Module: DataMapper::Validations::ValidatesWithMethod

Included in:
ClassMethods
Defined in:
lib/dm-validations/validators/method_validator.rb

Overview

class MethodValidator

Instance Method Summary collapse

Instance Method Details

#validates_with_method(*fields) ⇒ Object

Validate using method called on validated object. The method must to return either true, or a pair of [false, error message string], and is specified as a symbol passed with :method option.

This validator does support multiple fields being specified at a time, but we encourage you to use it with one property/method at a time.

Real world experience shows that method validation is often useful when attribute needs to be virtual and not a property name.

class Page include DataMapper::Resource

property :zip_code, String

validates_with_method :zip_code,
                     :method => :in_the_right_location?

def in_the_right_location?
 if @zip_code == "94301"
   return true
 else
   return [false, "You're in the wrong zip code"]
 end
end

# A call to valid? will return false and
# populate the object's errors with "You're in the
# wrong zip code" unless zip_code == "94301"

end

Examples:

Usage

require 'dm-validations'


59
60
61
 
# File 'lib/dm-validations/validators/method_validator.rb', line 59

def validates_with_method(*fields)
  validators.add(MethodValidator, *fields)
end