invocation.rb
202 lines
| 7.5 KiB
| text/x-ruby
|
RubyLexer
Jean-Philippe Lang
|
r962 | module ActionWebService # :nodoc: | ||
| module Invocation # :nodoc: | ||||
| class InvocationError < ActionWebService::ActionWebServiceError # :nodoc: | ||||
| end | ||||
| def self.included(base) # :nodoc: | ||||
| base.extend(ClassMethods) | ||||
| base.send(:include, ActionWebService::Invocation::InstanceMethods) | ||||
| end | ||||
| # Invocation interceptors provide a means to execute custom code before | ||||
| # and after method invocations on ActionWebService::Base objects. | ||||
| # | ||||
| # When running in _Direct_ dispatching mode, ActionController filters | ||||
| # should be used for this functionality instead. | ||||
| # | ||||
| # The semantics of invocation interceptors are the same as ActionController | ||||
| # filters, and accept the same parameters and options. | ||||
| # | ||||
| # A _before_ interceptor can also cancel execution by returning +false+, | ||||
| # or returning a <tt>[false, "cancel reason"]</tt> array if it wishes to supply | ||||
| # a reason for canceling the request. | ||||
| # | ||||
| # === Example | ||||
| # | ||||
| # class CustomService < ActionWebService::Base | ||||
| # before_invocation :intercept_add, :only => [:add] | ||||
| # | ||||
| # def add(a, b) | ||||
| # a + b | ||||
| # end | ||||
| # | ||||
| # private | ||||
| # def intercept_add | ||||
| # return [false, "permission denied"] # cancel it | ||||
| # end | ||||
| # end | ||||
| # | ||||
| # Options: | ||||
| # [<tt>:except</tt>] A list of methods for which the interceptor will NOT be called | ||||
| # [<tt>:only</tt>] A list of methods for which the interceptor WILL be called | ||||
| module ClassMethods | ||||
| # Appends the given +interceptors+ to be called | ||||
| # _before_ method invocation. | ||||
| def append_before_invocation(*interceptors, &block) | ||||
| conditions = extract_conditions!(interceptors) | ||||
| interceptors << block if block_given? | ||||
| add_interception_conditions(interceptors, conditions) | ||||
| append_interceptors_to_chain("before", interceptors) | ||||
| end | ||||
| # Prepends the given +interceptors+ to be called | ||||
| # _before_ method invocation. | ||||
| def prepend_before_invocation(*interceptors, &block) | ||||
| conditions = extract_conditions!(interceptors) | ||||
| interceptors << block if block_given? | ||||
| add_interception_conditions(interceptors, conditions) | ||||
| prepend_interceptors_to_chain("before", interceptors) | ||||
| end | ||||
| alias :before_invocation :append_before_invocation | ||||
| # Appends the given +interceptors+ to be called | ||||
| # _after_ method invocation. | ||||
| def append_after_invocation(*interceptors, &block) | ||||
| conditions = extract_conditions!(interceptors) | ||||
| interceptors << block if block_given? | ||||
| add_interception_conditions(interceptors, conditions) | ||||
| append_interceptors_to_chain("after", interceptors) | ||||
| end | ||||
| # Prepends the given +interceptors+ to be called | ||||
| # _after_ method invocation. | ||||
| def prepend_after_invocation(*interceptors, &block) | ||||
| conditions = extract_conditions!(interceptors) | ||||
| interceptors << block if block_given? | ||||
| add_interception_conditions(interceptors, conditions) | ||||
| prepend_interceptors_to_chain("after", interceptors) | ||||
| end | ||||
| alias :after_invocation :append_after_invocation | ||||
| def before_invocation_interceptors # :nodoc: | ||||
| read_inheritable_attribute("before_invocation_interceptors") | ||||
| end | ||||
| def after_invocation_interceptors # :nodoc: | ||||
| read_inheritable_attribute("after_invocation_interceptors") | ||||
| end | ||||
| def included_intercepted_methods # :nodoc: | ||||
| read_inheritable_attribute("included_intercepted_methods") || {} | ||||
| end | ||||
| def excluded_intercepted_methods # :nodoc: | ||||
| read_inheritable_attribute("excluded_intercepted_methods") || {} | ||||
| end | ||||
| private | ||||
| def append_interceptors_to_chain(condition, interceptors) | ||||
| write_inheritable_array("#{condition}_invocation_interceptors", interceptors) | ||||
| end | ||||
| def prepend_interceptors_to_chain(condition, interceptors) | ||||
| interceptors = interceptors + read_inheritable_attribute("#{condition}_invocation_interceptors") | ||||
| write_inheritable_attribute("#{condition}_invocation_interceptors", interceptors) | ||||
| end | ||||
| def extract_conditions!(interceptors) | ||||
| return nil unless interceptors.last.is_a? Hash | ||||
| interceptors.pop | ||||
| end | ||||
| def add_interception_conditions(interceptors, conditions) | ||||
| return unless conditions | ||||
| included, excluded = conditions[:only], conditions[:except] | ||||
| write_inheritable_hash("included_intercepted_methods", condition_hash(interceptors, included)) && return if included | ||||
| write_inheritable_hash("excluded_intercepted_methods", condition_hash(interceptors, excluded)) if excluded | ||||
| end | ||||
| def condition_hash(interceptors, *methods) | ||||
| interceptors.inject({}) {|hash, interceptor| hash.merge(interceptor => methods.flatten.map {|method| method.to_s})} | ||||
| end | ||||
| end | ||||
| module InstanceMethods # :nodoc: | ||||
| def self.included(base) | ||||
| base.class_eval do | ||||
| alias_method_chain :perform_invocation, :interception | ||||
| end | ||||
| end | ||||
| def perform_invocation_with_interception(method_name, params, &block) | ||||
| return if before_invocation(method_name, params, &block) == false | ||||
| return_value = perform_invocation_without_interception(method_name, params) | ||||
| after_invocation(method_name, params, return_value) | ||||
| return_value | ||||
| end | ||||
| def perform_invocation(method_name, params) | ||||
| send(method_name, *params) | ||||
| end | ||||
| def before_invocation(name, args, &block) | ||||
| call_interceptors(self.class.before_invocation_interceptors, [name, args], &block) | ||||
| end | ||||
| def after_invocation(name, args, result) | ||||
| call_interceptors(self.class.after_invocation_interceptors, [name, args, result]) | ||||
| end | ||||
| private | ||||
| def call_interceptors(interceptors, interceptor_args, &block) | ||||
| if interceptors and not interceptors.empty? | ||||
| interceptors.each do |interceptor| | ||||
| next if method_exempted?(interceptor, interceptor_args[0].to_s) | ||||
| result = case | ||||
| when interceptor.is_a?(Symbol) | ||||
| self.send(interceptor, *interceptor_args) | ||||
| when interceptor_block?(interceptor) | ||||
| interceptor.call(self, *interceptor_args) | ||||
| when interceptor_class?(interceptor) | ||||
| interceptor.intercept(self, *interceptor_args) | ||||
| else | ||||
| raise( | ||||
| InvocationError, | ||||
| "Interceptors need to be either a symbol, proc/method, or a class implementing a static intercept method" | ||||
| ) | ||||
| end | ||||
| reason = nil | ||||
| if result.is_a?(Array) | ||||
| reason = result[1] if result[1] | ||||
| result = result[0] | ||||
| end | ||||
| if result == false | ||||
| block.call(reason) if block && reason | ||||
| return false | ||||
| end | ||||
| end | ||||
| end | ||||
| end | ||||
| def interceptor_block?(interceptor) | ||||
| interceptor.respond_to?("call") && (interceptor.arity == 3 || interceptor.arity == -1) | ||||
| end | ||||
| def interceptor_class?(interceptor) | ||||
| interceptor.respond_to?("intercept") | ||||
| end | ||||
| def method_exempted?(interceptor, method_name) | ||||
| case | ||||
| when self.class.included_intercepted_methods[interceptor] | ||||
| !self.class.included_intercepted_methods[interceptor].include?(method_name) | ||||
| when self.class.excluded_intercepted_methods[interceptor] | ||||
| self.class.excluded_intercepted_methods[interceptor].include?(method_name) | ||||
| end | ||||
| end | ||||
| end | ||||
| end | ||||
| end | ||||