How to route all subdomain on Net core 3.1

Question

I want to use a different controller when users enter a subdomain. I´m using RequireHost .

How can it works this with any domain? For example I'm using domain.test just for development, but in production I have another.

Startup.cs

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Subdomain}/{action=Index}/{id?}").RequireHost("*.domain.test")


    endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Home}/{action=Index}/{id?}");
});

Answer 1

RequireHost is almost the same as adding [Host("...")] attributes everywhere, except that they only apply to that route.

Evaluation of Host rules seems to occur in HostMatcherPolicy . Which should treat "*.domain.test" as matching all subdomains, but not the domain itself. You will need to add "domain.test" if you want that to match too.

However, you do have a second route that can match everything. I suspect you will need to explicitly list the valid hosts for your default route. Or split your controllers into different areas to ensure they only match the expected rule.