with_options
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with_options(options, &block)
public
An elegant way to factor duplication out of options passed to a series of method calls. Each method called in the block, with the block variable as the receiver, will have its options merged with the default options Hash or Hash-like object provided. Each method called on the block variable must take an options hash as its final argument.
Without with_options, this code contains duplication:
class Account < ActiveRecord::Base has_many :customers, dependent: :destroy has_many :products, dependent: :destroy has_many :invoices, dependent: :destroy has_many :expenses, dependent: :destroy end
Using with_options, we can remove the duplication:
class Account < ActiveRecord::Base with_options dependent: :destroy do |assoc| assoc.has_many :customers assoc.has_many :products assoc.has_many :invoices assoc.has_many :expenses end end
It can also be used with an explicit receiver:
I18n.with_options locale: user.locale, scope: 'newsletter' do |i18n| subject i18n.t :subject body i18n.t :body, user_name: user.name end
When you don’t pass an explicit receiver, it executes the whole block in merging options context:
class Account < ActiveRecord::Base with_options dependent: :destroy do has_many :customers has_many :products has_many :invoices has_many :expenses end end
with_options can also be nested since the call is forwarded to its receiver.
NOTE: Each nesting level will merge inherited defaults in addition to their own.
class Post < ActiveRecord::Base with_options if: :persisted?, length: { minimum: 50 } do validates :content, if: -> { content.present? } end end
The code is equivalent to:
validates :content, length: { minimum: 50 }, if: -> { content.present? }
Hence the inherited default for if key is ignored.
NOTE: You cannot call class methods implicitly inside of with_options. You can access these methods using the class name instead:
class Phone < ActiveRecord::Base enum :phone_number_type, { home: 0, office: 1, mobile: 2 } with_options presence: true do validates :phone_number_type, inclusion: { in: Phone.phone_number_types.keys } end end
When the block argument is omitted, the decorated Object instance is returned:
module MyStyledHelpers def styled with_options style: "color: red;" end end styled.link_to "I'm red", "/" # => <a href="/" style="color: red;">I'm red</a> styled.button_tag "I'm red too!" # => <button style="color: red;">I'm red too!</button>
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Nested with_options
You can nest with_options blocks, and you can even use the same name for the block parameter each time. E.g.:
class Product with_options :dependent => :destroy do |product| product.with_options :class_name => 'Media' do |product| product.has_many :images, :conditions => {:content_type => 'image'} product.has_many :videos, :conditions => {:content_type => 'video'} end product.has_many :comments end end
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Beware nested with_options clobbers!
Careful:
with_options :foo => :bar do |something| something.with_options :foo => :baz do |inner| what_is(:foo) end end
:foo will be :baz. It will not be [:bar, :baz], for example.
This bit me when trying to do nested with_options for validation where both had :if => something.