txsocksx 1.13.0.0rc2

Authenticating

One specifies authentication methods to a SOCKS5ClientEndpoint via the methods parameter. For example, to connect using the username spam and password eggs:

exampleEndpoint = SOCKS5ClientEndpoint(
    'example.com', 6667, proxyEndpoint, methods={'login': ('spam', 'eggs')})

However, this will disable anonymous authentication. To use either login or anonymous authentication, specify both methods:

exampleEndpoint = SOCKS5ClientEndpoint(
    'example.com', 6667, proxyEndpoint, methods={'login': ('spam', 'eggs'),
                                                 'anonymous': ()})

The methods dict must always map from a string to a tuple.

exampleEndpoint = SOCKS4ClientEndpoint(
    'example.com', 6667, proxyEndpoint, user='spam')

Connecting to a thing over tor

To connect to example.com on port 6667 over tor, one creates a SOCKS5ClientEndpoint wrapping the endpoint of the tor server:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
exampleEndpoint = SOCKS5ClientEndpoint('example.com', 6667, torServerEndpoint)

Establishing the connection from there proceeds like usual:

deferred = exampleEndpoint.connect(someFactory)

txsocksx will not do any DNS resolution, so the hostname example.com will not leak; tor will receive the hostname directly and do the DNS lookup itself.

Tor allows connections by SOCKS4 or SOCKS5, and does not expect a user ID to be sent when using the SOCKS4 client.

Cancelling a connection

Sometimes one tires of waiting and wants to abort the connection attempt. For example, to abort the whole connection attempt after ten seconds:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
exampleEndpoint = SOCKS5ClientEndpoint('example.com', 6667, torServerEndpoint)
deferred = exampleEndpoint.connect(someFactory)
reactor.callLater(10, deferred.cancel)

This is a trivial example; real code should cancel the IDelayedCall returned by reactor.callLater when the deferred fires. The code would then look like this:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
exampleEndpoint = SOCKS5ClientEndpoint('example.com', 6667, torServerEndpoint)
deferred = exampleEndpoint.connect(someFactory)
canceler = reactor.callLater(10, deferred.cancel)

def cancelCanceler(result):
    if canceler.active():
        canceler.cancel()
    return result
deferred.addBoth(cancelCanceler)

Making HTTP requests

Twisted’s builtin Agent HTTP client does not support being handed an arbitrary endpoint. (Yet. Ticket #6634 was filed to make this an API directly supported by Twisted.) txsocksx provides an Agent as a workaround, but it uses a private API. There are no guarantees that this approach will run in newer versions of Twisted, but txsocksx.http will attempt to provide a consistent API.

While txsocksx requires only Twisted 10.1, txsocksx.http requires Twisted 12.1 or greater. Its usage is almost identical to normal Agent usage:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
agent = SOCKS5Agent(reactor, proxyEndpoint=torServerEndpoint)
deferred = agent.request('GET', 'http://example.com/')

Note that the proxyEndpoint parameter must be passed as a keyword argument. There is a second, optional, keyword-only argument for passing additional arguments to the SOCKS5ClientEndpoint as SOCKS5Agent constructs it:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
agent = SOCKS5Agent(reactor, proxyEndpoint=torServerEndpoint,
                    endpointArgs=dict(methods={'login': ('spam', 'eggs')}))
deferred = agent.request('GET', 'http://example.com/')

SOCKS5Agent transparently supports HTTPS via TLSStarterClientEndpointWrapper.

Upgrading to TLS

Sometimes one wants to switch to speaking TLS as soon as the proxy negotiation is finished. For that, there is txsocksx.ssl [1]. After wrapping an endpoint with TLSStarterClientEndpointWrapper, the connection will be upgraded to using TLS immediately after proxy negotiation finishes:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
exampleEndpoint = SOCKS5ClientEndpoint('example.com', 6667, torServerEndpoint)
tlsEndpoint = TLSStarterClientEndpointWrapper(exampleEndpoint)
deferred = tlsEndpoint.connect(someFactory)

Proxying over a proxy

Because of txsocksx’s composable design, it’s trivial to connect from one SOCKS proxy to another:

torServerEndpoint = TCP4ClientEndpoint(reactor, '127.0.0.1', 9050)
firstProxyEndpoint = SOCKS5ClientEndpoint(
    'first-proxy.example.com', 1080, torServerEndpoint)
secondProxyEndpoint = SOCKS4ClientEndpoint(
    'second-proxy.example.com', 1080, firstProxyEndpoint)
finalHop = SOCKS5ClientEndpoint(
    'example.com', 113, secondProxyEndpoint)
deferred = finalHop.connect(someFactory)