#--
# Copyright (c) 2004 David Heinemeier Hansson
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#++
# This class provides an interface for dispatching a CGI (or CGI-like) request
# to the appropriate controller and action. It also takes care of resetting
# the environment (when Dependencies.load? is true) after each request.
class Dispatcher
class << self
# Dispatch the given CGI request, using the given session options, and
# emitting the output via the given output. If you dispatch with your
# own CGI object be sure to handle the exceptions it raises on multipart
# requests (EOFError and ArgumentError).
def dispatch(cgi = nil, session_options = ActionController::CgiRequest::DEFAULT_SESSION_OPTIONS, output = $stdout)
controller = nil
if cgi ||= new_cgi(output)
request, response = ActionController::CgiRequest.new(cgi, session_options), ActionController::CgiResponse.new(cgi)
prepare_application
controller = ActionController::Routing::Routes.recognize(request)
controller.process(request, response).out(output)
end
rescue Exception => exception # errors from CGI dispatch
failsafe_response(output, '500 Internal Server Error', exception) do
controller ||= const_defined?(:ApplicationController) ? ApplicationController : ActionController::Base
controller.process_with_exception(request, response, exception).out(output)
end
ensure
# Do not give a failsafe response here.
reset_after_dispatch
end
# Reset the application by clearing out loaded controllers, views, actions,
# mailers, and so forth. This allows them to be loaded again without having
# to restart the server (WEBrick, FastCGI, etc.).
def reset_application!
ActiveRecord::Base.reset_subclasses if defined?(ActiveRecord)
Dependencies.clear
ActiveSupport::Deprecation.silence do # TODO: Remove after 1.2
Class.remove_class(*Reloadable.reloadable_classes)
end
end
# Add a preparation callback. Preparation callbacks are run before every
# request in development mode, and before the first request in production
# mode.
#
# An optional identifier may be supplied for the callback. If provided,
# to_prepare may 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 to_prepare(identifier = nil, &block)
unless identifier.nil?
callback = preparation_callbacks.detect { |ident, _| ident == identifier }
if callback # Already registered: update the existing callback
callback[-1] = block
return
end
end
preparation_callbacks << [identifier, block]
nil
end
private
attr_accessor :preparation_callbacks, :preparation_callbacks_run
alias_method :preparation_callbacks_run?, :preparation_callbacks_run
# CGI.new plus exception handling. CGI#read_multipart raises EOFError
# if body.empty? or body.size != Content-Length and raises ArgumentError
# if Content-Length is non-integer.
def new_cgi(output)
failsafe_response(output, '400 Bad Request') { CGI.new }
end
def prepare_application
if Dependencies.load?
ActionController::Routing::Routes.reload
self.preparation_callbacks_run = false
end
prepare_breakpoint
Dependencies.require_or_load('application.rb', "ApplicationController") unless Object.const_defined?(:ApplicationController)
ActiveRecord::Base.verify_active_connections! if defined?(ActiveRecord)
run_preparation_callbacks
end
def reset_after_dispatch
reset_application! if Dependencies.load?
Breakpoint.deactivate_drb if defined?(BREAKPOINT_SERVER_PORT)
end
def prepare_breakpoint
return unless defined?(BREAKPOINT_SERVER_PORT)
require 'breakpoint'
Breakpoint.activate_drb("druby://localhost:#{BREAKPOINT_SERVER_PORT}", nil, !defined?(FastCGI))
true
rescue
nil
end
def run_preparation_callbacks
return if preparation_callbacks_run?
preparation_callbacks.each { |_, callback| callback.call }
self.preparation_callbacks_run = true
end
# If the block raises, send status code as a last-ditch response.
def failsafe_response(output, status, exception = nil)
yield
rescue Exception # errors from executed block
begin
output.write "Status: #{status}\r\n"
if exception
message = exception.to_s + "\r\n" + exception.backtrace.join("\r\n")
error_path = File.join(RAILS_ROOT, 'public', '500.html')
if defined?(RAILS_DEFAULT_LOGGER) && !RAILS_DEFAULT_LOGGER.nil?
RAILS_DEFAULT_LOGGER.fatal(message)
output.write "Content-Type: text/html\r\n\r\n"
if File.exists?(error_path)
output.write(IO.read(error_path))
else
output.write("<html><body><h1>Application error (Rails)</h1></body></html>")
end
else
output.write "Content-Type: text/plain\r\n\r\n"
output.write(message)
end
end
rescue Exception # Logger or IO errors
end
end
end
self.preparation_callbacks = []
self.preparation_callbacks_run = false
end
Dispatcher.to_prepare :activerecord_instantiate_observers do
ActiveRecord::Base.instantiate_observers
end if defined?(ActiveRecord)
