Rails How can I restrict the total number of Devise users?

Question

For some reasons, I want to restrict the total number of Devise users, the new user won't save when greater than this number.

But I don't know how to do that, I didn't see any content about it in Devise doc.

Could anyone help me? Thanks.

But can you explain the difference between that two answers? — user3087000, Feb 21 '14 at 14:43
Sure. This is a model validation issue for your Devise users, so placing this logic is the controller does not follow Model-View-Controller. — wurde, Feb 21 '14 at 14:58

score 0 · Answer 1 · edited May 23 '17 at 12:03

0

You could modify the devise registration controller to count the number of users in your db before saving the user or you could add a before create callback in your user model to do the same.

However doing it in the user model will get your user an error that you cannot modify.

If you do it in your custom devise registration controller you could customize the error and how the application handle it.

Customize Devise Controller

edited May 23 '17 at 12:03

Community

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answered Feb 20 '14 at 13:49

Jeremy B

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But how can I see this controller ? – user3087000 Feb 20 '14 at 13:51
You cannot see it. You have to create a new one that will inherit from the devise one and use your custom method. I added a new link to my post that will show you how to customize it – Jeremy B Feb 20 '14 at 13:55
Avoid applying constraints on your models within controllers. – wurde Feb 20 '14 at 16:24

wurde · Accepted Answer · 2014-02-21T17:49:23.643

0

Implementing this within your model is more appropriate then your controller.
Below is an example of this:

class Moderator < ActiveRecord::Base
  before_create :check_moderator_limit

  private
  devise  :database_authenticatable,
          :trackable,
          :validatable,
          :timeoutable,
          :registerable

  def check_moderator_limit
    if Moderator.count > 3
      return false
    end
    true
  end
end

edited Feb 21 '14 at 17:49

answered Feb 20 '14 at 15:38

wurde

2,487
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Yes but can you customize the error displayed to the user when you do that in the model ? – Jeremy B Feb 20 '14 at 16:30
Sure, think of it as a custom validation. – wurde Feb 20 '14 at 16:56
I did not think of that, so yeah you should do it in the model then. – Jeremy B Feb 20 '14 at 17:00
1

Why would you call ".all.lenght" just to get the number ? That is not efficent. Just use Moderator.size or Moderator.count – Dmitri Feb 21 '14 at 17:46

Rails How can I restrict the total number of Devise users?

2 Answers2