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.
# File lib/action_dispatch/middleware/callbacks.rb, line 43 def call(env) _run_call_callbacks do _run_prepare_callbacks if @prepare_each_request @app.call(env) end end
# File lib/action_dispatch/middleware/callbacks.rb, line 34 def self.after(*args, &block) set_callback(:call, :after, *args, &block) end
# File lib/action_dispatch/middleware/callbacks.rb, line 30 def self.before(*args, &block) set_callback(:call, :before, *args, &block) end
# File lib/action_dispatch/middleware/callbacks.rb, line 38 def initialize(app, prepare_each_request = false) @app, @prepare_each_request = app, prepare_each_request _run_prepare_callbacks end
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.
# File lib/action_dispatch/middleware/callbacks.rb, line 21 def self.to_prepare(*args, &block) if args.first.is_a?(Symbol) && block_given? define_method :"__#{args.first}", &block set_callback(:prepare, :"__#{args.first}") else set_callback(:prepare, *args, &block) end end