Active Model Errors
Provides error related functionalities you can include in your object for handling error messages and interacting with Action View helpers.
A minimal implementation could be:
class Person
# Required dependency for ActiveModel::Errors
extend ActiveModel::Naming
def initialize
@errors = ActiveModel::Errors.new(self)
end
attr_accessor :name
attr_reader :errors
def validate!
errors.add(:name, :blank, message: "cannot be nil") if name.nil?
end
# The following methods are needed to be minimally implemented
def read_attribute_for_validation(attr)
send(attr)
end
def self.human_attribute_name(attr, options = {})
attr
end
def self.lookup_ancestors
[self]
end
end
The last three methods are required in your object for Errors
to be able to generate error messages correctly and also handle multiple languages. Of course, if you extend your object with ActiveModel::Translation
you will not need to implement the last two. Likewise, using ActiveModel::Validations
will handle the validation related methods for you.
The above allows you to do:
person = Person.new
person.validate! # => ["cannot be nil"]
person.errors.full_messages # => ["name cannot be nil"]
# etc..
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Attributes
[R] | errors | The actual array of |
[R] | objects | The actual array of |
Class Public methods
new(base) Link
Pass in the instance of the object that is using the errors object.
class Person
def initialize
@errors = ActiveModel::Errors.new(self)
end
end
Instance Public methods
[](attribute) Link
When passed a symbol or a name of a method, returns an array of errors for the method.
person.errors[:name] # => ["cannot be nil"]
person.errors['name'] # => ["cannot be nil"]
add(attribute, type = :invalid, **options) Link
Adds a new error of type
on attribute
. More than one error can be added to the same attribute
. If no type
is supplied, :invalid
is assumed.
person.errors.add(:name)
# Adds <#ActiveModel::Error attribute=name, type=invalid>
person.errors.add(:name, :not_implemented, message: "must be implemented")
# Adds <#ActiveModel::Error attribute=name, type=not_implemented,
options={:message=>"must be implemented"}>
person.errors.messages
# => {:name=>["is invalid", "must be implemented"]}
If type
is a string, it will be used as error message.
If type
is a symbol, it will be translated using the appropriate scope (see generate_message
).
person.errors.add(:name, :blank)
person.errors.messages
# => {:name=>["can't be blank"]}
person.errors.add(:name, :too_long, { count: 25 })
person.errors.messages
# => ["is too long (maximum is 25 characters)"]
If type
is a proc, it will be called, allowing for things like Time.now
to be used within an error.
If the :strict
option is set to true
, it will raise ActiveModel::StrictValidationFailed
instead of adding the error. :strict
option can also be set to any other exception.
person.errors.add(:name, :invalid, strict: true)
# => ActiveModel::StrictValidationFailed: Name is invalid
person.errors.add(:name, :invalid, strict: NameIsInvalid)
# => NameIsInvalid: Name is invalid
person.errors.messages # => {}
attribute
should be set to :base
if the error is not directly associated with a single attribute.
person.errors.add(:base, :name_or_email_blank,
message: "either name or email must be present")
person.errors.messages
# => {:base=>["either name or email must be present"]}
person.errors.details
# => {:base=>[{error: :name_or_email_blank}]}
# File activemodel/lib/active_model/errors.rb, line 317 def add(attribute, type = :invalid, **options) attribute, type, options = normalize_arguments(attribute, type, **options) error = Error.new(@base, attribute, type, **options) if exception = options[:strict] exception = ActiveModel::StrictValidationFailed if exception == true raise exception, error.full_message end @errors.append(error) error end
added?(attribute, type = :invalid, options = {}) Link
Returns true
if an error matches provided attribute
and type
, or false
otherwise. type
is treated the same as for add
.
person.errors.add :name, :blank
person.errors.added? :name, :blank # => true
person.errors.added? :name, "can't be blank" # => true
If the error requires options, then it returns true
with the correct options, or false
with incorrect or missing options.
person.errors.add :name, :too_long, { count: 25 }
person.errors.added? :name, :too_long, count: 25 # => true
person.errors.added? :name, "is too long (maximum is 25 characters)" # => true
person.errors.added? :name, :too_long, count: 24 # => false
person.errors.added? :name, :too_long # => false
person.errors.added? :name, "is too long" # => false
# File activemodel/lib/active_model/errors.rb, line 347 def added?(attribute, type = :invalid, options = {}) attribute, type, options = normalize_arguments(attribute, type, **options) if type.is_a? Symbol @errors.any? { |error| error.strict_match?(attribute, type, **options) } else messages_for(attribute).include?(type) end end
as_json(options = nil) Link
Returns a Hash
that can be used as the JSON representation for this object. You can pass the :full_messages
option. This determines if the json object should contain full messages or not (false by default).
person.errors.as_json # => {:name=>["cannot be nil"]}
person.errors.as_json(full_messages: true) # => {:name=>["name cannot be nil"]}
attribute_names() Link
Returns all error attribute names
person.errors.messages # => {:name=>["cannot be nil", "must be specified"]}
person.errors.attribute_names # => [:name]
delete(attribute, type = nil, **options) Link
Delete messages for key
. Returns the deleted messages.
person.errors[:name] # => ["cannot be nil"]
person.errors.delete(:name) # => ["cannot be nil"]
person.errors[:name] # => []
# File activemodel/lib/active_model/errors.rb, line 190 def delete(attribute, type = nil, **options) attribute, type, options = normalize_arguments(attribute, type, **options) matches = where(attribute, type, **options) matches.each do |error| @errors.delete(error) end matches.map(&:message).presence end
full_message(attribute, message) Link
Returns a full message for a given attribute.
person.errors.full_message(:name, 'is invalid') # => "Name is invalid"
full_messages() Link
Returns all the full error messages in an array.
class Person
validates_presence_of :name, :address, :email
validates_length_of :name, in: 5..30
end
person = Person.create(address: '123 First St.')
person.errors.full_messages
# => ["Name is too short (minimum is 5 characters)", "Name can't be blank", "Email can't be blank"]
full_messages_for(attribute) Link
Returns all the full error messages for a given attribute in an array.
class Person
validates_presence_of :name, :email
validates_length_of :name, in: 5..30
end
person = Person.create()
person.errors.full_messages_for(:name)
# => ["Name is too short (minimum is 5 characters)", "Name can't be blank"]
generate_message(attribute, type = :invalid, options = {}) Link
Translates an error message in its default scope (activemodel.errors.messages
).
Error
messages are first looked up in activemodel.errors.models.MODEL.attributes.ATTRIBUTE.MESSAGE
, if it’s not there, it’s looked up in activemodel.errors.models.MODEL.MESSAGE
and if that is not there also, it returns the translation of the default message (e.g. activemodel.errors.messages.MESSAGE
). The translated model name, translated attribute name, and the value are available for interpolation.
When using inheritance in your models, it will check all the inherited models too, but only if the model itself hasn’t been found. Say you have class Admin < User; end
and you wanted the translation for the :blank
error message for the title
attribute, it looks for these translations:
-
activemodel.errors.models.admin.attributes.title.blank
-
activemodel.errors.models.admin.blank
-
activemodel.errors.models.user.attributes.title.blank
-
activemodel.errors.models.user.blank
-
any default you provided through the
options
hash (in theactivemodel.errors
scope) -
activemodel.errors.messages.blank
-
errors.attributes.title.blank
-
errors.messages.blank
group_by_attribute() Link
import(error, override_options = {}) Link
Imports one error. Imported errors are wrapped as a NestedError
, providing access to original error object. If attribute or type needs to be overridden, use override_options
.
Options
-
:attribute
- Override the attribute the error belongs to. -
:type
- Override type of the error.
# File activemodel/lib/active_model/errors.rb, line 129 def import(error, override_options = {}) [:attribute, :type].each do |key| if override_options.key?(key) override_options[key] = override_options[key].to_sym end end @errors.append(NestedError.new(@base, error, override_options)) end
include?(attribute) Link
Returns true
if the error messages include an error for the given key attribute
, false
otherwise.
person.errors.messages # => {:name=>["cannot be nil"]}
person.errors.include?(:name) # => true
person.errors.include?(:age) # => false
merge!(other) Link
Merges the errors from other
, each Error
wrapped as NestedError
.
Parameters
-
other
- TheActiveModel::Errors
instance.
Examples
person.errors.merge!(other)
messages_for(attribute) Link
Returns all the error messages for a given attribute in an array.
class Person
validates_presence_of :name, :email
validates_length_of :name, in: 5..30
end
person = Person.create()
person.errors.messages_for(:name)
# => ["is too short (minimum is 5 characters)", "can't be blank"]
of_kind?(attribute, type = :invalid) Link
Returns true
if an error on the attribute with the given type is present, or false
otherwise. type
is treated the same as for add
.
person.errors.add :age
person.errors.add :name, :too_long, { count: 25 }
person.errors.of_kind? :age # => true
person.errors.of_kind? :name # => false
person.errors.of_kind? :name, :too_long # => true
person.errors.of_kind? :name, "is too long (maximum is 25 characters)" # => true
person.errors.of_kind? :name, :not_too_long # => false
person.errors.of_kind? :name, "is too long" # => false
to_hash(full_messages = false) Link
Returns a Hash
of attributes with their error messages. If full_messages
is true
, it will contain full messages (see full_message
).
person.errors.to_hash # => {:name=>["cannot be nil"]}
person.errors.to_hash(true) # => {:name=>["name cannot be nil"]}
where(attribute, type = nil, **options) Link
Search for errors matching attribute
, type
, or options
.
Only supplied params will be matched.
person.errors.where(:name) # => all name errors.
person.errors.where(:name, :too_short) # => all name errors being too short
person.errors.where(:name, :too_short, minimum: 2) # => all name errors being too short and minimum is 2