add CDN cache-control headers to status card image

Author: Mitch528

StatusPageSharp.slnx

@@ -9,5 +9,6 @@
   <Folder Name="/tests/">
     <Project Path="tests/StatusPageSharp.Domain.Tests/StatusPageSharp.Domain.Tests.csproj" />
     <Project Path="tests/StatusPageSharp.Infrastructure.Tests/StatusPageSharp.Infrastructure.Tests.csproj" />
+    <Project Path="tests/StatusPageSharp.Web.Tests/StatusPageSharp.Web.Tests.csproj" />
   </Folder>
 </Solution>

src/StatusPageSharp.Web/Caching/StatusCardResponseCacheHeaders.cs

@@ -0,0 +1,18 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Net.Http.Headers;
+
+namespace StatusPageSharp.Web.Caching;
+
+public static class StatusCardResponseCacheHeaders
+{
+    private const string CdnCacheControlHeaderName = "CDN-Cache-Control";
+    private const string CloudflareCdnCacheControlHeaderName = "Cloudflare-CDN-Cache-Control";
+    private const string NoStoreDirective = "no-store";
+
+    public static void Apply(IHeaderDictionary headers)
+    {
+        headers[HeaderNames.CacheControl] = NoStoreDirective;
+        headers[CdnCacheControlHeaderName] = NoStoreDirective;
+        headers[CloudflareCdnCacheControlHeaderName] = NoStoreDirective;
+    }
+}

src/StatusPageSharp.Web/Extensions/ApiEndpointRouteBuilderExtensions.cs

@@ -1,4 +1,5 @@
 using StatusPageSharp.Application.Abstractions;
+using StatusPageSharp.Web.Caching;
 using StatusPageSharp.Web.Rendering;
 
 namespace StatusPageSharp.Web.Extensions;
@@ -59,15 +60,19 @@ CancellationToken cancellationToken
             .MapGet(
                 "/status-card.png",
                 async (
+                    HttpContext httpContext,
                     IPublicStatusService publicStatusService,
                     CancellationToken cancellationToken
                 ) =>
-                    TypedResults.File(
+                {
+                    StatusCardResponseCacheHeaders.Apply(httpContext.Response.Headers);
+                    return TypedResults.File(
                         SocialStatusCardRenderer.Render(
                             await publicStatusService.GetSiteSummaryAsync(cancellationToken)
                         ),
                         "image/png"
-                    )
+                    );
+                }
             )
             .CacheOutput("StatusCard");
 

tests/StatusPageSharp.Web.Tests/Caching/StatusCardResponseCacheHeadersTests.cs

@@ -0,0 +1,20 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Net.Http.Headers;
+using StatusPageSharp.Web.Caching;
+
+namespace StatusPageSharp.Web.Tests.Caching;
+
+public class StatusCardResponseCacheHeadersTests
+{
+    [Fact]
+    public void Apply_SetsNoStoreHeaders_ForBrowsersAndCdns()
+    {
+        var headers = new HeaderDictionary();
+
+        StatusCardResponseCacheHeaders.Apply(headers);
+
+        Assert.Equal("no-store", headers[HeaderNames.CacheControl].ToString());
+        Assert.Equal("no-store", headers["CDN-Cache-Control"].ToString());
+        Assert.Equal("no-store", headers["Cloudflare-CDN-Cache-Control"].ToString());
+    }
+}

tests/StatusPageSharp.Web.Tests/StatusPageSharp.Web.Tests.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <LangVersion>14.0</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="xunit" />
+    <PackageReference Include="xunit.runner.visualstudio" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\StatusPageSharp.Web\StatusPageSharp.Web.csproj" />
+  </ItemGroup>
+</Project>