Question

First and foremost, thanks to everyone taking time to read through this post. Many, many thanks in advance.

I’m currently building a small registration system for classes. I’m stopping users from registering twice to the same event through the model with “validates :user_id, :uniqueness => {:scope => :occurrence_id}” in my Registration controller. I want to extend this to my views by greying out a “register” button.

I’m thinking that the best way is by writing a method in the occurrence model that goes something like this:

def already_registered?(user)
  if user.id == self.registrations.find()
    false
  else
    true
  end
end

Now I know for sure that this doesn’t work. How can I search if one occurrence has been has not been register by the current user?

models/registration.rb

class Registration < ActiveRecord::Base

  belongs_to :user
  belongs_to :occurrence

 attr_accessible :occurrence_id, :registration_date, :user_id, :occurrence, :user

 validates :user_id, :uniqueness => {:scope => :occurrence_id}

end

models/occurrence.rb

class Occurrence < ActiveRecord::Base

  belongs_to :course
  belongs_to :location
  has_many :registrations
  has_many :users, :through => :registrations

  validates :price, :presence => true

  attr_accessible :course_id, :datetime_end, :datetime_start, :location_id, :price, :teacher_id, :class_size

  def remaining_seats
    self.class_size - self.registrations.count
  end
end

Answer 1

I’m not sure if I really understand your question, but try with

def already_registered?(ocurrence)
  self.registrations.where(:ocurrence => ocurrence).any?
end

and you call it with

current_user.already_registered?(current_ocurrence)