validates associated with model's error message

Question

I have two model as follows

class User < ActiveRecord::Base
 validates_associated :account
end

class Account < ActiveRecord::Base

  belongs_to :user

  #----------------------------------Validations--Start-------------------------
  validates_length_of :unique_url, :within => 2..30 ,:message => "Should be atleast 3 characters long!"
  validates_uniqueness_of :unique_url ,:message => "Already Taken"
  validates_format_of :unique_url,:with => /^([a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])$/ , :message => " Cannot contain special charaters"
  #----------------------------------Validations--End---------------------------
end

Now when I associate an account to a user it says

"Account is invalid"

Instead I want to get the error message directly from that model. so it should say

"Should be atleast 3 characters long!" or "Already Taken" or " Cannot contain special charaters"

is there a way to do this ?

I don't want to give a generic message like :

validates_associated :account , :message=>"one of the three validations failed"

Answer 1

You can write your own custom validator, based on the code for the built-in validator.

Looking up the source code for validates_associated, we see that it uses the "AssociatedValidator". The source code for that is:

module ActiveRecord
  module Validations
    class AssociatedValidator < ActiveModel::EachValidator
      def validate_each(record, attribute, value)
        if Array.wrap(value).reject {|r| r.marked_for_destruction? || r.valid?}.any?
          record.errors.add(attribute, :invalid, options.merge(:value => value))
        end
      end
    end

    module ClassMethods
      
      def validates_associated(*attr_names)
        validates_with AssociatedValidator, _merge_attributes(attr_names)
      end
    end
  end
end

So you can use this as an example to create a custom validator that bubbles error messages like this (for instance, add this code to an initializer in config/initializers/associated_bubbling_validator.rb):

module ActiveRecord
  module Validations
    class AssociatedBubblingValidator < ActiveModel::EachValidator
      def validate_each(record, attribute, value)
        ((value.kind_of?(Enumerable) || value.kind_of?(ActiveRecord::Relation)) ? value : [value]).each do |v|
          unless v.valid?
            v.errors.full_messages.each do |msg|
              record.errors.add(attribute, msg, options.merge(:value => value))
            end
          end
        end
      end
    end

    module ClassMethods
      def validates_associated_bubbling(*attr_names)
        validates_with AssociatedBubblingValidator, _merge_attributes(attr_names)
      end
    end
  end
end

So you can now validate like so:

class User < ActiveRecord::Base
 validates_associated_bubbling :account
end

Also, be sure to add a validate: false in your has_many association, otherwise, Rails will validate the association by default and you'll end up with two error messages, one given by your new AssociatedBubblingValidator and one generic given by Rails.

Answer 2

May be you can try something as given below

validates_associated :account , :message=> lambda{|class_obj, obj| obj[:value].errors.full_messages.join(",") }

Through obj[:value] you're accessing the validated Account object. So will obj[:value].errors give you errors.

Answer 3

A vanilla solution would be to have a second error's rendering for the associated object:

<%= render :partial => 'shared/errors', :locals => {:instance => @account.owner} %>
<%= render :partial => 'shared/errors', :locals => {:instance => @account} %>

Answer 4

If anyway needs it, the following works on Rails 5.2

#app/validators/with_own_error_messages_validator.rb
class WithOwnErrorMessagesValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    Array(value).each do |v|
      unless v.valid?
        v.errors.full_messages.each do |msg|
          record.errors.add(attribute, msg, options.merge(value: value))
        end
      end
    end
  end
end

#app/models/project.rb
class Project < ApplicationRecord
  validates :attachments, with_own_error_messages: true
  has_many :attachments, as: :attachable, validate: false
end

Note the validate: false on the has_many association. This is necessary since Rails now validates associations by default. Without it, you get the Attachment error message(s) plus a generic Attachments is invalid.

Hope this helps.

Answer 5

I ran into the same issue... I want to validate the associated objects, and have the valid? method return false, but not add a (superfluous) message like 'Account invalid'. I just want the account validation messages to appear next to the account fields.

The only way I found to accomplish this is to override run_validations!, like below. In this example, the association is has_many :contacts:

def run_validations!
  valid = super
  contacts.each do |contact|
    valid = false unless contact.valid?(validation_context)
  end
  valid
end

Don't use valid &&= contacts.all? ... because that will prevent the validation on the contacts if the base class is already invalid, and will stop iteration if one of the contacts fails validation.

Perhaps it's an idea to generalize this into some Concern module, but I needed it only once.

Answer 6

For those still on Rails 2, you can overwrite validates_associated with the following code:

module ActiveRecord::Validations::ClassMethods
  def validates_associated(association, options = {})
    class_eval do
      validates_each(association) do |record, associate_name, value|
        associate = record.send(associate_name)
        if associate && !associate.valid?
          associate.errors.each do |key, value|
            record.errors.add(key, value)
          end
        end
      end
    end
  end
end

Source: http://pivotallabs.com/alias-method-chain-validates-associated-informative-error-message/

Answer 7

To get the error messages for account, you would have to call the errors method on that instance:

@user.account.errors

or

@account = @user.build_account
@account.errors

or in the view:

<%= error_messages_for :account %>

I'm making the assumption that it's a has_one relationship.