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evennia/evennia/server/portal/telnet.py

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"""
This module implements the telnet protocol.
This depends on a generic session module that implements
the actual login procedure of the game, tracks
sessions etc.
"""
import re
from twisted.internet.task import LoopingCall
from twisted.conch.telnet import Telnet, StatefulTelnetProtocol
from twisted.conch.telnet import IAC, NOP, LINEMODE, GA, WILL, WONT, ECHO
from django.conf import settings
from evennia.server.session import Session
from evennia.server.portal import ttype, mssp, telnet_oob, naws
from evennia.server.portal.mccp import Mccp, mccp_compress, MCCP
from evennia.server.portal.mxp import Mxp, mxp_parse
from evennia.utils import ansi
from evennia.utils.utils import to_str
_RE_N = re.compile(r"\{n$")
_RE_LEND = re.compile(r"\n$|\r$|\r\n$|\r\x00$|", re.MULTILINE)
_RE_SCREENREADER_REGEX = re.compile(r"%s" % settings.SCREENREADER_REGEX_STRIP, re.DOTALL + re.MULTILINE)
_IDLE_COMMAND = settings.IDLE_COMMAND + "\n"
class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
"""
Each player connecting over telnet (ie using most traditional mud
clients) gets a telnet protocol instance assigned to them. All
communication between game and player goes through here.
"""
def __init__(self, *args, **kwargs):
self.protocol_name = "telnet"
super(TelnetProtocol, self).__init__(*args, **kwargs)
def connectionMade(self):
"""
This is called when the connection is first established.
"""
# initialize the session
self.line_buffer = []
self.iaw_mode = False
self.no_lb_mode = False
client_address = self.transport.client
client_address = client_address[0] if client_address else None
# this number is counted down for every handshake that completes.
# when it reaches 0 the portal/server syncs their data
self.handshakes = 7 # naws, ttype, mccp, mssp, msdp, gmcp, mxp
self.init_session(self.protocol_name, client_address, self.factory.sessionhandler)
# negotiate client size
self.naws = naws.Naws(self)
# negotiate ttype (client info)
# Obs: mudlet ttype does not seem to work if we start mccp before ttype. /Griatch
self.ttype = ttype.Ttype(self)
# negotiate mccp (data compression) - turn this off for wireshark analysis
self.mccp = Mccp(self)
# negotiate mssp (crawler communication)
self.mssp = mssp.Mssp(self)
# oob communication (MSDP, GMCP) - two handshake calls!
self.oob = telnet_oob.TelnetOOB(self)
# mxp support
self.mxp = Mxp(self)
# add this new connection to sessionhandler so
# the Server becomes aware of it.
self.sessionhandler.connect(self)
# timeout the handshakes in case the client doesn't reply at all
from evennia.utils.utils import delay
delay(2, callback=self.handshake_done, force=True)
# TCP/IP keepalive watches for dead links
self.transport.setTcpKeepAlive(1)
# The TCP/IP keepalive is not enough for some networks;
# we have to complement it with a NOP keep-alive.
self.protocol_flags["NOPKEEPALIVE"] = True
self.nop_keep_alive = None
self.toggle_nop_keepalive()
def _send_nop_keepalive(self):
"Send NOP keepalive unless flag is set"
if self.protocol_flags.get("NOPKEEPALIVE"):
self._write(IAC + NOP)
def toggle_nop_keepalive(self):
"""
Allow to toggle the NOP keepalive for those sad clients that
can't even handle a NOP instruction. This is turned off by the
protocol_flag NOPKEEPALIVE (settable e.g. by the default
`@option` command).
"""
if self.nop_keep_alive and self.nop_keep_alive.running:
self.nop_keep_alive.stop()
else:
self.nop_keep_alive = LoopingCall(self._send_nop_keepalive)
self.nop_keep_alive.start(30, now=False)
def handshake_done(self, force=False):
"""
This is called by all telnet extensions once they are finished.
When all have reported, a sync with the server is performed.
The system will force-call this sync after a small time to handle
clients that don't reply to handshakes at all.
"""
if self.handshakes > 0:
if force:
self.sessionhandler.sync(self)
return
self.handshakes -= 1
if self.handshakes <= 0:
# do the sync
self.sessionhandler.sync(self)
def enableRemote(self, option):
"""
This sets up the remote-activated options we allow for this protocol.
Args:
option (char): The telnet option to enable.
Returns:
enable (bool): If this option should be enabled.
"""
return (option == LINEMODE or
option == ttype.TTYPE or
option == naws.NAWS or
option == MCCP or
option == mssp.MSSP)
def enableLocal(self, option):
"""
Call to allow the activation of options for this protocol
Args:
option (char): The telnet option to enable locally.
Returns:
enable (bool): If this option should be enabled.
"""
return (option == MCCP or option==ECHO)
def disableLocal(self, option):
"""
Disable a given option locally.
Args:
option (char): The telnet option to disable locally.
"""
if option == ECHO:
return True
if option == MCCP:
self.mccp.no_mccp(option)
return True
else:
return super(TelnetProtocol, self).disableLocal(option)
def connectionLost(self, reason):
"""
this is executed when the connection is lost for whatever
reason. it can also be called directly, from the disconnect
method
Args:
reason (str): Motivation for losing connection.
"""
self.sessionhandler.disconnect(self)
self.transport.loseConnection()
def _write(self, data):
"hook overloading the one used in plain telnet"
data = data.replace('\n', '\r\n').replace('\r\r\n', '\r\n')
#data = data.replace('\n', '\r\n')
super(TelnetProtocol, self)._write(mccp_compress(self, data))
def sendLine(self, line):
"""
Hook overloading the one used by linereceiver.
Args:
line (str): Line to send.
"""
#escape IAC in line mode, and correctly add \r\n
line += self.delimiter
line = line.replace(IAC, IAC + IAC).replace('\n', '\r\n')
return self.transport.write(mccp_compress(self, line))
def applicationDataReceived(self, string):
"""
Telnet method called when non-telnet-command data is coming in
over the telnet connection. We pass it on to the game engine
directly.
Args:
string (str): Incoming data.
"""
self.data_in(text=string)
# Session hooks
def disconnect(self, reason=None):
"""
generic hook for the engine to call in order to
disconnect this protocol.
Args:
reason (str): Reason for disconnecting.
"""
self.data_out(text=((reason or "",), {}))
self.connectionLost(reason)
def data_in(self, **kwargs):
"""
Data User -> Evennia
Kwargs:
kwargs (any): Options from the protocol.
"""
#from evennia.server.profiling.timetrace import timetrace
#text = timetrace(text, "telnet.data_in")
self.sessionhandler.data_in(self, **kwargs)
def data_out(self, **kwargs):
"""
Data Evennia -> User
Kwargs:
kwargs (any): Options to the protocol
"""
self.sessionhandler.data_out(self, **kwargs)
# send_* methods
def send_text(self, *args, **kwargs):
"""
Send text data. This is an in-band telnet operation.
Args:
text (str): The first argument is always the text string to send. No other arguments
are considered.
Kwargs:
options (dict): Send-option flags
- mxp: Enforce MXP link support.
- ansi: Enforce no ANSI colors.
- xterm256: Enforce xterm256 colors, regardless of TTYPE.
- noxterm256: Enforce no xterm256 color support, regardless of TTYPE.
- nomarkup: Strip all ANSI markup. This is the same as noxterm256,noansi
- raw: Pass string through without any ansi processing
(i.e. include Evennia ansi markers but do not
convert them into ansi tokens)
- echo: Turn on/off line echo on the client. Turn
off line echo for client, for example for password.
Note that it must be actively turned back on again!
"""
text = args[0] if args else ""
if text is None:
return
text = to_str(text, force_string=True)
# handle arguments
options = kwargs.get("options", {})
flags = self.protocol_flags
xterm256 = options.get("xterm256", flags.get('XTERM256', False) if flags["TTYPE"] else True)
useansi = options.get("ansi", flags.get('ANSI', False) if flags["TTYPE"] else True)
raw = options.get("raw", flags.get("RAW", False))
nomarkup = options.get("nomarkup", flags.get("NOMARKUP", not (xterm256 or useansi)))
echo = options.get("echo", None)
mxp = options.get("mxp", flags.get("MXP", False))
screenreader = options.get("screenreader", flags.get("SCREENREADER", False))
if screenreader:
# screenreader mode cleans up output
text = ansi.parse_ansi(text, strip_ansi=True, xterm256=False, mxp=False)
text = _RE_SCREENREADER_REGEX.sub("", text)
if options.get("send_prompt"):
# send a prompt instead.
if not raw:
# processing
prompt = ansi.parse_ansi(_RE_N.sub("", text) + "{n", strip_ansi=nomarkup, xterm256=xterm256)
if mxp:
prompt = mxp_parse(prompt)
prompt = prompt.replace(IAC, IAC + IAC).replace('\n', '\r\n')
prompt += IAC + GA
self.transport.write(mccp_compress(self, prompt))
else:
if echo is not None:
# turn on/off echo. Note that this is a bit turned around since we use
# echo as if we are "turning off the client's echo" when telnet really
# handles it the other way around.
if echo:
# by telling the client that WE WON'T echo, the client knows
# that IT should echo. This is the expected behavior from
# our perspective.
self.transport.write(mccp_compress(self, IAC+WONT+ECHO))
else:
# by telling the client that WE WILL echo, the client can
# safely turn OFF its OWN echo.
self.transport.write(mccp_compress(self, IAC+WILL+ECHO))
if raw:
# no processing
self.sendLine(text)
return
else:
# we need to make sure to kill the color at the end in order
# to match the webclient output.
linetosend = ansi.parse_ansi(_RE_N.sub("", text) + "{n", strip_ansi=nomarkup, xterm256=xterm256, mxp=mxp)
if mxp:
linetosend = mxp_parse(linetosend)
self.sendLine(linetosend)
def send_prompt(self, *args, **kwargs):
"""
Send a prompt - a text without a line end. See send_text for argument options.
"""
kwargs["options"].update({"send_prompt": True})
self.send_text(*args, **kwargs)
def send_default(self, cmdname, *args, **kwargs):
"""
Send other oob data
"""
if not cmdname == "options":
self.oob.data_out(cmdname, *args, **kwargs)
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