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Implements telnet NULL as a keepalive to keep compatibility with some legacy clients/servers. Resolves #1008.

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This commit is contained in:
Griatch 2016-08-07 14:38:36 +02:00
parent 818b8a9c51
commit bb577e563b
1 changed files with 9 additions and 2 deletions
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11
evennia/server/portal/telnet.py
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@ -9,7 +9,7 @@ sessions etc.
import re import re
from twisted.internet.task import LoopingCall from twisted.internet.task import LoopingCall
from twisted.conch.telnet import Telnet, StatefulTelnetProtocol, IAC, NOP, LINEMODE, GA, WILL, WONT, ECHO from twisted.conch.telnet import Telnet, StatefulTelnetProtocol, IAC, NOP, LINEMODE, GA, WILL, WONT, ECHO, NULL
from django.conf import settings from django.conf import settings
from evennia.server.session import Session from evennia.server.session import Session
from evennia.server.portal import ttype, mssp, telnet_oob, naws from evennia.server.portal import ttype, mssp, telnet_oob, naws
@ -21,6 +21,7 @@ from evennia.utils.utils import to_str
_RE_N = re.compile(r"\{n$") _RE_N = re.compile(r"\{n$")
_RE_LEND = re.compile(r"\n$|\r$|\r\n$|\r\x00$|", re.MULTILINE) _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) _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): class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
""" """
@ -207,6 +208,13 @@ class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
logger.log_trace(out) logger.log_trace(out)
return return
if data and data.strip() == NULL:
# This is an ancient type of keepalive still used by some
# legacy clients. There should never be a reason to send
# a lone NULL character so this seems ok to support for
# backwards compatibility.
data = _IDLE_COMMAND
if self.no_lb_mode and _RE_LEND.search(data): if self.no_lb_mode and _RE_LEND.search(data):
# we are in no_lb_mode and receive a line break; # we are in no_lb_mode and receive a line break;
# this means we should empty the buffer and send # this means we should empty the buffer and send
@ -222,7 +230,6 @@ class TelnetProtocol(Telnet, StatefulTelnetProtocol, Session):
return return
# if we get to this point the command should end with a linebreak. # if we get to this point the command should end with a linebreak.
# We make sure to add it, to fix some clients messing this up.
StatefulTelnetProtocol.dataReceived(self, data) StatefulTelnetProtocol.dataReceived(self, data)
def _write(self, data): def _write(self, data):