CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-3activerecordassociations
Ben
Ben

Reputation: 1368

Prevent Duplicate Associated Record in Rails

I'm working on a simple app where I have this two models:

class Report < ActiveRecord::Base
  attr_accessible :comments, :user_attributes

  belongs_to :user

  accepts_nested_attributes_for :user
end 

class User < ActiveRecord::Base
  attr_accessible :username

  has_many :reports
end

I also have this HAML new report view:

= form_for @report do |f|
  .field
    = f.fields_for :user do |u|
      = u.label :username
      = u.text_field :username
  .field
    = f.label :comments
    = f.text_area :comments

  .action
   = f.submit "Submit report"

The form sends this JSON parameters:

{ user_attributes => { :username => "superuser" }, :comments => "Sample comment 1." }

And the simple report controller handles the creation of the record report and user.

def create
  @report = Report.new(params[:report])
  @report.save
end

This successfully creates a report and a user at the same time. What I need to do is prevent the creation of another User if I submit another report with the same username (superuser). Is there an easy way to do this in Rails model or controller? Thank you.

Upvotes: 1

Views: 1320

Answers (1)

John
John

Reputation: 4382

You can use the reject_if options to reject the user creation

accepts_nested_attributes_for :user, reject_if: Proc.new { |attributes| User.where(username: attributes['username']).first.present? }

I would refactor it to:

accepts_nested_attributes_for :user, reject_if: :user_already_exists?

def user_already_exists?(attributes)
  User.where(username: attributes['username']).first.present?
end

Upvotes: 2

Related Questions