Ruby on Rails

On Wed, Feb 1, 2012 at 9:22 AM, sandip ransing <sandip@funonrails.com> wrote:

consider scenario,

User model with name, birth_date fields (here birth_date is not mandatory field)

inside view form birth_date is assigned as '31/31/1985' which is invalid

ideally user object should be invalid and while save raise an error on birth_date field but that's not happening and user object gets saved with birth_date as blank which is completely misleading.

You are probably tripped up by the same unexpected behavior I recently discovered.

At least with Postgresql, if you assign a completely invalid string to a date (or a datetime)
field, it does not  throw an exception but simply sets the value to nil:

> c.birth_date = "2012-01-15"
 => "2012-01-15"
1.9.3-p0 :011 > c.save!
   (0.2ms)  BEGIN
   (0.4ms)  UPDATE "children" SET "birth_date" = '2012-01-15', "updated_at" = '2012-02-01 08:52:13.063755' WHERE "children"."id" = 1
   (8.5ms)  COMMIT
 => true
1.9.3-p0 :012 > c.birth_date = "2012-01-45"
 => "2012-01-45"
1.9.3-p0 :013 > c.save!
   (0.2ms)  BEGIN
   (0.4ms)  UPDATE "children" SET "birth_date" = NULL, "updated_at" = '2012-02-01 08:54:46.965404' WHERE "children"."id" = 1
   (18.8ms)  COMMIT
 => true

I would have expected an exception here as the POLS.

But on 'true' it does raise an exception (I discovered this
because Rails.logger.warning now returns true).

c.birth_date = true
 => true
1.9.3-p0 :015 > c.save!
   (0.2ms)  BEGIN
   (0.4ms)  UPDATE "children" SET "birth_date" = 't', "updated_at" = '2012-02-01 08:56:00.771141' WHERE "children"."id" = 1
PGError: ERROR:  invalid input syntax for type date: "t"
LINE 1: UPDATE "children" SET "birth_date" = 't', "updated_at" = '20...
                                             ^
: UPDATE "children" SET "birth_date" = 't', "updated_at" = '2012-02-01 08:56:00.771141' WHERE "children"."id" = 1
   (0.2ms)  ROLLBACK
ActiveRecord::StatementInvalid: PGError: ERROR:  invalid input syntax for type date: "t"

After debugging found that while assigning attributes birth_date value it gets assigned as blank and as birth_date is optional object gets saved.

class User < ActiveRecord::Base
    def initialize(args={})
    logger.info args[:birth_date] #invalid value comes upto here but vanishes afterwords
         super
  end
end

Any clue how to get validation working properly for not mandatory date fields ??

As for the validation. You could use a regex, as suggested by Neethu, but that has the limitation
that it is hard do calculate that 2012-01-29 is OK en 2013-01-29 is not OK.

Better may be to use a combination of strptime and rescue ArgumentError


1.9.3-p0 :051 > begin
1.9.3-p0 :052 >     Date.strptime("29/02/2012", "%d/%m/%Y")
1.9.3-p0 :053?>   rescue ArgumentError
1.9.3-p0 :054?>   puts "This date is invalid"
1.9.3-p0 :055?>   end
 => Wed, 29 Feb 2012

1.9.3-p0 :056 > begin
1.9.3-p0 :057 >     Date.strptime("2012-31-31", "%Y-%m-%d")
1.9.3-p0 :058?>   rescue ArgumentError
1.9.3-p0 :059?>   puts "This date is invalid"
1.9.3-p0 :060?>   end
This date is invalid
 => nil #This comes from the last line in the rescue block, which is puts here

1.9.3-p0 :061 > begin
1.9.3-p0 :062 >     Date.strptime("10/01/2012", "%d/%m/%Y")
1.9.3-p0 :063?>   rescue ArgumentError
1.9.3-p0 :064?>   puts "This date is invalid"
1.9.3-p0 :065?>   end
 => Tue, 10 Jan 2012  # Correct EU dd/mm/yyyy intepretation

1.9.3-p0 :066 > begin
1.9.3-p0 :067 >     Date.strptime("10/01/2012", "%m/%d/%Y")
1.9.3-p0 :068?>   rescue ArgumentError
1.9.3-p0 :069?>   puts "This date is invalid"
1.9.3-p0 :070?>   end
 => Mon, 01 Oct 2012 # Correct US mm/dd/yyyy interpretation

 HTH,

Peter

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