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..
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- Rails START:includes
| 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.
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. 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.
# File activemodel/lib/active_model/errors.rb, line 233 233: def add(attribute, message = nil, options = {}) 234: message = normalize_message(attribute, message, options) 235: if options[:strict] 236: raise ActiveModel::StrictValidationFailed, full_message(attribute, message) 237: end 238: 239: self[attribute] << message 240: end
Will add an error message to each of the attributes in attributes that is blank (using Object#blank?).
# File activemodel/lib/active_model/errors.rb, line 252 252: def add_on_blank(attributes, options = {}) 253: [attributes].flatten.each do |attribute| 254: value = @base.send(:read_attribute_for_validation, attribute) 255: add(attribute, :blank, options) if value.blank? 256: end 257: end
Will add an error message to each of the attributes in attributes that is empty.
# File activemodel/lib/active_model/errors.rb, line 243 243: def add_on_empty(attributes, options = {}) 244: [attributes].flatten.each do |attribute| 245: value = @base.send(:read_attribute_for_validation, attribute) 246: is_empty = value.respond_to?(:empty?) ? value.empty? : false 247: add(attribute, :empty, options) if value.nil? || is_empty 248: end 249: 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.
p.errors.add :name, :blank p.errors.added? :name, :blank # => true
Returns an ActiveSupport::OrderedHash that can be used as the JSON representation for this object.
Alias for empty?
Clear the messages
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
Delete messages for key
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 true if no errors are found, false otherwise. If the error message is a string it can be empty.
Returns a full message for a given attribute.
company.errors.full_message(:name, "is invalid") # =>
"Name is invalid"
# File activemodel/lib/active_model/errors.rb, line 286 286: def full_message(attribute, message) 287: return message if attribute == :base 288: attr_name = attribute.to_s.gsub('.', '_').humanize 289: attr_name = @base.class.human_attribute_name(attribute, :default => attr_name) 290: I18n.t(:"errors.format", { 291: :default => "%{attribute} %{message}", 292: :attribute => attr_name, 293: :message => message 294: }) 295: 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:
- 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
# File activemodel/lib/active_model/errors.rb, line 321 321: def generate_message(attribute, type = :invalid, options = {}) 322: type = options.delete(:message) if options[:message].is_a?(Symbol) 323: 324: if @base.class.respond_to?(:i18n_scope) 325: defaults = @base.class.lookup_ancestors.map do |klass| 326: [ :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.attributes.#{attribute}.#{type}", 327: :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.#{type}" ] 328: end 329: else 330: defaults = [] 331: end 332: 333: defaults << options.delete(:message) 334: defaults << :"#{@base.class.i18n_scope}.errors.messages.#{type}" if @base.class.respond_to?(:i18n_scope) 335: defaults << :"errors.attributes.#{attribute}.#{type}" 336: defaults << :"errors.messages.#{type}" 337: 338: defaults.compact! 339: defaults.flatten! 340: 341: key = defaults.shift 342: value = (attribute != :base ? @base.send(:read_attribute_for_validation, attribute) : nil) 343: 344: options = { 345: :default => defaults, 346: :model => @base.class.model_name.human, 347: :attribute => @base.class.human_attribute_name(attribute), 348: :value => value 349: }.merge(options) 350: 351: I18n.translate(key, options) 352: end
Get messages for key
Alias for include?
Do the error messages include an error with key error?
Returns all message keys
Set messages for key to value
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>