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# This is the Twisted Get Poetry Now! client, version 5.1
import optparse, random, sys
from twisted.internet import defer
from twisted.internet.protocol import Protocol, ClientFactory
def parse_args():
usage = """usage: %prog [options] [hostname]:port ...
This is the Get Poetry Now! client, Twisted version 5.1
Run it like this:
python get-poetry-1.py port1 port2 port3 ...
If you are in the base directory of the twisted-intro package,
you could run it like this:
python twisted-client-5/get-poetry-1.py 10001 10002 10003
to grab poetry from servers on ports 10001, 10002, and 10003.
Of course, there need to be servers listening on those ports
for that to work.
"""
parser = optparse.OptionParser(usage)
_, addresses = parser.parse_args()
if not addresses:
print parser.format_help()
parser.exit()
def parse_address(addr):
if ':' not in addr:
host = '127.0.0.1'
port = addr
else:
host, port = addr.split(':', 1)
if not port.isdigit():
parser.error('Ports must be integers.')
return host, int(port)
return map(parse_address, addresses)
class PoetryProtocol(Protocol):
poem = ''
def dataReceived(self, data):
self.poem += data
def connectionLost(self, reason):
self.poemReceived(self.poem)
def poemReceived(self, poem):
self.factory.poem_finished(poem)
class PoetryClientFactory(ClientFactory):
protocol = PoetryProtocol
def __init__(self, deferred):
self.deferred = deferred
def poem_finished(self, poem):
if self.deferred is not None:
d, self.deferred = self.deferred, None
d.callback(poem)
def clientConnectionFailed(self, connector, reason):
if self.deferred is not None:
d, self.deferred = self.deferred, None
d.errback(reason)
def get_poetry(host, port):
"""
Download a poem from the given host and port. This function
returns a Deferred which will be fired with the complete text of
the poem or a Failure if the poem could not be downloaded.
"""
d = defer.Deferred()
from twisted.internet import reactor
factory = PoetryClientFactory(d)
reactor.connectTCP(host, port, factory)
return d
class GibberishError(Exception): pass
class CannotCummingsify(Exception): pass
def cummingsify(poem):
"""
Randomly do one of the following:
1. Return a cummingsified version of the poem.
2. Raise a GibberishError.
3. Raise a CannotCummingsify error with the original poem
as the first argument.
"""
def success():
return poem.lower()
def gibberish():
raise GibberishError()
def bug():
raise CannotCummingsify(poem)
return random.choice([success, gibberish, bug])()
def poetry_main():
addresses = parse_args()
from twisted.internet import reactor
poems = []
errors = []
def cummingsify_failed(err):
if err.check(CannotCummingsify):
print 'Cummingsify failed!'
return err.value.args[0]
return err
def got_poem(poem):
print poem
poems.append(poem)
def poem_failed(err):
print >>sys.stderr, 'The poem download failed.'
errors.append(err)
def poem_done(_):
if len(poems) + len(errors) == len(addresses):
reactor.stop()
for address in addresses:
host, port = address
d = get_poetry(host, port)
d.addCallback(cummingsify)
d.addErrback(cummingsify_failed)
d.addCallbacks(got_poem, poem_failed)
d.addBoth(poem_done)
reactor.run()
if __name__ == '__main__':
poetry_main()