Class: Reform::Form::UniqueValidator

Inherits:
ActiveModel::EachValidator
  • Object
show all
Defined in:
lib/reform/form/validation/unique_validator.rb

Overview

Unique Validation

Reform's own implementation for uniqueness which does not write to model

Usage

Pass a true boolean value to validate a field against all values available in the database: validates :title, unique: true

Options

Case Sensitivity

Case sensitivity is true by default, but can be set to false:

validates :title, unique: { case_sensitive: false }

Scope

A scope can be used to filter the records that need to be compare with the current value to validate. A scope array can have one to many fields define.

A scope can be define the following ways: validates :title, unique: { scope: :album_id } validates :title, unique: { scope: [:album_id] } validates :title, unique: { scope: [:album_id, ...] }

All fields included in a scope must be declared as a property like this: property :album_id validates :title, unique: { scope: :album_id }

Just remove write access to the property if the field must not be change: property :album_id, writeable: false validates :title, unique: { scope: :album_id }

This use case is useful if album_id is set to a Song this way: song = album.songs.new album_id is automatically set and can't be change by the operation

Conditions

A condition can be passed to filter the records with partial indexes

Conditions can be define the following ways: validates :title, unique: { conditions: -> { where(archived_at: nil) } }

  • This will check that the title is unique for non archived records validates :title, unique: { conditions: ->(record) { published_at = record.published_at where(published_at: published_at.beginning_of_year..published_at.end_of_year) } }

Instance Method Summary collapse

Instance Method Details

#validate_each(form, attribute, value) ⇒ Object 



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# File 'lib/reform/form/validation/unique_validator.rb', line 52

def validate_each(form, attribute, value)
  model = form.model_for_property(attribute)
  original_attribute = form.options_for(attribute)[:private_name]

  # search for models with attribute equals to form field value
  query = if options[:case_sensitive] == false && value
            model.class.where("lower(#{original_attribute}) = ?", value.downcase)
          else
            model.class.where(original_attribute => value)
          end

  # if model persisted, query should bypass model
  if model.persisted?
    query = query.where("#{model.class.primary_key} != ?", model.id)
  end

  # apply scope if options has been declared
  Array(options[:scope]).each do |field|
    # add condition to only check unique value with the same scope
    query = query.where(field => form.send(field))
  end

  if options[:conditions]
    conditions = options[:conditions]

    query = if conditions.arity.zero?
              query.instance_exec(&conditions)
            else
              query.instance_exec(form, &conditions)
            end
  end

  form.errors.add(attribute, :taken) if query.count > 0
end