the best way to implement a friendship model in rails

Question

I want to implement a user\'s friends system in my app so i found the rails space solution very nice, the idea there is to create two lines in the Friends

Answer 1

I would prefer the version that needs two connections between the friends, one for each direction. The reason is the same you mentioned: It allows more Rails-like queries on a user's friends.

Furthermore I think it would be clearer to have different tables for friendship request (one direction) and existing friendships (two directions)

Since you have a friendship model in the middle, I suggest to use the magic of callbacks. If you define some callbacks, it must be possible that you only have to take cake for one side of the connection, the callback should should be able to create (or delete) the matching complement.

# in friendship_requests
after_save :created_friendship

def accept
  update_attributes(:status  => 'accepted')
end

private
  def created_friendship
    sender.friends << receiver  if status_changed? && status == 'accepted'
  end


# in user.rb
has_and_belongs_to_many :friends, after_add:    :create_complement_friendship,
                                  after_remove: :remove_complement_friendship

private
  def create_complement_friendship(friend)
    friend.friends << self  unless friend.friends.include?(self)
  end

  def remove_complement_friendship(friend)
    friend.friends.delete(self)
  end

This is just a first idea, for sure some validators and callbacks are missing...