Fix path base.

backend/src/Squidex.Web/PathBaseMiddlewareExtensions.cs

@@ -0,0 +1,47 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Squidex.Hosting;
+
+namespace Squidex.Web;
+
+public static class PathBaseMiddlewareExtensions
+{
+    public static IApplicationBuilder UseFallbackPathBase(this IApplicationBuilder app)
+    {
+        var urlGenerator = app.ApplicationServices.GetRequiredService<IUrlGenerator>();
+
+        var configuredBase = urlGenerator.BuildBasePath();
+        if (string.IsNullOrWhiteSpace(configuredBase))
+        {
+            return app;
+        }
+
+        var pathBase = new PathString(configuredBase);
+
+        return app.Use(async (context, next) =>
+        {
+            if (context.Request.PathBase.HasValue)
+            {
+                await next();
+                return;
+            }
+
+            context.Request.PathBase = pathBase;
+
+            if (context.Request.Path.StartsWithSegments(pathBase, StringComparison.Ordinal, out var remainder))
+            {
+                context.Request.Path = remainder;
+            }
+
+            await next();
+        });
+    }
+}

backend/src/Squidex.Web/Resources.cs

@@ -170,7 +170,6 @@ public sealed class Resources(ApiController controller)
         var url = Controller.Url(action, values);
 
         var basePath = Controller.HttpContext.Request.PathBase;
-
         if (url.StartsWith(Controller.HttpContext.Request.PathBase, StringComparison.OrdinalIgnoreCase))
         {
             url = url[basePath.Value!.Length..];

backend/src/Squidex/Startup.cs

@@ -73,7 +73,7 @@ public sealed class Startup(IConfiguration config)
     {
         app.UseWebSockets();
         app.UseCookiePolicy();
-        app.UseDefaultPathBase();
+        app.UseFallbackPathBase();
         app.UseDefaultForwardRules();
         app.UseSquidexLogging();
         app.UseSquidexLocalization();