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Diffstat (limited to 'actionpack/lib/action_dispatch/middleware/reloader.rb')
-rw-r--r-- | actionpack/lib/action_dispatch/middleware/reloader.rb | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/middleware/reloader.rb b/actionpack/lib/action_dispatch/middleware/reloader.rb new file mode 100644 index 0000000000..29289a76b4 --- /dev/null +++ b/actionpack/lib/action_dispatch/middleware/reloader.rb @@ -0,0 +1,76 @@ +module ActionDispatch + # ActionDispatch::Reloader provides prepare and cleanup callbacks, + # intended to assist with code reloading during development. + # + # Prepare callbacks are run before each request, and cleanup callbacks + # after each request. In this respect they are analogs of ActionDispatch::Callback's + # before and after callbacks. However, cleanup callbacks are not called until the + # request is fully complete -- that is, after #close has been called on + # the response body. This is important for streaming responses such as the + # following: + # + # self.response_body = lambda { |response, output| + # # code here which refers to application models + # } + # + # Cleanup callbacks will not be called until after the response_body lambda + # is evaluated, ensuring that it can refer to application models and other + # classes before they are unloaded. + # + # By default, ActionDispatch::Reloader is included in the middleware stack + # only in the development environment; specifically, when config.cache_classes + # is false. Callbacks may be registered even when it is not included in the + # middleware stack, but are executed only when +ActionDispatch::Reloader.prepare!+ + # or +ActionDispatch::Reloader.cleanup!+ are called manually. + # + class Reloader + include ActiveSupport::Callbacks + + define_callbacks :prepare, :scope => :name + define_callbacks :cleanup, :scope => :name + + # Add a prepare callback. Prepare callbacks are run before each request, prior + # to ActionDispatch::Callback's before callbacks. + def self.to_prepare(*args, &block) + set_callback(:prepare, *args, &block) + end + + # Add a cleanup callback. Cleanup callbacks are run after each request is + # complete (after #close is called on the response body). + def self.to_cleanup(*args, &block) + set_callback(:cleanup, *args, &block) + end + + # Execute all prepare callbacks. + def self.prepare! + new(nil).run_callbacks :prepare + end + + # Execute all cleanup callbacks. + def self.cleanup! + new(nil).run_callbacks :cleanup + end + + def initialize(app) + @app = app + end + + module CleanupOnClose + def close + super if defined?(super) + ensure + ActionDispatch::Reloader.cleanup! + end + end + + def call(env) + run_callbacks :prepare + response = @app.call(env) + response[2].extend(CleanupOnClose) + response + rescue Exception + run_callbacks :cleanup + raise + end + end +end |