Just a follow-up with my own sanity check example.
http://twistedmatrix.com/documents/current/web/howto/web-in-60/asynchronous-deferred.html
My conclusion is that deferLater is a blocking method - am I wrong?
On Wed, Dec 16, 2015 at 4:11 PM, Kevin Mcintyre <kebi...@gmail.com> wrote:
> Hey - I'm confused, so nothing new :) ...but I'm running at this example
> and I'm scratching my head.
>
>
> http://twistedmatrix.com/documents/current/web/howto/web-in-60/asynchronous-deferred.html
>
> I would've thought 2 requests could be served simultaneously, but when I
> fire off 2 requests the first received gets it's response after 5 seconds,
> while the second response takes 10 seconds.
>
> I think I understand what's happening, but I don't know why...and I would
> love an example where the subsequent request doesn't have to wait for the
> first request to finish.
>
> Thanks,
> Kevin
>
>
>
>
>
>
from twisted.internet.task import deferLater
from twisted.web.resource import Resource
from twisted.web.server import NOT_DONE_YET, Site
from twisted.internet import reactor, defer, threads
from twisted.web.xmlrpc import Proxy
from twisted.web.xmlrpc import XMLRPC
from twisted.web.client import getPage
import time
import xmlrpclib
class TestResource(Resource):
isLeaf = True
def render_ERROR(self, err, request):
print 'xmlrpc error:', self.__class__.__name__, err
request.finish()
def render_TIMESTAMP(self, ts, request):
request.write(str(ts))
request.finish()
def render_GET(self, request):
print 'test:', int(time.time())
d = Proxy('http://localhost:8082').callRemote('timestamp')
d.addCallback(self.render_TIMESTAMP, request)
d.addErrback(self.render_ERROR, request)
return NOT_DONE_YET
class Test1Resource(TestResource):
isLeaf = True
def render_GET(self, request):
print 'test1:', int(time.time())
d = threads.deferToThread(xmlrpclib.ServerProxy("http://localhost:8082";).timestamp)
d.addCallback(self.render_TIMESTAMP, request)
d.addErrback(self.render_ERROR, request)
return NOT_DONE_YET
class Test2Resource(XMLRPC):
def delayed_html(self):
time.sleep(5)
return int(time.time())
def xmlrpc_timestamp(self):
print 'timestamp:', int(time.time())
'''
blocking!!!!!!
return self.delayed_html()
'''
return threads.deferToThread(self.delayed_html)
def done_or_error(ans = None):
print 'done_or_error:', ans
reactor.stop()
def results(res, init_time):
print init_time, res[0][1], res[1][1], res[2][1], res[3][1], int(time.time())
def quad_request():
init_time = int(time.time())
dl = defer.DeferredList([getPage('http://localhost:8080'), getPage('http://localhost:8080'), getPage('http://localhost:8081'), getPage('http://localhost:8081')])
dl.addCallback(results, init_time)
dl.addBoth(done_or_error)
if __name__ == '__main__':
print 'start reactor'
reactor.listenTCP(8080, Site(TestResource()))
reactor.listenTCP(8081, Site(Test1Resource()))
reactor.listenTCP(8082, Site(Test2Resource()))
reactor.callWhenRunning(quad_request)
reactor.run()_______________________________________________
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