The GoingPostal mixin provides classes with postcode formatting and validation methods. It does not provide external verification methods such as checking for the existence of a postcode against the UK PAF database.

$ gem install going_postal

GoingPostal can be used as a mixin:

class Address
  include GoingPostal
  attr_accessor :number, :street, :city, :postcode, :country_code

  def initialize(number, street, :city, postcode, country_code="GB")
    self.number = number
    self.street = street
    self.city = city
    self.postcode = postcode
    self.country_code = country_code
  end

  def postcode=(value)
    @postcode = format_postcode(value)
  end

  def valid?
    number && street && city && postcode_valid?
  end
end

or as a namespaced collection of methods:

GoingPostal.postcode?("sl41eg", "GB")      #=> "SL4 1EG"
GoingPostal.postcode?("200378001", "US")   #=> "20037-8001"

The methods available are #postcode? for checking validity, and format_postcode which returns a formatted postcode. Both take arguments of a string, the postcode, and a two letter country code. If the class has a #country_code method, the country_code argument on the provided methods becomes optional. If the class also has one of #postcode, #post_code, #zipcode, #zip_code, or #zip, the string argument on the provided methods becomes optional.

postcode? is aliased as post_code?, zip?, zipcode?, zip_code?, valid_postcode?, valid_post_code?, valid_zip?, valid_zipcode?, valid_zip_code?, postcode_valid?, post_code_valid?, zip_valid?, zipcode_valid? and zip_code_valid? The alias valid? is also available directly on the GoingPostal module.

format_postcode is aliased as format_post_code, format_zip, format_zipcode, and format_zip_code.

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