From ec233ebc3cf092c75c603ed3ad59a42ece543bf4 Mon Sep 17 00:00:00 2001
From: Robert Foster <robert@youritgroup.com.au>
Date: Thu, 23 Jul 2026 08:46:41 +1000
Subject: [PATCH] Version 0.4.0 added UseViteUnhashedAssetRedirects()

---
 README.md                                     |  30 ++-
 Vite.dotnet.Tests/ManifestTestContext.cs      |  44 +++--
 .../UnhashedAssetRedirectTests.cs             | 184 ++++++++++++++++++
 Vite.dotnet/Extensions.cs                     |  75 +++++++
 Vite.dotnet/ServiceExtensions.cs              |  51 -----
 Vite.dotnet/Services/IViteManifestService.cs  |   7 +
 Vite.dotnet/Services/ViteManifestService.cs   |  87 ++++++++-
 Vite.dotnet/Vite.dotnet.csproj                |   2 +-
 .../ViteUnhashedAssetRedirectMiddleware.cs    |  33 ++++
 9 files changed, 447 insertions(+), 66 deletions(-)
 create mode 100644 Vite.dotnet.Tests/UnhashedAssetRedirectTests.cs
 create mode 100644 Vite.dotnet/Extensions.cs
 delete mode 100644 Vite.dotnet/ServiceExtensions.cs
 create mode 100644 Vite.dotnet/ViteUnhashedAssetRedirectMiddleware.cs

diff --git a/README.md b/README.md
index 074e963..2190b29 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ Options bind from the `ViteManifest` section of `appsettings.json`:
 | `DefaultEntry`    | `index.html`   | The logical entry assumed by the parameterless service getters.          |
 | `DefaultBasePath` | `/`            | The base path hashed assets are served from when none is supplied.       |
 
-Registration overloads (`ViteServiceExtensions`):
+Registration overloads (`ViteServiceCollectionExtensions`):
 
 ```csharp
 // Defaults only
@@ -141,10 +141,38 @@ Returned URLs are prefixed with the supplied base path. Pass `""` as the base pa
 | `GetCssFiles()` / `(entry, basePath)` / `(ViteManifestEntry, basePath)`  | `IReadOnlyList<string>`| Resolved CSS URLs.                                 |
 | `GetJsFile()` / `(entry, basePath)` / `(ViteManifestEntry, basePath)`    | `string?`              | Resolved JS URL.                                   |
 | `GetModulePreloadFiles(ViteManifestEntry, basePath)`                     | `IReadOnlyList<string>`| Transitively-imported chunk URLs (for modulepreload). |
+| `TryResolveHashedAsset(requestPath, out hashedPath)`                     | `bool`                 | Resolve an unhashed asset path to its hashed build output. |
 | `RenderCss(entry, basePath, preload)`                                    | `IHtmlContent`         | CSS `<link>` tags only.                            |
 | `RenderJs(entry, basePath)`                                              | `IHtmlContent`         | `<link rel="modulepreload">` for imported chunks + the module `<script>` tag. |
 | `RenderEntry(entry, basePath, preloadCss, assets, devServer)`            | `IHtmlContent`         | Full render; handles dev-server + not-found cases. |
 
+## Redirecting unhashed asset requests
+
+Vite fingerprints its output (`main-COZv9l4K.css`), which is great for caching but awkward when
+something needs to reference an asset by a stable, unhashed name (`/assets/main.css`). Register the
+redirect middleware and those requests are 302-redirected to the current hashed file:
+
+```csharp
+app.UseViteUnhashedAssetRedirects();  // register BEFORE app.UseStaticFiles()
+app.UseStaticFiles();
+```
+
+Registering the middleware is the only switch — there is no config flag. Leave the call out and the
+feature is off (and its manifest lookup is never built).
+
+- The unhashed → hashed lookup is derived once from the manifest (every entry/chunk JS file and
+  all CSS, including imported-chunk CSS), so it always tracks the latest build.
+- A **302** (never 301) is used because the hashed target changes every build — the unhashed URL
+  must not be cached permanently.
+- The middleware only acts on GET/HEAD requests whose path is a known unhashed asset; everything
+  else passes straight through.
+- Dehashing recognises Vite's default `[name]-[hash].[ext]` pattern (hash ≥ 8 chars). If two
+  build outputs dehash to the same unhashed name the first wins and a warning is logged — an
+  ambiguous redirect is never emitted.
+
+The service also exposes `TryResolveHashedAsset(requestPath, out hashedPath)` if you need the same
+resolution outside the middleware.
+
 ## Development mode
 
 When the environment is `Development` **and** a `dev-server` is supplied, `RenderEntry` skips the manifest entirely and points straight at the Vite dev server for HMR:
diff --git a/Vite.dotnet.Tests/ManifestTestContext.cs b/Vite.dotnet.Tests/ManifestTestContext.cs
index b248901..c8a151f 100644
--- a/Vite.dotnet.Tests/ManifestTestContext.cs
+++ b/Vite.dotnet.Tests/ManifestTestContext.cs
@@ -1,6 +1,6 @@
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.FileProviders;
-using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Vite.Configuration;
 using Vite.Services;
@@ -16,15 +16,20 @@ namespace Vite.dotnet.Tests;
 public sealed class ManifestTestContext : IDisposable
 {
   private readonly string _webRoot;
+  private readonly CapturingLogger _logger;
 
-  private ManifestTestContext(string webRoot, ViteManifestService service)
+  private ManifestTestContext(string webRoot, ViteManifestService service, CapturingLogger logger)
   {
     _webRoot = webRoot;
+    _logger = logger;
     Service = service;
   }
 
   public ViteManifestService Service { get; }
 
+  /// <summary>Warning-level (and above) log messages captured from the service.</summary>
+  public IReadOnlyList<string> Warnings => _logger.Warnings;
+
   public static ManifestTestContext Create(string manifestJson, ViteManifestOptions? options = null)
   {
     var webRoot = Path.Combine(Path.GetTempPath(), "vite-dotnet-tests", Guid.NewGuid().ToString("N"));
@@ -32,13 +37,11 @@ public static ManifestTestContext Create(string manifestJson, ViteManifestOption
     Directory.CreateDirectory(viteDir);
     File.WriteAllText(Path.Combine(viteDir, "manifest.json"), manifestJson);
 
+    var logger = new CapturingLogger();
     var env = new FakeWebHostEnvironment { WebRootPath = webRoot };
-    var service = new ViteManifestService(
-      env,
-      NullLogger<ViteManifestService>.Instance,
-      Options.Create(options ?? new ViteManifestOptions()));
+    var service = new ViteManifestService(env, logger, Options.Create(options ?? new ViteManifestOptions()));
 
-    return new ManifestTestContext(webRoot, service);
+    return new ManifestTestContext(webRoot, service, logger);
   }
 
   /// <summary>Creates a context whose manifest file does not exist on disk.</summary>
@@ -47,13 +50,11 @@ public static ManifestTestContext CreateWithoutManifest(ViteManifestOptions? opt
     var webRoot = Path.Combine(Path.GetTempPath(), "vite-dotnet-tests", Guid.NewGuid().ToString("N"));
     Directory.CreateDirectory(webRoot);
 
+    var logger = new CapturingLogger();
     var env = new FakeWebHostEnvironment { WebRootPath = webRoot };
-    var service = new ViteManifestService(
-      env,
-      NullLogger<ViteManifestService>.Instance,
-      Options.Create(options ?? new ViteManifestOptions()));
+    var service = new ViteManifestService(env, logger, Options.Create(options ?? new ViteManifestOptions()));
 
-    return new ManifestTestContext(webRoot, service);
+    return new ManifestTestContext(webRoot, service, logger);
   }
 
   public void Dispose()
@@ -71,6 +72,25 @@ public void Dispose()
     }
   }
 
+  private sealed class CapturingLogger : ILogger<ViteManifestService>
+  {
+    private readonly List<string> _warnings = [];
+
+    public IReadOnlyList<string> Warnings => _warnings;
+
+    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+    public bool IsEnabled(LogLevel logLevel) => true;
+
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+      if (logLevel >= LogLevel.Warning)
+      {
+        _warnings.Add(formatter(state, exception));
+      }
+    }
+  }
+
   private sealed class FakeWebHostEnvironment : IWebHostEnvironment
   {
     public string WebRootPath { get; set; } = "";
diff --git a/Vite.dotnet.Tests/UnhashedAssetRedirectTests.cs b/Vite.dotnet.Tests/UnhashedAssetRedirectTests.cs
new file mode 100644
index 0000000..559d2eb
--- /dev/null
+++ b/Vite.dotnet.Tests/UnhashedAssetRedirectTests.cs
@@ -0,0 +1,184 @@
+using Microsoft.AspNetCore.Http;
+using Vite;
+using Vite.Configuration;
+using Xunit;
+
+namespace Vite.dotnet.Tests;
+
+public class UnhashedAssetRedirectTests
+{
+  private const string Manifest = """
+  {
+    "_client.gen-WrdE9yCN.js": {
+      "file": "assets/client.gen-WrdE9yCN.js",
+      "name": "client.gen",
+      "css": ["assets/client-CYzq3z7c.css"]
+    },
+    "index.html": {
+      "file": "assets/main-espf9ZVg.js",
+      "name": "main",
+      "isEntry": true,
+      "imports": ["_client.gen-WrdE9yCN.js"],
+      "css": ["assets/main-COZv9l4K.css"]
+    }
+  }
+  """;
+
+  private static ViteManifestOptions WithBasePath(string basePath) =>
+    new() { DefaultBasePath = basePath };
+
+  [Fact]
+  public void TryResolveHashedAsset_MapsUnhashedJsEntryToHashedFile()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+
+    Assert.True(ctx.Service.TryResolveHashedAsset("/assets/main.js", out var hashed));
+    Assert.Equal("/assets/main-espf9ZVg.js", hashed);
+  }
+
+  [Fact]
+  public void TryResolveHashedAsset_MapsUnhashedCssToHashedFile()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+
+    Assert.True(ctx.Service.TryResolveHashedAsset("/assets/main.css", out var hashed));
+    Assert.Equal("/assets/main-COZv9l4K.css", hashed);
+  }
+
+  [Fact]
+  public void TryResolveHashedAsset_MapsCssFromImportedChunk()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+
+    Assert.True(ctx.Service.TryResolveHashedAsset("/assets/client.css", out var hashed));
+    Assert.Equal("/assets/client-CYzq3z7c.css", hashed);
+  }
+
+  [Fact]
+  public void TryResolveHashedAsset_KeepsNamesContainingDots()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+
+    Assert.True(ctx.Service.TryResolveHashedAsset("/assets/client.gen.js", out var hashed));
+    Assert.Equal("/assets/client.gen-WrdE9yCN.js", hashed);
+  }
+
+  [Fact]
+  public void TryResolveHashedAsset_AppliesConfiguredBasePath()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest, WithBasePath("/dist/"));
+
+    Assert.True(ctx.Service.TryResolveHashedAsset("/dist/assets/main.css", out var hashed));
+    Assert.Equal("/dist/assets/main-COZv9l4K.css", hashed);
+  }
+
+  [Fact]
+  public void TryResolveHashedAsset_ReturnsFalseForUnknownPath()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+
+    Assert.False(ctx.Service.TryResolveHashedAsset("/assets/nope.css", out _));
+  }
+
+  [Fact]
+  public void TryResolveHashedAsset_DoesNotMatchTheHashedPathItself()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+
+    // The already-hashed file is served by static files, not redirected.
+    Assert.False(ctx.Service.TryResolveHashedAsset("/assets/main-COZv9l4K.css", out _));
+  }
+
+  [Fact]
+  public void BuildMap_SkipsAndWarnsOnAmbiguousCollision()
+  {
+    // Two hashed files in the same folder that dehash to the same unhashed name.
+    const string manifest = """
+    {
+      "a.html": { "file": "assets/app-AAAAAAAA.js", "isEntry": true },
+      "b.html": { "file": "assets/app-BBBBBBBB.js", "isEntry": true }
+    }
+    """;
+    using var ctx = ManifestTestContext.Create(manifest);
+
+    Assert.True(ctx.Service.TryResolveHashedAsset("/assets/app.js", out var hashed));
+    // First-seen wins; exactly one of the two, never both.
+    Assert.Contains(hashed, new[] { "/assets/app-AAAAAAAA.js", "/assets/app-BBBBBBBB.js" });
+    Assert.Contains(ctx.Warnings, w => w.Contains("Ambiguous unhashed asset"));
+  }
+
+  [Fact]
+  public void BuildMap_IgnoresFilesWithoutAHashSegment()
+  {
+    const string manifest = """
+    { "index.html": { "file": "assets/plain.js", "isEntry": true, "css": ["assets/plain.css"] } }
+    """;
+    using var ctx = ManifestTestContext.Create(manifest);
+
+    Assert.False(ctx.Service.TryResolveHashedAsset("/assets/plain.js", out _));
+    Assert.False(ctx.Service.TryResolveHashedAsset("/assets/plain.css", out _));
+  }
+
+  [Fact]
+  public async Task Middleware_Redirects302ToHashedFile()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+    var context = new DefaultHttpContext();
+    context.Request.Method = HttpMethods.Get;
+    context.Request.Path = "/assets/main.css";
+    var nextCalled = false;
+
+    var middleware = new ViteUnhashedAssetRedirectMiddleware(_ => { nextCalled = true; return Task.CompletedTask; }, ctx.Service);
+    await middleware.InvokeAsync(context);
+
+    Assert.False(nextCalled);
+    Assert.Equal(StatusCodes.Status302Found, context.Response.StatusCode);
+    Assert.Equal("/assets/main-COZv9l4K.css", context.Response.Headers.Location);
+  }
+
+  [Fact]
+  public async Task Middleware_PreservesQueryString()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+    var context = new DefaultHttpContext();
+    context.Request.Method = HttpMethods.Get;
+    context.Request.Path = "/assets/main.css";
+    context.Request.QueryString = new QueryString("?v=1");
+
+    var middleware = new ViteUnhashedAssetRedirectMiddleware(_ => Task.CompletedTask, ctx.Service);
+    await middleware.InvokeAsync(context);
+
+    Assert.Equal("/assets/main-COZv9l4K.css?v=1", context.Response.Headers.Location);
+  }
+
+  [Fact]
+  public async Task Middleware_PassesThroughUnknownPath()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+    var context = new DefaultHttpContext();
+    context.Request.Method = HttpMethods.Get;
+    context.Request.Path = "/assets/unknown.css";
+    var nextCalled = false;
+
+    var middleware = new ViteUnhashedAssetRedirectMiddleware(_ => { nextCalled = true; return Task.CompletedTask; }, ctx.Service);
+    await middleware.InvokeAsync(context);
+
+    Assert.True(nextCalled);
+    Assert.Equal(StatusCodes.Status200OK, context.Response.StatusCode);
+  }
+
+  [Fact]
+  public async Task Middleware_PassesThroughNonGetRequests()
+  {
+    using var ctx = ManifestTestContext.Create(Manifest);
+    var context = new DefaultHttpContext();
+    context.Request.Method = HttpMethods.Post;
+    context.Request.Path = "/assets/main.css";
+    var nextCalled = false;
+
+    var middleware = new ViteUnhashedAssetRedirectMiddleware(_ => { nextCalled = true; return Task.CompletedTask; }, ctx.Service);
+    await middleware.InvokeAsync(context);
+
+    Assert.True(nextCalled);
+  }
+}
diff --git a/Vite.dotnet/Extensions.cs b/Vite.dotnet/Extensions.cs
new file mode 100644
index 0000000..0e5a60e
--- /dev/null
+++ b/Vite.dotnet/Extensions.cs
@@ -0,0 +1,75 @@
+using Microsoft.Extensions.Configuration;
+using Vite;
+using Vite.Configuration;
+using Vite.Services;
+
+// Extension methods are placed in the namespace of the type they extend so they surface
+// without an extra `using`: service registrations under Microsoft.Extensions.DependencyInjection,
+// middleware registration under Microsoft.AspNetCore.Builder.
+
+namespace Microsoft.Extensions.DependencyInjection
+{
+  public static class ViteServiceCollectionExtensions
+  {
+    extension(IServiceCollection services)
+    {
+      /// <summary>
+      /// Registers the Vite manifest service used by the &lt;vite&gt; tag helper.
+      /// Registered as a singleton so the manifest is read and parsed once and
+      /// cached for the lifetime of the application.
+      /// </summary>
+      /// <param name="configure">Optional configuration of <see cref="ViteManifestOptions"/> (e.g. the default entry and base path).</param>
+      public IServiceCollection AddViteManifest(Action<ViteManifestOptions>? configure = null)
+      {
+        if (configure is not null)
+        {
+          services.Configure(configure);
+        }
+
+        return services.AddViteManifestCore();
+      }
+
+      /// <summary>
+      /// Registers the Vite manifest service, binding <see cref="ViteManifestOptions"/> from the
+      /// "<see cref="ViteManifestOptions.SectionName"/>" configuration section (e.g. appsettings.json).
+      /// </summary>
+      /// <param name="configuration">Application configuration to bind options from.</param>
+      /// <param name="configure">Optional code-based overrides applied on top of the bound configuration.</param>
+      public IServiceCollection AddViteManifest(IConfiguration configuration, Action<ViteManifestOptions>? configure = null)
+      {
+        services.Configure<ViteManifestOptions>(configuration.GetSection(ViteManifestOptions.SectionName));
+
+        if (configure is not null)
+        {
+          services.Configure(configure);
+        }
+
+        return services.AddViteManifestCore();
+      }
+
+      private IServiceCollection AddViteManifestCore()
+      {
+        services.AddSingleton<IViteManifestService, ViteManifestService>();
+        return services;
+      }
+    }
+  }
+}
+
+namespace Microsoft.AspNetCore.Builder
+{
+  public static class ViteApplicationBuilderExtensions
+  {
+    extension(IApplicationBuilder app)
+    {
+      /// <summary>
+      /// Adds middleware that 302-redirects unhashed asset requests (e.g. <c>/assets/main.css</c>)
+      /// to their current hashed build output. Registering this call is what enables the feature.
+      /// Register it before <c>UseStaticFiles</c> so unhashed paths are redirected rather than
+      /// falling through to a 404.
+      /// </summary>
+      public IApplicationBuilder UseViteUnhashedAssetRedirects()
+        => app.UseMiddleware<ViteUnhashedAssetRedirectMiddleware>();
+    }
+  }
+}
diff --git a/Vite.dotnet/ServiceExtensions.cs b/Vite.dotnet/ServiceExtensions.cs
deleted file mode 100644
index 91f2379..0000000
--- a/Vite.dotnet/ServiceExtensions.cs
+++ /dev/null
@@ -1,51 +0,0 @@
-using Microsoft.Extensions.Configuration;
-using Vite.Services;
-using Vite.Configuration;
-
-namespace Microsoft.Extensions.DependencyInjection;
-
-public static class ServiceExtensions
-{
-  extension(IServiceCollection services)
-  {
-    /// <summary>
-    /// Registers the Vite manifest service used by the &lt;vite&gt; tag helper.
-    /// Registered as a singleton so the manifest is read and parsed once and
-    /// cached for the lifetime of the application.
-    /// </summary>
-    /// <param name="configure">Optional configuration of <see cref="ViteManifestOptions"/> (e.g. the default entry and base path).</param>
-    public IServiceCollection AddViteManifest(Action<ViteManifestOptions>? configure = null)
-    {
-      if (configure is not null)
-      {
-        services.Configure(configure);
-      }
-
-      return services.AddViteManifestCore();
-    }
-
-    /// <summary>
-    /// Registers the Vite manifest service, binding <see cref="ViteManifestOptions"/> from the
-    /// "<see cref="ViteManifestOptions.SectionName"/>" configuration section (e.g. appsettings.json).
-    /// </summary>
-    /// <param name="configuration">Application configuration to bind options from.</param>
-    /// <param name="configure">Optional code-based overrides applied on top of the bound configuration.</param>
-    public IServiceCollection AddViteManifest(IConfiguration configuration, Action<ViteManifestOptions>? configure = null)
-    {
-      services.Configure<ViteManifestOptions>(configuration.GetSection(ViteManifestOptions.SectionName));
-
-      if (configure is not null)
-      {
-        services.Configure(configure);
-      }
-
-      return services.AddViteManifestCore();
-    }
-
-    private IServiceCollection AddViteManifestCore()
-    {
-      services.AddSingleton<IViteManifestService, ViteManifestService>();
-      return services;
-    }
-  }
-}
diff --git a/Vite.dotnet/Services/IViteManifestService.cs b/Vite.dotnet/Services/IViteManifestService.cs
index e6074cc..c2dcb7b 100644
--- a/Vite.dotnet/Services/IViteManifestService.cs
+++ b/Vite.dotnet/Services/IViteManifestService.cs
@@ -76,6 +76,13 @@ public interface IViteManifestService
   /// <param name="basePath">Base path the hashed assets are served from (e.g. "/").</param>
   IHtmlContent RenderJs(ViteManifestEntry entry, string basePath);
 
+  /// <summary>
+  /// Attempts to resolve an unhashed asset request path (e.g. "/assets/main.css") to the
+  /// current hashed build output (e.g. "/assets/main-COZv9l4K.css"). Both paths are
+  /// base-path-prefixed. Returns false when the path is not a known unhashed asset.
+  /// </summary>
+  bool TryResolveHashedAsset(string requestPath, out string hashedPath);
+
   /// <summary>
   /// Renders the requested asset tags for a Vite entry. Handles the dev-server
   /// short-circuit and the "entry not found" case, then composes the CSS and/or
diff --git a/Vite.dotnet/Services/ViteManifestService.cs b/Vite.dotnet/Services/ViteManifestService.cs
index 9f42425..778128a 100644
--- a/Vite.dotnet/Services/ViteManifestService.cs
+++ b/Vite.dotnet/Services/ViteManifestService.cs
@@ -5,15 +5,22 @@
 using Microsoft.Extensions.Options;
 using System.Text;
 using System.Text.Json;
+using System.Text.RegularExpressions;
 using Vite.Configuration;
 using Vite.Models;
 
 namespace Vite.Services;
 
-public sealed class ViteManifestService : IViteManifestService
+public sealed partial class ViteManifestService : IViteManifestService
 {
   private static readonly JsonSerializerOptions JsonOptions = new() { PropertyNameCaseInsensitive = true };
 
+  // Vite's default output filename is "[name]-[hash].[ext]". The hash is the trailing
+  // "-" group; requiring >=8 chars from Vite's default hash alphabet avoids stripping a
+  // real "-" word (e.g. "vue-tel-input") that happens to sit before the extension.
+  [GeneratedRegex(@"^(?<name>.+)-[A-Za-z0-9_-]{8,}(?<ext>\.[^.]+)$")]
+  private static partial Regex HashedFileRegex();
+
   private readonly IWebHostEnvironment _env;
   private readonly ILogger<ViteManifestService> _logger;
   private readonly ViteManifestOptions _options;
@@ -23,6 +30,10 @@ public sealed class ViteManifestService : IViteManifestService
   // exactly once, no matter how many requests hit the tag helper concurrently.
   private readonly Lazy<IReadOnlyDictionary<string, ViteManifestEntry>> _manifest;
 
+  // Unhashed URL path -> hashed URL path, derived once from the manifest and prefixed
+  // with the configured base path. Populated only when RedirectUnhashedAssets is enabled.
+  private readonly Lazy<IReadOnlyDictionary<string, string>> _unhashedAssetMap;
+
   public ViteManifestService(IWebHostEnvironment env, ILogger<ViteManifestService> logger, IOptions<ViteManifestOptions> options)
   {
     _env = env;
@@ -30,6 +41,7 @@ public ViteManifestService(IWebHostEnvironment env, ILogger<ViteManifestService>
     _options = options.Value;
     _manifestPath = Path.Combine(env.WebRootPath, ".vite", "manifest.json");
     _manifest = new Lazy<IReadOnlyDictionary<string, ViteManifestEntry>>(LoadManifest);
+    _unhashedAssetMap = new Lazy<IReadOnlyDictionary<string, string>>(BuildUnhashedAssetMap);
   }
 
   public ViteManifestEntry? GetEntry(string entry)
@@ -255,6 +267,79 @@ public IHtmlContent RenderEntry(string? entry = null, string? basePath = null, b
     return content;
   }
 
+  public bool TryResolveHashedAsset(string requestPath, out string hashedPath)
+  {
+    hashedPath = "";
+    if (string.IsNullOrEmpty(requestPath))
+    {
+      return false;
+    }
+
+    if (_unhashedAssetMap.Value.TryGetValue(requestPath, out var resolved))
+    {
+      hashedPath = resolved;
+      return true;
+    }
+
+    return false;
+  }
+
+  // Builds the unhashed -> hashed lookup from every output file the manifest references
+  // (entry/chunk JS files and all CSS files). Keys and values are base-path-prefixed URL
+  // paths so the middleware can compare against the incoming request path directly.
+  // Built lazily, so the cost is only paid when the redirect middleware is registered.
+  private IReadOnlyDictionary<string, string> BuildUnhashedAssetMap()
+  {
+    var basePrefix = _options.DefaultBasePath.TrimEnd('/');
+    var map = new Dictionary<string, string>(StringComparer.Ordinal);
+
+    void Add(string? file)
+    {
+      if (string.IsNullOrEmpty(file))
+      {
+        return;
+      }
+
+      var match = HashedFileRegex().Match(file);
+      if (!match.Success)
+      {
+        return; // No hash segment -> nothing to redirect from.
+      }
+
+      var unhashed = match.Groups["name"].Value + match.Groups["ext"].Value;
+      var unhashedUrl = $"{basePrefix}/{unhashed}";
+      var hashedUrl = $"{basePrefix}/{file}";
+
+      if (map.TryGetValue(unhashedUrl, out var existing))
+      {
+        if (!string.Equals(existing, hashedUrl, StringComparison.Ordinal))
+        {
+          _logger.LogWarning(
+            "Ambiguous unhashed asset '{Unhashed}' maps to both '{Existing}' and '{New}'; keeping the first and skipping the redirect for the second.",
+            unhashedUrl, existing, hashedUrl);
+        }
+        return; // First mapping wins; never emit an ambiguous redirect.
+      }
+
+      map[unhashedUrl] = hashedUrl;
+    }
+
+    foreach (var entry in _manifest.Value.Values)
+    {
+      Add(entry.File);
+
+      if (entry.Css is { Count: > 0 })
+      {
+        foreach (var css in entry.Css)
+        {
+          Add(css);
+        }
+      }
+    }
+
+    return map;
+  }
+
   private IReadOnlyDictionary<string, ViteManifestEntry> LoadManifest()
   {
     if (File.Exists(_manifestPath))
diff --git a/Vite.dotnet/Vite.dotnet.csproj b/Vite.dotnet/Vite.dotnet.csproj
index 36b6292..8bd2b84 100644
--- a/Vite.dotnet/Vite.dotnet.csproj
+++ b/Vite.dotnet/Vite.dotnet.csproj
@@ -4,7 +4,7 @@
     <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
-    <Version>0.3.0</Version>
+    <Version>0.4.0</Version>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/Vite.dotnet/ViteUnhashedAssetRedirectMiddleware.cs b/Vite.dotnet/ViteUnhashedAssetRedirectMiddleware.cs
new file mode 100644
index 0000000..07fe3e0
--- /dev/null
+++ b/Vite.dotnet/ViteUnhashedAssetRedirectMiddleware.cs
@@ -0,0 +1,33 @@
+using Microsoft.AspNetCore.Http;
+using Vite.Services;
+
+namespace Vite;
+
+/// <summary>
+/// Redirects requests for unhashed asset paths (e.g. <c>/assets/main.css</c>) to their
+/// current hashed build output (e.g. <c>/assets/main-COZv9l4K.css</c>) with a 302.
+/// The mapping is derived from the Vite manifest, so it always tracks the latest build.
+/// Passes through for non-GET/HEAD requests and for paths that are not known unhashed assets.
+/// The feature is enabled simply by registering this middleware via
+/// <c>app.UseViteUnhashedAssetRedirects()</c>.
+/// </summary>
+public sealed class ViteUnhashedAssetRedirectMiddleware(RequestDelegate next, IViteManifestService manifest)
+{
+  public Task InvokeAsync(HttpContext context)
+  {
+    var request = context.Request;
+
+    if ((HttpMethods.IsGet(request.Method) || HttpMethods.IsHead(request.Method))
+        && request.Path.HasValue
+        && manifest.TryResolveHashedAsset(request.Path.Value, out var hashedPath))
+    {
+      // 302, not 301: the hashed target changes on every build, so the mapping must
+      // never be cached permanently. Preserve the query string on the way through.
+      var location = hashedPath + request.QueryString;
+      context.Response.Redirect(location, permanent: false);
+      return Task.CompletedTask;
+    }
+
+    return next(context);
+  }
+}