Return user to previous page after login (Rails)

Question

On a rails 2.3.8 site I have login links on each page (that takes a user to a separate signin page). After a successful login the user is currently redirected to root. Instead I'd like to redirect to the page they were previously viewing.

I've tried using request.referer:

redirect_back_or_default(request.referer)

Where redirect_back_or_default:

def redirect_back_or_default(default)
    redirect_to(session[:return_to] || default)
    session[:return_to] = nil
end

But that generates an "access denied" error, even though the login is successful.

Answer 1

Before all you must store your url by cookies:

cookies[:return_to_url] = request.url

And then after success logging:

redirect_to cookies[:return_to_url] || root_path
cookies[:return_to_url] = nil

# or even better code in one line:
redirect_to cookies[:return_to_url].delete || root_path

https://api.rubyonrails.org/classes/ActionDispatch/Cookies.html