我正在尝试编写一个简单的http服务器来处理在数据结构中查找响应或超时的异步请求：

>请求到达

>时间

>如果回复,请将其退回

>如果超时,则返回超时消息

我是新手,我想知道做异步响应的最佳方法是什么.我看了some twisted Deferred docs和callLater,但我不清楚到底应该做些什么.现在我使用deferToThread运行阻塞方法并等待超时.我的延迟方法得到一个字符串不可调用的错误：

Unhandled error in Deferred:

Traceback (most recent call last):

File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 497, in __bootstrap

self.__bootstrap_inner()

File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 522, in __bootstrap_inner

self.run()

File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 477, in run

self.__target(*self.__args, **self.__kwargs)

--- ---

File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/python/threadpool.py", line 210, in _worker

result = context.call(ctx, function, *args, **kwargs)

File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/python/context.py", line 59, in callWithContext

return self.currentContext().callWithContext(ctx, func, *args, **kw)

File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/python/context.py", line 37, in callWithContext

return func(*args,**kw)

exceptions.TypeError: 'str' object is not callable

这是我的代码：

from twisted.web import server, resource

from twisted.internet import reactor, threads

import json

import time

connectedClients = {}

responseCollector = {}

# add fake data to the collector

class FakeData(resource.Resource):

isLeaf = True

def render_GET(self, request):

request.setHeader("content-type", "application/json")

if 'rid' in request.args and 'data' in request.args:

rid = request.args['rid'][0]

data = request.args['data'][0]

responseCollector[str(rid)] = data

return json.dumps(responseCollector)

return "{}"

class RequestHandler(resource.Resource):

isLeaf = True

def render_GET(self, request):

#request.setHeader("content-type", "application/json")

if not ('rid' in request.args and and 'json' in request.args):

return '{"success":"false","response":"invalid request"}'

rid = request.args['rid'][0]

json = request.args['id'][0]

# TODO: Wait for data to show up in the responseCollector with same rid

# as our request without blocking other requests OR timeout

d = threads.deferToThread(self.blockingMethod(rid))

d.addCallback(self.ret)

d.addErrback(self.err)

def blockingMethod(self,rid):

timeout = 5.0

timeElapsed = 0.0

while timeElapsed

if rid in responseCollector:

return responseCollector[rid]

else:

timeElapsed+=0.01

time.sleep(0.01)

return "timeout"

def ret(self, hdata):

return hdata

def err(self, failure):

return failure

reactor.listenTCP(8080, server.Site(RequestHandler()))

reactor.listenTCP(9080, server.Site(FakeData()))

reactor.run()

发出请求(当前没有返回任何有用的内容)：

http://localhost:8080/?rid=1234&json={%22foo%22:%22bar%22}

添加一些假数据以用于请求：

http://localhost:9080/?rid=1234&data=foo

更新了工作版本

from twisted.web import server, resource

from twisted.internet import reactor, threads

import json

import time

connectedClients = {}

responseCollector = {}

# add fake data to the collector

class FakeData(resource.Resource):

isLeaf = True

def render_GET(self, request):

request.setHeader("content-type", "application/json")

if 'rid' in request.args and 'data' in request.args:

rid = request.args['rid'][0]

data = request.args['data'][0]

responseCollector[str(rid)] = data

return json.dumps(responseCollector)

return "{}"

class RequestHandler(resource.Resource):

isLeaf = True

def render_GET(self, request):

if not ('rid' in request.args and 'data' in request.args):

return '{"success":"false","response":"invalid request"}'

rid = request.args['rid'][0]

json = request.args['data'][0]

# TODO: Wait for data to show up in the responseCollector with same rid

# as our request without blocking other requests OR timeout

d = threads.deferToThread(self.blockingMethod,rid)

d.addCallback(self.ret, request)

d.addErrback(self.err)

return server.NOT_DONE_YET

def blockingMethod(self,rid):

timeout = 5.0

timeElapsed = 0.0

while timeElapsed

if rid in responseCollector:

return responseCollector[rid]

else:

timeElapsed+=0.01

time.sleep(0.01)

return "timeout"

def ret(self, result, request):

request.write(result)

request.finish()

def err(self, failure):

return failure

reactor.listenTCP(8080, server.Site(RequestHandler()))

reactor.listenTCP(9080, server.Site(FakeData()))

reactor.run()

解决方法:

在render_GET()中,您应该返回twisted.web.server.NOT_DONE_YET.您应该将请求对象传递给ret方法：d.addCallback(self.ret,request)

然后在ret(请求)中,您应该使用request.write(hdata)编写异步数据并关闭与request.finish()的连接.

def ret(self, result, request):

request.write(result)

request.finish()

Resource rendering occurs when Twisted Web locates a leaf Resource

object to handle a web request. A Resource’s render method may do

various things to produce output which will be sent back to the

browser:

Return a string

Request a Deferred, return server.NOT_DONE_YET,

and call request.write(“stuff”) and request.finish() later, in a

callback on the Deferred.

标签：python,twisted,twisted-web

来源： https://codeday.me/bug/20190729/1573193.html