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#!/usr/bin/env python3.7
#
# Copyright (c) 2013-2024 by Ron Frederick <ronf@timeheart.net> and others.
#
# This program and the accompanying materials are made available under
# the terms of the Eclipse Public License v2.0 which accompanies this
# distribution and is available at:
#
# http://www.eclipse.org/legal/epl-2.0/
#
# This program may also be made available under the following secondary
# licenses when the conditions for such availability set forth in the
# Eclipse Public License v2.0 are satisfied:
#
# GNU General Public License, Version 2.0, or any later versions of
# that license
#
# SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
#
# Contributors:
# Ron Frederick - initial implementation, API, and documentation
# To run this program, the file ``ssh_host_key`` must exist with an SSH
# private key in it to use as a server host key. An SSH host certificate
# can optionally be provided in the file ``ssh_host_key-cert.pub``.
#
# The file ``ssh_user_ca`` must exist with a cert-authority entry of
# the certificate authority which can sign valid client certificates.
import asyncio, asyncssh, sys
from typing import cast
async def handle_client(process: asyncssh.SSHServerProcess):
channel = cast(asyncssh.SSHLineEditorChannel, process.channel)
username = process.get_extra_info('username')
process.stdout.write(f'Welcome to my SSH server, {username}!\n\n')
channel.set_echo(False)
process.stdout.write('Tell me a secret: ')
secret = await process.stdin.readline()
channel.set_line_mode(False)
process.stdout.write('\nYour secret is safe with me! '
'Press any key to exit...')
await process.stdin.read(1)
process.stdout.write('\n')
process.exit(0)
async def start_server() -> None:
await asyncssh.listen('', 8022, server_host_keys=['ssh_host_key'],
authorized_client_keys='ssh_user_ca',
process_factory=handle_client)
loop = asyncio.new_event_loop()
try:
loop.run_until_complete(start_server())
except (OSError, asyncssh.Error) as exc:
sys.exit('Error starting server: ' + str(exc))
loop.run_forever()
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