On create error, should I render `new` or redirect to `new`?

Question

Suppose I have something like this:

def new
  @user = User.new
end
def create
  @user = User.create(params[:user])
  if @user.save
    flash[:notice] = 'User created'
    redirect_to :action => 'list'
  else
    flash[:error] = 'Some error here!'
    render 'new'
  end
end

I think the code is clear.
The problem here is, when the @user object is not saved successfully, should I render new (as above) or should redirect to new?

I know if redirect to new the data input by the user is lost, but if I render new, the URL will be /users/create instead of /users/new (which is ugly!).

Answer 1

You are correct in not using redirect. Redirect is loading an entirely new resource.

render however will keep your session data fresh, and depending on how your form is set up, should repopulate whatever data was inputted.

You mention:

I know if redirect to new the data input by the user is lost, but if I render new, the URL will be /users/create instead of /users/new (which is ugly!).

No, this is not true. If you say render 'new', it will go to the url users/new not create. Create as an action only handles POST requests to your controller, and generally never has a view associated with it. It will instead refer to the new action to handle any errors and displaying of forms.

The create action has this in common with the update action which does the same thing by handling only PUT requests, but refers to the edit action to handle the displaying of views.