How to ignore routes in ASP.NET Core?

Question

Previously, one would add something like this to Global.aspx.cs, which is gone in .NET Core:

  routes.IgnoreRoute("{*favicon}", new { favicon = @"(.*/)?favicon.ico(/.*)?" });

Here's what I currently have in my Startup.cs (for .NET Core):

  app.UseDefaultFiles();

  app.UseStaticFiles();

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

      routes.MapSpaFallbackRoute(
          name: "spa-fallback",
          defaults: new { controller = "Home", action = "Index" });
  });

The problem is that in MVC (pre-Core) routes was a RouteCollection and in .NET Core it's a Microsoft.AspNetCore.Routing.IRouteBuilder so IgnoreRoute is not a valid method.

Answer 1

You could write middleware for this.

public void Configure(IApplciationBuilder app) {
    app.UseDefaultFiles();

    // Make sure your middleware is before whatever handles 
    // the resource currently, be it MVC, static resources, etc.
    app.UseMiddleware<IgnoreRouteMiddleware>();

    app.UseStaticFiles();
    app.UseMvc();
}

public class IgnoreRouteMiddleware {

    private readonly RequestDelegate next;

    // You can inject a dependency here that gives you access
    // to your ignored route configuration.
    public IgnoreRouteMiddleware(RequestDelegate next) {
        this.next = next;
    }

    public async Task Invoke(HttpContext context) {
        if (context.Request.Path.HasValue &&
            context.Request.Path.Value.Contains("favicon.ico")) {

            context.Response.StatusCode = 404;

            Console.WriteLine("Ignored!");

            return;
        }

        await next.Invoke(context);
    }
}