135 lines
4.4 KiB
Ruby
135 lines
4.4 KiB
Ruby
require 'active_support/callbacks'
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module ActiveModel
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# == Active Model Callbacks
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#
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# Provides an interface for any class to have Active Record like callbacks.
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#
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# Like the Active Record methods, the callback chain is aborted as soon as
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# one of the methods in the chain returns false.
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#
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# First, extend ActiveModel::Callbacks from the class you are creating:
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#
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# class MyModel
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# extend ActiveModel::Callbacks
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# end
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#
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# Then define a list of methods that you want callbacks attached to:
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#
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# define_model_callbacks :create, :update
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#
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# This will provide all three standard callbacks (before, around and after) for
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# both the :create and :update methods. To implement, you need to wrap the methods
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# you want callbacks on in a block so that the callbacks get a chance to fire:
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#
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# def create
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# run_callbacks :create do
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# # Your create action methods here
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# end
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# end
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#
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# Then in your class, you can use the +before_create+, +after_create+ and +around_create+
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# methods, just as you would in an Active Record module.
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#
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# before_create :action_before_create
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#
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# def action_before_create
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# # Your code here
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# end
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#
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# You can choose not to have all three callbacks by passing a hash to the
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# define_model_callbacks method.
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#
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# define_model_callbacks :create, :only => [:after, :before]
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#
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# Would only create the after_create and before_create callback methods in your
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# class.
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module Callbacks
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def self.extended(base)
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base.class_eval do
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include ActiveSupport::Callbacks
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end
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end
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# define_model_callbacks accepts the same options define_callbacks does, in case
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# you want to overwrite a default. Besides that, it also accepts an :only option,
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# where you can choose if you want all types (before, around or after) or just some.
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#
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# define_model_callbacks :initializer, :only => :after
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#
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# Note, the <tt>:only => <type></tt> hash will apply to all callbacks defined on
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# that method call. To get around this you can call the define_model_callbacks
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# method as many times as you need.
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#
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# define_model_callbacks :create, :only => :after
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# define_model_callbacks :update, :only => :before
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# define_model_callbacks :destroy, :only => :around
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#
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# Would create +after_create+, +before_update+ and +around_destroy+ methods only.
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#
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# You can pass in a class to before_<type>, after_<type> and around_<type>, in which
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# case the callback will call that class's <action>_<type> method passing the object
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# that the callback is being called on.
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#
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# class MyModel
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# extend ActiveModel::Callbacks
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# define_model_callbacks :create
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#
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# before_create AnotherClass
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# end
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#
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# class AnotherClass
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# def self.before_create( obj )
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# # obj is the MyModel instance that the callback is being called on
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# end
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# end
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#
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def define_model_callbacks(*callbacks)
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options = callbacks.extract_options!
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options = {
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:terminator => "result == false",
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:skip_after_callbacks_if_terminated => true,
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:scope => [:kind, :name],
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:only => [:before, :around, :after]
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}.merge(options)
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types = Array(options.delete(:only))
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callbacks.each do |callback|
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define_callbacks(callback, options)
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types.each do |type|
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send("_define_#{type}_model_callback", self, callback)
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end
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end
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end
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def _define_before_model_callback(klass, callback) #:nodoc:
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klass.class_eval <<-CALLBACK, __FILE__, __LINE__ + 1
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def self.before_#{callback}(*args, &block)
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set_callback(:#{callback}, :before, *args, &block)
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end
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CALLBACK
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end
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def _define_around_model_callback(klass, callback) #:nodoc:
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klass.class_eval <<-CALLBACK, __FILE__, __LINE__ + 1
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def self.around_#{callback}(*args, &block)
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set_callback(:#{callback}, :around, *args, &block)
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end
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CALLBACK
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end
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def _define_after_model_callback(klass, callback) #:nodoc:
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klass.class_eval <<-CALLBACK, __FILE__, __LINE__ + 1
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def self.after_#{callback}(*args, &block)
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options = args.extract_options!
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options[:prepend] = true
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options[:if] = Array(options[:if]) << "value != false"
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set_callback(:#{callback}, :after, *(args << options), &block)
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end
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CALLBACK
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end
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end
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end
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