module ActionDispatch # Provide callbacks to be executed before and after the request dispatch. # # It also provides a to_prepare callback, which is performed in all requests # in development by only once in production and notification callback for async # operations. # class Callbacks include ActiveSupport::Callbacks define_callbacks :call, :rescuable => true define_callbacks :prepare, :scope => :name # Add a preparation callback. Preparation callbacks are run before every # request in development mode, and before the first request in production mode. # # If a symbol with a block is given, the symbol is used as an identifier. # That allows to_prepare to be called again with the same identifier to # replace the existing callback. Passing an identifier is a suggested # practice if the code adding a preparation block may be reloaded. def self.to_prepare(*args, &block) first_arg = args.first if first_arg.is_a?(Symbol) && block_given? remove_method :"__#{first_arg}" if method_defined?(:"__#{first_arg}") define_method :"__#{first_arg}", &block set_callback(:prepare, :"__#{first_arg}") else set_callback(:prepare, *args, &block) end end def self.before(*args, &block) set_callback(:call, :before, *args, &block) end def self.after(*args, &block) set_callback(:call, :after, *args, &block) end def initialize(app, prepare_each_request = false) @app, @prepare_each_request = app, prepare_each_request _run_prepare_callbacks end def call(env) _run_call_callbacks do _run_prepare_callbacks if @prepare_each_request @app.call(env) end end end end