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, :terminator => "result == false", :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)
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
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_callbacks(:prepare)
end
def call(env)
run_callbacks(:call) do
run_callbacks(:prepare) if @prepare_each_request
@app.call(env)
end
end
end
end
