Method: Scrivito::AttributeContent::ClassMethods#default_for

Defined in:

app/cms/scrivito/attribute_content.rb

#default_for(attribute_name, &block) ⇒ Object

Sets the default value of an attribute defined by #attribute or for the built-in attributes _path and _permalink.

If Obj.create or Widget.new are called without providing a value for a specific custom attribute, the block is called, and its return value is used as the initial value of this attribute.

The block is called with two parameters.

The first parameter is an ActiveSupport::HashWithIndifferentAccess containing the attributes that were passed to Obj.create or Widget.new.

The second parameter, context, is a hash. If the default_for callback is triggered by a UI user creating a CMS object or a Widget, Scrivito places the :scrivito_user and the :current_page (originating from the UI calling the creation method) into this hash. :current_page won’t be present in the context if the user creates the object or widget while viewing a page which isn’t a CMS object. The context hash is empty if the object or widget is not created using the UI but, for example, via the console.

Examples:

Setting a simple default:

class MyPage < Obj
  attribute :title, :string
  default_for(:title) { 'Spam' }
end

my_page = MyPage.create
my_page.title # => 'Spam'

A default depending on the given attributes:

class MyPage < Obj
  attribute :title, :string

  default_for :title do |attributes|
    if (path = attributes[:_path]) && path.starts_with('/de')
      'Hier den Titel eingeben'
    else
      'Your title here'
    end
  end
end

my_page = MyPage.create(_path: '/en/test')
my_page.title # => 'Your title here'

my_page = MyPage.create(_path: '/de/test')
my_page.title # => 'Hier den Titel eingeben'

A more complex default, depending on the given attributes and the current user:

class MyPage < Obj
  attribute :title, :string

  default_for :title do |attributes, context|
    if use_german_title?(context[:scrivito_user], attributes[:_path])
      'Hier den Titel eingeben'
    else
      'Your title here'
    end
  end

  private

  #
  # Assuming there is a +MyUser+ model equipped with a +preferences+ method which
  # returns the preferences of the current user.
  # The +email+ of a +MyUser+ is the +id+ of the corresponding +Scrivito::User+ as set in
  # +Scrivito::Configuration.editing_auth+.
  #
  def use_german_title?(scrivito_user, path)
    scrivito_user && MyUser.find_by(email: scrivito_user.id).preferences[:locale] == 'de' ||
      path && path.starts_with?('/de')
  end
end

MyUser.find_by(email: 'alice@scrivito.com').preferences[:locale] # => 'en'
alice = Scrivito::User.define('alice@scrivito.com')

my_page = MyPage.create({_path: '/de/test'}, alice)
my_page.title # => 'Your title here'

MyUser.find_by(email: 'bob@scrivito.com').preferences[:locale] # => 'de'
bob = Scrivito::User.define('bob@scrivito.com')

my_page = MyPage.create({_path: '/en/test'}, bob)
my_page.title # => 'Hier den Titel eingeben'

Parameters:

• attribute_name (Symbol, String) —

  the name of the attribute.

• block (Proc) —

  that returns the default value.

Returns:

• nil

Raises:

• (Scrivito::ScrivitoError) —

  if no block is present

See Also:

• BasicObj.create
• BasicWidget.new
• Configuration.editing_auth
• Specifying default attribute values

# File 'app/cms/scrivito/attribute_content.rb', line 573

def default_for(attribute_name, &block)
  attribute_name = attribute_name.to_s
  raise ScrivitoError, 'No block given' unless block_given?
  attribute_default_definitions[attribute_name] = block
  nil
end