1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
require "active_support/core_ext/module/anonymous"
module ActiveModel
# == Active Model Validator
#
# A simple base class that can be used along with
# ActiveModel::Validations::ClassMethods.validates_with
#
# class Person
# include ActiveModel::Validations
# validates_with MyValidator
# end
#
# class MyValidator < ActiveModel::Validator
# def validate(record)
# 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 ActiveModel::Validator must implement a method
# called +validate+ which accepts a +record+.
#
# class Person
# include ActiveModel::Validations
# validates_with MyValidator
# end
#
# class MyValidator < ActiveModel::Validator
# def validate(record)
# 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 +record+'s errors directly
# from within the validators message.
#
# class MyValidator < ActiveModel::Validator
# def validate(record)
# record.errors.add :base, "This is some custom error message"
# record.errors.add :first_name, "This is some complex validation"
# # etc...
# end
# end
#
# To add behavior to the initialize method, use the following signature:
#
# class MyValidator < ActiveModel::Validator
# def initialize(options)
# super
# @my_custom_field = options[:field_name] || :first_name
# end
# end
#
# The easiest way to add custom validators for validating individual attributes
# is with the convenient <tt>ActiveModel::EachValidator</tt>.
#
# class TitleValidator < ActiveModel::EachValidator
# def validate_each(record, attribute, value)
# record.errors.add attribute, 'must be Mr., Mrs., or Dr.' unless %w(Mr. Mrs. Dr.).include?(value)
# end
# end
#
# This can now be used in combination with the +validates+ method
# (see <tt>ActiveModel::Validations::ClassMethods.validates</tt> for more on this).
#
# class Person
# include ActiveModel::Validations
# attr_accessor :title
#
# validates :title, :presence => true
# end
#
# Validator may also define a +setup+ instance method which will get called
# with the class that using that validator as its argument. This can be
# useful when there are prerequisites such as an +attr_accessor+ being present.
#
# class MyValidator < ActiveModel::Validator
# def setup(klass)
# klass.send :attr_accessor, :custom_attribute
# end
# end
#
# This setup method is only called when used with validation macros or the
# class level <tt>validates_with</tt> method.
class Validator
attr_reader :options
# Returns the kind of the validator.
#
# PresenceValidator.kind # => :presence
# UniquenessValidator.kind # => :uniqueness
def self.kind
@kind ||= name.split('::').last.underscore.sub(/_validator$/, '').to_sym unless anonymous?
end
# Accepts options that will be made available through the +options+ reader.
def initialize(options)
@options = options.freeze
end
# Return the kind for this validator.
#
# PresenceValidator.new.kind # => :presence
# UniquenessValidator.new.kind # => :uniqueness
def kind
self.class.kind
end
# Override this method in subclasses with validation logic, adding errors
# to the records +errors+ array where necessary.
def validate(record)
raise NotImplementedError, "Subclasses must implement a validate(record) method."
end
end
# +EachValidator+ is a validator which iterates through the attributes given
# in the options hash invoking the <tt>validate_each</tt> method passing in the
# record, attribute and value.
#
# All Active Model validations are built on top of this validator.
class EachValidator < Validator #:nodoc:
attr_reader :attributes
# Returns a new validator instance. All options will be available via the
# +options+ reader, however the <tt>:attributes</tt> option will be removed
# and instead be made available through the +attributes+ reader.
def initialize(options)
@attributes = Array(options.delete(:attributes))
raise ":attributes cannot be blank" if @attributes.empty?
super
check_validity!
end
# Performs validation on the supplied record. By default this will call
# +validates_each+ to determine validity therefore subclasses should
# override +validates_each+ with validation logic.
def validate(record)
attributes.each do |attribute|
value = record.read_attribute_for_validation(attribute)
next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
validate_each(record, attribute, value)
end
end
# Override this method in subclasses with the validation logic, adding
# errors to the records +errors+ array where necessary.
def validate_each(record, attribute, value)
raise NotImplementedError, "Subclasses must implement a validate_each(record, attribute, value) method"
end
# Hook method that gets called by the initializer allowing verification
# that the arguments supplied are valid. You could for example raise an
# +ArgumentError+ when invalid options are supplied.
def check_validity!
end
end
# +BlockValidator+ is a special +EachValidator+ which receives a block on initialization
# and call this block for each attribute being validated. +validates_each+ uses this validator.
class BlockValidator < EachValidator #:nodoc:
def initialize(options, &block)
@block = block
super
end
private
def validate_each(record, attribute, value)
@block.call(record, attribute, value)
end
end
end
|
