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::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:

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, :strict]
 
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 125
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 133
def []=(attribute, error)
  self[attribute] << error
end
add(attribute, message = nil, options = {})

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.

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 232
def add(attribute, message = nil, options = {})
  message = normalize_message(attribute, message, options)
  if options[:strict]
    raise ActiveModel::StrictValidationFailed,  message
  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 251
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 242
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
added?(attribute, message = nil, options = {})

Returns true if an error on the attribute with the given message is present, false otherwise. message is treated the same as for add.

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 262
def added?(attribute, message = nil, options = {})
  message = normalize_message(attribute, message, options)
  self[attribute].include? message
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 218
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 95
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 191
def count
  to_a.size
end
delete(key)

Delete messages for key

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 116
def delete(key)
  messages.delete(key)
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 151
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. If the error message is a string it can be empty.

Also aliased as: blank?

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 197
def empty?
  all? { |k, v| v && v.empty? && !v.is_a?(String) }
end
full_message(attribute, message)

Returns a full message for a given attribute.

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

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 285
def full_message(attribute, message)
  return message if attribute == :base
  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
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 277
def full_messages
  map { |attribute, message| full_message(attribute, message) }
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 320
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.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 106
def get(key)
  messages[key]
end
has_key?(error)
include?(error)

Do the error messages include an error with key error?

Also aliased as: has_key?

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 100
def include?(error)
  (v = messages[error]) && v.any?
end
initialize_dup(other)

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 81
def initialize_dup(other)
  @messages = other.messages.dup
end
keys()

Returns all message keys

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 173
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 111
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 163
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 182
def to_a
  full_messages
end
to_hash()

Source: show | on GitHub 

# File activemodel/lib/active_model/errors.rb, line 222
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 213
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 168
def values
  messages.values
end