Active Model Errors

Provides a modified OrderedHash that you can include in your object for handling error messages and interacting with Action Pack 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, "can not 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::Translations 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:

p = Person.new
p.validate!             # => ["can not be nil"]
p.errors.full_messages  # => ["name can not be nil"]
# etc..
Methods
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Included Modules
Constants
CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank]
Attributes
[R] messages
Class Public methods
new(base)

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

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 76
def initialize(base)
  @base     = base
  @messages = ActiveSupport::OrderedHash.new
end
Instance Public methods
[](attribute)

When passed a symbol or a name of a method, returns an array of errors for the method.

p.errors[:name]   # => ["can not be nil"]
p.errors['name']  # => ["can not be nil"]

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 106
def [](attribute)
  get(attribute.to_sym) || set(attribute.to_sym, [])
end
[]=(attribute, error)

Adds to the supplied attribute the supplied error message.

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 114
def []=(attribute, error)
  self[attribute.to_sym] << error
end
add(attribute, message = nil, options = {})

Adds message to the error messages on attribute, which will be returned on a call to on(attribute) for the same attribute. More than one error can be added to the same attribute in which case an array will be returned on a call to on(attribute). If no message is supplied, :invalid is assumed.

If message is a symbol, it will be translated using the appropriate scope (see translate_error). If message is a proc, it will be called, allowing for things like Time.now to be used within an error.

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 212
def add(attribute, message = nil, options = {})
  message ||= :invalid

  if message.is_a?(Symbol)
    message = generate_message(attribute, message, options.except(*CALLBACKS_OPTIONS))
  elsif message.is_a?(Proc)
    message = message.call
  end

  self[attribute] << message
end
add_on_blank(attributes, options = {})

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 234
def add_on_blank(attributes, options = {})
  [attributes].flatten.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 = {})

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 225
def add_on_empty(attributes, options = {})
  [attributes].flatten.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
as_json(options=nil)

Returns an ActiveSupport::OrderedHash that can be used as the JSON representation for this object.

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 197
def as_json(options=nil)
  to_hash
end
blank?()
clear()

Clear the messages

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 82
def clear
  messages.clear
end
count()

Returns the number of error messages.

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 172
def count
  to_a.size
end
each()

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.

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

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 132
def each
  messages.each_key do |attribute|
    self[attribute].each { |error| yield attribute, error }
  end
end
empty?()

Returns true if no errors are found, false otherwise.

This method is also aliased as blank?

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 177
def empty?
  all? { |k, v| v && v.empty? }
end
full_messages()

Returns all the full error messages in an array.

class Company
  validates_presence_of :name, :address, :email
  validates_length_of :name, :in => 5..30
end

company = Company.create(:address => '123 First St.')
company.errors.full_messages # =>
  ["Name is too short (minimum is 5 characters)", "Name can't be blank", "Email can't be blank"]

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 251
def full_messages
  map { |attribute, message|
    if attribute == :base
      message
    else
      attr_name = attribute.to_s.gsub('.', '_').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
  }
end
generate_message(attribute, type = :invalid, options = {})

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 292
def generate_message(attribute, type = :invalid, options = {})
  type = options.delete(:message) if options[:message].is_a?(Symbol)

  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

  defaults << options.delete(:message)
  defaults << :"#{@base.class.i18n_scope}.errors.messages.#{type}"
  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.class.model_name.human,
    :attribute => @base.class.human_attribute_name(attribute),
    :value => value
  }.merge(options)

  I18n.translate(key, options)
end
get(key)

Get messages for key

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 92
def get(key)
  messages[key]
end
include?(error)

Do the error messages include an error with key error?

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 87
def include?(error)
  (v = messages[error]) && v.any?
end
keys()

Returns all message keys

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 154
def keys
  messages.keys
end
set(key, value)

Set messages for key to value

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 97
def set(key, value)
  messages[key] = value
end
size()

Returns the number of error messages.

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 144
def size
  values.flatten.size
end
to_a()

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

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 163
def to_a
  full_messages
end
to_hash()

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 201
def to_hash
  messages.dup
end
to_xml(options={})

Returns an xml formatted representation of the Errors hash.

p.errors.add(:name, "can't be blank")
p.errors.add(:name, "must be specified")
p.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>

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 192
def to_xml(options={})
  to_a.to_xml options.reverse_merge(:root => "errors", :skip_types => true)
end
values()

Returns all message values

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 149
def values
  messages.values
end