Manually giving the twisted (web) network stack a packet to process?

I am running an HTTP server using the twisted framework. Is there any way I can "manually" ask it to process some payload? For example, if I've constructed some Ethernet frame can I 开发者_运维技巧ask twisted's reactor to handle it just as if it had just arrived on my network card?

You can do something like this:

from twisted.web import server
from twisted.web.resource import Resource
from twisted.internet import reactor
from twisted.internet.protocol import Protocol, ClientFactory

class SomeWebThing(Resource):
    def render_GET(self, request):
        return "hello\n"

class SomeClient(Protocol):
    def dataReceived(self, data):
        p = self.factory.site.buildProtocol(self.transport.addr)
        p.transport = self.transport
        p.dataReceived(data)

class SomeClientFactory(ClientFactory):
    protocol = SomeClient
    def __init__(self, site):
        self.site = site

if __name__ == '__main__':
    root = Resource()
    root.putChild('thing', SomeWebThing())
    site = server.Site(root)
    reactor.listenTCP(8000, site)

    factory = SomeClientFactory(site)
    reactor.connectTCP('localhost', 9000, factory)

    reactor.run()

and save it as simpleinjecter.py, if you then do (from the commandline):

echo -e "GET /thing HTTP/1.1\r\n\r\n" | nc -l 9000  # runs a server, ready to send req to first client connection
python simpleinjecter.py

it should work as expected, with the request from the nc server on port 9000 getting funneled as the payload into the twisted web server, and the response coming back as expected.

The key lines are in SomeClient.dataRecieved(). You'll need a transport object with the right methods -- in the example above, I just steal the object from the client connection. If you aren't going to do that, I imagine you'll have to make one up, as the stack will want to do things like call getPeer() on it.

What is the use-case?

Perhaps you want to create your own Datagram Protocol

At the base, the place where you actually implement the protocol parsing and handling, is the DatagramProtocol class. This class will usually be decended from twisted.internet.protocol.DatagramProtocol. Most protocol handlers inherit either from this class or from one of its convenience children. The DatagramProtocol class receives datagrams, and can send them out over the network. Received datagrams include the address they were sent from, and when sending datagrams the address to send to must be specified.

If you want to see wire-level transmissions rather than inject them, install and run WireShark, the fantastic, free packet sniffer.