Active Model Errors
Provides a modified Hash
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 person.validate! # => ["can not be nil"] person.errors.full_messages # => ["name can not be nil"] # etc..
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CALLBACKS_OPTIONS | = | [:if, :unless, :on, :allow_nil, :allow_blank, :strict] |
[R] | messages |
Pass in the instance of the object that is using the errors object.
class Person def initialize @errors = ActiveModel::Errors.new(self) end end
When passed a symbol or a name of a method, returns an array of errors for the method.
person.errors[:name] # => ["can not be nil"] person.errors['name'] # => ["can not be nil"]
Adds to the supplied attribute the supplied error message.
person.errors[:name] = "must be set" person.errors[:name] # => ['must be set']
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 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 # => {}
# File activemodel/lib/active_model/errors.rb, line 291 def add(attribute, message = nil, 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
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"]}
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"]}
# File activemodel/lib/active_model/errors.rb, line 307 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
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 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.as_json # => {:name=>["can not be nil"]} person.as_json(full_messages: true) # => {:name=>["name can not be nil"]}
aliases empty?
Clear the error messages.
person.errors.full_messages # => ["name can not be nil"] person.errors.clear person.errors.full_messages # => []
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
Delete messages for key
. Returns the deleted messages.
person.errors.get(:name) # => ["can not be nil"] person.errors.delete(:name) # => ["can not be nil"] person.errors.get(:name) # => nil
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
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 can not be nil"] person.errors.empty? # => false
Returns a full message for a given attribute.
person.errors.full_message(:name, 'is invalid') # => "Name is invalid"
# File activemodel/lib/active_model/errors.rb, line 369 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
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"]
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"]
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 theactivemodel.errors
scope) -
activemodel.errors.messages.blank
-
errors.attributes.title.blank
-
errors.messages.blank
# File activemodel/lib/active_model/errors.rb, line 404 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 messages for key
.
person.errors.messages # => {:name=>["can not be nil"]} person.errors.get(:name) # => ["can not be nil"] person.errors.get(:age) # => nil
aliases include?
Returns true
if the error messages include an error for the
given key attribute
, false
otherwise.
person.errors.messages # => {:name=>["can not be nil"]} person.errors.include?(:name) # => true person.errors.include?(:age) # => false
Returns all message keys.
person.errors.messages # => {:name=>["can not be nil", "must be specified"]} person.errors.keys # => [:name]
Set messages for key
to value
.
person.errors.get(:name) # => ["can not be nil"] person.errors.set(:name, ["can't be nil"]) person.errors.get(:name) # => ["can't be nil"]
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
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"]
Returns a Hash of attributes with their error
messages. If full_messages
is true
, it will
contain full messages (see full_message
).
person.to_hash # => {:name=>["can not be nil"]} person.to_hash(true) # => {:name=>["name can not be nil"]}
# File activemodel/lib/active_model/errors.rb, line 251 def to_hash(full_messages = false) if full_messages messages = {} self.messages.each do |attribute, array| messages[attribute] = array.map { |message| full_message(attribute, message) } end messages else self.messages.dup end end
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>