comma_as_decimal_separator.rb

# Using comma as decimal separator in Rails 4 based on
# http://stjhimy.com/posts/11-using-comma-as-decimal-separator

ActiveRecord::ConnectionAdapters::Column.class_eval do
  class << self
    def value_to_float(value)
      if value.class == Float 
        value
      elsif value.class == String
        value.gsub(',', '.').to_f
      else
        value.to_f
      end
    end

    def value_to_decimal_with_comma_separator(value)
      if value.class == BigDecimal
        value
      elsif value.class == String
        value.gsub(',', '.').to_d
      elsif value.respond_to?(:to_d)
        value.to_d
      else
        value.to_s.to_d
      end
    end
    alias_method_chain :value_to_decimal, :comma_separator
  end

  def type_cast_with_comma_separator(value)
    return nil if value.nil?
    return coder.load(value) if encoded?

    klass = self.class

    case type
    when :string, :text        then value
    when :integer              then klass.value_to_integer(value)
    when :float                then klass.value to_float(value)
    when :decimal              then klass.value_to_decimal(value)
    when :datetime, :timestamp then klass.string_to_time(value)
    when :time                 then klass.string_to_dummy_time(value)
    when :date                 then klass.value_to_date(value)
    when :binary               then klass.binary_to_string(value)
    when :boolean              then klass.value_to_boolean(value)
    else value
    end
  end

  alias_method_chain :type_cast, :comma_separator
end