Twisted带宽节流

Question

我试图设置下载/上传文件的速度限制，并发现扭曲的twisted.protocols.policies.ThrottlingFactory提供了处理这项工作的能力，但我做不到。我设置了readLimit和writeLimit，但是文件仍然在以最大速度下载。我做错了什么？

from twisted.protocols.basic import FileSender
from twisted.protocols.policies import ThrottlingFactory
from twisted.web import server, resource
from twisted.internet import reactor
import os

class DownloadPage(resource.Resource):
    isLeaf = True

    def __init__(self, producer):
        self.producer = producer

    def render(self, request):
        size = os.stat(somefile).st_size
        request.setHeader('Content-Type', 'application/octet-stream')
        request.setHeader('Content-Length', size)
        request.setHeader('Content-Disposition', 'attachment; filename="' + somefile + '"')
        request.setHeader('Accept-Ranges', 'bytes')

        fp = open(somefile, 'rb')
        d = self.producer.beginFileTransfer(fp, request)

        def err(error):
            print "error %s", error

        def cbFinished(ignored):
            fp.close()
            request.finish()
        d.addErrback(err).addCallback(cbFinished)

        return server.NOT_DONE_YET


producer = FileSender()
root_resource = resource.Resource()
root_resource.putChild('download', DownloadPage(producer))
site = server.Site(root_resource)
tsite = ThrottlingFactory(site, readLimit=10000, writeLimit=10000)
tsite.protocol.producer = producer
reactor.listenTCP(8080, tsite)
reactor.run()

更新

所以在我运行之后的某个时候：

2012-10-25 09:17:03+0600 [-] Unhandled Error
Traceback (most recent call last):
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/application/app.py", line 402, in startReactor
        self.config, oldstdout, oldstderr, self.profiler, reactor)
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/application/app.py", line 323, in runReactorWithLogging
        reactor.run()
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/internet/base.py", line 1169, in run
        self.mainLoop()
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/internet/base.py", line 1178, in mainLoop
        self.runUntilCurrent()
    --- <exception caught here> ---
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/internet/base.py", line 800, in runUntilCurrent
        call.func(*call.args, **call.kw)
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/protocols/policies.py", line 334, in unthrottleWrites
        p.unthrottleWrites()
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/protocols/policies.py", line 225, in unthrottleWrites
        self.producer.resumeProducing()
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/protocols/basic.py", line 919, in resumeProducing
        self.consumer.unregisterProducer()
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/web/http.py", line 811, in unregisterProducer
        self.transport.unregisterProducer()
      File "/home/chambylov/environments/transfer/local/lib/python2.7/site-packages/twisted/protocols/policies.py", line 209, in unregisterProducer
        del self.producer
    exceptions.AttributeError: ThrottlingProtocol instance has no attribute 'producer'

我发现我不应该像我知道tsite.protocol.producer = producer那样指派制片人，我对Twisted并不熟悉，我不知道如何用另一种方式去做。

Answer 1

每个生产者都需要(最终)注册您想要使用的数据。。我不认为这里任何地方都会发生注册。也许这就是你遇到的问题？

在像Friendster这样的大型项目中已经使用了Twisted，但是所有的回调都与我用python编写的方式不太一样(而且我对函数式编程也有一些经验)。我转到盖特姆。

如果您正在使用gevent库，那么许多细节(提供异步功能的回调/生成器)都会被抽象出来，这样您通常就可以只对代码进行猴子修补，并按照您习惯的面向对象的风格编写代码。如果您正在从事一个项目，任何不熟悉诸如js/lisp之类的回调重的语言的人，我敢打赌他们肯定会欣赏gevent而不是twisted。

Answer 2

正如牛油所说，你必须注册一个制片人。所以，不是这样的：

tsite.protocol.producer = producer

必须显式调用registerProducer方法：

tsite.protocol.registerProducer( ... )

或者，如果您使用FileSender作为生产者，则调用其方法，在本例中：

file_to_send = open( ... )
producer.beginFileTransfer(file_to_send, tsite.protocol)