See issue 4 <https://github.com/smurfix/asynctelnet/issues/4>_.
Short version: the current code has a lot of problems and bugs; it inherited many of the former from telnetlib3, the latter are mainly a result of incomplete conversion to async-land.
It will be modularized and rewritten. The API will change.
Its current state is "be prepared to code some bug workarounds if you want to use it".
asynctelnet is an asynchronous Telnet Client and Server library for python. This project requires python 3.6 and later, using the anyio module.
asynctelnet is a heavily modified anyio-ization of the telnetlib3 module.
Authoring a Telnet Server using Streams interface that offers a basic war game:
import anyio, asynctelnet
async def shell(tcp):
async with asynctelnet.TelnetServer(tcp) as stream:
# this will fail if no charset has been negotiated
await stream.send('\r\nWould you like to play a game? ')
inp = await reader.receive(1)
if inp:
await stream.echo(inp)
await stream.send('\r\nThey say the only way to win '
'is to not play at all.\r\n')
async def main():
listener = await anyio.create_tcp_listener(local_port=56023)
await listener.serve(shell)
anyio.run(main)Authoring a Telnet Client that plays the war game with this server:
import anyio, asynctelnet
async def shell(tcp):
async with asynctelnet.TelnetClient(tcp, client=True) as stream:
while True:
# read stream until '?' mark is found
outp = await stream.receive(1024)
if not outp:
# End of File
break
elif '?' in outp:
# reply all questions with 'y'.
await stream.send('y')
# display all server output
print(outp, flush=True)
# EOF
print()
async def main():
async with await connect_tcp('localhost', 56023) as client:
await shell(client)
anyio.run(main)Two command line scripts are distributed with this package.
asynctelnet-client
Small terminal telnet client. Some example destinations and options:
asynctelnet-client nethack.alt.org asynctelnet-client --encoding=cp437 --force-binary blackflag.acid.org asynctelnet-client htc.zapto.org
asynctelnet-server
Telnet server providing the default debugging shell. This provides a simple shell server that allows introspection of the session's values, for example:
tel:sh> help quit, writer, slc, toggle [option|all], reader, proto tel:sh> writer <TelnetWriter server mode:kludge +lineflow -xon_any +slc_sim server-will:BINARY,ECHO,SGA client-will:BINARY,NAWS,NEW_ENVIRON,TTYPE> tel:sh> reader <TelnetReaderUnicode encoding='utf8' limit=65536 buflen=0 eof=False> tel:sh> toggle all wont echo. wont suppress go-ahead. wont outbinary. dont inbinary. xon-any enabled. lineflow disabled. tel:sh> reader <TelnetReaderUnicode encoding='US-ASCII' limit=65536 buflen=1 eof=False> tel:sh> writer <TelnetWriter server mode:local -lineflow +xon_any +slc_sim client-will:NAWS,NEW_ENVIRON,TTYPE>
Both command-line scripts accept argument --shell=my_module.fn_shell
describing a python module path to a coroutine of signature
shell(reader, writer), just as the above examples.
The following RFC specifications are implemented:
- rfc-727, "Telnet Logout Option," Apr 1977.
- rfc-779, "Telnet Send-Location Option", Apr 1981.
- rfc-854, "Telnet Protocol Specification", May 1983.
- rfc-855, "Telnet Option Specifications", May 1983.
- rfc-856, "Telnet Binary Transmission", May 1983.
- rfc-857, "Telnet Echo Option", May 1983.
- rfc-858, "Telnet Suppress Go Ahead Option", May 1983.
- rfc-859, "Telnet Status Option", May 1983.
- rfc-860, "Telnet Timing mark Option", May 1983.
- rfc-885, "Telnet End of Record Option", Dec 1983.
- rfc-1073, "Telnet Window Size Option", Oct 1988.
- rfc-1079, "Telnet Terminal Speed Option", Dec 1988.
- rfc-1091, "Telnet Terminal-Type Option", Feb 1989.
- rfc-1096, "Telnet X Display Location Option", Mar 1989.
- rfc-1123, "Requirements for Internet Hosts", Oct 1989.
- rfc-1184, "Telnet Linemode Option (extended options)", Oct 1990.
- rfc-1372, "Telnet Remote Flow Control Option", Oct 1992.
- rfc-1408, "Telnet Environment Option", Jan 1993.
- rfc-1571, "Telnet Environment Option Interoperability Issues", Jan 1994.
- rfc-1572, "Telnet Environment Option", Jan 1994.
- rfc-2066, "Telnet Charset Option", Jan 1997.
Further documentation available at https://asynctelnet.readthedocs.org/