Updating attributes of one model from a different model's controller - mysql

Question

I have a simple post and user app where users submit and upvote posts. I have two models, post and user, and right now I'm working with the post model to add "upvoting" functionality.
Each post has an :id, :upvote and :users_voted_by attribute.
Each user has a :username, :posts_voted_on and good_karma attribute
When a user clicks the upvote button on a post, I need to make sure the current user isn't in the :users_voted_by column for that post, if not, add 1 to the :upvote attribute of that post. This part is done.
But I also need to add the post :id into the current user's :posts_voted_on field and add 1 to the submitter's :good_karma field.
Post model:
class Post < ActiveRecord::Base
attr_accessible :comment_count, :downvote, :id, :text, :title, :upvote, :url, :user, :users_voted_by
end
User model:
class User < ActiveRecord::Base
attr_accessible :email, :password, :password_confirmation, :username, :posts_voted_on, :good_karma, :bad_karma
attr_accessor :password
before_save :encrypt_password
validates_confirmation_of :password
validates_presence_of :password, :on => :create
validates_presence_of :email
validates_uniqueness_of :email
validates_presence_of :username
validates_uniqueness_of :username
def self.authenticate(email, password)
user = find_by_email(email)
if user && user.password_hash == BCrypt::Engine.hash_secret(password, user.password_salt)
user
else
nil
end
end
def encrypt_password
if password.present?
self.password_salt = BCrypt::Engine.generate_salt
self.password_hash = BCrypt::Engine.hash_secret(password, password_salt)
end
end
end
My upvote method is within posts_controller:
def upvote
#post = Post.find(params[:post_id])
respond_to do |format|
if #post.users_voted_by.index(current_user.username) == nil && #post.update_attributes(:upvote => #post.upvote + 1, :users_voted_by => #post.users_voted_by + ',' + current_user.username)
format.html { redirect_to #post }
format.json { head :no_content }
else
format.html { render action: "edit" }
format.json { render json: #post.errors, status: :unprocessable_entity }
end
end
end
The 5th line is where the magic is. Is makes sure the post I'm voting on doesn't have the current user in the :users_voted_by field. Then it updates the :upvote and :users_voted_by fields.
How can I add to this method (action?) so that it also updates the attributes of the voting user and the post submitter to store the increase in karma.

Answer 1

Guess a service object can help here, something like (not tested)
class Voter
def initialize(post, user)
#post = post
#user = user
end
def upvote
return false unless #post.users_voted_by.index(#user.username)
#post.upvote += 1
#post.users_voted_by = #post.users_voted_by + ',' + #user.username
#user.good_carma += 1
#post.save && #user.save
end
def downvote
...
end
end
Then controller will look like
def upvote
#post = Post.find(params[:post_id])
respond_to do |format|
if Voter.new(#post, current_user).upvote
format.html { redirect_to #post }
format.json { head :no_content }
else
format.html { render action: "edit" }
format.json { render json: #post.errors, status: :unprocessable_entity }
end
end
end