module ActiveRecord module Validations class PresenceValidator < ActiveModel::Validations::PresenceValidator # :nodoc: def validate(record) return unless should_validate?(record) super attributes.each do |attribute| next unless record.class._reflect_on_association(attribute) associated_records = Array.wrap(record.send(attribute)) # Superclass validates presence. Ensure present records aren't about to be destroyed. if associated_records.present? && associated_records.all?(&:marked_for_destruction?) record.errors.add(attribute, :blank, options) end end end end module ClassMethods # Validates that the specified attributes are not blank (as defined by # Object#blank?), and, if the attribute is an association, that the # associated object is not marked for destruction. Happens by default # on save. # # class Person < ActiveRecord::Base # has_one :face # validates_presence_of :face # end # # The face attribute must be in the object and it cannot be blank or marked # for destruction. # # If you want to validate the presence of a boolean field (where the real values # are true and false), you will want to use # validates_inclusion_of :field_name, in: [true, false]. # # This is due to the way Object#blank? handles boolean values: # false.blank? # => true. # # This validator defers to the ActiveModel validation for presence, adding the # check to see that an associated object is not marked for destruction. This # prevents the parent object from validating successfully and saving, which then # deletes the associated object, thus putting the parent object into an invalid # state. # # Configuration options: # * :message - A custom error message (default is: "can't be blank"). # * :on - Specifies the contexts where this validation is active. # Runs in all validation contexts by default (nil). You can pass a symbol # or an array of symbols. (e.g. on: :create or # on: :custom_validation_context or # on: [:create, :custom_validation_context]) # * :if - Specifies a method, proc or string to call to determine if # the validation should occur (e.g. if: :allow_validation, or # if: Proc.new { |user| user.signup_step > 2 }). The method, proc # or string should return or evaluate to a +true+ or +false+ value. # * :unless - Specifies a method, proc or string to call to determine # if the validation should not occur (e.g. unless: :skip_validation, # or unless: Proc.new { |user| user.signup_step <= 2 }). The method, # proc or string should return or evaluate to a +true+ or +false+ value. # * :strict - Specifies whether validation should be strict. # See ActiveModel::Validation#validates! for more information. def validates_presence_of(*attr_names) validates_with PresenceValidator, _merge_attributes(attr_names) end end end end