Class: AccountNameValidator Abstract

Inherits:
ActiveModel::EachValidator
  • Object
show all
Defined in:
lib/account_name_validator.rb

Overview

This class is abstract.

Subclass this validator to perform your specific account name validations.

Generic ‘EachValidator` that validates account names on various communication services such as Skype, Yahoo!, etc. This class provides a simple DSL for describing valid account names on these sites, performing all validation for you.

Subclass this class and use the provided DSL to describe account names on a given site. An example for a fictional service called Talkalot:

““ ruby class TalkalotValidator < AccountNameValidator

min_length 5
max_length 64
valid_chars "A-Z0-9_"

end ““

With your validator defined you can now use it in your Active Record models like any other ‘EachValidator`:

““ ruby

validates :talkalot_id,
          talkalot: true

““

This class automatically handles the following options passed to the ‘validates` method:

| | | |:————-|:——————————–| | ‘:allow_nil` | Allows `nil` values. | | `:message` | Provide a custom error message. |

Error messages generated by this class are stored in the translation table. The localization keys used are generated by the ‘ActiveModel::Errors#generate_message` method (see its documentation for more information). The lastmost element of the localization key is the error message key. The error message key is a combination of a validator subclass’s AccountNameValidator.error_key_prefix and the error key suffix for a given constraint.

By default the error key prefix is the underscored

As an example, for the ‘TalkalotValidator` example above, the error message key used in the event that a two-letter account name is given would be `:talkalot_too_short`. If you wanted to override the prefix, you could do:

““ ruby class TalkalotValidator < AccountNameValidator

error_key_prefix :talky

end ““

In this case the error message key for a two-letter account name would be ‘:talky_too_short`. (You’d do this if Talkalot accounts were called “talkies,” for example.)

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.add_validation(key) {|value| ... } ⇒ Object

Describes a custom restraint on account names.

Parameters:

  • key (Symbol) —

    The error message key suffix to use.

Yields:

  • (value) —

    The custom validation.

Yield Parameters:

  • value (String) —

    The value to validate. This will have been coerced into a ‘String`.

Yield Returns:

  • (true, false) —

    Whether or not the validation succeeded.



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# File 'lib/account_name_validator.rb', line 98

def self.add_validation(key, &block)
  return unless block

  self.validations += [[block, key]]
end

.error_key_prefix ⇒ Symbol .error_key_prefix(value) ⇒ Object

Overloads:

  • .error_key_prefix ⇒ Symbol

    Returns the prefix for error message keys used by this class.

    Returns:

    • (Symbol) —

      The error message key prefix.

  • .error_key_prefix(value) ⇒ Object

    Sets the error message key prefix this class uses.

    Parameters:

    • value (Symbol) —

      The new error message key prefix.



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# File 'lib/account_name_validator.rb', line 84

def self.error_key_prefix(value=nil)
  return @error_key_prefix || to_s.demodulize.sub(/Validator$/, "").underscore.to_sym unless value

  @error_key_prefix = value
end

.first_char(charlist) ⇒ Object

Enforces a valid set of characters for the first character of the account name. Uses the “invalid_first_char” error message key suffix.

Parameters:

  • charlist (String) —

    A set of valid characters, in regex character class format (e.g., “[A-Z0-9_]”).



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# File 'lib/account_name_validator.rb', line 138

def self.first_char(charlist)
  add_validation(:invalid_first_char) { |value| value[0] =~ /\A[#{charlist}]\z/ }
end

.max_length(num) ⇒ Object

Enforces a maximum length on account names. Uses the “too_long” error message key suffix.

Parameters:

  • num (Fixnum) —

    The maximum number of characters.



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# File 'lib/account_name_validator.rb', line 118

def self.max_length(num)
  add_validation(:too_long) { |value| value.length <= num }
end

.min_length(num) ⇒ Object

Enforces a minimum length on account names. Uses the “too_short” error message key suffix.

Parameters:

  • num (Fixnum) —

    The minimum number of characters.



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# File 'lib/account_name_validator.rb', line 109

def self.min_length(num)
  add_validation(:too_short) { |value| value.length >= num }
end

.valid_chars(charlist) ⇒ Object

Enforces a valid set of characters. Uses the “invalid_chars” error message key suffix.

Parameters:

  • charlist (String) —

    A set of valid characters, in regex character class format (e.g., “[A-Z0-9_]”).



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# File 'lib/account_name_validator.rb', line 128

def self.valid_chars(charlist)
  add_validation(:invalid_chars) { |value| value =~ /\A[#{charlist}]+\z/ }
end

Instance Method Details

#validate_each(record, attribute, value) ⇒ Object 



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# File 'lib/account_name_validator.rb', line 68

def validate_each(record, attribute, value)
  return if options[:allow_nil] && value.nil?
  return if options[:allow_blank] && value.blank?
  return unless self.class.validations

  self.class.validations.each { |block, key| record.errors.add(attribute, options[:message] || record.errors.generate_message(attribute, :"#{self.class.error_key_prefix}_#{key}")) unless block[value.to_s] }
end