Question

So, I’m new at this and trying to learn by jumping right in.

I have a slightly odd login in my rails app that works like this:

• Admins generate a code and specify an upper limit
• Users log in by entering this code and some details which are saved

Models:

class Code < ActiveRecord::Base  
  has_many :users, dependent: :destroy
  attr_accessible :code, :maxusers
end

class User < ActiveRecord::Base
  belongs_to :code
  attr_accessible :name, :email, :code_id
end

Users controller:

class UsersController < ApplicationController
  def create
    @user = User.new(params[:user])
    if @user.save
      redirect_to "/welcome"
    end
  end
end

So for example the code is 123456 with a limit of 5

The first 5 users can sign up with their Name, Email and 123456

So the question is: How do I check that the code is valid before saving? It must exist and have less than 5 users already assigned.

It seems really simple but I can’t figure out the syntax, I was playing with a before_filter in the controller or before save in the model but I’m stuck.

Answer 1

before_filter is a bad idea: models have to bothered about their integrity, not controllers.

You can try something like:

# in your respective model

validate :at_least_five_codes

def at_least_five_codes
  errors.add(:base, 'Try another code') unless User.where(code: code).count < 5
end

And you’ll be unable to save your model if current code was used for 5 times.