diff options
| -rw-r--r-- | activesupport/CHANGELOG.md | 5 | ||||
| -rw-r--r-- | activesupport/lib/active_support.rb | 1 | ||||
| -rw-r--r-- | activesupport/lib/active_support/current_attributes.rb | 190 | ||||
| -rw-r--r-- | activesupport/lib/active_support/railtie.rb | 5 | ||||
| -rw-r--r-- | activesupport/test/current_attributes_test.rb | 96 | ||||
| -rw-r--r-- | railties/test/application/current_attributes_integration_test.rb | 88 |
6 files changed, 385 insertions, 0 deletions
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md index bae573cf37..b5db0693fe 100644 --- a/activesupport/CHANGELOG.md +++ b/activesupport/CHANGELOG.md @@ -1,3 +1,8 @@ +* Add ActiveSupport::CurrentAttributes to provide a thread-isolated attributes singleton. + Primary use case is keeping all the per-request attributes easily available to the whole system. + + *DHH* + * Fix implicit coercion calculations with scalars and durations Previously calculations where the scalar is first would be converted to a duration diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb index 03e3ce821a..a667fbb54a 100644 --- a/activesupport/lib/active_support.rb +++ b/activesupport/lib/active_support.rb @@ -32,6 +32,7 @@ module ActiveSupport extend ActiveSupport::Autoload autoload :Concern + autoload :CurrentAttributes autoload :Dependencies autoload :DescendantsTracker autoload :ExecutionWrapper diff --git a/activesupport/lib/active_support/current_attributes.rb b/activesupport/lib/active_support/current_attributes.rb new file mode 100644 index 0000000000..6b859cc6cc --- /dev/null +++ b/activesupport/lib/active_support/current_attributes.rb @@ -0,0 +1,190 @@ +module ActiveSupport + # Abstract super class that provides a thread-isolated attributes singleton, which resets automatically + # before and after reach request. This allows you to keep all the per-request attributes easily + # available to the whole system. + # + # The following full app-like example demonstrates how to use a Current class to + # facilitate easy access to the global, per-request attributes without passing them deeply + # around everywhere: + # + # # app/models/current.rb + # class Current < ActiveSupport::CurrentAttributes + # attribute :account, :user + # attribute :request_id, :user_agent, :ip_address + # + # resets { Time.zone = nil } + # + # def user=(user) + # super + # self.account = user.account + # Time.zone = user.time_zone + # end + # end + # + # # app/controllers/concerns/authentication.rb + # module Authentication + # extend ActiveSupport::Concern + # + # included do + # before_action :authenticate + # end + # + # private + # def authenticate + # if authenticated_user = User.find(cookies.signed[:user_id]) + # Current.user = authenticated_user + # else + # redirect_to new_session_url + # end + # end + # end + # + # # app/controllers/concerns/set_current_request_details.rb + # module SetCurrentRequestDetails + # extend ActiveSupport::Concern + # + # included do + # before_action do + # Current.request_id = request.uuid + # Current.user_agent = request.user_agent + # Current.ip_address = request.ip + # end + # end + # end + # + # class ApplicationController < ActionController::Base + # include Authentication + # include SetCurrentRequestDetails + # end + # + # class MessagesController < ApplicationController + # def create + # Current.account.messages.create(message_params) + # end + # end + # + # class Message < ApplicationRecord + # belongs_to :creator, default: -> { Current.user } + # after_create { |message| Event.create(record: message) } + # end + # + # class Event < ApplicationRecord + # before_create do + # self.request_id = Current.request_id + # self.user_agent = Current.user_agent + # self.ip_address = Current.ip_address + # end + # end + # + # A word of caution: It's easy to overdo a global singleton like Current and tangle your model as a result. + # Current should only be used for a few, top-level globals, like account, user, and request details. + # The attributes stuck in Current should be used by more or less all actions on all requests. If you start + # sticking controller-specific attributes in there, you're going to create a mess. + class CurrentAttributes + include ActiveSupport::Callbacks + define_callbacks :reset + + class << self + # Returns singleton instance for this class in this thread. If none exists, one is created. + def instance + Thread.current[:"current_attributes_for_#{name}"] ||= new.tap do |instance| + current_instances << instance + end + end + + # Declares one or more attributes that will be given both class and instance accessor methods. + def attribute(*names) + generated_attribute_methods.module_eval do + names.each do |name| + define_method(name) do + attributes[name.to_sym] + end + + define_method("#{name}=") do |attribute| + attributes[name.to_sym] = attribute + end + end + end + + names.each do |name| + define_singleton_method(name) do + instance.public_send(name) + end + + define_singleton_method("#{name}=") do |attribute| + instance.public_send("#{name}=", attribute) + end + end + end + + # Calls this block after #reset is called on the instance. Used for resetting external collaborators, like Time.zone. + def resets(&block) + set_callback :reset, :after, &block + end + + delegate :set, :reset, to: :instance + + def reset_all # :nodoc: + current_instances.each(&:reset) + end + + private + def generated_attribute_methods + @generated_attribute_methods ||= Module.new.tap { |mod| include mod } + end + + def current_instances + Thread.current[:current_attributes_instances] ||= [] + end + + def method_missing(name, *args, &block) + # Caches the method definition as a singleton method of the receiver. + # + # By letting #delegate handle it, we avoid an enclosure that'll capture args. + singleton_class.delegate name, to: :instance + + send(name, *args, &block) + end + end + + attr_accessor :attributes + + def initialize + @attributes = {} + end + + # Expose one or more attributes within a block. Old values are returned after the block concludes. + # Example demonstrating the common use of needing to set Current attributes outside the request-cycle: + # + # class Chat::PublicationJob < ApplicationJob + # def perform(attributes, room_number, creator) + # Current.set(person: creator) do + # Chat::Publisher.publish(attributes: attributes, room_number: room_number) + # end + # end + # end + def set(set_attributes) + old_attributes = compute_attributes(set_attributes.keys) + assign_attributes(set_attributes) + yield + ensure + assign_attributes(old_attributes) + end + + # Reset all attributes. Should be called before and after actions, when used as a per-request singleton. + def reset + run_callbacks :reset do + self.attributes = {} + end + end + + private + def assign_attributes(new_attributes) + new_attributes.each { |key, value| public_send("#{key}=", value) } + end + + def compute_attributes(keys) + keys.collect { |key| [ key, public_send(key) ] }.to_h + end + end +end diff --git a/activesupport/lib/active_support/railtie.rb b/activesupport/lib/active_support/railtie.rb index b875875afe..39c83f65a3 100644 --- a/activesupport/lib/active_support/railtie.rb +++ b/activesupport/lib/active_support/railtie.rb @@ -7,6 +7,11 @@ module ActiveSupport config.eager_load_namespaces << ActiveSupport + initializer "active_support.reset_all_current_attributes_instances" do |app| + app.executor.to_run { ActiveSupport::CurrentAttributes.reset_all } + app.executor.to_complete { ActiveSupport::CurrentAttributes.reset_all } + end + initializer "active_support.deprecation_behavior" do |app| if deprecation = app.config.active_support.deprecation ActiveSupport::Deprecation.behavior = deprecation diff --git a/activesupport/test/current_attributes_test.rb b/activesupport/test/current_attributes_test.rb new file mode 100644 index 0000000000..67ef6ef619 --- /dev/null +++ b/activesupport/test/current_attributes_test.rb @@ -0,0 +1,96 @@ +require "abstract_unit" + +class CurrentAttributesTest < ActiveSupport::TestCase + Person = Struct.new(:name, :time_zone) + + class Current < ActiveSupport::CurrentAttributes + attribute :world, :account, :person, :request + delegate :time_zone, to: :person + + resets { Time.zone = "UTC" } + + def account=(account) + super + self.person = "#{account}'s person" + end + + def person=(person) + super + Time.zone = person.try(:time_zone) + end + + def request + "#{super} something" + end + + def intro + "#{person.name}, in #{time_zone}" + end + end + + setup { Current.reset } + + test "read and write attribute" do + Current.world = "world/1" + assert_equal "world/1", Current.world + end + + test "read overwritten attribute method" do + Current.request = "request/1" + assert_equal "request/1 something", Current.request + end + + test "set attribute via overwritten method" do + Current.account = "account/1" + assert_equal "account/1", Current.account + assert_equal "account/1's person", Current.person + end + + test "set auxiliary class via overwritten method" do + Current.person = Person.new("David", "Central Time (US & Canada)") + assert_equal "Central Time (US & Canada)", Time.zone.name + end + + test "resets auxiliary class via callback" do + Current.person = Person.new("David", "Central Time (US & Canada)") + assert_equal "Central Time (US & Canada)", Time.zone.name + + Current.reset + assert_equal "UTC", Time.zone.name + end + + test "set attribute only via scope" do + Current.world = "world/1" + + Current.set(world: "world/2") do + assert_equal "world/2", Current.world + end + + assert_equal "world/1", Current.world + end + + test "set multiple attributes" do + Current.world = "world/1" + Current.account = "account/1" + + Current.set(world: "world/2", account: "account/2") do + assert_equal "world/2", Current.world + assert_equal "account/2", Current.account + end + + assert_equal "world/1", Current.world + assert_equal "account/1", Current.account + end + + test "delegation" do + Current.person = Person.new("David", "Central Time (US & Canada)") + assert_equal "Central Time (US & Canada)", Current.time_zone + assert_equal "Central Time (US & Canada)", Current.instance.time_zone + end + + test "all methods forward to the instance" do + Current.person = Person.new("David", "Central Time (US & Canada)") + assert_equal "David, in Central Time (US & Canada)", Current.intro + assert_equal "David, in Central Time (US & Canada)", Current.instance.intro + end +end diff --git a/railties/test/application/current_attributes_integration_test.rb b/railties/test/application/current_attributes_integration_test.rb new file mode 100644 index 0000000000..eea2a791a2 --- /dev/null +++ b/railties/test/application/current_attributes_integration_test.rb @@ -0,0 +1,88 @@ +require "isolation/abstract_unit" +require "rack/test" + +class CurrentAttributesIntegrationTest < ActiveSupport::TestCase + include ActiveSupport::Testing::Isolation + include Rack::Test::Methods + + setup do + build_app + + app_file "app/services/current.rb", <<-RUBY + class Current < ActiveSupport::CurrentAttributes + attribute :customer + + resets { Time.zone = "UTC" } + + def customer=(customer) + super + Time.zone = customer.try(:time_zone) + end + end + RUBY + + app_file "app/models/customer.rb", <<-RUBY + class Customer < Struct.new(:name) + def time_zone + "Copenhagen" + end + end + RUBY + + app_file "config/routes.rb", <<-RUBY + Rails.application.routes.draw do + get "/customers/:action", controller: :customers + end + RUBY + + app_file "app/controllers/customers_controller.rb", <<-RUBY + class CustomersController < ApplicationController + def set_current_customer + Current.customer = Customer.new("david") + render :index + end + + def set_no_customer + render :index + end + end + RUBY + + app_file "app/views/customers/index.html.erb", <<-RUBY + <%= Current.customer.try(:name) || 'noone' %>,<%= Time.zone.name %> + RUBY + + app_file "app/executor_intercept.rb", <<-RUBY + check_state = -> { puts [ Current.customer.try(:name) || "noone", Time.zone.name ].join(",") } + + check_state.call + + Rails.application.executor.wrap do + Current.customer = Customer.new("david") + check_state.call + end + + check_state.call + RUBY + + require "#{app_path}/config/environment" + end + + teardown :teardown_app + + test "current customer is assigned and cleared" do + get "/customers/set_current_customer" + assert_equal 200, last_response.status + assert_match(/david,Copenhagen/, last_response.body) + + get "/customers/set_no_customer" + assert_equal 200, last_response.status + assert_match(/noone,UTC/, last_response.body) + end + + test "resets after execution" do + Dir.chdir(app_path) do + assert_equal "noone,UTC\ndavid,Copenhagen\nnoone,UTC\n", `bin/rails runner app/executor_intercept.rb` + end + end +end |