How to return HTTP 404 - asp.net-core

Question

I am building an asp.net core Web API and I need to be able to hide some of the actions in a controller.
I use the following code to return HTTP 404 (Not Found):
[HttpGet]
public IActionResult Index()
{
if(!_isEnabled)
{
return NotFound();
}
However, in my browser I get this result:
{
"type": "https://tools.ietf.org/html/rfc7231#section-6.5.4",
"title": "Not Found",
"status": 404,
"traceId": "00-502319d62a6027718d2ee2cb3c9f263f-28de7bfdfb48f2d8-00"
}
I need to make the call as if the controller does not exists and the browser shows this:
How can a Controller returns a "real" HTTP 404 experience as if the controller dos not exists at that route?
Update 1
The answers return a JSON data and response code 404.
I am trying to do something different.
I am trying to hide the controller as if it doesn't exist for security reasons. I like the end user browser see above screenshot (Edge in my example)
Update 2
I changed to the following code:
[HttpGet]
[ProducesResponseType(StatusCodes.Status404NotFound)]
[ProducesResponseType(StatusCodes.Status200OK)]
public IActionResult Index()
{
if(!_isEnabled)
{
return StatusCode(StatusCodes.Status404NotFound);
}
and the controller returns the following result:
{"type":"https://tools.ietf.org/html/rfc7231#section-6.5.4","title":"Not Found","status":404,"traceId":"00-3275026575270e11a4b1a5ab0817776a-a4777e626460faeb-00"}
The behavior is strange. Is it a new feature in aspnet code 6 ?
Update 3
Here is my middleware setup in the Program.c. It is plain oob setup:
public static void Main(string[] args)
{
var builder = WebApplication.CreateBuilder(args);
builder.Logging.ClearProviders();
builder.Logging.AddConsole();
builder.Logging.AddAzureWebAppDiagnostics();
// Add services to the container.
builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
.AddMicrosoftIdentityWebApi(builder.Configuration.GetSection("AzureAd"));
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddApplicationInsightsTelemetry();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseAuthentication();
app.UseAuthorization();
app.MapControllers();
app.Run();
}

Answer 1

Solution For Update 1:
Middleware could be your savior here thus can be achived what you are trying to implement.
Controller:
[ProducesResponseType(StatusCodes.Status404NotFound)]
public IActionResult GetById(int id)
{
// return Ok(NotFound());
return StatusCode(StatusCodes.Status404NotFound);
}
Note: You can choose either of the status pattern.
Middleware:
public class CustomResponseMiddleware
{
private readonly RequestDelegate _next;
public CustomResponseMiddleware(RequestDelegate next)
{
_next = next;
}
public async Task InvokeAsync(HttpContext httpContext)
{
if (httpContext.Response.StatusCode == 404)
{
httpContext.Response.Redirect("/WrongControllerName/WrongAction");
}
await _next(httpContext);
}
}
Note: As you can see, we are checking the controller status code and checking if any 404 decteced. Once the desired status code we will redirect a controller which doesn't exist at all that eventually generate the expected output.
Register Middleware In Program.cs:
app.UseMiddleware<CustomResponseMiddleware>();
Output: