Rails Validation numbericality fails on form object - ruby-on-rails

Question

Related/Fixed: Ruby on Rails: Validations on Form Object are not working
I have the below validation..
validates :age, numericality: { greater_than_or_equal_to: 0,
only_integer: true,
:allow_blank => true
}
It is not required, if entered needs to be a number. I have noticed that if someone types in a word instead of a number, the field value changes to 0 after submit and passes validation. I would prefer it to be blank or the entered value.
Update:
Still no solution, but here is more information.
rspec test
it "returns error when age is not a number" do
params[:age] = "string"
profile = Registration::Profile.new(user, params)
expect(profile.valid?).to eql false
expect(profile.errors[:age]).to include("is not a number")
end
Failing Rspec Test:
Registration::Profile Validations when not a number returns error when age is not a number
Failure/Error: expect(profile.errors[:age]).to include("is not a number")
expected [] to include "is not a number"
2.6.5 :011 > p=Registration::Profile.new(User.first,{age:"string"})
2.6.5 :013 > p.profile.attributes_before_type_cast["age"]
=> "string"
2.6.5 :014 > p.age
=> 0
2.6.5 :015 > p.errors[:age]
=> []
2.6.5 :016 > p.valid?
=> true
#Form Object Registration:Profile:
module Registration
class Profile
include ActiveModel::Model
validates :age, numericality: { greater_than_or_equal_to: 0,
only_integer: true,
:allow_blank => true
}
attr_reader :user
delegate :age , :age=, to: :profile
def validate!
raise ArgumentError, "user cant be nil" if #user.blank?
end
def persisted?
false
end
def user
#user ||= User.new
end
def teacher
#teacher ||= user.build_teacher
end
def profile
#profile ||= teacher.build_profile
end
def submit(params)
profile.attributes = params.slice(:age)
if valid?
profile.save!
true
else
false
end
end
def self.model_name
ActiveModel::Name.new(self, nil, "User")
end
def initialize(user=nil, attributes={})
validate!
#user = user
end
end
end
#Profile Model:
class Profile < ApplicationRecord
belongs_to :profileable, polymorphic: true
strip_commas_fields = %i[age]
strip_commas_fields.each do |field|
define_method("#{field}=".intern) do |value|
value = value.gsub(/[\,]/, "") if value.is_a?(String) # remove ,
self[field.intern] = value
end
end
end
The interesting thing is that if move the validation to the profile model and check p.profile.errors, I see the expected result, but not on my form object. I need to keep my validations on my form object.

Answer 1

If the underlying column in the DB is a numeric type, then Rails castes the value. I assume this is done in [ActiveRecord::Type::Integer#cast_value][1]
def cast_value(value)
value.to_i rescue nil
end
Assuming model is a ActiveRecord model where age is a integer column:
irb(main):008:0> model.age = "something"
=> "something"
irb(main):009:0> model.age
=> 0
irb(main):010:0>
This is because submitting a form will always submit key value pairs, where the keys values are strings.
No matter if your DB column is a number, boolean, date, ...
It has nothing to do with the validation itself.
You can access the value before the type cast like so:
irb(main):012:0> model.attributes_before_type_cast["age"]
=> "something"
If your requirements dictate another behaviour you could do something like this:
def age_as_string=(value)
#age_as_string = value
self.age = value
end
def age_as_string
#age_as_string
end
And then use age_as_string in your form (or whatever). You can also add validations for this attribute, e.g.:
validates :age_as_string, format: {with: /\d+/, message: "Only numbers"}
You could also add a custom type:
class StrictIntegerType < ActiveRecord::Type::Integer
def cast(value)
return super(value) if value.kind_of?(Numeric)
return super(value) if value && value.match?(/\d+/)
end
end
And use it in your ActiveRecord class through the "Attributes API":
attribute :age, :strict_integer
This will keep the age attribute nil if the value you are trying to assign is invalid.
ActiveRecord::Type.register(:strict_integer, StrictIntegerType)
[1]: https://github.com/rails/rails/blob/fbe2433be6e052a1acac63c7faf287c52ed3c5ba/activemodel/lib/active_model/type/integer.rb#L34

Answer 2

Why don't you add validations in frontend? You can use <input type="number" /> instead of <input type="text" />, which will only accept number from the user. The way I see you explaining the issue, this is a problem to be resolved in the frontend rather than backend.
You can read more about it here: Number Type Input
Please let me know if this doesn't work for you, I will be glad to help you.