使用 Twisted 的twisted.web 类，如何刷新我的传出缓冲区? [英] Using Twisted's twisted.web classes, how do I flush my outgoing buffers?
问题描述
我使用 Twisted 创建了一个简单的 http 服务器，它发送 Content-Type: multipart/x-mixed-replace 标头.我正在使用它来测试我想设置为接受长期流的 http 客户端.
I've made a simple http server using Twisted, which sends the Content-Type: multipart/x-mixed-replace header. I'm using this to test an http client which I want to set up to accept a long-term stream.
出现的问题是我的客户端请求挂起，直到 http.Request 调用 self.finish()，然后它一次接收所有多部分文档.
The problem that has arisen is that my client request hangs until the http.Request calls self.finish(), then it receives all multipart documents at once.
有没有办法手动将输出缓冲区刷新到客户端?我想这就是我没有收到单独的多部分文档的原因.
Is there a way to manually flush the output buffers down to the client? I'm assuming this is why I'm not receiving the individual multipart documents.
#!/usr/bin/env python
import time
from twisted.web import http
from twisted.internet import protocol
class StreamHandler(http.Request):
BOUNDARY = 'BOUNDARY'
def writeBoundary(self):
self.write("--%s\n" % (self.BOUNDARY))
def writeStop(self):
self.write("--%s--\n" % (self.BOUNDARY))
def process(self):
self.setHeader('Connection', 'Keep-Alive')
self.setHeader('Content-Type', "multipart/x-mixed-replace;boundary=%s" % (self.BOUNDARY))
self.writeBoundary()
self.write("Content-Type: text/html\n")
s = "<html>foo</html>\n"
self.write("Content-Length: %s\n\n" % (len(s)))
self.write(s)
self.writeBoundary()
time.sleep(2)
self.write("Content-Type: text/html\n")
s = "<html>bar</html>\n"
self.write("Content-Length: %s\n\n" % (len(s)))
self.write(s)
self.writeBoundary()
time.sleep(2)
self.write("Content-Type: text/html\n")
s = "<html>baz</html>\n"
self.write("Content-Length: %s\n\n" % (len(s)))
self.write(s)
self.writeStop()
self.finish()
class StreamProtocol(http.HTTPChannel):
requestFactory = StreamHandler
class StreamFactory(http.HTTPFactory):
protocol = StreamProtocol
if __name__ == '__main__':
from twisted.internet import reactor
reactor.listenTCP(8800, StreamFactory())
reactor.run()
推荐答案
使用 time.sleep() 可以防止 twisted 执行其工作.为了使它工作，你不能使用 time.sleep()，你必须将控制权返回给扭曲.修改现有代码的最简单方法是使用 twisted.internet.defer.inlineCallbacks，这是自切片面包以来的下一个最好的东西:
Using time.sleep() prevents twisted from doing its job. To make it work you can't use time.sleep(), you must return control to twisted instead. The easiest way to modify your existing code to do that is by using twisted.internet.defer.inlineCallbacks, which is the next best thing since sliced bread:
#!/usr/bin/env python
import time
from twisted.web import http
from twisted.internet import protocol
from twisted.internet import reactor
from twisted.internet import defer
def wait(seconds, result=None):
"""Returns a deferred that will be fired later"""
d = defer.Deferred()
reactor.callLater(seconds, d.callback, result)
return d
class StreamHandler(http.Request):
BOUNDARY = 'BOUNDARY'
def writeBoundary(self):
self.write("--%s\n" % (self.BOUNDARY))
def writeStop(self):
self.write("--%s--\n" % (self.BOUNDARY))
@defer.inlineCallbacks
def process(self):
self.setHeader('Connection', 'Keep-Alive')
self.setHeader('Content-Type', "multipart/x-mixed-replace;boundary=%s" % (self.BOUNDARY))
self.writeBoundary()
self.write("Content-Type: text/html\n")
s = "<html>foo</html>\n"
self.write("Content-Length: %s\n\n" % (len(s)))
self.write(s)
self.writeBoundary()
yield wait(2)
self.write("Content-Type: text/html\n")
s = "<html>bar</html>\n"
self.write("Content-Length: %s\n\n" % (len(s)))
self.write(s)
self.writeBoundary()
yield wait(2)
self.write("Content-Type: text/html\n")
s = "<html>baz</html>\n"
self.write("Content-Length: %s\n\n" % (len(s)))
self.write(s)
self.writeStop()
self.finish()
class StreamProtocol(http.HTTPChannel):
requestFactory = StreamHandler
class StreamFactory(http.HTTPFactory):
protocol = StreamProtocol
if __name__ == '__main__':
reactor.listenTCP(8800, StreamFactory())
reactor.run()
这在 Firefox 中有效，我想它可以正确回答您的问题.
That works in firefox, I guess it answers your question correctly.
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