Allow anonymous/guest user to “try out” functionality without registering in Rails/Devise/CanCan app

Question

I\'m developing a Rails 3 app using Devise and CanCan.

The app allows anonymous (not registered) users to access some of the app, and registered users to access other par

Answer 1

In Ryan's introduction to CanCan he offers the following suggestion:

Make a New User object in memory for guest users on the site, but don't save it. This way all of your functions that need to associate to a user will still work, but they won't save.

See the railscast here: http://railscasts.com/episodes/192-authorization-with-cancan

Ryan's code example is:

class Ability  
  include CanCan::Ability  

  def initialize(user)  
    user ||= User.new # This initializer is creating your memory-only guest users

    if user.role? :admin  
      can :manage, :all  
    else  
      can :read, :all  
      can :create, Comment  
      can :update, Comment do |comment|  
        comment.try(:user) == user || user.role?(:moderator)  
      end  
      if user.role?(:author)  
        can :create, Article  
        can :update, Article do |article|  
          article.try(:user) == user  
        end  
      end  
    end  
  end  
end

So, in your app if you used this approach, then in your view you could check for current_user.new_record?, and rendering a different "save" button for registered users versus guests.

You could make this pretty simple (avoiding storing this in session etc.) by providing a hidden account signup form on the sequence creation page. Then just make your "save" button for guests reveal the account creation form, and when they submit that form they're submitting a user registration and a sequence creation at the same time.

Then all your Sequences#create action needs to do is something like:

...
current_user.update_attributes(params[:user]) if current_user.new_record?

if current_user.sequences.create(params[:sequence])
   redirect_to ...
else
   render ...
end
...

You'll need to turn that into working code but I'm confident the basic idea would work.

Good luck!

Answer 2

I'm also working on a rails 3 project w/ devise and cancan. My needs are a little different in that I need to persist anonymous users' activity in the db (no need to sweep). Here's what I did to sign in the anonymous user. Hope this helps.

def sign_in_anonymous_user
  unless user_signed_in?
    user = User.new
    role = "anonymous"
    user.confirmed_at = Time.now-1.minute
    user.save :validate => false
    sign_in :user, user
  end
end