discourse/lib/post_action_creator.rb

# creates post actions based on a post and a user
class PostActionCreator

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

  def perform(action)
    guardian.ensure_post_can_act!(@post, action, taken_actions: PostAction.counts_for([@post].compact, @user)[@post.try(:id)])
    PostAction.act(@user, @post, action)
  end

  private

  def guardian
    @guardian ||= Guardian.new(@user)
  end

end