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External Validations using only ActiveModel
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require 'delegate' | |
require 'active_model' | |
class DraftPostValidator < SimpleDelegator | |
include ActiveModel::Validations | |
validates :title, :presence => true | |
validate :future_publication_date | |
private | |
def errors | |
__getobj__.errors | |
end | |
def future_publication_date | |
errors.add(:publication_date, "must be in the future") if publication_date && publication_date <= Date.today | |
end | |
end |
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irb(main):063:0> post = Post.new | |
=> #<Post:0x10d196f28 @errors=#<ActiveModel::Errors:0x10d196ed8 @messages=#<OrderedHash {}>, @base=#<Post:0x10d196f28 ...>>> | |
irb(main):064:0> PublishedPostValidator.new(post).valid? | |
=> false | |
irb(main):065:0> post.errors.full_messages | |
=> ["title can't be blank", "author can't be blank"] | |
irb(main):070:0> post.publication_date = Date.yesterday | |
=> Tue, 19 Jun 2012 | |
irb(main):071:0> DraftPostValidator.new(post).valid? | |
=> false | |
irb(main):072:0> post.errors.full_messages | |
=> ["title can't be blank", "publication_date must be in the future"] | |
irb(main):073:0> |
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require 'active_model' | |
# Most of this is the basic boilerplate described in the docs for active_model/errors; ie, the bare minimum | |
# a class must have to use AM::Errors | |
class Post | |
extend ActiveModel::Naming | |
attr_reader :errors | |
attr_accessor :title, :author, :publication_date | |
def initialize | |
@errors = ActiveModel::Errors.new(self) | |
end | |
def read_attribute_for_validation(attr) | |
send(attr) | |
end | |
def self.human_attribute_name(attr, options = {}) | |
attr | |
end | |
def self.lookup_ancestors | |
[self] | |
end | |
en |
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# A Validator for published objects. It may have more stringent validation rules than unpublished posts. | |
require 'delegate' | |
require 'active_model' | |
class PublishedPostValidator < SimpleDelegator | |
include ActiveModel::Validations | |
validates :title, :presence => true | |
validates :author, :presence => true | |
validates :publication_date, :presence => true | |
private | |
def errors | |
__getobj__.errors | |
end | |
end |
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