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, "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 Person.human_attribute_name(attr, options = {})
    attr
  end

  def Person.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]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#exclude?, #index_by, #many?, #sum

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 71

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

Instance Attribute Details

#messagesObject (readonly)

Returns the value of attribute messages


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# File 'activemodel/lib/active_model/errors.rb', line 62

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"]

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# File 'activemodel/lib/active_model/errors.rb', line 136

def [](attribute)
  get(attribute.to_sym) || set(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 144

def []=(attribute, error)
  self[attribute] << error
end

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

Adds message to the error messages 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, 'must be implemented')# => ["is invalid", "must be implemented"]


person.errors.messages# => {:name=>["must be implemented", "is 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, nil, strict: true)# => ActiveModel::StrictValidationFailed: name is invalid

person.errors.add(:name, nil, 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, "either name or email must be present")
person.errors.messages# => {:base=>["either name or email must be present"]}


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

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

  self[attribute] << 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 329

def add_on_blank(attributes, options = {})
  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 315

def add_on_empty(attributes, options = {})
  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, false otherwise. message is treated the same as for add.

person.errors.add :name, :blank
person.errors.added? :name, :blank # => true

Returns:

  • (Boolean)

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# File 'activemodel/lib/active_model/errors.rb', line 341

def added?(attribute, message = :invalid, options = {})
  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 245

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 86

def clear
  messages.clear
end

#countObject

Returns the number of error messages.

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

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# File 'activemodel/lib/active_model/errors.rb', line 209

def count
  to_a.size
end

#delete(key) ⇒ Object

Delete messages for key. Returns the deleted messages.

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

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# File 'activemodel/lib/active_model/errors.rb', line 127

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

person.errors.add(:name, "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 162

def each
  messages.each_key do |attribute|
    self[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 218

def empty?
  all? { |k, v| v && v.empty? && !v.is_a?(String) }
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 377

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

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 356

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 370

def full_messages_for(attribute)
  (get(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 models.MODEL.attributes.ATTRIBUTE.MESSAGE, if it's not there, it's looked up in 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 412

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 << options.delete(:message)
  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
  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
  }.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)  # => nil

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# File 'activemodel/lib/active_model/errors.rb', line 109

def get(key)
  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 96

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

#initialize_dup(other) ⇒ Object

:nodoc:


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# File 'activemodel/lib/active_model/errors.rb', line 76

def initialize_dup(other) # :nodoc:
  @messages = other.messages.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 190

def keys
  messages.keys
end

#set(key, value) ⇒ Object

Set messages for key to value.

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

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

def set(key, value)
  messages[key] = value
end

#sizeObject

Returns the number of error messages.

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

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# File 'activemodel/lib/active_model/errors.rb', line 174

def size
  values.flatten.size
end

#to_aObject

Returns an array of error messages, with the attribute name included.

person.errors.add(:name, "can't be blank")
person.errors.add(:name, "must be specified")
person.errors.to_a # => ["name can't be blank", "name must be specified"]

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# File 'activemodel/lib/active_model/errors.rb', line 199

def to_a
  full_messages
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 254

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
    self.messages.dup
  end
end

#to_xml(options = {}) ⇒ Object

Returns an xml formatted representation of the Errors hash.

person.errors.add(:name, "can't be blank")
person.errors.add(:name, "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 235

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 182

def values
  messages.values
end