Cache HTML and bypass controller completely

src/web/CareLeavers.Web/Contentful/ContentfulContentService.cs

@@ -28,7 +28,7 @@ public ContentfulContentService(
             var pages = new QueryBuilder<Page>()
                 .ContentTypeIs(Page.ContentType)
                 .FieldEquals(c => c.Slug, slug)
-                .Include(5)
+                .Include(4)
                 .Limit(1);
 
             var pageEntries = await _contentfulClient.GetEntries(pages);
@@ -56,7 +56,7 @@ public ContentfulContentService(
         {
             var config = new QueryBuilder<ContentfulConfigurationEntity>()
                 .ContentTypeIs(ContentfulConfigurationEntity.ContentType)
-                .Include(5)
+                .Include(2)
                 .Limit(1);
 
             var configEntries = await _contentfulClient.GetEntries(config);

src/web/CareLeavers.Web/Controllers/ContentfulController.cs

@@ -1,13 +1,9 @@
 using System.Diagnostics.CodeAnalysis;
-using System.Text;
-using System.Xml.Linq;
 using CareLeavers.Web.Configuration;
 using CareLeavers.Web.Contentful;
-using Contentful.Core.Configuration;
+using CareLeavers.Web.Filters;
 using Microsoft.AspNetCore.Mvc;
 using Newtonsoft.Json;
-using Newtonsoft.Json.Serialization;
-using Formatting = Newtonsoft.Json.Formatting;
 
 namespace CareLeavers.Web.Controllers;
 
@@ -41,6 +37,7 @@ public async Task<IActionResult> GetContentAsJson(string slug, [FromServices] IW
     }
 
     [Route("/{**slug}")]
+    [ContentfulCaching]
     public async Task<IActionResult> GetContent(string slug)
     {
         var page = await contentService.GetPage(slug);

src/web/CareLeavers.Web/Filters/ContentfulCachingAttribute.cs

@@ -0,0 +1,76 @@
+using System.Text;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.Extensions.Caching.Distributed;
+
+namespace CareLeavers.Web.Filters;
+
+public class ContentfulCaching : ActionFilterAttribute
+{
+    private MemoryStream? _memoryStream;
+    private Stream? _originalBodyStream;
+
+    public override async Task OnActionExecutionAsync(
+        ActionExecutingContext context,
+        ActionExecutionDelegate next)
+    {
+        _memoryStream = null;
+        _originalBodyStream = null;
+
+        var distributedCache = context.HttpContext.RequestServices.GetRequiredService<IDistributedCache>();
+
+        var slug = context.RouteData.Values["slug"]?.ToString();
+
+        if (slug == null)
+        {
+            await base.OnActionExecutionAsync(context, next);
+            return;
+        }
+
+        var cachedResponse = await distributedCache.GetAsync($"contentful:html:{slug}");
+
+        if (cachedResponse != null)
+        {
+            context.Result = new ContentResult
+            {
+                Content = Encoding.UTF8.GetString(cachedResponse),
+                ContentType = "text/html"
+            };
+
+            return;
+        }
+
+        _memoryStream = new MemoryStream();
+        _originalBodyStream = context.HttpContext.Response.Body;
+        context.HttpContext.Response.Body = _memoryStream;
+
+        await base.OnActionExecutionAsync(context, next);
+    }
+
+    public override async Task OnResultExecutionAsync(
+        ResultExecutingContext context,
+        ResultExecutionDelegate next)
+    {
+        await base.OnResultExecutionAsync(context, next);
+
+        var slug = context.RouteData.Values["slug"]?.ToString();
+
+        if (slug == null || _memoryStream == null || _originalBodyStream == null)
+        {
+            return;
+        }
+
+        var distributedCache = context.HttpContext.RequestServices.GetRequiredService<IDistributedCache>();
+
+        _memoryStream.Seek(0, SeekOrigin.Begin);
+
+        var responseBody = await new StreamReader(_memoryStream).ReadToEndAsync();
+
+        _memoryStream.Seek(0, SeekOrigin.Begin);
+
+        context.HttpContext.Response.Body = _originalBodyStream!;
+        await context.HttpContext.Response.Body!.WriteAsync(_memoryStream.ToArray());
+
+        await distributedCache.SetAsync($"contentful:html:{slug}", Encoding.UTF8.GetBytes(responseBody));
+    }
+}

src/web/CareLeavers.Web/appsettings.json

@@ -21,7 +21,7 @@
     "ShowCookieBanner": true
   },
   "Caching": {
-    "Type": "None",
+    "Type": "Memory",
     "ConnectionString": "",
     "Duration": "30.00:00:00"
   },