Question

I am trying to build a soccer game to experiment with ruby. The associations are below:

Match.rb

class Match < ActiveRecord::Base
  belongs_to :home_user, :class_name => 'User', :foreign_key => 'home_user_id'
  belongs_to :away_user, :class_name => 'User', :foreign_key => 'away_user_id'

User.rb

class User < ActiveRecord::Base
  has_many :home_matches, :class_name => 'Match', :foreign_key => 'home_user_id'
  has_many :away_matches, :class_name => 'Match', :foreign_key => 'away_user_id'

My question is how I can assign the home_user and away_user for a match? I thought of an initializing method like:

  def initialize(home_user, away_user)
    @home_user = User.find(1)
    @away_user = User.find(2)
  end

but how to put the code to find the user deciding to match and the user offered to match? I suppose I should define them at the moment the user clicks the “set_match” link and send these user_ids to the method but how? The problem is that ruby is the first OOL I’m learning. I already learned the classes and objects and encapsulation and variables etc.. but need further guidance about methods. Thank you in advance.

Answer 1

I wouldn’t use the initialize method, as when your model subclasses ActiveRecord::Base, it has a good initialize method for setting all the attributes.

However, you can do something like this.

def set_users(home_user, away_user)
  if home_user && away_user
    self.home_user = User.find(home_user)
    self.away_user = User.find(away_user)
    true
  else
    false
  end
end

Then in your controller

def update
  @match = Match.find(params[:id])
  if @match.set_users(params[:home_user_id], params[:away_user_id])
    @match.save
  else
    @match.update_attributes(params[:match])
  end
end

I basically set it up so the update action on the match controller will accept one option to update the user relationships, or just accept the usual hash of update parameters.