Checking for a session

Question

In my Rails app, if the user is trying to create a new account, and already has a session going (i.e. is logged in), I want to display a message that says "It looks like you already have an account".

To do this, I'm trying to check for a current session with the following code:

<% if session[:user_id]? %>
<div id="error_expanation">Seems like you already have an account with us.
  <% link_to "Sign in now", login %></div>
<% end %>

However, this code results in the following error:

compile error
/path/to/app/views/users/_form.html.erb:17: syntax error, unexpected ';'
');@output_buffer.safe_concat('     ...
   ^
/path/to/app/views/users/_form.html.erb:42: syntax error, unexpected kENSURE, expecting $end

I'm pretty sure is the 'session[:user_id]?' that's causing the problem, because if I replace it with something from another if statement, it works.

Any idea on what I need to fix to check for this? Thanks!

Oh, and here's my sessions_controller.rb if it's needed:

class SessionsController < ApplicationController

  def edit
    session[:return_to] = request.referer
  end

  def new
  end

  def create
    if user = User.authenticate(params[:email], params[:password])
      session[:user_id] = user.id
      session[:user_name] = user.name
      redirect_to admin_url
    else
      redirect_to login_url, :alert => "Invalid username / password combination"
    end
  end

  def destroy
    session[:user_id] = nil
    redirect_to admin_url, notice => "You've successfully logged out."
  end  

end

Answer 1

I would suggest changing this line:

<% if session[:user_id]? %>

to

<% if session[:user_id] %>

That should fix the problem. The cleaner solution would be to add a function call to your application controller like this:

class ApplicationController
  def user_is_logged_in?
    !!session[:user_id]
  end
end

Then you could do the following:

<% if user_is_logged_in? %>

Answer 2

I would strongly urge you to use something like Device for login logic, as it'll be more secure than any roll-your-own-code. Then you can do something like: <%= dowhatever if user_signed_in? %>