Guarda

Is another authorization gem that was heavily inspired by Pundit.

It assumes you are using Current Attributes to get your currently authenticated user.

Install the gem and add to the application's Gemfile by executing:

bundle add guarda

Include Guarda::Authorization in your application controller:

class ApplicationController < ActionController::Base
  include Guarda::Authorization
end

In the controller:

class PostsController < ApplicationController
  def index
    authorize
  end

  def update
    authorize @post
  end
end

In the view:

<% if policy("posts").index? %>
  <%= link_to "Posts", "#" %>
<% end %>

<% if policy("posts", @post).update? %>
  <%= link_to "Edit Post", "#" %>
<% end %>

With this policy class app/policies/posts_policy.rb:

class PostsPolicy
  def initialize(post = nil)
    @post = post
  end

  def index?
    Current.person.admin?
  end

  def update?
    @post.author == Current.person
  end
end

The gem is available as open source under the terms of the MIT License.