class ActiveModel::Errors
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..
Attributes
The actual array of Error
objects This method is aliased to objects
.
The actual array of Error
objects This method is aliased to objects
.
Public Class Methods
Source
# File lib/active_model/errors.rb, line 92 def initialize(base) @base = base @errors = [] end
Pass in the instance of the object that is using the errors object.
class Person def initialize @errors = ActiveModel::Errors.new(self) end end
Public Instance Methods
Source
# File lib/active_model/errors.rb, line 204 def [](attribute) messages_for(attribute) end
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"]
Source
# File 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
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}]}
Source
# File 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
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
Source
# File lib/active_model/errors.rb, line 222 def as_json(options = nil) to_hash(options && options[:full_messages]) end
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"]}
Source
# File lib/active_model/errors.rb, line 212 def attribute_names @errors.map(&:attribute).uniq.freeze end
Returns all error attribute names
person.errors.messages # => {:name=>["cannot be nil", "must be specified"]} person.errors.attribute_names # => [:name]
Source
# File 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
Delete messages for key
. Returns the deleted messages.
person.errors[:name] # => ["cannot be nil"] person.errors.delete(:name) # => ["cannot be nil"] person.errors[:name] # => []
Source
# File lib/active_model/errors.rb, line 251 def details hash = group_by_attribute.transform_values do |errors| errors.map(&:details) end hash.default = EMPTY_ARRAY hash.freeze hash end
Returns a Hash of attributes with an array of their error details.
Source
# File lib/active_model/errors.rb, line 426 def full_message(attribute, message) Error.full_message(attribute, message, @base) end
Returns a full message for a given attribute.
person.errors.full_message(:name, 'is invalid') # => "Name is invalid"
Source
# File lib/active_model/errors.rb, line 390 def full_messages @errors.map(&:full_message) end
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"]
Source
# File lib/active_model/errors.rb, line 405 def full_messages_for(attribute) where(attribute).map(&:full_message).freeze end
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"]
Source
# File lib/active_model/errors.rb, line 454 def generate_message(attribute, type = :invalid, options = {}) Error.generate_message(attribute, type, @base, options) end
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
Source
# File lib/active_model/errors.rb, line 264 def group_by_attribute @errors.group_by(&:attribute) end
Returns a Hash of attributes with an array of their Error
objects.
person.errors.group_by_attribute # => {:name=>[<#ActiveModel::Error>, <#ActiveModel::Error>]}
Source
# File 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
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.
Source
# File lib/active_model/errors.rb, line 177 def include?(attribute) @errors.any? { |error| error.match?(attribute.to_sym) } end
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
Source
# File lib/active_model/errors.rb, line 149 def merge!(other) return errors if equal?(other) other.errors.each { |error| import(error) } end
Merges the errors from other
, each Error
wrapped as NestedError
.
Parameters¶ ↑
-
other
- TheActiveModel::Errors
instance.
Examples¶ ↑
person.errors.merge!(other)
Source
# File lib/active_model/errors.rb, line 243 def messages hash = to_hash hash.default = EMPTY_ARRAY hash.freeze hash end
Returns a Hash of attributes with an array of their error messages.
Source
# File lib/active_model/errors.rb, line 419 def messages_for(attribute) where(attribute).map(&:message) end
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"]
Source
# File lib/active_model/errors.rb, line 370 def of_kind?(attribute, type = :invalid) attribute, type = normalize_arguments(attribute, type) if type.is_a? Symbol !where(attribute, type).empty? else messages_for(attribute).include?(type) end end
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
Source
# File lib/active_model/errors.rb, line 231 def to_hash(full_messages = false) message_method = full_messages ? :full_message : :message group_by_attribute.transform_values do |errors| errors.map(&message_method) end end
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"]}
Source
# File lib/active_model/errors.rb, line 164 def where(attribute, type = nil, **options) attribute, type, options = normalize_arguments(attribute, type, **options) @errors.select { |error| error.match?(attribute, type, **options) } end
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
Private Instance Methods
Source
# File lib/active_model/errors.rb, line 465 def normalize_arguments(attribute, type, **options) # Evaluate proc first if type.respond_to?(:call) type = type.call(@base, options) end [attribute.to_sym, type, options] end