Laravel 5.2 Auth中间件重定向回问题

Question

Goal: When a user tries to access a route only meant for 'logged in users'. I want to redirect the user back from where he came with a basic login modal shown.

My Auth middleware:

public function handle($request, Closure $next, $guard = null)
{
    if (Auth::guard($guard)->guest()) {
        if ($request->ajax() || $request->wantsJson()) {
            return response('Unauthorized.', 401);
        } else {
            return redirect()->back()->with('error_code', 5);
        }
    }
}

On redirect i successfuly managed to open the basic login modal.

Problem: After entering the credentials and hitting login. The user is redirected to homepage and not to the intended route/page.

The logic works fine when i use

public function handle($request, Closure $next, $guard = null)
{
    if (Auth::guard($guard)->guest()) {
       if ($request->ajax() || $request->wantsJson()) {
           return response('Unauthorized.', 401);
       } else {
           return redirect()->guest('/')->with('error_code', 5);
       }
   }
}

But this always redirects to homepage with the modal open. Which is not what i desire.

How can i fix this?

TIA