Using Twisted's Twisted.web Classes, How Do I Flush My Outgoing Buffers?
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
Solution 1:
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 pythonimport time
from twisted.web import http
from twisted.internet import protocol
from twisted.internet import reactor
from twisted.internet import defer
defwait(seconds, result=None):
"""Returns a deferred that will be fired later"""
d = defer.Deferred()
reactor.callLater(seconds, d.callback, result)
return d
classStreamHandler(http.Request):
BOUNDARY = 'BOUNDARY'defwriteBoundary(self):
self.write("--%s\n" % (self.BOUNDARY))
defwriteStop(self):
self.write("--%s--\n" % (self.BOUNDARY))
@defer.inlineCallbacksdefprocess(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()
classStreamProtocol(http.HTTPChannel):
requestFactory = StreamHandler
classStreamFactory(http.HTTPFactory):
protocol = StreamProtocol
if __name__ == '__main__':
reactor.listenTCP(8800, StreamFactory())
reactor.run()
That works in firefox, I guess it answers your question correctly.
Solution 2:
The reason seems to be explained in the FAQ for twisted. The twisted server does not actually write anything to the underlining connection until the reactor thread is free to run, in this case at the end of your method. However you can use reactor.doSelect(timeout) before each of your sleeps to make the reactor write what it has to the connection.
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