Case Insensitive Active Record

active_record_ci_helpers.rb

module ActiveRecordHelpers
  extend ActiveSupport::Concern

  included do
    scope :ci_where, ->(attrs) {
      t = arel_table
      attrs.reduce(self) do |rel, (name, value)|
        rel.where(t[name].matches(value.strip))
      end
    }
  end

  class CiUniquenessValidator < ActiveModel::EachValidator
    def validate_each(record, attribute, value)
      relation = record.class.ci_where(attribute => value)
      relation = relation.where.not(id: record.id) if record.persisted?
      relation = ci_scope.reduce(relation) do |rel, col|
        rel.ci_where(col => record[col])
      end
      relation = scope.reduce(relation) do |rel, col|
        rel.where(col => record[col])
      end

      record.errors.add(attribute, :taken) if relation.exists?
    end

    private

    def scope
      Array.wrap(options[:scope])
    end

    def ci_scope
      Array.wrap(options[:ci_scope])
    end
  end
end