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  1. #!/usr/bin/env ruby
  2. # -*- coding: utf-8 -*-
  3.  
  4. module Callbacks
  5.   def self.included(base)
  6.     base.extend ClassMethods
  7.   end
  8.  
  9.   module ClassMethods
  10.     def define_callbacks(*names, &block)
  11.       names.each do |name|
  12.         unless method_defined?("#{name}_with_callback")
  13.           define_method(:"#{name}_with_callback") do |*args, &block|
  14.             _run_callbacks(:"#{name}", [:before, :around], *args, &block)
  15.             result = send(:"#{name}_without_callback", *args, &block)
  16.             _run_callbacks(:"#{name}", [:around, :after], *args, &block)
  17.             result
  18.           end
  19.           alias_method :"#{name}_without_callback", :"#{name}"
  20.           alias_method :"#{name}", :"#{name}_with_callback"
  21.         end
  22.       end
  23.     end
  24.   end
  25.  
  26.   def _callbacks
  27.     @_callbacks ||= {}
  28.   end
  29.   private :_callbacks
  30.  
  31.   def _run_callbacks(name, types, *args, &block)
  32.     named_callbacks = _callbacks[name] || {}
  33.     types.each do |type|
  34.       (named_callbacks[type] || []).each do |callback|
  35.         callback.call(*args, &block)
  36.       end
  37.     end
  38.   end
  39.   private :_run_callbacks
  40.  
  41.   def _insert_callbacks(names, type, block, options = {})
  42.     prepend = options[:prepend]
  43.     names.each do |name|
  44.       named_callbacks = (_callbacks[:"#{name}"] ||= {})
  45.       callbacks = (named_callbacks[type] ||= [])
  46.       if prepend
  47.         callbacks.unshift block
  48.       else
  49.         callbacks.push block
  50.       end
  51.     end
  52.   end
  53.   private :_insert_callbacks
  54.  
  55.   def _remove_callbacks(names, type, block)
  56.     names.each do |name|
  57.       named_callbacks = (_callbacks[:"#{name}"] ||= {})
  58.       callbacks = (named_callbacks[type] ||= [])
  59.       callbacks.delete block
  60.     end
  61.   end
  62.   private :_remove_callbacks
  63.  
  64.   [:before, :after, :around].each do |type|
  65.     define_method(:"#{type}_filter") do |*names, &block|
  66.       _insert_callbacks(names, type, block)
  67.     end
  68.  
  69.     define_method(:"prepend_#{type}_filter") do |*names, &block|
  70.       _insert_callbacks(names, type, block, :prepend => true)
  71.     end
  72.  
  73.     define_method(:"remove_#{type}_filter") do |*names, &block|
  74.       _remove_callbacks(names, type, block)
  75.     end
  76.  
  77.     alias_method :"append_#{type}_filter", :"#{type}_filter"
  78.   end
  79. end
  80.  
  81.  
  82. class Record
  83.   include Callbacks
  84.  
  85.   def save(v)
  86.     puts "#{v}: - save"
  87.   end
  88.   define_callbacks :save
  89. end
  90.  
  91. record = Record.new
  92. record.before_filter :save do |v|
  93.   puts "#{v}: saving..."
  94. end
  95. record.after_filter :save do |v|
  96.   puts "#{v}: saved"
  97. end
  98.  
  99. record.save 123
  100.  
  101.  
Success #stdin #stdout 0s 4896KB
comments (?)
stdin 
Standard input is empty
stdout 
123: saving...
123: - save
123: saved
https://ideone.com/qJO5i
language:
Ruby (ruby 2.5.5)
created:
14 years ago
visibility:
public

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