Class: ActiveModel::Errors

Inherits:
ActiveSupport::OrderedHash show all
Includes:
DeprecatedErrorMethods
Defined in:
activemodel/lib/active_model/errors.rb

Overview

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..

Direct Known Subclasses

ActiveResource::Errors

Constant Summary

CALLBACKS_OPTIONS =
[:if, :unless, :on, :allow_nil, :allow_blank]

Instance Method Summary (collapse)

Methods included from DeprecatedErrorMethods

#add_to_base, #each_full, #invalid?, #on, #on_base

Methods inherited from ActiveSupport::OrderedHash

[], #clear, #delete, #delete_if, #each_key, #each_value, #initialize_copy, #inspect, #invert, #keys, #merge, #merge!, #reject, #reject!, #replace, #shift, #to_hash, #to_yaml, #to_yaml_type, #values

Methods inherited from Hash

#assert_valid_keys, #deep_merge, #deep_merge!, #diff, #encode_json, #except, #except!, #extract!, #extractable_options?, from_xml, #reverse_merge, #reverse_merge!, #slice, #slice!, #stringify_keys, #stringify_keys!, #symbolize_keys, #symbolize_keys!, #to_param, #with_indifferent_access

Constructor Details

- (Errors) initialize(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


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

def initialize(base)
  @base = base
  super()
end

Instance Method Details

- (Object) [](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"]


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# File 'activemodel/lib/active_model/errors.rb', line 88

def [](attribute)
  get(attribute.to_sym) || set(attribute.to_sym, [])
end

- (Object) []=(attribute, error)

Adds to the supplied attribute the supplied error message.

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


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# File 'activemodel/lib/active_model/errors.rb', line 96

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

- (Object) 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.



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

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

- (Object) add_on_blank(attributes, options = {})

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



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

def add_on_blank(attributes, options = {})
  if options && !options.is_a?(Hash)
    options = { :message => options }
    ActiveSupport::Deprecation.warn \
      "ActiveModel::Errors#add_on_blank(attributes, custom_message) has been deprecated.\n" +
      "Instead of passing a custom_message pass an options Hash { :message => custom_message }."
  end

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

- (Object) add_on_empty(attributes, options = {})

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



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

def add_on_empty(attributes, options = {})
  if options && !options.is_a?(Hash)
    options = { :message => options }
    ActiveSupport::Deprecation.warn \
      "ActiveModel::Errors#add_on_empty(attributes, custom_message) has been deprecated.\n" +
      "Instead of passing a custom_message pass an options Hash { :message => custom_message }."
  end

  [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

- (Object) as_json(options = nil)

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



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# File 'activemodel/lib/active_model/errors.rb', line 169

def as_json(options=nil)
  self
end

- (Object) 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


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# File 'activemodel/lib/active_model/errors.rb', line 144

def count
  to_a.size
end

- (Object) 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


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# File 'activemodel/lib/active_model/errors.rb', line 114

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

- (Boolean) empty?

Returns true if there are any errors, false if not.

Returns:

  • (Boolean)


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# File 'activemodel/lib/active_model/errors.rb', line 149

def empty?
  all? { |k, v| v && v.empty? }
end

- (Object) 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", "Address can't be blank"]


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# File 'activemodel/lib/active_model/errors.rb', line 233

def full_messages
  full_messages = []

  each do |attribute, messages|
    messages = Array.wrap(messages)
    next if messages.empty?

    if attribute == :base
      messages.each {|m| full_messages << m }
    else
      attr_name = attribute.to_s.gsub('.', '_').humanize
      attr_name = @base.class.human_attribute_name(attribute, :default => attr_name)
      options = { :default => "%{attribute} %{message}", :attribute => attr_name }

      messages.each do |m|
        full_messages << I18n.t(:errors.format", options.merge(:message => m))
      end
    end
  end

  full_messages
end

- (Object) 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:

<ol> <li>activemodel.errors.models.admin.attributes.title.blank</li> <li>activemodel.errors.models.admin.blank</li> <li>activemodel.errors.models.user.attributes.title.blank</li> <li>activemodel.errors.models.user.blank</li> <li>any default you provided through the options hash (in the activemodel.errors scope)</li> <li>activemodel.errors.messages.blank</li> <li>errors.attributes.title.blank</li> <li>errors.messages.blank</li> </ol>



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# File 'activemodel/lib/active_model/errors.rb', line 281

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

  if options[:default]
    ActiveSupport::Deprecation.warn \
      "Giving :default as validation option to errors.add has been deprecated.\n" +
      "Please use :message instead."
    options[:message] = options.delete(:default)
  end

  defaults = @base.class.lookup_ancestors.map do |klass|
    [ :#{@base.class.i18n_scope}.errors.models.#{klass.model_name.underscore}.attributes.#{attribute}.#{type}",
      :#{@base.class.i18n_scope}.errors.models.#{klass.model_name.underscore}.#{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

- (Object) get



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# File 'activemodel/lib/active_model/errors.rb', line 80

alias_method :get, :[]

- (Object) set



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# File 'activemodel/lib/active_model/errors.rb', line 81

alias_method :set, :[]=

- (Object) 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


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# File 'activemodel/lib/active_model/errors.rb', line 126

def size
  values.flatten.size
end

- (Object) 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"]


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

def to_a
  full_messages
end

- (Object) 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>


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# File 'activemodel/lib/active_model/errors.rb', line 164

def to_xml(options={})
  to_a.to_xml options.reverse_merge(:root => "errors", :skip_types => true)
end