J.P's excellent article http://jcalderone.livejournal.com/50890.html explains how to avoid calling Request.finish() on a request after its connection was lost, because that now raises an exception. The code in the article is able to avoid calling finish() because it handles the rendering itself. The call to finish() is right there in _delayedRender. But I'm using Nevow (because it's awesome) and all that stuff is done behind the scenes, where I can't get to it.
My application has a form, which uses the Post/Redirect/Get pattern (http://en.wikipedia.org/wiki/Post/Redirect/Get) to avoid double-posting. Because processing is not instant, the browser receives the HTTP header telling it to redirect before the processing has finished. When the processing finishes, the Deferred embedded in the web page fires with a value, Stan finishes flattening the page, and Nevow calls Request.finish(). By then the browser has closed the connection and sent in the GET request. So I get an error every single time. What is the correct method to tell Nevow to abandon the request, please? This is a completely self-contained example, to be run with twistd: from nevow import tags, inevow, loaders, appserver from nevow.rend import Page from nevow.url import URL from twisted.internet.task import deferLater from twisted.internet import reactor from twisted.application import service from twisted.application.internet import TCPServer from twisted.web import http class Redirector(Page): count = 0 message = 0 def _increment(self): self.count += 1 return self.count def slow_operation(self): return deferLater(reactor, 3, self._increment) def beforeRender(self, ctx): req = inevow.IRequest(ctx) if req.method == 'POST': oldurl = URL.fromContext(ctx) newurl = oldurl.remove('cmd') req.setResponseCode(http.SEE_OTHER) req.setHeader("Location", newurl) self.message = self.slow_operation() def render_message(self, ctx, data): return self.message docFactory = loaders.stan( tags.html[ tags.head[tags.title['Slow page']], tags.body[ tags.h1['Problem with interrupted connections'], tags.form(method='post', action='')[ tags.button(type='submit', name='cmd', value='click')[ 'Click' ] ], tags.p(render=tags.directive('message')) ] ] ) application = service.Application('Demo') site = appserver.NevowSite(Redirector()) webservice = TCPServer(8123, site) webservice.setName('WUI') webservice.setServiceParent(application) Thanks in advance, Peter. _______________________________________________ Twisted-web mailing list [email protected] http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-web
