Convert User input to integer

Question

So I have a form where users can input a price. I'm trying to make a before_validation that normalizes the data, clipping the $ if the user puts it.

before_validation do
 unless self.price.blank? then self.price= self.price.to_s.gsub(/\D/, '').to_i end
end

If user inputs $50 This code is giving me 0. If user inputs 50$ this code gives me 50. I think since the data type is integer that rails is running .to_i prior to my before_validation and clipping everything after the $. This same code works fine if the data type is a string.

Anyone have a solution that will let me keep the integer datatype?

Ben Lee · Accepted Answer · 2014-05-26 15:40:01Z

22

One way is to override the mechanism on the model that sets the price, like this:

def price=(val)
    write_attribute :price, val.to_s.gsub(/\D/, '').to_i
end

So when you do @model.price = whatever, it will go to this method instead of the rails default attribute writer. Then you can convert the number and use write_attribute to do the actual writing (you have to do it this way because the standard price= is now this method!).

I like this method best, but for reference another way to do it is in your controller before assigning it to the model. The parameter comes in as a string, but the model is converting that string to a number, so work with the parameter directly. Something like this (just adapt it to your controller code):

def create
    @model = Model.new(params[:model])
    @model.price = params[:model][:price].gsub(/\D/, '').to_i
    @model.save
end

For either solution, remove that before_validation.

edited May 26, 2014 at 15:40

answered Mar 13, 2012 at 7:35

Ben Lee

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1 Comment

Damon Aw Over a year ago

Thank you. I always thought using a before_validation is pretty clumsy. This is definitely more elegant.

offbyjuan · Accepted Answer · 2012-03-13 07:52:46Z

4

I would define a virtual attribute and do my manipulation there allowing you to format and modify both the getter and setter at will:

class Model < ActiveRecord::Base

  def foo_price=(price)
    self.price = price... #=> Mods to string here
  end

  def foo_price
    "$#{price}"
  end

You also might want to note that:

"$50.00".gsub(/\D/, '').to_i #=> 5000

answered Mar 13, 2012 at 7:52

offbyjuan

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3 Comments

Robert Over a year ago

Thanks, I'll give this a try too. I gave other answer because I tried out his comment first. Also, thanks for the .00 catch, I'll update my regex.

offbyjuan Over a year ago

Np. I suggested that approach because I am not a fan of additional logic in the controller and there is clarity since you are not overriding a field that at first glance should match the db field and I'm guessing a string is not the correct data type :)

Artur INTECH Over a year ago

I would create additional presenter class for formatting logic here

gilcierweb · Accepted Answer · 2017-10-21 21:14:42Z

My soluction colum price type decimal

t.decimal :price, precision: 12, scale: 6

# app/concern/sanitize_fields.rb
    module SanitizeFields
      extend ActiveSupport::Concern

      def clear_decimal(field)
        return (field.to_s.gsub(/[^\d]/, '').to_d / 100.to_d) unless field.blank?

      end

      def clear_integer(field)
        field.to_s.strip.gsub(/[^\d]/, '') unless field.blank?
      end

      # module ClassMethods
      #   def filter(filtering_params)
      #     results = self.where(nil)
      #     filtering_params.each do |key, value|
      #       results = results.public_send(key, value) if value.present?
      #     end
      #     results
      #   end
      #
      #   #use
      #   #def index
      #   #  @products = Product.filter(params.slice(:status, :location, :starts_with))
      #   #end
      #
      # end

    end

#app/controllers/products_controller.rb

include SanitizeFields

params[:product][:price] = clear_decimal(params[:product][:price])

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