Hiding a div while user is logged in in rails - ruby-on-rails

Question

This is my session's controller code
def create
user = User.authenticate(params[:login], params[:password])
if user
session[:user_id] = user.id
redirect_to_target_or_default root_url, :notice => "Logged in successfully."
else
flash.now[:alert] = "Invalid login or password."
render :action => 'new'
end
end
I need a div id="welcomebuttons" located in layouts/application.html.erb to display when the user is not in session (logged out) but disappear completely and remain hidden when the user is logged in. I tried adding javascript:hideDiv_welcomebuttons() to the if user but of course that didn't work.
Could anyone help?

Answer 1

in application layout
<% if session[:user_id].nil? %>
<div id="welcomebuttons">
</div>
<% end %>

Answer 2

I'm using block helper like this (just added them to your application_helper.rb and you're good to go):
# application_helper.rb
def not_logged_in(&block)
capture(&block) unless session[:user_id]
end
def logged_in(&block)
capture(&block) if session[:user_id]
end
#application.html.erb
<div>I'm visible for everyone</div>
<%= logged_in do %>
<div>I'm only visible if you are logged in</div>
<% end %>
<%= not_logged_in do %>
<div>I'm only visible unless you are logged in</div>
<% end %>

Answer 3

You define a current_user method in the application controller:
def current_user
# Look up the current user based on user_id in the session cookie:
#TIP: The ||= part ensures this helper doesn't hit the database every time a user hits a web page. It will look it up once, then cache it in the #current_user variable.
#This is called memoization and it helps make our app more efficient and scalable.
#current_user ||= User.find(session[:user_id]) if session[:user_id]
end
and then use it as a condition for an if block in your layout:
<% if current_user %>
<div> <%= "Logged in as #{current_user.email}" %> | <%= link_to 'Home', root_path %> | <%= link_to 'Log Out', logout_path, method: :delete %> </div>
<% else %>
<div> <%= link_to 'Home', root_path %> | <%= link_to 'Log In', login_path %> or <%= link_to 'Sign Up', new_user_path %> </div>
<% end %>