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Introduce validates_with to encapsulate attribute validations in a cl…

…ass.

[#2630 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>
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1 parent 7975885 commit 22f339825329e2d4463a4130e9fa68baf9d27eb6 @zilkey zilkey committed with jeremy Aug 9, 2009
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@@ -0,0 +1,5 @@
+*Edge*
+
+* Introduce validates_with to encapsulate attribute validations in a class. #2630 [Jeff Dean]
+
+* Extracted from Active Record and Active Resource.
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@@ -9,4 +9,4 @@ Changes from extracting bits to ActiveModel
klass.add_observer(self)
klass.class_eval 'def after_find() end' unless
klass.respond_to?(:after_find)
- end
+ end
@@ -0,0 +1,64 @@
+module ActiveModel
+ module Validations
+ module ClassMethods
+
+ # Passes the record off to the class or classes specified and allows them to add errors based on more complex conditions.
+ #
+ # class Person < ActiveRecord::Base
+ # validates_with MyValidator
+ # end
+ #
+ # class MyValidator < ActiveRecord::Validator
+ # def validate
+ # if some_complex_logic
+ # record.errors[:base] << "This record is invalid"
+ # end
+ # end
+ #
+ # private
+ # def some_complex_logic
+ # # ...
+ # end
+ # end
+ #
+ # You may also pass it multiple classes, like so:
+ #
+ # class Person < ActiveRecord::Base
+ # validates_with MyValidator, MyOtherValidator, :on => :create
+ # end
+ #
+ # Configuration options:
+ # * <tt>on</tt> - Specifies when this validation is active (<tt>:create</tt> or <tt>:update</tt>
+ # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+ # occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).
+ # The method, proc or string should return or evaluate to a true or false value.
+ # * <tt>unless</tt> - Specifies a method, proc or string to call to determine if the validation should
+ # not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).
+ # The method, proc or string should return or evaluate to a true or false value.
+ #
+ # If you pass any additional configuration options, they will be passed to the class and available as <tt>options</tt>:
+ #
+ # class Person < ActiveRecord::Base
+ # validates_with MyValidator, :my_custom_key => "my custom value"
+ # end
+ #
+ # class MyValidator < ActiveRecord::Validator
+ # def validate
+ # options[:my_custom_key] # => "my custom value"
+ # end
+ # end
+ #
+ def validates_with(*args)
+ configuration = args.extract_options!
+
+ send(validation_method(configuration[:on]), configuration) do |record|
+ args.each do |klass|
+ klass.new(record, configuration.except(:on, :if, :unless)).validate
+ end
+ end
+ end
+ end
+ end
+end
+
+
@@ -0,0 +1,116 @@
+# encoding: utf-8
+require 'cases/helper'
+
+require 'models/topic'
+
+class ValidatesWithTest < ActiveRecord::TestCase
+ include ActiveModel::ValidationsRepairHelper
+
+ repair_validations(Topic)
+
+ ERROR_MESSAGE = "Validation error from validator"
+ OTHER_ERROR_MESSAGE = "Validation error from other validator"
+
+ class ValidatorThatAddsErrors < ActiveRecord::Validator
+ def validate()
+ record.errors[:base] << ERROR_MESSAGE
+ end
+ end
+
+ class OtherValidatorThatAddsErrors < ActiveRecord::Validator
+ def validate()
+ record.errors[:base] << OTHER_ERROR_MESSAGE
+ end
+ end
+
+ class ValidatorThatDoesNotAddErrors < ActiveRecord::Validator
+ def validate()
+ end
+ end
+
+ class ValidatorThatValidatesOptions < ActiveRecord::Validator
+ def validate()
+ if options[:field] == :first_name
+ record.errors[:base] << ERROR_MESSAGE
+ end
+ end
+ end
+
+ test "vaidation with class that adds errors" do
+ Topic.validates_with(ValidatorThatAddsErrors)
+ topic = Topic.new
+ assert !topic.valid?, "A class that adds errors causes the record to be invalid"
+ assert topic.errors[:base].include?(ERROR_MESSAGE)
+ end
+
+ test "with a class that returns valid" do
+ Topic.validates_with(ValidatorThatDoesNotAddErrors)
+ topic = Topic.new
+ assert topic.valid?, "A class that does not add errors does not cause the record to be invalid"
+ end
+
+ test "with a class that adds errors on update and a new record" do
+ Topic.validates_with(ValidatorThatAddsErrors, :on => :update)
+ topic = Topic.new
+ assert topic.valid?, "Validation doesn't run on create if 'on' is set to update"
+ end
+
+ test "with a class that adds errors on create and a new record" do
+ Topic.validates_with(ValidatorThatAddsErrors, :on => :create)
+ topic = Topic.new
+ assert !topic.valid?, "Validation does run on create if 'on' is set to create"
+ assert topic.errors[:base].include?(ERROR_MESSAGE)
+ end
+
+ test "with multiple classes" do
+ Topic.validates_with(ValidatorThatAddsErrors, OtherValidatorThatAddsErrors)
+ topic = Topic.new
+ assert !topic.valid?
+ assert topic.errors[:base].include?(ERROR_MESSAGE)
+ assert topic.errors[:base].include?(OTHER_ERROR_MESSAGE)
+ end
+
+ test "with if statements that return false" do
+ Topic.validates_with(ValidatorThatAddsErrors, :if => "1 == 2")
+ topic = Topic.new
+ assert topic.valid?
+ end
+
+ test "with if statements that return true" do
+ Topic.validates_with(ValidatorThatAddsErrors, :if => "1 == 1")
+ topic = Topic.new
+ assert !topic.valid?
+ assert topic.errors[:base].include?(ERROR_MESSAGE)
+ end
+
+ test "with unless statements that return true" do
+ Topic.validates_with(ValidatorThatAddsErrors, :unless => "1 == 1")
+ topic = Topic.new
+ assert topic.valid?
+ end
+
+ test "with unless statements that returns false" do
+ Topic.validates_with(ValidatorThatAddsErrors, :unless => "1 == 2")
+ topic = Topic.new
+ assert !topic.valid?
+ assert topic.errors[:base].include?(ERROR_MESSAGE)
+ end
+
+ test "passes all non-standard configuration options to the validator class" do
+ topic = Topic.new
+ validator = mock()
+ validator.expects(:new).with(topic, {:foo => :bar}).returns(validator)
+ validator.expects(:validate)
+
+ Topic.validates_with(validator, :if => "1 == 1", :foo => :bar)
+ assert topic.valid?
+ end
+
+ test "validates_with with options" do
+ Topic.validates_with(ValidatorThatValidatesOptions, :field => :first_name)
+ topic = Topic.new
+ assert !topic.valid?
+ assert topic.errors[:base].include?(ERROR_MESSAGE)
+ end
+
+end
@@ -69,6 +69,7 @@ def self.load_all!
autoload :TestCase, 'active_record/test_case'
autoload :Timestamp, 'active_record/timestamp'
autoload :Transactions, 'active_record/transactions'
+ autoload :Validator, 'active_record/validator'
autoload :Validations, 'active_record/validations'
module AttributeMethods
@@ -0,0 +1,68 @@
+module ActiveRecord #:nodoc:
+
+ # A simple base class that can be used along with ActiveRecord::Base.validates_with
+ #
+ # class Person < ActiveRecord::Base
+ # validates_with MyValidator
+ # end
+ #
+ # class MyValidator < ActiveRecord::Validator
+ # def validate
+ # if some_complex_logic
+ # record.errors[:base] = "This record is invalid"
+ # end
+ # end
+ #
+ # private
+ # def some_complex_logic
+ # # ...
+ # end
+ # end
+ #
+ # Any class that inherits from ActiveRecord::Validator will have access to <tt>record</tt>,
+ # which is an instance of the record being validated, and must implement a method called <tt>validate</tt>.
+ #
+ # class Person < ActiveRecord::Base
+ # validates_with MyValidator
+ # end
+ #
+ # class MyValidator < ActiveRecord::Validator
+ # def validate
+ # record # => The person instance being validated
+ # options # => Any non-standard options passed to validates_with
+ # end
+ # end
+ #
+ # To cause a validation error, you must add to the <tt>record<tt>'s errors directly
+ # from within the validators message
+ #
+ # class MyValidator < ActiveRecord::Validator
+ # def validate
+ # record.errors[:base] << "This is some custom error message"
+ # record.errors[:first_name] << "This is some complex validation"
+ # # etc...
+ # end
+ # end
+ #
+ # To add behavior to the initialize method, use the following signature:
+ #
+ # class MyValidator < ActiveRecord::Validator
+ # def initialize(record, options)
+ # super
+ # @my_custom_field = options[:field_name] || :first_name
+ # end
+ # end
+ #
+ class Validator
+ attr_reader :record, :options
+
+ def initialize(record, options)
+ @record = record
+ @options = options
+ end
+
+ def validate
+ raise "You must override this method"
+ end
+ end
+end

3 comments on commit 22f3398

Contributor

adzap replied Aug 10, 2009

This is a great addition, but given it introduces the Validator class could not all ActiveModel validations defined in terms a of validator class? I am thinking of the Merb style of validation.

Where should one install their Validator class(es)?

Contributor

zilkey replied Aug 14, 2009

I alternate between putting validator classes in app/models (for small apps) or in a separate app/validators directory, and adding that directory to the load path in environment.rb.

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