Add Results.Empty

Background and Motivation

Sometimes you want to return a result that does not mutate the response in anyway. This happens when you have multiple branches in a route handle and one of them should be a noop. You are forced to return an IResult and we don’t have a built in result type that fills this role. Mvc has EmptyResult for this purpose.

Proposed API

namespace Microsoft.AspNetCore.Http
{
    public static class Results
    {
        public static IResult Empty(); // This could also be a property
    }
}

Usage Examples

app.MapGet("/{id}", (HttpContext context, string id) =>
{
    var httpProcessor = GetTargetStream(id);
    if (httpProcessor is null) return Results.NotFound();
 
    await httpProcessor.ProcessAsync(context);
     // Don't change what the httpProcessor did
    return Results.Empty();
});

Alternative Designs

Force people to write their own.

Risks

None

[pranavkm]

API review:

We’ll use properties instead. Here’s the approved API:

public static class Results
{
+   public static IResult Empty { get; } = new EmptyResult();
}

public class ControllerBase
{
+    public static EmptyResult Empty { get; } = new ();
}

[davidfowl]

Yep