Rails 4. Country validation in model

Question

I'm creating rails API and want to want to add validation for countries field which contains an ISO 3166-1 code on model level.

For example if use gem carmen-rails, it provides only helper country_select. Is that way to use validation for accordance country for ISO 3166-1 code in the model?

Answer 1

Here is the newest syntax for validation with the countries gem:

validates :country, inclusion: { in: ISO3166::Country.all.map(&:alpha2) }

Answer 2

You are just trying to validate that the country code entered is appropriate? this should work with carmen

validates :country, inclusion: { in: Carmen::Country.all.map(&:code) }

But if this is all you need seems like the countries gem might work well too. With countries you could do

validates :country, inclusion: { in: Country.all.map(&:pop) }

Or

validate :country_is_iso_compliant

def country_is_iso_compliant
  errors.add(:country, "must be 2 characters (ISO 3166-1).") unless Country[country]
end

Update

For Region and State you can validate all 3 at the same time like this.

validates :country, :region, :state, presence: true
validate :location


def location
  current_country = Country[country]
  if current_country
    #valid regions would be something Like "Europe" or "Americas" or "Africa"  etc.
    errors.add(:region, "incorrect region for country #{current_country.name}.") unless current_country.region == region
    #this will work for short codes like "CA" or "01" etc.
    #for named states use current_country.states.map{ |k,v| v["name"}.include?(state)
    #which would work for "California" Or "Lusaka"(it's in Zambia learn something new every day)
    errors.add(:state, "incorrect state for country #{current_country.name}.") unless current_country.states.keys.include?(state)
  else
    errors.add(:country, "must be a 2 character country representation (ISO 3166-1).")
  end
end

Although Region seems unnecessary as you could imply this from the country like

before_validation {|record| record.region = Country[country].region if Country[country]}