CODEWITHSUNDEEP
pythonsslhttpstwisted
Carl
Carl

Reputation: 715

Python Twisted How To Set the SSL Method for twisted.web.client.Agent using new IPolicyForHTTPS?

The Twisted howto docs for using Agent over SSL suggest using creating a ContextFactory, but the API docs for t.w.c.Agent show that the contextFactory argument is now supposed to be an object that implements t.w.i.IPolicyForHTTPS. The source code looks like it wraps old ContextFactories to implement the new interface, but it issues a deprecation warning.

How is one supposed to set the SSL method (e.g. SSLv3), using the new interface?

Using the old ContextFactory, I can understand where my code can receive a PyOpenSSL OpenSSL.SSL.Context and set the SSL method using that object. Using the new interface, it is not clear to me where my code can set the SSL method.

Upvotes: 2

Views: 1178

Answers (1)

L. Daniel Burr
L. Daniel Burr

Reputation: 26

If you really need to set the SSL method (the default is TLS 1.0 or higher), you will need to subclass twisted.web.client.BrowserLikePolicyForHTTPS (untested):

from OpenSSL import SSL
from twisted.internet import reactor, ssl
from twisted.web import client

class MyPolicy(client.BrowserLikePolicyForHTTPS):
    def creatorForNetloc(self, hostname, port):
        return ssl.optionsForClientTLS(
            hostname.decode("ascii"),
            extraCertificateOptions={'method': SSL.SSLv3_METHOD},
            trustRoot=self._trustRoot
        )

myAgent = client.Agent(reactor, contextFactory=MyPolicy())

Upvotes: 1

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