eventlet/examples/forwarder.py

   1 """ This is an incredibly simple port forwarder from port 7000 to 22 on
   2 localhost.  It calls a callback function when the socket is closed, to
   3 demonstrate one way that you could start to do interesting things by
   4 starting from a simple framework like this.
   5 """
   6
   7 import eventlet
   8
   9
  10 def closed_callback():
  11     print("called back")
  12
  13
  14 def forward(source, dest, cb=lambda: None):
  15     """Forwards bytes unidirectionally from source to dest"""
  16     while True:
  17         d = source.recv(32384)
  18         if d == '':
  19             cb()
  20             break
  21         dest.sendall(d)
  22
  23 listener = eventlet.listen(('localhost', 7000))
  24 while True:
  25     client, addr = listener.accept()
  26     server = eventlet.connect(('localhost', 22))
  27     # two unidirectional forwarders make a bidirectional one
  28     eventlet.spawn_n(forward, client, server, closed_callback)
  29     eventlet.spawn_n(forward, server, client)