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Diffstat (limited to 'activemodel/lib/active_model/callbacks.rb')
| -rw-r--r-- | activemodel/lib/active_model/callbacks.rb | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb new file mode 100644 index 0000000000..b27a39b787 --- /dev/null +++ b/activemodel/lib/active_model/callbacks.rb @@ -0,0 +1,146 @@ +require 'active_support/core_ext/array/extract_options' + +module ActiveModel + # == Active \Model \Callbacks + # + # Provides an interface for any class to have Active Record like callbacks. + # + # Like the Active Record methods, the callback chain is aborted as soon as + # one of the methods in the chain returns +false+. + # + # First, extend ActiveModel::Callbacks from the class you are creating: + # + # class MyModel + # extend ActiveModel::Callbacks + # end + # + # Then define a list of methods that you want callbacks attached to: + # + # define_model_callbacks :create, :update + # + # This will provide all three standard callbacks (before, around and after) + # for both the <tt>:create</tt> and <tt>:update</tt> methods. To implement, + # you need to wrap the methods you want callbacks on in a block so that the + # callbacks get a chance to fire: + # + # def create + # run_callbacks :create do + # # Your create action methods here + # end + # end + # + # Then in your class, you can use the +before_create+, +after_create+ and + # +around_create+ methods, just as you would in an Active Record model. + # + # before_create :action_before_create + # + # def action_before_create + # # Your code here + # end + # + # When defining an around callback remember to yield to the block, otherwise + # it won't be executed: + # + # around_create :log_status + # + # def log_status + # puts 'going to call the block...' + # yield + # puts 'block successfully called.' + # end + # + # You can choose not to have all three callbacks by passing a hash to the + # +define_model_callbacks+ method. + # + # define_model_callbacks :create, only: [:after, :before] + # + # Would only create the +after_create+ and +before_create+ callback methods in + # your class. + module Callbacks + def self.extended(base) #:nodoc: + base.class_eval do + include ActiveSupport::Callbacks + end + end + + # define_model_callbacks accepts the same options +define_callbacks+ does, + # in case you want to overwrite a default. Besides that, it also accepts an + # <tt>:only</tt> option, where you can choose if you want all types (before, + # around or after) or just some. + # + # define_model_callbacks :initializer, only: :after + # + # Note, the <tt>only: <type></tt> hash will apply to all callbacks defined + # on that method call. To get around this you can call the define_model_callbacks + # method as many times as you need. + # + # define_model_callbacks :create, only: :after + # define_model_callbacks :update, only: :before + # define_model_callbacks :destroy, only: :around + # + # Would create +after_create+, +before_update+ and +around_destroy+ methods + # only. + # + # You can pass in a class to before_<type>, after_<type> and around_<type>, + # in which case the callback will call that class's <action>_<type> method + # passing the object that the callback is being called on. + # + # class MyModel + # extend ActiveModel::Callbacks + # define_model_callbacks :create + # + # before_create AnotherClass + # end + # + # class AnotherClass + # def self.before_create( obj ) + # # obj is the MyModel instance that the callback is being called on + # end + # end + def define_model_callbacks(*callbacks) + options = callbacks.extract_options! + options = { + terminator: ->(_,result) { result == false }, + skip_after_callbacks_if_terminated: true, + scope: [:kind, :name], + only: [:before, :around, :after] + }.merge!(options) + + types = Array(options.delete(:only)) + + callbacks.each do |callback| + define_callbacks(callback, options) + + types.each do |type| + send("_define_#{type}_model_callback", self, callback) + end + end + end + + private + + def _define_before_model_callback(klass, callback) #:nodoc: + klass.define_singleton_method("before_#{callback}") do |*args, &block| + set_callback(:"#{callback}", :before, *args, &block) + end + end + + def _define_around_model_callback(klass, callback) #:nodoc: + klass.define_singleton_method("around_#{callback}") do |*args, &block| + set_callback(:"#{callback}", :around, *args, &block) + end + end + + def _define_after_model_callback(klass, callback) #:nodoc: + klass.define_singleton_method("after_#{callback}") do |*args, &block| + options = args.extract_options! + options[:prepend] = true + conditional = ActiveSupport::Callbacks::Conditionals::Value.new { |v| + v != false + } + options[:if] = Array(options[:if]) << conditional + set_callback(:"#{callback}", :after, *(args << options), &block) + end + end + end +end |