Module: CouchFoo::Validations::ClassMethods

Defined in:
lib/couch_foo/validations.rb

Overview

All of the following validations are defined in the class scope of the model that you’re interested in validating. They offer a more declarative way of specifying when the model is valid and when it is not. It is recommended to use these over the low-level calls to validate and validate_on_create when possible.

Constant Summary collapse

DEFAULT_VALIDATION_OPTIONS = 
{
  :on => :save,
  :allow_nil => false,
  :allow_blank => false,
  :message => nil
}.freeze
ALL_RANGE_OPTIONS = 
[ :is, :within, :in, :minimum, :maximum ].freeze
ALL_NUMERICALITY_CHECKS = 
{ :greater_than => '>', :greater_than_or_equal_to => '>=',
:equal_to => '==', :less_than => '<', :less_than_or_equal_to => '<=',
:odd => 'odd?', :even => 'even?' }.freeze

Instance Method Summary collapse

Instance Method Details

#create!(attributes = nil, &block) ⇒ Object

Creates an object just like Base.create but calls save! instead of save so an exception is raised if the record is invalid.



842
843
844
845
846
847
848
849
850
851
 
# File 'lib/couch_foo/validations.rb', line 842

def create!(attributes = nil, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| create!(attr, &block) }
  else
    object = new(attributes)
    yield(object) if block_given?
    object.save!
    object
  end
end

#validates_acceptance_of(*attr_names) ⇒ Object

Encapsulates the pattern of wanting to validate the acceptance of a terms of service check box (or similar agreement). Example:

class Person < CouchFoo::Base
  validates_acceptance_of :terms_of_service
  validates_acceptance_of :eula, :message => "must be abided"
end

If the database property does not exist, the terms_of_service attribute is entirely virtual. This check is performed only if terms_of_service is not nil and by default on save.

Configuration options:

  • :message - A custom error message (default is: “must be accepted”).

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :allow_nil - Skip validation if attribute is nil (default is true).

  • :accept - Specifies value that is considered accepted. The default value is a string “1”, which makes it easy to relate to an HTML checkbox. This should be set to true if you are validating a database property, since the attribute is typecast from “1” to true before validation.

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



435
436
437
438
439
440
441
442
443
444
445
 
# File 'lib/couch_foo/validations.rb', line 435

def validates_acceptance_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:accepted], :on => :save, :allow_nil => true, :accept => "1" }
  configuration.update(attr_names.extract_options!)

  names = attr_names.reject { |name| property_names.include?(name) }
  attr_accessor(*names)

  validates_each(attr_names,configuration) do |record, attr_name, value|
    record.errors.add(attr_name, configuration[:message]) unless value == configuration[:accept]
  end
end

#validates_associated(*attr_names) ⇒ Object

Validates whether the associated object or objects are all valid themselves. Works with any kind of association.

class Book < CouchFoo::Base
  has_many :pages
  belongs_to :library

  validates_associated :pages, :library
end

Warning: If, after the above definition, you then wrote:

class Page < CouchFoo::Base
  belongs_to :book

  validates_associated :book
end

this would specify a circular dependency and cause infinite recursion.

NOTE: This validation will not fail if the association hasn’t been assigned. If you want to ensure that the association is both present and guaranteed to be valid, you also need to use validates_presence_of.

Configuration options:

  • :message - A custom error message (default is: “is invalid”)

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



760
761
762
763
764
765
766
767
768
 
# File 'lib/couch_foo/validations.rb', line 760

def validates_associated(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:invalid], :on => :save }
  configuration.update(attr_names.extract_options!)

  validates_each(attr_names, configuration) do |record, attr_name, value|
    record.errors.add(attr_name, configuration[:message]) unless
      (value.is_a?(Array) ? value : [value]).inject(true) { |v, r| (r.nil? || r.valid?) && v }
  end
end

#validates_confirmation_of(*attr_names) ⇒ Object

Encapsulates the pattern of wanting to validate a password or email address field with a confirmation. Example:

Model:
  class Person < CouchFoo::Base
    validates_confirmation_of :user_name, :password
    validates_confirmation_of :email_address, :message => "should match confirmation"
  end

View:
  <%= password_field "person", "password" %>
  <%= password_field "person", "password_confirmation" %>

The added password_confirmation attribute is virtual; it exists only as an in-memory attribute for validating the password. To achieve this, the validation adds accessors to the model for the confirmation attribute. NOTE: This check is performed only if password_confirmation is not nil, and by default only on save. To require confirmation, make sure to add a presence check for the confirmation attribute:

validates_presence_of :password_confirmation, :if => :password_changed?

Configuration options:

  • :message - A custom error message (default is: “doesn’t match confirmation”).

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



396
397
398
399
400
401
402
403
404
405
 
# File 'lib/couch_foo/validations.rb', line 396

def validates_confirmation_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:confirmation], :on => :save }
  configuration.update(attr_names.extract_options!)

  attr_accessor(*(attr_names.map { |n| "#{n}_confirmation" }))

  validates_each(attr_names, configuration) do |record, attr_name, value|
    record.errors.add(attr_name, configuration[:message]) unless record.send("#{attr_name}_confirmation").nil? or value == record.send("#{attr_name}_confirmation")
  end
end

#validates_each(*attrs) ⇒ Object

Validates each attribute against a block.

class Person < CouchFoo::Base
  validates_each :first_name, :last_name do |record, attr, value|
    record.errors.add attr, 'starts with z.' if value[0] == ?z
  end
end

Options:

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :allow_nil - Skip validation if attribute is nil.

  • :allow_blank - Skip validation if attribute is blank.

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



350
351
352
353
354
355
356
357
358
359
360
361
362
 
# File 'lib/couch_foo/validations.rb', line 350

def validates_each(*attrs)
  options = attrs.extract_options!.symbolize_keys
  attrs   = attrs.flatten

  # Declare the validation.
  send(validation_method(options[:on] || :save), options) do |record|
    attrs.each do |attr|
      value = record.send(attr)
      next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
      yield record, attr, value
    end
  end
end

#validates_exclusion_of(*attr_names) ⇒ Object

Validates that the value of the specified attribute is not in a particular enumerable object.

class Person < CouchFoo::Base
  validates_exclusion_of :username, :in => %w( admin superuser ), :message => "You don't belong here"
  validates_exclusion_of :age, :in => 30..60, :message => "This site is only for under 30 and over 60"
  validates_exclusion_of :format, :in => %w( mov avi ), :message => "extension %s is not allowed"
end

Configuration options:

  • :in - An enumerable object of items that the value shouldn’t be part of.

  • :message - Specifies a custom error message (default is: “is reserved”).

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

Raises:

  • (ArgumentError) 


716
717
718
719
720
721
722
723
724
725
726
727
 
# File 'lib/couch_foo/validations.rb', line 716

def validates_exclusion_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:exclusion], :on => :save }
  configuration.update(attr_names.extract_options!)

  enum = configuration[:in] || configuration[:within]

  raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?("include?")

  validates_each(attr_names, configuration) do |record, attr_name, value|
    record.errors.add(attr_name, configuration[:message] % value) if enum.include?(value)
  end
end

#validates_format_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is of the correct form by matching it against the regular expression provided.

class Person < CouchFoo::Base
  validates_format_of :email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, :on => :create
end

Note: use \A and \Z to match the start and end of the string, ^ and $ match the start/end of a line.

A regular expression must be provided or else an exception will be raised.

Configuration options:

  • :message - A custom error message (default is: “is invalid”).

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :with - The regular expression used to validate the format with (note: must be supplied!).

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

Raises:

  • (ArgumentError) 


654
655
656
657
658
659
660
661
662
663
 
# File 'lib/couch_foo/validations.rb', line 654

def validates_format_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:invalid], :on => :save, :with => nil }
  configuration.update(attr_names.extract_options!)

  raise(ArgumentError, "A regular expression must be supplied as the :with option of the configuration hash") unless configuration[:with].is_a?(Regexp)

  validates_each(attr_names, configuration) do |record, attr_name, value|
    record.errors.add(attr_name, configuration[:message] % value) unless value.to_s =~ configuration[:with]
  end
end

#validates_inclusion_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is available in a particular enumerable object.

class Person < CouchFoo::Base
  validates_inclusion_of :gender, :in => %w( m f ), :message => "woah! what are you then!??!!"
  validates_inclusion_of :age, :in => 0..99
  validates_inclusion_of :format, :in => %w( jpg gif png ), :message => "extension %s is not included in the list"
end

Configuration options:

  • :in - An enumerable object of available items.

  • :message - Specifies a custom error message (default is: “is not included in the list”).

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

Raises:

  • (ArgumentError) 


684
685
686
687
688
689
690
691
692
693
694
695
 
# File 'lib/couch_foo/validations.rb', line 684

def validates_inclusion_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:inclusion], :on => :save }
  configuration.update(attr_names.extract_options!)

  enum = configuration[:in] || configuration[:within]

  raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?("include?")

  validates_each(attr_names, configuration) do |record, attr_name, value|
    record.errors.add(attr_name, configuration[:message] % value) unless enum.include?(value)
  end
end

#validates_length_of(*attrs) ⇒ Object Also known as: validates_size_of

Validates that the specified attribute matches the length restrictions supplied. Only one option can be used at a time:

class Person < CouchFoo::Base
  validates_length_of :first_name, :maximum=>30
  validates_length_of :last_name, :maximum=>30, :message=>"less than %d if you don't mind"
  validates_length_of :fax, :in => 7..32, :allow_nil => true
  validates_length_of :phone, :in => 7..32, :allow_blank => true
  validates_length_of :user_name, :within => 6..20, :too_long => "pick a shorter name", :too_short => "pick a longer name"
  validates_length_of :fav_bra_size, :minimum => 1, :too_short => "please enter at least %d character"
  validates_length_of :smurf_leader, :is => 4, :message => "papa is spelled with %d characters... don't play me."
  validates_length_of :essay, :minimum => 100, :too_short => "Your essay must be at least %d words."), :tokenizer => lambda {|str| str.scan(/\w+/) }
end

Configuration options:

  • :minimum - The minimum size of the attribute.

  • :maximum - The maximum size of the attribute.

  • :is - The exact size of the attribute.

  • :within - A range specifying the minimum and maximum size of the attribute.

  • :in - A synonym(or alias) for :within.

  • :allow_nil - Attribute may be nil; skip validation.

  • :allow_blank - Attribute may be blank; skip validation.

  • :too_long - The error message if the attribute goes over the maximum (default is: “is too long (maximum is %d characters)”).

  • :too_short - The error message if the attribute goes under the minimum (default is: “is too short (min is %d characters)”).

  • :wrong_length - The error message if using the :is method and the attribute is the wrong size (default is: “is the wrong length (should be %d characters)”).

  • :message - The error message to use for a :minimum, :maximum, or :is violation. An alias of the appropriate too_long/too_short/wrong_length message.

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :tokenizer - Specifies how to split up the attribute string. (e.g. :tokenizer => lambda {|str| str.scan(/\w+/)} to count words as in above example.) Defaults to lambda{ |value| value.split(//) } which counts individual characters.



515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
 
# File 'lib/couch_foo/validations.rb', line 515

def validates_length_of(*attrs)
  # Merge given options with defaults.
  options = {
    :too_long     => CouchFoo::Errors.default_error_messages[:too_long],
    :too_short    => CouchFoo::Errors.default_error_messages[:too_short],
    :wrong_length => CouchFoo::Errors.default_error_messages[:wrong_length],
    :tokenizer    => lambda {|value| value.split(//)}
  }.merge(DEFAULT_VALIDATION_OPTIONS)
  options.update(attrs.extract_options!.symbolize_keys)

  # Ensure that one and only one range option is specified.
  range_options = ALL_RANGE_OPTIONS & options.keys
  case range_options.size
    when 0
      raise ArgumentError, 'Range unspecified.  Specify the :within, :maximum, :minimum, or :is option.'
    when 1
      # Valid number of options; do nothing.
    else
      raise ArgumentError, 'Too many range options specified.  Choose only one.'
  end

  # Get range option and value.
  option = range_options.first
  option_value = options[range_options.first]

  case option
    when :within, :in
      raise ArgumentError, ":#{option} must be a Range" unless option_value.is_a?(Range)

      too_short = options[:too_short] % option_value.begin
      too_long  = options[:too_long]  % option_value.end

      validates_each(attrs, options) do |record, attr, value|
        value = options[:tokenizer].call(value) if value.kind_of?(String)
        if value.nil? or value.size < option_value.begin
          record.errors.add(attr, too_short)
        elsif value.size > option_value.end
          record.errors.add(attr, too_long)
        end
      end
    when :is, :minimum, :maximum
      raise ArgumentError, ":#{option} must be a nonnegative Integer" unless option_value.is_a?(Integer) and option_value >= 0

      # Declare different validations per option.
      validity_checks = { :is => "==", :minimum => ">=", :maximum => "<=" }
      message_options = { :is => :wrong_length, :minimum => :too_short, :maximum => :too_long }

      message = (options[:message] || options[message_options[option]]) % option_value

      validates_each(attrs, options) do |record, attr, value|
        value = options[:tokenizer].call(value) if value.kind_of?(String)
        record.errors.add(attr, message) unless !value.nil? and value.size.method(validity_checks[option])[option_value]
      end
  end
end

#validates_numericality_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is numeric by trying to convert it to a float with Kernel.Float (if only_integer is false) or applying it to the regular expression /\A[+\-]?\d+\Z/ (if only_integer is set to true).

class Person < CouchFoo::Base
  validates_numericality_of :value, :on => :create
end

Configuration options:

  • :message - A custom error message (default is: “is not a number”).

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :only_integer - Specifies whether the value has to be an integer, e.g. an integral value (default is false).

  • :allow_nil - Skip validation if attribute is nil (default is false). Notice that for fixnum and float properties empty strings are converted to nil.

  • :greater_than - Specifies the value must be greater than the supplied value.

  • :greater_than_or_equal_to - Specifies the value must be greater than or equal the supplied value.

  • :equal_to - Specifies the value must be equal to the supplied value.

  • :less_than - Specifies the value must be less than the supplied value.

  • :less_than_or_equal_to - Specifies the value must be less than or equal the supplied value.

  • :odd - Specifies the value must be an odd number.

  • :even - Specifies the value must be an even number.

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
 
# File 'lib/couch_foo/validations.rb', line 796

def validates_numericality_of(*attr_names)
  configuration = { :on => :save, :only_integer => false, :allow_nil => false }
  configuration.update(attr_names.extract_options!)


  numericality_options = ALL_NUMERICALITY_CHECKS.keys & configuration.keys

  (numericality_options - [ :odd, :even ]).each do |option|
    raise ArgumentError, ":#{option} must be a number" unless configuration[option].is_a?(Numeric)
  end

  validates_each(attr_names,configuration) do |record, attr_name, value|
    raw_value = record.send("#{attr_name}_before_type_cast") || value

    next if configuration[:allow_nil] and raw_value.nil?

    if configuration[:only_integer]
      unless raw_value.to_s =~ /\A[+-]?\d+\Z/
        record.errors.add(attr_name, configuration[:message] || CouchFoo::Errors.default_error_messages[:not_a_number])
        next
      end
      raw_value = raw_value.to_i
    else
     begin
        raw_value = Kernel.Float(raw_value)
      rescue ArgumentError, TypeError
        record.errors.add(attr_name, configuration[:message] || CouchFoo::Errors.default_error_messages[:not_a_number])
        next
      end
    end

    numericality_options.each do |option|
      case option
        when :odd, :even
          record.errors.add(attr_name, configuration[:message] || CouchFoo::Errors.default_error_messages[option]) unless raw_value.to_i.method(ALL_NUMERICALITY_CHECKS[option])[]
        else
          message = configuration[:message] || CouchFoo::Errors.default_error_messages[option]
          message = message % configuration[option] if configuration[option]
          record.errors.add(attr_name, message) unless raw_value.method(ALL_NUMERICALITY_CHECKS[option])[configuration[option]]
      end
    end
  end
end

#validates_presence_of(*attr_names) ⇒ Object

Validates that the specified attributes are not blank (as defined by Object#blank?). Happens by default on save. Example:

class Person < CouchFoo::Base
  validates_presence_of :first_name
end

The first_name attribute must be in the object and it cannot be blank.

If you want to validate the presence of a boolean field (where the real values are true and false), you will want to use validates_inclusion_of :field_name, :in => [true, false] This is due to the way Object#blank? handles boolean values. false.blank? # => true

Configuration options:

  • message - A custom error message (default is: “can’t be blank”).

  • on - Specifies when this validation is active (default is :save, other options :create, :update).

  • if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



469
470
471
472
473
474
475
476
477
478
 
# File 'lib/couch_foo/validations.rb', line 469

def validates_presence_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:blank], :on => :save }
  configuration.update(attr_names.extract_options!)

  # can't use validates_each here, because it cannot cope with nonexistent attributes,
  # while errors.add_on_empty can
  send(validation_method(configuration[:on]), configuration) do |record|
    record.errors.add_on_blank(attr_names, configuration[:message])
  end
end

#validates_uniqueness_of(*attr_names) ⇒ Object

Validates whether the value of the specified attributes are unique across the system. Useful for making sure that only one user can be named “davidhh”.

class Person < CouchFoo::Base
  validates_uniqueness_of :user_name, :scope => :account_id
end

It can also validate whether the value of the specified attributes are unique based on multiple scope parameters. For example, making sure that a teacher can only be on the schedule once per semester for a particular class.

class TeacherSchedule < CouchFoo::Base
  validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
end

When the record is created, a check is performed to make sure that no record exists in the database with the given value for the specified attribute (that maps to a property). When the record is updated, the same check is made but disregarding the record itself.

Because this check is performed outside the database there is still a chance that duplicate values will be inserted in two parallel transactions. To guarantee against this you should create a unique index on the field. See add_index for more information.

Configuration options:

  • :message - Specifies a custom error message (default is: “has already been taken”).

  • :scope - One or more properties by which to limit the scope of the uniqueness constraint, specified like conditions, eg :scope => => “article”

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.



605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
 
# File 'lib/couch_foo/validations.rb', line 605

def validates_uniqueness_of(*attr_names)
  configuration = { :message => CouchFoo::Errors.default_error_messages[:taken], :case_sensitive => true }
  configuration.update(attr_names.extract_options!)

  validates_each(attr_names,configuration) do |record, attr_name, value|
    # The check for an existing value should be run from a class that
    # isn't abstract. This means working down from the current class
    # (self), to the first non-abstract class. Since classes don't know
    # their subclasses, we have to build the hierarchy between self and
    # the record's class.
    class_hierarchy = [record.class]
    while class_hierarchy.first != self
      class_hierarchy.insert(0, class_hierarchy.first.superclass)
    end

    # Now we can work our way down the tree to the first non-abstract class
    finder_class = class_hierarchy.detect { |klass| !klass.abstract_class? }
    
    scope = {configuration[:scope] => record.send(configuration[:scope])} if configuration[:scope] 
    result = finder_class.find_view(:conditions => {attr_name => value}.merge(scope || {}))
    if !result.empty? && result.first.send(:_id) != record.send(:_id)
      record.errors.add(attr_name, configuration[:message])
    end
  end
end