1#!/usr/bin/env python3.6
2#
3# Copyright (c) 2013-2018 by Ron Frederick <ronf@timeheart.net> and others.
4#
5# This program and the accompanying materials are made available under
6# the terms of the Eclipse Public License v2.0 which accompanies this
7# distribution and is available at:
8#
9#     http://www.eclipse.org/legal/epl-2.0/
10#
11# This program may also be made available under the following secondary
12# licenses when the conditions for such availability set forth in the
13# Eclipse Public License v2.0 are satisfied:
14#
15#    GNU General Public License, Version 2.0, or any later versions of
16#    that license
17#
18# SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
19#
20# Contributors:
21#     Ron Frederick - initial implementation, API, and documentation
22
23# To run this program, the file ``ssh_host_key`` must exist with an SSH
24# private key in it to use as a server host key. An SSH host certificate
25# can optionally be provided in the file ``ssh_host_key-cert.pub``.
26#
27# The file ``ssh_user_ca`` must exist with a cert-authority entry of
28# the certificate authority which can sign valid client certificates.
29
30import asyncio, asyncssh, sys
31
32class MySSHServerSession(asyncssh.SSHServerSession):
33    def __init__(self):
34        self._input = ''
35        self._total = 0
36
37    def connection_made(self, chan):
38        self._chan = chan
39
40    def shell_requested(self):
41        return True
42
43    def session_started(self):
44        self._chan.write('Enter numbers one per line, or EOF when done:\n')
45
46    def data_received(self, data, datatype):
47        self._input += data
48
49        lines = self._input.split('\n')
50        for line in lines[:-1]:
51            try:
52                if line:
53                    self._total += int(line)
54            except ValueError:
55                self._chan.write_stderr('Invalid number: %s\n' % line)
56
57        self._input = lines[-1]
58
59    def eof_received(self):
60        self._chan.write('Total = %s\n' % self._total)
61        self._chan.exit(0)
62
63    def break_received(self, msec):
64        self.eof_received()
65
66class MySSHServer(asyncssh.SSHServer):
67    def session_requested(self):
68        return MySSHServerSession()
69
70async def start_server():
71    await asyncssh.create_server(MySSHServer, '', 8022,
72                                 server_host_keys=['ssh_host_key'],
73                                 authorized_client_keys='ssh_user_ca')
74
75loop = asyncio.get_event_loop()
76
77try:
78    loop.run_until_complete(start_server())
79except (OSError, asyncssh.Error) as exc:
80    sys.exit('Error starting server: ' + str(exc))
81
82loop.run_forever()
83