Downloads

Get Started with Pip

$virtualenvtry-twisted
$ . try-twisted/bin/activate
$ pip install twisted[tls]
$ twist --help

Download Direct from PyPI

​https://pypi.org/project/Twisted/

Optional Dependencies

• ​Install Extras

Community

See the code ​for Twisted (​and more) on GitHub

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What is Twisted?

Twisted is an event-driven networking engine written in Python and licensed under the open source ​MIT license. Twisted runs on Python 2 and an ever growing subset also works with Python 3.

Code Examples

• Echo Server
• Web Server
• Publish/Subscribe
• Mail Client

Twisted makes it easy to implement custom network applications. Here's a TCP server that echoes back everything that's written to it:

from twisted.internet import protocol, reactor, endpoints

class Echo(protocol.Protocol):
    def dataReceived(self, data):
        self.transport.write(data)

class EchoFactory(protocol.Factory):
    def buildProtocol(self, addr):
        return Echo()

endpoints.serverFromString(reactor, "tcp:1234").listen(EchoFactory())
reactor.run()

Learn more about ​writing servers, ​writing clients and the ​core networking libraries , including support for SSL, UDP, scheduled events, unit testing infrastructure, and much more.

Twisted includes an event-driven web server. Here's a sample web application; notice how the resource object persists in memory, rather than being recreated on each request:

from twisted.web import server, resource
from twisted.internet import reactor, endpoints

class Counter(resource.Resource):
    isLeaf = True
    numberRequests = 0

    def render_GET(self, request):
        self.numberRequests += 1
        request.setHeader(b"content-type", b"text/plain")
        content = u"I am request #{}\n".format(self.numberRequests)
        return content.encode("ascii")

endpoints.serverFromString(reactor, "tcp:8080").listen(server.Site(Counter()))
reactor.run()

Learn more about ​web application development, ​templates and Twisted's ​HTTP client.

Here's a simple publish/subscribe server, where clients see all messages posted by other clients:

from twisted.internet import reactor, protocol, endpoints
from twisted.protocols import basic

class PubProtocol(basic.LineReceiver):
    def __init__(self, factory):
        self.factory = factory

    def connectionMade(self):
        self.factory.clients.add(self)

    def connectionLost(self, reason):
        self.factory.clients.remove(self)

    def lineReceived(self, line):
        for c in self.factory.clients:
            source = u"<{}> ".format(self.transport.getHost()).encode("ascii")
            c.sendLine(source + line)

class PubFactory(protocol.Factory):
    def __init__(self):
        self.clients = set()

    def buildProtocol(self, addr):
        return PubProtocol(self)

endpoints.serverFromString(reactor, "tcp:1025").listen(PubFactory())
reactor.run()

You can test this out by opening two terminals and doing telnet localhost 1025 in each, then typing things.

Twisted includes a sophisticated IMAP4 client library.

from __future__ import print_function

import sys

from twisted.internet import protocol, defer, endpoints, task
from twisted.mail import imap4
from twisted.python import failure

@defer.inlineCallbacks
def main(reactor, username="alice", password="secret",
         strport="tls:example.com:993"):
    endpoint = endpoints.clientFromString(reactor, strport)
    factory = protocol.Factory.forProtocol(imap4.IMAP4Client)
    try:
        client = yield endpoint.connect(factory)
        yield client.login(username, password)
        yield client.select('INBOX')
        info = yield client.fetchEnvelope(imap4.MessageSet(1))
        print('First message subject:', info[1]['ENVELOPE'][1])
    except:
        print("IMAP4 client interaction failed")
        failure.Failure().printTraceback()

task.react(main, sys.argv[1:])

Give this a try, supplying your IMAP4 username, password, and ​client endpoint description for your IMAP4 server. You'll see the subject of the first message in your mailbox printed.

See the TwistedMail documentation for more information.

More Protocols

Twisted also supports many common network protocols, including SMTP, POP3, IMAP, SSHv2, and DNS. For more information see our documentation and ​API reference.

Community

• Get in touch with the Twisted community through email, ​Stack Overflow or IRC;
• Learn about the Twisted development process and how to contribute;
• Read about software using Twisted and their success stories;
• Find out what Twisted Matrix Laboratories is;
• Learn about the individuals and organisations that aid Twisted with donations of hardware, software, hosting and other things;
• Help improve Twisted on Windows!