meantime_filter.rb

来自「ruby on rails web敏捷开发之路第二版 源代码」· RB 代码 · 共 117 行

#---
# Excerpted from "Agile Web Development with Rails, 2nd Ed."
# We make no guarantees that this code is fit for any purpose. 
# Visit http://www.pragmaticprogrammer.com/titles/rails2 for more book information.
#---
#--
# Copyright (c) 2006 Roman LE NEGRATE
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#++

module ActionController
  module Filters
    
    # See the README file for usage informations.
    module MeantimeFilter
      def self.included(base) #:nodoc:
        base.extend ClassMethods
        base.send :include, InstanceMethods
      end
      
      module ClassMethods
        
        # The passed <tt>filters</tt> will be appended to the array of filters
        # that's run _while_ actions on this controller are performed.
        def append_meantime_filter(*filters)
          conditions = extract_conditions!(filters)
          add_action_conditions(filters, conditions)
          append_filter_to_chain('meantime', filters)
        end
        
        # The passed <tt>filters</tt> will be prepended to the array of filters
        # that's run _while_ actions on this controller are performed.
        def prepend_meantime_filter(*filters)
          conditions = extract_conditions!(filters)
          add_action_conditions(filters, conditions)
          prepend_filter_to_chain('meantime', filters)
        end
        
        # Short-hand for append_while_filter since that's the most common of the
        # two.
        alias :meantime_filter :append_meantime_filter
        
        # Returns all the while filters for this class and all its ancestors.
        def meantime_filters #:nodoc:
          @meantime_filters ||= read_inheritable_attribute('meantime_filters') || []
        end
      end
      
      module InstanceMethods
        def self.included(base) #:nodoc:
          base.module_eval do
            alias :perform_action :perform_action_with_filters
          end
        end
        
        def perform_action_with_filters
          before_action_result = before_action
          
          unless before_action_result == false || performed?
            during_action { perform_action_without_filters }
            after_action
          end
          
          @before_filter_chain_aborted = (before_action_result == false)
        end
        
        private
        
        def during_action(&action)
          filters_and_action = self.class.meantime_filters.reject {|filter| action_exempted?(filter) } << action
          call_meantime_filters_or_action(filters_and_action)
        end
        
        def call_meantime_filters_or_action(filters_and_action)
          filter = filters_and_action.shift
          
          # Case 1: it is the action
          if filters_and_action.empty?
            filter.call
          
          # Case 2: it is a filter
          else
            todo = lambda { call_meantime_filters_or_action(filters_and_action) }
            case
            when filter.is_a?(Symbol) then  self.method(filter).call(&todo)
            when filter.is_a?(Method) then  filter.call(self, &todo)
            when filter_class?(filter) then filter.filter(self, &todo)
            else
              raise(
                ActionControllerError, 
                'Meantime filters need to be either a symbol, a method, or any type of object implementing a static filter method which receives the controller as only parameter'
              )
            end
          end
        end
      end # InstanceMethods
    end # MeantimeFilter
  end # Filters
end # ActionController