Limit create action to 1 post per user

Question

I want to make user to have only one matriculation per user. However I get error "undefined method `matriculations' for nil:NilClass". How could I make it work? (I use devise as user auth if its matter).

 def matriculation_limit
  if self.user.matriculations(:reload).count <= 1
    errors.add(:base, "Yuo already have one matriculation form")
  else
    redirect_to new_matriculation_path
  end
 end

Have you built the relationship in the controller using "current_user.matriculations.build" (or something similar)? EDIT in the create action — dodgerogers747, May 08 '13 at 16:10
What this error message is saying is that `self.user` is nil. Figure out why that is, and you are on the road to solving your problem. — Sam Ruby, May 08 '13 at 16:14

Mike Campbell · Answer 1 · 2013-05-09T08:34:00.213

With a has_one association, then the association finder method is singular like @user.matriculation, not @user.matriculations. And there's no point counting them because there will only be one.

Regarding comment:

You don't need to check anywhere how many matriculations the user has, because it's a singular association, so you'll just be updating the association (changing the ID in the foreign key column matriculation_id in the users table)

class User < ActiveRecord::Base
  has_one :matriculation, :class_name => "User", :foreign_key => "matriculation_id"
end

class Matriculation < ActiveRecord::Base
  belongs_to :user
end

# some controller action...
  @user.matriculation = Matriculation.find(params[:matriculation_id]) # or something!

Did try to correct create or update action with no success. I'm getting error "Couldn't find Matriculation without an ID". It returns nil, because can't find ID?! Have little understanding how to show ID! — , May 09 '13 at 15:18

Avdept · Answer 2 · 2013-05-12T11:41:05.253

0

self.user == user_object.user. And seems like you dont have method user for class user. ANd another things, you have has_one, so you have to use self.matriculation

so correct would be

if self.matriculation
    errors.add(:base, "Yuo already have one matriculation form")
  else
    redirect_to new_matriculation_path
  end

edited May 12 '13 at 11:41

answered May 08 '13 at 16:27

Avdept

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`self.matriculation.count` will cause an exception because a Matriculation object will be returned, and that won't have a `count` method. – Mike Campbell May 08 '13 at 18:53

Limit create action to 1 post per user

2 Answers2