Handle file paths as not found in delivery API by route requests

src/Umbraco.Cms.Api.Delivery/Controllers/Content/ByRouteContentApiController.cs

@@ -145,6 +145,11 @@ private async Task<IActionResult> HandleRequest(string path)
         path = DecodePath(path);
         path = path.Length == 0 ? "/" : path;
 
+        if (_apiContentPathResolver.IsResolvablePath(path) is false)
+        {
+            return NotFound();
+        }
+
         IPublishedContent? contentItem = GetContent(path);
         if (contentItem is not null)
         {

src/Umbraco.Core/DeliveryApi/ApiContentPathResolver.cs

@@ -15,6 +15,23 @@ public ApiContentPathResolver(IRequestRoutingService requestRoutingService, IApi
         _apiPublishedContentCache = apiPublishedContentCache;
     }
 
+    public virtual bool IsResolvablePath(string path)
+    {
+        // File requests will blow up with an downstream exception in GetRequiredPublishedSnapshot, which fails due to an UmbracoContext
+        // not being available for what's considered a static file request.
+        // See: https://github.com/umbraco/Umbraco-CMS/issues/19051
+        // Given a URL segment and hence route can't contain a period, we can safely assume that if the last segment of the path contains
+        // a period, it's a file request and should return null here.
+        if (IsFileRequest(path))
+        {
+            return false;
+        }
+
+        return true;
+    }
+
+    private static bool IsFileRequest(string path) => path.Split('/', StringSplitOptions.RemoveEmptyEntries).Last().Contains('.');
+
     public virtual IPublishedContent? ResolveContentPath(string path)
     {
         path = path.EnsureStartsWith("/");

src/Umbraco.Core/DeliveryApi/IApiContentPathResolver.cs

@@ -4,5 +4,7 @@ namespace Umbraco.Cms.Core.DeliveryApi;
 
 public interface IApiContentPathResolver
 {
+    bool IsResolvablePath(string path) => true;
+
     IPublishedContent? ResolveContentPath(string path);
 }

tests/Umbraco.Tests.UnitTests/Umbraco.Core/DeliveryApi/ApiContentPathResolverTests.cs

@@ -0,0 +1,47 @@
+using Moq;
+using NUnit.Framework;
+using Umbraco.Cms.Core.DeliveryApi;
+using Umbraco.Cms.Core.Models.PublishedContent;
+
+namespace Umbraco.Cms.Tests.UnitTests.Umbraco.Core.DeliveryApi;
+
+[TestFixture]
+public class ApiContentPathResolverTests
+{
+    private const string TestPath = "/test/page";
+
+    [TestCase(TestPath, true)]
+    [TestCase("file.txt", false)]
+    [TestCase("test/file.txt", false)]
+    [TestCase("test/test2/file.txt", false)]
+    [TestCase("/file.txt", false)]
+    [TestCase("/test/file.txt", false)]
+    [TestCase("/test/test2/file.txt", false)]
+    public void Can_Verify_Resolveable_Paths(string path, bool expected)
+    {
+        var resolver = CreateResolver();
+        var result = resolver.IsResolvablePath(path);
+        Assert.AreEqual(expected, result);
+    }
+
+    [Test]
+    public void Resolves_Content_For_Path()
+    {
+        var resolver = CreateResolver();
+        var result = resolver.ResolveContentPath(TestPath);
+        Assert.IsNotNull(result);
+    }
+
+    private static ApiContentPathResolver CreateResolver()
+    {
+        var mockRequestRoutingService = new Mock<IRequestRoutingService>();
+        mockRequestRoutingService
+            .Setup(x => x.GetContentRoute(It.IsAny<string>()))
+            .Returns((string path) => path);
+        var mockApiPublishedContentCache = new Mock<IApiPublishedContentCache>();
+        mockApiPublishedContentCache
+            .Setup(x => x.GetByRoute(It.Is<string>(y => y == TestPath)))
+            .Returns(new Mock<IPublishedContent>().Object);
+        return new ApiContentPathResolver(mockRequestRoutingService.Object, mockApiPublishedContentCache.Object);
+    }
+}