Class: ActiveModel::Errors

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

Overview

Active Model Errors

Provides a modified Hash that 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..

Constant Summary collapse

CALLBACKS_OPTIONS =
[:if, :unless, :on, :allow_nil, :allow_blank, :strict]
MESSAGE_OPTIONS =
[:message]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#exclude?, #index_by, #many?, #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 72

def initialize(base)
  @base     = base
  @messages = apply_default_array({})
  @details = apply_default_array({})
end

Instance Attribute Details

#detailsObject (readonly)

Returns the value of attribute details


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# File 'activemodel/lib/active_model/errors.rb', line 63

def details
  @details
end

#messagesObject (readonly)

Returns the value of attribute messages


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# File 'activemodel/lib/active_model/errors.rb', line 63

def messages
  @messages
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"]

Note that, if you try to get errors of an attribute which has no errors associated with it, this method will instantiate an empty error list for it and keys will return an array of error keys which includes this attribute.

person.errors.keys    # => []
person.errors[:name]  # => []
person.errors.keys    # => [:name]

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# File 'activemodel/lib/active_model/errors.rb', line 172

def [](attribute)
  messages[attribute.to_sym]
end

#[]=(attribute, error) ⇒ Object

Adds to the supplied attribute the supplied error message.

person.errors[:name] = "must be set"
person.errors[:name] # => ['must be set']

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

def []=(attribute, error)
  ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
    ActiveModel::Errors#[]= is deprecated and will be removed in Rails 5.1.

    Use model.errors.add(:#{attribute}, #{error.inspect}) instead.
  MESSAGE

  messages[attribute.to_sym] << error
end

#add(attribute, message = :invalid, options = {}) ⇒ Object

Adds message to the error messages and used validator type to details on attribute. More than one error can be added to the same attribute. If no message is supplied, :invalid is assumed.

person.errors.add(:name)
# => ["is invalid"]
person.errors.add(:name, :not_implemented, message: "must be implemented")
# => ["is invalid", "must be implemented"]

person.errors.messages
# => {:name=>["is invalid", "must be implemented"]}

person.errors.details
# => {:name=>[{error: :not_implemented}, {error: :invalid}]}

If message is a symbol, it will be translated using the appropriate scope (see generate_message).

If message 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 328

def add(attribute, message = :invalid, options = {})
  message = message.call if message.respond_to?(:call)
  detail  = normalize_detail(message, options)
  message = normalize_message(attribute, message, options)
  if exception = options[:strict]
    exception = ActiveModel::StrictValidationFailed if exception == true
    raise exception, full_message(attribute, message)
  end

  details[attribute.to_sym]  << detail
  messages[attribute.to_sym] << message
end

#add_on_blank(attributes, options = {}) ⇒ Object

Will add an error message to each of the attributes in attributes that is blank (using Object#blank?).

person.errors.add_on_blank(:name)
person.errors.messages
# => {:name=>["can't be blank"]}

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# File 'activemodel/lib/active_model/errors.rb', line 369

def add_on_blank(attributes, options = {})
  ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
    ActiveModel::Errors#add_on_blank is deprecated and will be removed in Rails 5.1.

    To achieve the same use:

      errors.add(attribute, :empty, options) if value.blank?
  MESSAGE

  Array(attributes).each do |attribute|
    value = @base.send(:read_attribute_for_validation, attribute)
    add(attribute, :blank, options) if value.blank?
  end
end

#add_on_empty(attributes, options = {}) ⇒ Object

Will add an error message to each of the attributes in attributes that is empty.

person.errors.add_on_empty(:name)
person.errors.messages
# => {:name=>["can't be empty"]}

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# File 'activemodel/lib/active_model/errors.rb', line 347

def add_on_empty(attributes, options = {})
  ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
    ActiveModel::Errors#add_on_empty is deprecated and will be removed in Rails 5.1.

    To achieve the same use:

      errors.add(attribute, :empty, options) if value.nil? || value.empty?
  MESSAGE

  Array(attributes).each do |attribute|
    value = @base.send(:read_attribute_for_validation, attribute)
    is_empty = value.respond_to?(:empty?) ? value.empty? : false
    add(attribute, :empty, options) if value.nil? || is_empty
  end
end

#added?(attribute, message = :invalid, options = {}) ⇒ Boolean

Returns true if an error on the attribute with the given message is present, or false otherwise. message 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 message requires an option, then it returns true with the correct option, or false with an incorrect or missing option.

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 400

def added?(attribute, message = :invalid, options = {})
  message = message.call if message.respond_to?(:call)
  message = normalize_message(attribute, message, options)
  self[attribute].include? message
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 268

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

#clearObject

Clear the error messages.

person.errors.full_messages # => ["name cannot be nil"]
person.errors.clear
person.errors.full_messages # => []

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# File 'activemodel/lib/active_model/errors.rb', line 101

def clear
  messages.clear
  details.clear
end

#copy!(other) ⇒ Object

Copies the errors from other.

other - The ActiveModel::Errors instance.

Examples

person.errors.copy!(other)

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# File 'activemodel/lib/active_model/errors.rb', line 91

def copy!(other) # :nodoc:
  @messages = other.messages.dup
  @details  = other.details.dup
end

#delete(key) ⇒ 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 153

def delete(key)
  details.delete(key)
  messages.delete(key)
end

#eachObject

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, error|
  # Will yield :name and "can't be blank"
end

person.errors.add(:name, :not_specified, message: "must be specified")
person.errors.each do |attribute, error|
  # 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 204

def each
  messages.each_key do |attribute|
    messages[attribute].each { |error| yield attribute, error }
  end
end

#empty?Boolean Also known as: blank?

Returns true if no errors are found, false otherwise. If the error message is a string it can be empty.

person.errors.full_messages # => ["name cannot be nil"]
person.errors.empty?        # => false

Returns:

  • (Boolean)

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# File 'activemodel/lib/active_model/errors.rb', line 242

def empty?
  size.zero?
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 438

def full_message(attribute, message)
  return message if attribute == :base
  attr_name = attribute.to_s.tr('.', '_').humanize
  attr_name = @base.class.human_attribute_name(attribute, default: attr_name)
  I18n.t(:"errors.format", {
    default:  "%{attribute} %{message}",
    attribute: attr_name,
    message:   message
  })
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 416

def full_messages
  map { |attribute, message| full_message(attribute, 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 431

def full_messages_for(attribute)
  messages[attribute].map { |message| full_message(attribute, message) }
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 473

def generate_message(attribute, type = :invalid, options = {})
  type = options.delete(:message) if options[:message].is_a?(Symbol)

  if @base.class.respond_to?(:i18n_scope)
    defaults = @base.class.lookup_ancestors.map do |klass|
      [ :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.attributes.#{attribute}.#{type}",
        :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.#{type}" ]
    end
  else
    defaults = []
  end

  defaults << :"#{@base.class.i18n_scope}.errors.messages.#{type}" if @base.class.respond_to?(:i18n_scope)
  defaults << :"errors.attributes.#{attribute}.#{type}"
  defaults << :"errors.messages.#{type}"

  defaults.compact!
  defaults.flatten!

  key = defaults.shift
  defaults = options.delete(:message) if options[:message]
  value = (attribute != :base ? @base.send(:read_attribute_for_validation, attribute) : nil)

  options = {
    default: defaults,
    model: @base.model_name.human,
    attribute: @base.class.human_attribute_name(attribute),
    value: value,
    object: @base
  }.merge!(options)

  I18n.translate(key, options)
end

#get(key) ⇒ Object

Get messages for key.

person.errors.messages   # => {:name=>["cannot be nil"]}
person.errors.get(:name) # => ["cannot be nil"]
person.errors.get(:age)  # => []

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# File 'activemodel/lib/active_model/errors.rb', line 123

def get(key)
  ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
    ActiveModel::Errors#get is deprecated and will be removed in Rails 5.1.

    To achieve the same use model.errors[:#{key}].
  MESSAGE

  messages[key]
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 112

def include?(attribute)
  messages.key?(attribute) && messages[attribute].present?
end

#initialize_dup(other) ⇒ Object

:nodoc:


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# File 'activemodel/lib/active_model/errors.rb', line 78

def initialize_dup(other) # :nodoc:
  @messages = other.messages.dup
  @details  = other.details.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 233

def keys
  messages.keys
end

#marshal_dumpObject


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# File 'activemodel/lib/active_model/errors.rb', line 507

def marshal_dump
  [@base, without_default_proc(@messages), without_default_proc(@details)]
end

#marshal_load(array) ⇒ Object


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# File 'activemodel/lib/active_model/errors.rb', line 511

def marshal_load(array)
  @base, @messages, @details = array
  apply_default_array(@messages)
  apply_default_array(@details)
end

#set(key, value) ⇒ Object

Set messages for key to value.

person.errors[:name] # => ["cannot be nil"]
person.errors.set(:name, ["can't be nil"])
person.errors[:name] # => ["can't be nil"]

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# File 'activemodel/lib/active_model/errors.rb', line 138

def set(key, value)
  ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
    ActiveModel::Errors#set is deprecated and will be removed in Rails 5.1.

    Use model.errors.add(:#{key}, #{value.inspect}) instead.
  MESSAGE

  messages[key] = value
end

#sizeObject Also known as: count

Returns the number of error messages.

person.errors.add(:name, :blank, message: "can't be blank")
person.errors.size # => 1
person.errors.add(:name, :not_specified, message: "must be specified")
person.errors.size # => 2

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# File 'activemodel/lib/active_model/errors.rb', line 216

def size
  values.flatten.size
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 277

def to_hash(full_messages = false)
  if full_messages
    self.messages.each_with_object({}) do |(attribute, array), messages|
      messages[attribute] = array.map { |message| full_message(attribute, message) }
    end
  else
    without_default_proc(self.messages)
  end
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 258

def to_xml(options={})
  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 225

def values
  messages.values
end