ASP.NET core it's possible to configure an action in controller only in development mode?

Question

In my ASP.NET core web application, I want to have an action that runs only in development mode. In production mode, maybe a 404 error will be good enough. Is it possible to do that?

Answer 1

This can be achieved by injecting IHostEnvironment into your controller and using its IsDevelopment() method inside of the action itself. Here's a complete example that returns a 404 when running in anything other than the Development environment:

public class SomeController : Controller
{
    private readonly IHostEnvironment hostEnvironment;

    public SomeController(IHostEnvironment hostEnvironment)
    {
        this.hostEnvironment = hostEnvironment;
    }

    public IActionResult SomeAction()
    {
        if (!hostEnvironment.IsDevelopment())
            return NotFound();

        // Otherwise, return something else for Development.
    }
}

If you want to apply this more globally or perhaps you just want to separate out the concerns, Daboul explains how to do so with an action filter in this answer.

---

For ASP.NET Core < 3.0, use IHostingEnvironment in place of IHostEnvironment.

Answer 2

One nice way to do it is to create a DevOnlyActionFilter filter https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-2.2

The filter would look like that:

public class DevOnlyActionFilter : ActionFilterAttribute
{
    private IHostingEnvironment HostingEnv { get; }
    public DevOnlyActionFilter(IHostingEnvironment hostingEnv)
    {
        HostingEnv = hostingEnv;
    }

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        if(!HostingEnv.IsDevelopment())
        {
            context.Result = new NotFoundResult();
            return;
        }    

        base.OnActionExecuting(context);
    }
}

And to annotate your controller action with [TypeFilter(typeof(DevOnlyActionFilter))]