CODEWITHSUNDEEP
ruby-on-railsrubyvalidationactiverecord
jckly
jckly

Reputation: 851

passing two parameters to exist? in rails

I have a friendships model, friendships is a join table that contains a user_id a friend_id and a status (which is a string). In the create method for the friendship I need to do some validation and check that a friendship doesn't exist already between that user and that friend to do this I've called: 

unless userID == friendID or Friendship.exists?(userID, friendID)

However exists? throws this error when create is called: 

ArgumentError (wrong number of arguments (2 for 0..1)):

I can't correctly do the validation without checking the userID and friendID exist in one friendship. My question is is there a better way I can do this not using exists? or is there a way I can pass two parameters to the exists? method in rails.

Thanks for any help or advice.

Upvotes: 0

Views: 1448

Answers (2)

Joe Kennedy
Joe Kennedy

Reputation: 9443

You can use rails validation methods to do this.

class Friendship < ActiveRecord::Base
  # ensure that user/friend combo does not already exist
  validates :user, uniqueness: { scope: friend }

  # ensure that friend != user
  validate :friend_is_not_user

  # other Friendship model code

  def friend_is_not_user
    if self.friend == self.user
      errors.add(:user, 'cannot be friends with his or her self.')
    end
  end
end

Upvotes: 0

matanco
matanco

Reputation: 2129

@userid = any_user_id
@friendid = any_friend_id
(@userid == @friendid || Friendship.where(user_id: @userid,friend_id: @friendid).present?) ? true : false

OR if you want to use exists?:

(@userid == @friendid || Friendship.exists?(user_id: @userid,friend_id: @friendid)) ? true : false

this will do exactly what you need.

Upvotes: 1

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