Class: ActiveModel::Errors

Inherits:
Object show all
Extended by:
Forwardable
Includes:
Enumerable
Defined in:
activemodel/lib/active_model/errors.rb

Overview

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..

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#compact_blank, #exclude?, #excluding, #including, #index_by, #index_with, #many?, #pick, #pluck, #sum, #without

Constructor Details

#initialize(base) ⇒ Errors

Pass in the instance of the object that is using the errors object.

class Person
  def initialize
    @errors = ActiveModel::Errors.new(self)
  end
end

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# File 'activemodel/lib/active_model/errors.rb', line 85

def initialize(base)
  @base = base
  @errors = []
end

Instance Attribute Details

#errorsObject (readonly) Also known as: objects

The actual array of Error objects This method is aliased to objects.


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# File 'activemodel/lib/active_model/errors.rb', line 75

def errors
  @errors
end

Instance Method Details

#[](attribute) ⇒ Object

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"]

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# File 'activemodel/lib/active_model/errors.rb', line 207

def [](attribute)
  DeprecationHandlingMessageArray.new(messages_for(attribute), self, attribute)
end

#add(attribute, type = :invalid, **options) ⇒ Object

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).

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}]}

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# File 'activemodel/lib/active_model/errors.rb', line 395

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 = {}) ⇒ Boolean

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

Returns:

  • (Boolean)

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# File 'activemodel/lib/active_model/errors.rb', line 425

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) ⇒ Object

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"]}

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# File 'activemodel/lib/active_model/errors.rb', line 310

def as_json(options = nil)
  to_hash(options && options[:full_messages])
end

#attribute_namesObject

Returns all error attribute names

person.errors.messages        # => {:name=>["cannot be nil", "must be specified"]}
person.errors.attribute_names # => [:name]

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# File 'activemodel/lib/active_model/errors.rb', line 284

def attribute_names
  @errors.map(&:attribute).uniq.freeze
end

#copy!(other) ⇒ Object

Copies the errors from other. For copying errors but keep @base as is.

other - The ActiveModel::Errors instance.

Examples

person.errors.copy!(other)

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# File 'activemodel/lib/active_model/errors.rb', line 103

def copy!(other) # :nodoc:
  @errors = other.errors.deep_dup
  @errors.each { |error|
    error.instance_variable_set(:@base, @base)
  }
end

#delete(attribute, type = nil, **options) ⇒ Object

Delete messages for key. Returns the deleted messages.

person.errors[:name]        # => ["cannot be nil"]
person.errors.delete(:name) # => ["cannot be nil"]
person.errors[:name]        # => []

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# File 'activemodel/lib/active_model/errors.rb', line 193

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

#detailsObject


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# File 'activemodel/lib/active_model/errors.rb', line 342

def details
  hash = {}
  group_by_attribute.each do |attribute, errors|
    hash[attribute] = errors.map(&:detail)
  end
  DeprecationHandlingDetailsHash.new(hash)
end

#each(&block) ⇒ Object

Iterates through each error object.

person.errors.add(:name, :too_short, count: 2)
person.errors.each do |error|
  # Will yield <#ActiveModel::Error attribute=name, type=too_short,
                                    options={:count=>3}>
end

To be backward compatible with past deprecated hash-like behavior, when block accepts two parameters instead of one, it iterates through each error key, value pair in the error messages hash. Yields the attribute and the error for that attribute. If the attribute has more than one error message, yields once for each error message.

person.errors.add(:name, :blank, message: "can't be blank")
person.errors.each do |attribute, message|
  # Will yield :name and "can't be blank"
end

person.errors.add(:name, :not_specified, message: "must be specified")
person.errors.each do |attribute, message|
  # Will yield :name and "can't be blank"
  # then yield :name and "must be specified"
end

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# File 'activemodel/lib/active_model/errors.rb', line 235

def each(&block)
  if block.arity <= 1
    @errors.each(&block)
  else
    ActiveSupport::Deprecation.warn(<<~MSG)
      Enumerating ActiveModel::Errors as a hash has been deprecated.
      In Rails 6.1, `errors` is an array of Error objects,
      therefore it should be accessed by a block with a single block
      parameter like this:

      person.errors.each do |error|
        attribute = error.attribute
        message = error.message
      end

      You are passing a block expecting two parameters,
      so the old hash behavior is simulated. As this is deprecated,
      this will result in an ArgumentError in Rails 6.2.
    MSG
    @errors.
      sort { |a, b| a.attribute <=> b.attribute }.
      each { |error| yield error.attribute, error.message }
  end
end

#full_message(attribute, message) ⇒ Object

Returns a full message for a given attribute.

person.errors.full_message(:name, 'is invalid') # => "Name is invalid"

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# File 'activemodel/lib/active_model/errors.rb', line 494

def full_message(attribute, message)
  Error.full_message(attribute, message, @base.class)
end

#full_messagesObject Also known as: to_a

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"]

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# File 'activemodel/lib/active_model/errors.rb', line 468

def full_messages
  @errors.map(&:full_message)
end

#full_messages_for(attribute) ⇒ Object

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"]

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# File 'activemodel/lib/active_model/errors.rb', line 483

def full_messages_for(attribute)
  where(attribute).map(&:full_message).freeze
end

#generate_message(attribute, type = :invalid, options = {}) ⇒ Object

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 the activemodel.errors scope)

  • activemodel.errors.messages.blank

  • errors.attributes.title.blank

  • errors.messages.blank


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# File 'activemodel/lib/active_model/errors.rb', line 522

def generate_message(attribute, type = :invalid, options = {})
  Error.generate_message(attribute, type, @base, options)
end

#group_by_attributeObject


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# File 'activemodel/lib/active_model/errors.rb', line 350

def group_by_attribute
  @errors.group_by(&:attribute)
end

#import(error, override_options = {}) ⇒ Object

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`.

override_options - Hash

Parameters:

  • override_options (Hash) (defaults to: {})

    a customizable set of options

Options Hash (override_options):

  • :attribute (Symbol)

    Override the attribute the error belongs to

  • :type (Symbol)

    Override type of the error.


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# File 'activemodel/lib/active_model/errors.rb', line 118

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) ⇒ Boolean Also known as: has_key?, key?

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

Returns:

  • (Boolean)

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# File 'activemodel/lib/active_model/errors.rb', line 180

def include?(attribute)
  @errors.any? { |error|
    error.match?(attribute.to_sym)
  }
end

#init_with(coder) ⇒ Object

:nodoc:


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# File 'activemodel/lib/active_model/errors.rb', line 533

def init_with(coder) # :nodoc:
  data = coder.map

  data.each { |k, v|
    next if LEGACY_ATTRIBUTES.include?(k.to_sym)
    instance_variable_set(:"@#{k}", v)
  }

  @errors ||= []

  # Legacy support Rails 5.x details hash
  add_from_legacy_details_hash(data["details"]) if data.key?("details")
end

#initialize_dup(other) ⇒ Object

:nodoc:


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# File 'activemodel/lib/active_model/errors.rb', line 90

def initialize_dup(other) # :nodoc:
  @errors = other.errors.deep_dup
  super
end

#keysObject

Returns all message keys.

person.errors.messages # => {:name=>["cannot be nil", "must be specified"]}
person.errors.keys     # => [:name]

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# File 'activemodel/lib/active_model/errors.rb', line 273

def keys
  deprecation_removal_warning(:keys, "errors.attribute_names")
  keys = @errors.map(&:attribute)
  keys.uniq!
  keys.freeze
end

#marshal_load(array) ⇒ Object

:nodoc:


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# File 'activemodel/lib/active_model/errors.rb', line 526

def marshal_load(array) # :nodoc:
  # Rails 5
  @errors = []
  @base = array[0]
  add_from_legacy_details_hash(array[2])
end

#merge!(other) ⇒ Object

Merges the errors from other, each Error wrapped as NestedError.

other - The ActiveModel::Errors instance.

Examples

person.errors.merge!(other)

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# File 'activemodel/lib/active_model/errors.rb', line 135

def merge!(other)
  other.errors.each { |error|
    import(error)
  }
end

#messagesObject


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# File 'activemodel/lib/active_model/errors.rb', line 338

def messages
  DeprecationHandlingMessageHash.new(self)
end

#messages_for(attribute) ⇒ Object


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# File 'activemodel/lib/active_model/errors.rb', line 487

def messages_for(attribute)
  where(attribute).map(&:message)
end

#of_kind?(attribute, type = :invalid) ⇒ Boolean

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

Returns:

  • (Boolean)

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# File 'activemodel/lib/active_model/errors.rb', line 448

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

#slice!(*keys) ⇒ Object

Removes all errors except the given keys. Returns a hash containing the removed errors.

person.errors.keys                  # => [:name, :age, :gender, :city]
person.errors.slice!(:age, :gender) # => { :name=>["cannot be nil"], :city=>["cannot be nil"] }
person.errors.keys                  # => [:age, :gender]

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# File 'activemodel/lib/active_model/errors.rb', line 146

def slice!(*keys)
  deprecation_removal_warning(:slice!)

  keys = keys.map(&:to_sym)

  results = messages.dup.slice!(*keys)

  @errors.keep_if do |error|
    keys.include?(error.attribute)
  end

  results
end

#to_hObject


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# File 'activemodel/lib/active_model/errors.rb', line 328

def to_h
  ActiveSupport::Deprecation.warn(<<~EOM)
    ActiveModel::Errors#to_h is deprecated and will be removed in Rails 6.2.
    Please use `ActiveModel::Errors.to_hash` instead. The values in the hash
    returned by `ActiveModel::Errors.to_hash` is an array of error messages.
  EOM

  to_hash.transform_values { |values| values.last }
end

#to_hash(full_messages = false) ⇒ Object

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"]}

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# File 'activemodel/lib/active_model/errors.rb', line 319

def to_hash(full_messages = false)
  hash = {}
  message_method = full_messages ? :full_message : :message
  group_by_attribute.each do |attribute, errors|
    hash[attribute] = errors.map(&message_method)
  end
  hash
end

#to_xml(options = {}) ⇒ Object

Returns an xml formatted representation of the Errors hash.

person.errors.add(:name, :blank, message: "can't be blank")
person.errors.add(:name, :not_specified, message: "must be specified")
person.errors.to_xml
# =>
#  <?xml version=\"1.0\" encoding=\"UTF-8\"?>
#  <errors>
#    <error>name can't be blank</error>
#    <error>name must be specified</error>
#  </errors>

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# File 'activemodel/lib/active_model/errors.rb', line 299

def to_xml(options = {})
  deprecation_removal_warning(:to_xml)
  to_a.to_xml({ root: "errors", skip_types: true }.merge!(options))
end

#valuesObject

Returns all message values.

person.errors.messages # => {:name=>["cannot be nil", "must be specified"]}
person.errors.values   # => [["cannot be nil", "must be specified"]]

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# File 'activemodel/lib/active_model/errors.rb', line 264

def values
  deprecation_removal_warning(:values, "errors.map { |error| error.message }")
  @errors.map(&:message).freeze
end

#where(attribute, type = nil, **options) ⇒ Object

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

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# File 'activemodel/lib/active_model/errors.rb', line 167

def where(attribute, type = nil, **options)
  attribute, type, options = normalize_arguments(attribute, type, **options)
  @errors.select { |error|
    error.match?(attribute, type, **options)
  }
end