will support Deferreds so this will get easier. However, until then, you can still have asynchronous render_GET implementations. You just have to use NOT_DONE_YET.
I have made some changes to my test code and it works. A request to module_1 is possible will there is a request to moduleSlow2. Multiple calls to moduleSlow2 have to wait until the other one finishes. But calling module_1 still works. Should be oke for my webapplication. changed it to: from twisted.web import resource, static, server from twisted.web.server import NOT_DONE_YET from twisted.internet import reactor from twisted.internet.defer import Deferred from twisted.internet.threads import deferToThread import datetime, time def tijd(): return datetime.datetime.today().strftime("%Y-%m-%dT%H:%M:%S") class module_1(resource.Resource): def render_GET(self, request): request.write(tijd()) return "" class moduleSlow2(resource.Resource): def render_GET(self, request): d = deferToThread(self.answer, request) d.addCallback(request.write) d.addCallback(lambda _: request.finish()) return NOT_DONE_YET def answer(self, request): time.sleep(10) return "finished %s" % tijd() root = static.File("d:/www") root.putChild("module1", module_1()) root.putChild("slow2", moduleSlow2()) reactor.listenTCP(8900, server.Site(root)) print "Reactor run" reactor.run( ) Regars, Tjerk