Active Record validation is reported to and from this object, which is used by ActiveRecord::Base#save to determine whether the object in a valid state to be saved. See usage example in Validations.

Methods
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Included Modules
Instance Public methods
[](attribute)
add(attribute, msg = @@default_error_messages[:invalid])

Adds an error message (msg) to the attribute, which will be returned on a call to on(attribute) for the same attribute and ensure that this error object returns false when asked if empty?. 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 msg is supplied, “invalid” is assumed.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 57
def add(attribute, msg = @@default_error_messages[:invalid])
  @errors[attribute.to_s] = [] if @errors[attribute.to_s].nil?
  @errors[attribute.to_s] << msg
end
add_on_blank(attributes, msg = @@default_error_messages[:blank])

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

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 72
def add_on_blank(attributes, msg = @@default_error_messages[:blank])
  for attr in [attributes].flatten
    value = @base.respond_to?(attr.to_s) ? @base.send(attr.to_s) : @base[attr.to_s]
    add(attr, msg) if value.blank?
  end
end
add_on_boundary_breaking(attributes, range, too_long_msg = @@default_error_messages[:too_long], too_short_msg = @@default_error_messages[:too_short])

Will add an error message to each of the attributes in attributes that has a length outside of the passed boundary range. If the length is above the boundary, the too_long_msg message will be used. If below, the too_short_msg.

Also aliased as: add_on_boundry_breaking

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 81
def add_on_boundary_breaking(attributes, range, too_long_msg = @@default_error_messages[:too_long], too_short_msg = @@default_error_messages[:too_short])
  for attr in [attributes].flatten
    value = @base.respond_to?(attr.to_s) ? @base.send(attr.to_s) : @base[attr.to_s]
    add(attr, too_short_msg % range.begin) if value && value.length < range.begin
    add(attr, too_long_msg % range.end) if value && value.length > range.end
  end
end
add_on_boundry_breaking(attributes, range, too_long_msg = @@default_error_messages[:too_long], too_short_msg = @@default_error_messages[:too_short])
add_on_empty(attributes, msg = @@default_error_messages[:empty])

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

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 63
def add_on_empty(attributes, msg = @@default_error_messages[:empty])
  for attr in [attributes].flatten
    value = @base.respond_to?(attr.to_s) ? @base.send(attr.to_s) : @base[attr.to_s]
    is_empty = value.respond_to?("empty?") ? value.empty? : false
    add(attr, msg) unless !value.nil? && !is_empty
  end
end
add_to_base(msg)

Adds an error to the base object instead of any particular attribute. This is used to report errors that don’t tie to any specific attribute, but rather to the object as a whole. These error messages don’t get prepended with any field name when iterating with #each_full, so they should be complete sentences.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 49
def add_to_base(msg)
  add(:base, msg)
end
clear()

Removes all the errors that have been added.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 148
def clear
  @errors = {}
end
count()
each()

Yields each attribute and associated message per error added.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 114
def each
  @errors.each_key { |attr| @errors[attr].each { |msg| yield attr, msg } }
end
each_full()

Yields each full error message added. So Person.errors.add(“first_name”, “can’t be empty”) will be returned through iteration as “First name can’t be empty”.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 120
def each_full
  full_messages.each { |msg| yield msg }
end
empty?()

Returns true if no errors have been added.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 143
def empty?
  @errors.empty?
end
full_messages()

Returns all the full error messages in an array.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 125
def full_messages
  full_messages = []

  @errors.each_key do |attr|
    @errors[attr].each do |msg|
      next if msg.nil?

      if attr == "base"
        full_messages << msg
      else
        full_messages << @base.class.human_attribute_name(attr) + " " + msg
      end
    end
  end
  full_messages
end
invalid?(attribute)

Returns true if the specified attribute has errors associated with it.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 93
def invalid?(attribute)
  !@errors[attribute.to_s].nil?
end
length()
on(attribute)

  • Returns nil, if no errors are associated with the specified attribute.

  • Returns the error message, if one error is associated with the specified attribute.

  • Returns an array of error messages, if more than one error is associated with the specified attribute.

Also aliased as: []

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 100
def on(attribute)
  errors = @errors[attribute.to_s]
  return nil if errors.nil?
  errors.size == 1 ? errors.first : errors
end
on_base()

Returns errors assigned to base object through #add_to_base according to the normal rules of on(attribute).

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 109
def on_base
  on(:base)
end
size()

Returns the total number of errors added. Two errors added to the same attribute will be counted as such with this as well.

Also aliased as: count, length

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 154
def size
  @errors.values.inject(0) { |error_count, attribute| error_count + attribute.size }
end
to_xml(options={})

Return an XML representation of this error object.

Source: show 

# File rails/activerecord/lib/active_record/validations.rb, line 162
def to_xml(options={})
  options[:root] ||= "errors"
  options[:indent] ||= 2
  options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent])

  options[:builder].instruct! unless options.delete(:skip_instruct)
  options[:builder].errors do |e|
    full_messages.each { |msg| e.error(msg) }
  end
end