Question

I’ve got an active record query which is pretty simple

def show
  user = User.find(params[:id])
  render :text => user.to_json(:include=>:classes)
end

However, in my Class model, I have a method

def self.get_avg_prev_score(id)
  return Scores.calc_score(id)
end

I am trying to get the avg_prev_score returned in my JSON hash, but seeing as it isn’t a column in the database, I’m not sure how to do that.

Answer 1

If you’re trying to return an average previous score for each of the classes you’re including, you could do:

def show
  @user = User.find(params[:id])
  render :text => JSON::parse(@user.to_json(:include=>:classes)).merge("avg_prev_scores" => @user.get_avg_prev_scores_for_classes).to_json
end

and then have your other method return a hash of all scores correlated to the class_id:

# User.rb model
def get_avg_prev_scores_for_classes
  average_scores = []
  self.classes.each {|c| average_scores << [c.id, Scores.calc_score(c.id)]}
  return Hash[*average_scores.flatten]
end