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rails提供的validators
Returns true
if attribute
is an attribute method, false
otherwise.
class Person include ActiveModel::Validations attr_accessor :name end User.attribute_method?(:name) # => true User.attribute_method?(:age) # => false
Source: show | on GitHub
Clears all of the validators and validations.
Note that this will clear anything that is being used to validate the model for both the validates_with
and validate
methods. It clears the validators that are created with an invocation of validates_with
and the callbacks that are set by an invocation of validate
.
class Person include ActiveModel::Validations validates_with MyValidator validates_with OtherValidator, on: :create validates_with StrictValidator, strict: true validate :cannot_be_robot def cannot_be_robot errors.add(:base, ‘A person cannot be a robot‘) if person_is_robot end end Person.validators # => [ # #<MyValidator:0x007fbff403e808 @options={}>, # #<OtherValidator:0x007fbff403d930 @options={on: :create}>, # #<StrictValidator:0x007fbff3204a30 @options={strict:true}> # ]
If one runs Person.clear_validators! and then checks to see what validators this class has, you would obtain:
Person.validators # => []
Also, the callback set by +validate :cannot_be_robot+ will be erased so that:
Person._validate_callbacks.empty? # => true
Source: show | on GitHub
Adds a validation method or block to the class. This is useful when overriding the validate
instance method becomes too unwieldy and you’re looking for more descriptive declaration of your validations.
This can be done with a symbol pointing to a method:
class Comment include ActiveModel::Validations validate :must_be_friends def must_be_friends errors.add(:base, ‘Must be friends to leave a comment‘) unless commenter.friend_of?(commentee) end end
With a block which is passed with the current record to be validated:
class Comment include ActiveModel::Validations validate do |comment| comment.must_be_friends end def must_be_friends errors.add(:base, ‘Must be friends to leave a comment‘) unless commenter.friend_of?(commentee) end end
Or with a block where self points to the current record to be validated:
class Comment include ActiveModel::Validations validate do errors.add(:base, ‘Must be friends to leave a comment‘) unless commenter.friend_of?(commentee) end end
Options:
-
:on
- Specifies the context where this validation is active (e.g.on: :create
oron: :custom_validation_context
) -
:allow_nil
- Skip validation if attribute isnil
. -
: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
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value.
Source: show | on GitHub
This method is a shortcut to all default validators and any custom validator classes ending in ‘Validator’. Note that Rails default validators can be overridden inside specific classes by creating custom validator classes in their place such as PresenceValidator.
Examples of using the default rails validators:
validates :terms, acceptance: true validates :password, confirmation: true validates :username, exclusion: { in: %w(admin superuser) } validates :email, format: { with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, on: :create } validates :age, inclusion: { in: 0..9 } validates :first_name, length: { maximum: 30 } validates :age, numericality: true validates :username, presence: true validates :username, uniqueness: true
The power of the validates
method comes when using custom validators and default validators in one call for a given attribute.
class EmailValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) record.errors.add attribute, (options[:message] || "is not an email") unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/ end end class Person include ActiveModel::Validations attr_accessor :name, :email validates :name, presence: true, uniqueness: true, length: { maximum: 100 } validates :email, presence: true, email: true end
Validator classes may also exist within the class being validated allowing custom modules of validators to be included as needed.
class Film include ActiveModel::Validations class TitleValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) record.errors.add attribute, "must start with ‘the‘" unless value =~ /\Athe/ end end validates :name, title: true end
Additionally validator classes may be in another namespace and still used within any class.
validates :name, :‘film/title‘ => true
The validators hash can also handle regular expressions, ranges, arrays and strings in shortcut form.
validates :email, format: /@/ validates :gender, inclusion: %w(male female) validates :password, length: 6..20
When using shortcut form, ranges and arrays are passed to your validator’s initializer as options[:in]
while other types including regular expressions and strings are passed as options[:with]
.
There is also a list of options that could be used along with validators:
-
:on
- Specifies when this validation is active. Runs in all validation contexts by default (nil
), other options are:create
and:update
. -
:if
- Specifies a method, proc or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:strict
- if the:strict
option is set to true will raise ActiveModel::StrictValidationFailed instead of adding the error.:strict
option can also be set to any other exception.
Example:
validates :password, presence: true, confirmation: true, if: :password_required? validates :token, uniqueness: true, strict: TokenGenerationException
Finally, the options :if
, :unless
, :on
, :allow_blank
, :allow_nil
, :strict
and :message
can be given to one specific validator, as a hash:
validates :password, presence: { if: :password_required?, message: ‘is forgotten.‘ }, confirmation: true
Source: show | on GitHub
This method is used to define validations that cannot be corrected by end users and are considered exceptional. So each validator defined with bang or :strict
option set to true
will always raiseActiveModel::StrictValidationFailed
instead of adding error when validation fails. See validates
for more information about the validation itself.
class Person include ActiveModel::Validations attr_accessor :name validates! :name, presence: true end person = Person.new person.name = ‘‘ person.valid? # => ActiveModel::StrictValidationFailed: Name can‘t be blank
Source: show | on GitHub
Validates each attribute against a block.
class Person include ActiveModel::Validations attr_accessor :first_name, :last_name validates_each :first_name, :last_name, allow_blank: true do |record, attr, value| record.errors.add attr, ‘starts with z.‘ if value.to_s[0] == z end end
Options:
-
:on
- Specifies the context where this validation is active (e.g.on: :create
oron: :custom_validation_context
) -
:allow_nil
- Skip validation if attribute isnil
. -
: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
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value.
Source: show | on GitHub
Passes the record off to the class or classes specified and allows them to add errors based on more complex conditions.
class Person include ActiveModel::Validations validates_with MyValidator end class MyValidator < ActiveModel::Validator def validate(record) if some_complex_logic record.errors.add :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 include ActiveModel::Validations validates_with MyValidator, MyOtherValidator, on: :create end
Configuration options:
-
:on
- Specifies when this validation is active (:create
or:update
. -
:if
- Specifies a method, proc or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:strict
- Specifies whether validation should be strict. SeeActiveModel::Validation#validates!
for more information.
If you pass any additional configuration options, they will be passed to the class and available as options
:
class Person include ActiveModel::Validations validates_with MyValidator, my_custom_key: ‘my custom value‘ end class MyValidator < ActiveModel::Validator def validate(record) options[:my_custom_key] # => "my custom value" end end
Source: show | on GitHub
List all validators that are being used to validate the model using validates_with
method.
class Person include ActiveModel::Validations validates_with MyValidator validates_with OtherValidator, on: :create validates_with StrictValidator, strict: true end Person.validators # => [ # #<MyValidator:0x007fbff403e808 @options={}>, # #<OtherValidator:0x007fbff403d930 @options={on: :create}>, # #<StrictValidator:0x007fbff3204a30 @options={strict:true}> # ]
Source: show | on GitHub
List all validators that are being used to validate a specific attribute.
class Person include ActiveModel::Validations attr_accessor :name , :age validates_presence_of :name validates_inclusion_of :age, in: 0..99 end Person.validators_on(:name) # => [ # #<ActiveModel::Validations::PresenceValidator:0x007fe604914e60 @attributes=[:name], @options={}>, # #<ActiveModel::Validations::InclusionValidator:0x007fe603bb8780 @attributes=[:age], @options={in:0..99}> # ]
Returns true
if attribute
is an attribute method, false
otherwise.
class Person include ActiveModel::Validations attr_accessor :name end User.attribute_method?(:name) # => true User.attribute_method?(:age) # => false
Source: show | on GitHub
Clears all of the validators and validations.
Note that this will clear anything that is being used to validate the model for both the validates_with
and validate
methods. It clears the validators that are created with an invocation of validates_with
and the callbacks that are set by an invocation of validate
.
class Person include ActiveModel::Validations validates_with MyValidator validates_with OtherValidator, on: :create validates_with StrictValidator, strict: true validate :cannot_be_robot def cannot_be_robot errors.add(:base, ‘A person cannot be a robot‘) if person_is_robot end end Person.validators # => [ # #<MyValidator:0x007fbff403e808 @options={}>, # #<OtherValidator:0x007fbff403d930 @options={on: :create}>, # #<StrictValidator:0x007fbff3204a30 @options={strict:true}> # ]
If one runs Person.clear_validators! and then checks to see what validators this class has, you would obtain:
Person.validators # => []
Also, the callback set by +validate :cannot_be_robot+ will be erased so that:
Person._validate_callbacks.empty? # => true
Source: show | on GitHub
Adds a validation method or block to the class. This is useful when overriding the validate
instance method becomes too unwieldy and you’re looking for more descriptive declaration of your validations.
This can be done with a symbol pointing to a method:
class Comment include ActiveModel::Validations validate :must_be_friends def must_be_friends errors.add(:base, ‘Must be friends to leave a comment‘) unless commenter.friend_of?(commentee) end end
With a block which is passed with the current record to be validated:
class Comment include ActiveModel::Validations validate do |comment| comment.must_be_friends end def must_be_friends errors.add(:base, ‘Must be friends to leave a comment‘) unless commenter.friend_of?(commentee) end end
Or with a block where self points to the current record to be validated:
class Comment include ActiveModel::Validations validate do errors.add(:base, ‘Must be friends to leave a comment‘) unless commenter.friend_of?(commentee) end end
Options:
-
:on
- Specifies the context where this validation is active (e.g.on: :create
oron: :custom_validation_context
) -
:allow_nil
- Skip validation if attribute isnil
. -
: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
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value.
Source: show | on GitHub
This method is a shortcut to all default validators and any custom validator classes ending in ‘Validator’. Note that Rails default validators can be overridden inside specific classes by creating custom validator classes in their place such as PresenceValidator.
Examples of using the default rails validators:
validates :terms, acceptance: true validates :password, confirmation: true validates :username, exclusion: { in: %w(admin superuser) } validates :email, format: { with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, on: :create } validates :age, inclusion: { in: 0..9 } validates :first_name, length: { maximum: 30 } validates :age, numericality: true validates :username, presence: true validates :username, uniqueness: true
The power of the validates
method comes when using custom validators and default validators in one call for a given attribute.
class EmailValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) record.errors.add attribute, (options[:message] || "is not an email") unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/ end end class Person include ActiveModel::Validations attr_accessor :name, :email validates :name, presence: true, uniqueness: true, length: { maximum: 100 } validates :email, presence: true, email: true end
Validator classes may also exist within the class being validated allowing custom modules of validators to be included as needed.
class Film include ActiveModel::Validations class TitleValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) record.errors.add attribute, "must start with ‘the‘" unless value =~ /\Athe/ end end validates :name, title: true end
Additionally validator classes may be in another namespace and still used within any class.
validates :name, :‘film/title‘ => true
The validators hash can also handle regular expressions, ranges, arrays and strings in shortcut form.
validates :email, format: /@/ validates :gender, inclusion: %w(male female) validates :password, length: 6..20
When using shortcut form, ranges and arrays are passed to your validator’s initializer as options[:in]
while other types including regular expressions and strings are passed as options[:with]
.
There is also a list of options that could be used along with validators:
-
:on
- Specifies when this validation is active. Runs in all validation contexts by default (nil
), other options are:create
and:update
. -
:if
- Specifies a method, proc or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:strict
- if the:strict
option is set to true will raise ActiveModel::StrictValidationFailed instead of adding the error.:strict
option can also be set to any other exception.
Example:
validates :password, presence: true, confirmation: true, if: :password_required? validates :token, uniqueness: true, strict: TokenGenerationException
Finally, the options :if
, :unless
, :on
, :allow_blank
, :allow_nil
, :strict
and :message
can be given to one specific validator, as a hash:
validates :password, presence: { if: :password_required?, message: ‘is forgotten.‘ }, confirmation: true
Source: show | on GitHub
This method is used to define validations that cannot be corrected by end users and are considered exceptional. So each validator defined with bang or :strict
option set to true
will always raiseActiveModel::StrictValidationFailed
instead of adding error when validation fails. See validates
for more information about the validation itself.
class Person include ActiveModel::Validations attr_accessor :name validates! :name, presence: true end person = Person.new person.name = ‘‘ person.valid? # => ActiveModel::StrictValidationFailed: Name can‘t be blank
Source: show | on GitHub
Validates each attribute against a block.
class Person include ActiveModel::Validations attr_accessor :first_name, :last_name validates_each :first_name, :last_name, allow_blank: true do |record, attr, value| record.errors.add attr, ‘starts with z.‘ if value.to_s[0] == z end end
Options:
-
:on
- Specifies the context where this validation is active (e.g.on: :create
oron: :custom_validation_context
) -
:allow_nil
- Skip validation if attribute isnil
. -
: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
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value.
Source: show | on GitHub
Passes the record off to the class or classes specified and allows them to add errors based on more complex conditions.
class Person include ActiveModel::Validations validates_with MyValidator end class MyValidator < ActiveModel::Validator def validate(record) if some_complex_logic record.errors.add :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 include ActiveModel::Validations validates_with MyValidator, MyOtherValidator, on: :create end
Configuration options:
-
:on
- Specifies when this validation is active (:create
or:update
. -
:if
- Specifies a method, proc or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:strict
- Specifies whether validation should be strict. SeeActiveModel::Validation#validates!
for more information.
If you pass any additional configuration options, they will be passed to the class and available as options
:
class Person include ActiveModel::Validations validates_with MyValidator, my_custom_key: ‘my custom value‘ end class MyValidator < ActiveModel::Validator def validate(record) options[:my_custom_key] # => "my custom value" end end
Source: show | on GitHub
List all validators that are being used to validate the model using validates_with
method.
class Person include ActiveModel::Validations validates_with MyValidator validates_with OtherValidator, on: :create validates_with StrictValidator, strict: true end Person.validators # => [ # #<MyValidator:0x007fbff403e808 @options={}>, # #<OtherValidator:0x007fbff403d930 @options={on: :create}>, # #<StrictValidator:0x007fbff3204a30 @options={strict:true}> # ]
Source: show | on GitHub
List all validators that are being used to validate a specific attribute.
class Person include ActiveModel::Validations attr_accessor :name , :age validates_presence_of :name validates_inclusion_of :age, in: 0..99 end Person.validators_on(:name) # => [ # #<ActiveModel::Validations::PresenceValidator:0x007fe604914e60 @attributes=[:name], @options={}>, # #<ActiveModel::Validations::InclusionValidator:0x007fe603bb8780 @attributes=[:age], @options={in:0..99}> # ]
rails提供的validators