Using SSL With Evy
========================

Evy makes it easy to use non-blocking SSL sockets.  If you're using Python 2.6
or later, you're all set, evy wraps the built-in ssl module.  If on Python 2.5
or 2.4, you have to install pyOpenSSL_ to use evy.

In either case, the ``patched`` modules handle SSL sockets transparently, just
like their standard counterparts.  As an example, :mod:`evy.patched.urllib2` can
be used to fetch https urls in as non-blocking a fashion as you please::

    from evy.patched import urllib2
    from evy.green.threads import spawn
    bodies = [spawn(urllib2.urlopen, url)
         for url in ("https://secondlife.com","https://google.com")]
    for b in bodies:
        print b.wait().read()
 
 
With Python 2.6
----------------

To use ssl sockets directly in Python 2.6, use :mod:`evy.patched.ssl`, which is
a non-blocking wrapper around the standard Python :mod:`ssl` module, and which
has the same interface.  See the standard documentation for instructions on use.

PyOpenSSL
----------

:mod:`evy.patched.OpenSSL` has exactly the same interface as
pyOpenSSL_ `(docs) <http://pyopenssl.sourceforge.net/pyOpenSSL.html/>`_, 
and works in all versions of Python.  This module is much more powerful than
:func:`socket.ssl`, and may have some advantages over :mod:`ssl`, depending
on your needs.

Here's an example of a server::

    from evy.patched import socket
    from evy.patched.OpenSSL import SSL
    
    # insecure context, only for example purposes
    context = SSL.Context(SSL.SSLv23_METHOD)
    context.set_verify(SSL.VERIFY_NONE, lambda *x: True))

    # create underlying green socket and wrap it in ssl
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    connection = SSL.Connection(context, sock)
    
    # configure as server
    connection.set_accept_state()
    connection.bind(('127.0.0.1', 80443))
    connection.listen(50)
    
    # accept one client connection then close up shop
    client_conn, addr = connection.accept()
    print client_conn.read(100)
    client_conn.shutdown()
    client_conn.close()
    connection.close()

.. _pyOpenSSL: https://launchpad.net/pyopenssl