Class: ActiveModel::Errors

Inherits:
Object show all
Includes:
Enumerable
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 collapse

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#each_with_object, #exclude?, #group_by, #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 77

def initialize(base)
  @base     = base
  @messages = ActiveSupport::OrderedHash.new
end

Instance Attribute Details

#messagesObject (readonly)

Returns the value of attribute messages


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# File 'activemodel/lib/active_model/errors.rb', line 68

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.

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 107

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

#[]=(attribute, error) ⇒ Object

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 115

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

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

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 213

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 = {}) ⇒ Object

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 235

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 = {}) ⇒ Object

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 226

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) ⇒ Object

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 198

def as_json(options=nil)
  to_hash
end

#clearObject

Clear the messages


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# File 'activemodel/lib/active_model/errors.rb', line 83

def clear
  messages.clear
end

#countObject

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 173

def count
  to_a.size
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.

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 133

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.


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# File 'activemodel/lib/active_model/errors.rb', line 178

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

#full_messagesObject

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"]

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# File 'activemodel/lib/active_model/errors.rb', line 252

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 = {}) ⇒ 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 293

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) ⇒ Object

Get messages for key


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# File 'activemodel/lib/active_model/errors.rb', line 93

def get(key)
  messages[key]
end

#include?(error) ⇒ Boolean

Do the error messages include an error with key error?


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

def include?(error)
  (v = messages[error]) && v.any?
end

#keysObject

Returns all message keys


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# File 'activemodel/lib/active_model/errors.rb', line 155

def keys
  messages.keys
end

#set(key, value) ⇒ Object

Set messages for key to value


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# File 'activemodel/lib/active_model/errors.rb', line 98

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

#sizeObject

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 145

def size
  values.flatten.size
end

#to_aObject

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 164

def to_a
  full_messages
end

#to_hashObject


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# File 'activemodel/lib/active_model/errors.rb', line 202

def to_hash
  messages.dup
end

#to_xml(options = {}) ⇒ Object

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 193

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

#valuesObject

Returns all message values


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# File 'activemodel/lib/active_model/errors.rb', line 150

def values
  messages.values
end