Http/{errorCode}
       endpoints.MapTopicRoute("Error");                  // Error/{path}; e.g., Error/Unauthorized
     }

OnTopic.AspNetCore.Mvc/ServiceCollectionExtensions.cs

@@ -221,11 +221,18 @@ public static void MapImplicitAreaControllerRoute(this IEndpointRouteBuilder rou
     ///   StatusCodePagesExtensions.UseStatusCodePages(IApplicationBuilder)"/>, by providing a route for capturing the <c>
     ///   errorCode</c>.
     /// </remarks>
-    public static ControllerActionEndpointConventionBuilder MapTopicErrors(this IEndpointRouteBuilder routes, string rootTopic = "Error") =>
+    /// <param name="routes">The <see cref="IEndpointRouteBuilder"/> this route is being added to.</param>
+    /// <param name="rootTopic">The name of the root topic that the route should be mapped to. Defaults to <c>Error</c>.</param>
+    /// <param name="includeStaticFiles">Determines if static resources should be covered. Defaults to <c>true</c>.</param>
+    public static ControllerActionEndpointConventionBuilder MapTopicErrors(
+      this                      IEndpointRouteBuilder           routes,
+      string                    rootTopic                       = "Error",
+      bool                      includeStaticFiles              = true
+    ) =>
       routes.MapControllerRoute(
         name: "TopicError",
         pattern: $"{rootTopic}/{{id:int}}/",
-        defaults: new { controller = "Error", action = "Http", rootTopic }
+        defaults: new { controller = "Error", action = "Http", rootTopic, includeStaticFiles }
       );
 
     /*==========================================================================================================================