Using SSL With Eventlet
***********************

Eventlet makes it easy to use non-blocking SSL sockets.  If you're
using Python 2.7 or later, you're all set, eventlet wraps the built-in
ssl module.

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

   from eventlet.green import urllib2
   from eventlet import spawn
   bodies = [spawn(urllib2.urlopen, url)
        for url in ("https://secondlife.com","https://google.com")]
   for b in bodies:
       print(b.wait().read())


PyOpenSSL
=========

"eventlet.green.OpenSSL" has exactly the same interface as pyOpenSSL
(docs), and works in all versions of Python.  This module is much more
powerful than "socket.ssl()", and may have some advantages over "ssl",
depending on your needs.

For testing purpose first create self-signed certificate using
following commands

   $ openssl genrsa 1024 > server.key
   $ openssl req -new -x509 -nodes -sha1 -days 365 -key server.key > server.cert

Keep these Private key and Self-signed certificate in same directory
as *server.py* and *client.py* for simplicity sake.

Here's an example of a server (*server.py*)

   from eventlet.green import socket
   from eventlet.green.OpenSSL import SSL

   # insecure context, only for example purposes
   context = SSL.Context(SSL.SSLv23_METHOD)
   # Pass server's private key created
   context.use_privatekey_file('server.key')
   # Pass self-signed certificate created
   context.use_certificate_file('server.cert')

   # 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', 8443))
   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()

Here's an example of a client (*client.py*)

   import socket
   # Create socket
   s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
   # Connect to server
   s.connect(('127.0.0.1', 8443))
   sslSocket = socket.ssl(s)
   print repr(sslSocket.server())
   print repr(sslSocket.issuer())
   sslSocket.write('Hello secure socket\n')
   # Close client
   s.close()

Running example:

In first terminal

   $ python server.py

In another terminal

   $ python client.py
