Class | ActiveModel::Errors |
In: |
lib/active_model/errors.rb
|
Parent: | Object |
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..
CALLBACKS_OPTIONS | = | [:if, :unless, :on, :allow_nil, :allow_blank] |
messages | [R] |
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.
p.errors[:name] # => ["can not be nil"] p.errors['name'] # => ["can not be nil"]
Adds to the supplied attribute the supplied error message.
p.errors[:name] = "must be set" p.errors[:name] # => ['must be set']
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.
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
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
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"]
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:
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
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"]
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>