Pundit- Index Method for Admin and Users

Question

So, I'm trying to use the gem pundit. I'm just trying to figure out how to have an index view for users and admins. I want to render all results for an admin and only related posts for a user. I've googled and searched on github, but I'm not find any luck. What do I have to put in my policy and controller?

original code

class PostsPolicy
   attr_reader :current_user, :model

  def initialize(current_user, model)
    @current_user = current_user
    @post = model
  end

  def index?
    @current_user.admin?
  end
end

controller

class PostsController < ApplicationController
  before_filter :load_user
  before_filter :authenticate_user!
  after_action :verify_authorized

  def index
    @posts = Post.order('title').page(params[:page]).per(25)
    authorize User
  end

private

  def load_user
    @user = User.find_by_id(params[:user_id])
  end

end

second update

class PostsPolicy
 class Scope
  attr_reader :user, :scope

  def initialize(user, scope)
     @user = user
     @scope = scope
  end

  def resolve
    if user.admin?
      scope.all
    else
      scope.where(user: user)
    end
   end

  end

end

controller

class PostsController < ApplicationController
  before_filter :load_user
  before_filter :authenticate_user!
  after_action :verify_authorized

 def index
   @posts = policy_scope(Post).order('title').page(params[:page]).per(25)
   authorize User
 end

private

 def load_user
   @user = User.find_by_id(params[:user_id])
 end
end

third update

class PostPolicy

   class Scope
    attr_reader :user, :scope

      def initialize(user, scope)
         @user = user
         @scope = scope
      end

      def resolve
        if user.admin?
          scope.all
        else
          scope.where(user: user)
        end
      end
   end

  def index?
   user.admin? || user.posts.count > 0
  end
end

controller

class PostsController < ApplicationController
  before_filter :load_user
  before_filter :authenticate_user!
  after_action :verify_authorized

 def index
   @posts = policy_scope(Post).order('title').page(params[:page]).per(25)
   authorize User
 end

private

 def load_user
   @user = User.find_by_id(params[:user_id])
 end

end

** final update with working code **

class PostPolicy
attr_reader :user, :model

def initialize(user, model)
  @user = user
  @post = model
end

   class Scope
    attr_reader :user, :scope

      def initialize(user, scope)
         @user = user
         @scope = scope
      end

      def resolve
        if user.admin?
          scope.all
        else
          scope.where(user: user)
        end
      end
   end

  def index?
   user.admin? || user.posts.count
  end
end

controller

class PostsController < ApplicationController
  before_filter :load_user
  before_filter :authenticate_user!
  after_action :verify_authorized

 def index
   @posts = policy_scope(Post).order('title').page(params[:page]).per(25)
   authorize Post
 end

private

 def load_user
   @user = User.find_by_id(params[:user_id])
 end

end

Answer 1

What you're looking for is a Scope:

class PostsPolicy
  class Scope
    attr_reader :user, :scope

    def initialize(user, scope)
       @user = user
       @scope = scope
    end

    def resolve
      if user.admin?
        scope.all
      else
        scope.where(user: user)
      end
    end
  end
end

Then in your controller

def index
  @posts = policy_scope(Post).order('title').page(params[:page]).per(25)
  authorize User
end

Edit

As a side note, authorize User will probably not serve you well in the long run. You're essentially creating an index policy that would need to serve every index. If you want to to authorize visibility to the index page you can still do something like this in your policy:

def index?
  user.admin? || user.posts.count > 0
end

Assuming that relationship is set up, then you would call authorize Post in your index controller before your policy_scope.