How to pass arguments from Controller to a Model method in Ruby on Rails?

Question

I am including a custom method for formatting my json data.

My controller looks like this:

("def" is taken out for brevity sake)

respond_to do |format|
  format.json { render json: @user, :methods => [:follower_count(params[:id])] }
end

My model looks like this:

 def follower_count user_id
    User.find(user_id).friendships.count
  end

However, this throws a syntax error, unexpected '('.

I'm not sure how to pass in an argument to the follower_count method in the controller. I tried wrapping in square – didn't work. I tried no brackets – still doesn't work. How do you pass in arguments?!

Answer 1

Syntax error tells you that you're trying to use symbol :follower_count as a function. But the main question is why are you passing user_id to instance method when you already have it available as @id in all instance methods of User class.

Correct code looks something like this:

# controller
format.json { render json: @user, :methods => [:follower_count] }

# User.rb
def follower_count
    friendships.count
end