ASP.NET Core route mapping: prefix is ignored

Question

I have a .NET 6 ASP.net Core web application where I want to configure all calls with a particular path prefix to map to a specific controller.

What I want is for all calls that are of the form http://myhost/ipc/some_action to invoke the action some_action of the controller LocalIpcController. Here's how I setup my route in Startup class:

//Configure routing
app.UseEndpoints(endpoints =>
{
    //Local IPC endpoint
    endpoints.MapControllerRoute(
        name: "Ipc",
        pattern: "ipc/{action}",
        defaults: new { controller = "LocalIpc" }
    );
}

However, it is not working. Specifically:

• If I make a call to http://myhost/ipc/some_action I get a 404 error
• If I make a call to http://myhost/some_action it works correctly

So it looks like the /ipc prefix in the path is completely ignored. Why is this happening?

PS: I know I can also use the [Route] attribute on the controller to do this, but I want to why it isn't working via MapControllerRoute() and what I am doing wrong.

Answer 1

I tested it out and it is working for me. Here is the pipeline configuration and the test controller:

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

// Don't forget to use the UseRouting middleware.
app.UseRouting();

app.UseHttpsRedirection();

app.UseAuthorization();

app.UseEndpoints( endpoints => {
    //Local IPC endpoint
    endpoints.MapControllerRoute(
        name: "Ipc",
        pattern: "ipc/{action}",
        defaults: new { controller = "LocalIpc" }
    );
});

Note: do not forget to include the app.UseRouting();

public class LocalIpcController : ControllerBase
{
    public LocalIpcController()
    {
    }

    [HttpGet]
    public IActionResult Get()
    {
        return Content("I'm here.");
    }
}

---

Also I would like to add, that defining the URL routes in endpoints middleware options is not in my opinion the best approach from readability perspective and I would use it only in some edge cases. It is much more clear to specify it in Route attribute (or you can even put it into HTTP method attribute constructor e.g. [HttpGet("ipc/some_action")]).