ASP.NET Core 404 Error on IIS 10

Question

I have a problem with ASP.NET Core web application running on IIS 10. I am developing a Single Page Application with AngularJS.

The index.html loads perfectly but the backend requests are failing with 404 error code on the IIS 10. From Visual Studio with IIS Express it works perfectly.

Can anyone spot how can I fix the backend requests?

Here's my Program.cs

public static void Main(string[] args)
{
    var host = new WebHostBuilder()
        .UseKestrel()
        .UseContentRoot(Directory.GetCurrentDirectory())
        .UseIISIntegration()
        .UseStartup<Startup>()
        .Build();

    host.Run();
}

And here's my Configure method from Startup.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    app.UseDefaultFiles();

    app.UseStaticFiles();

    app.UseIdentity();

    // Custom middleware for Angular UI-Router
    app.Use(async (context, next) =>
    {
        if (!Path.HasExtension(context.Request.Path.Value)
        && context.Request.HttpContext.Request.Headers["X-Requested-With"] != "XMLHttpRequest"
        && context.Request.Method.ToUpper() != "POST"
        && context.Request.Method.ToUpper() != "PUT"
        && context.Request.Method.ToUpper() != "DELETE")
        {
            await context.Response.WriteAsync(File.ReadAllText(env.WebRootPath + "/index.html"));
        }

        await next();
    });

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "api/{controller=Home}/{action=Index}/{id?}");
    });
}

Answer 1

You code is working on my machine with Kestrel. A good troubleshooting step is to find out whether the problem is with your ASP.NET Core application or with your IIS Hosting configuration.

Try this from the root of your project.

dotnet restore
dotnet run

You will see something like this:

Hosting environment: Production
Content root path: C:\MyApplicationPath
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

In your browser go to the following two URLs. If they don't work, then something is wrong with your application. If they do work, something is wrong with your IIS hosting.

localhost:5000        // you will see your index.html page
localhost:5000/api    // you will see your default routes output