DeviceBridge/Controllers/NotFoundResultFilterAttribute.cs

// Copyright (c) Microsoft Corporation. All rights reserved.

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;

/// <summary>
/// Converts a null return value into a 404.
/// </summary>
public class NotFoundResultFilterAttribute : ResultFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext context)
    {
        if (context.Result is ObjectResult objectResult && objectResult.Value == null)
        {
            context.Result = new NotFoundResult();
        }
    }
}