Source code for evennia.server.portal.naws
"""
NAWS - Negotiate About Window Size
This implements the NAWS telnet option as per
https://www.ietf.org/rfc/rfc1073.txt
NAWS allows telnet clients to report their current window size to the
client and update it when the size changes
"""
from codecs import encode as codecs_encode
import weakref
from django.conf import settings
NAWS = bytes([31]) # b"\x1f"
IS = bytes([0]) # b"\x00"
# default taken from telnet specification
DEFAULT_WIDTH = settings.CLIENT_DEFAULT_WIDTH
DEFAULT_HEIGHT = settings.CLIENT_DEFAULT_HEIGHT
# try to get the customized mssp info, if it exists.
[docs]class Naws:
"""
Implements the NAWS protocol. Add this to a variable on the telnet
protocol to set it up.
"""
[docs] def __init__(self, protocol):
"""
initialize NAWS by storing protocol on ourselves and calling
the client to see if it supports NAWS.
Args:
protocol (Protocol): The active protocol instance.
"""
self.naws_step = 0
self.protocol = weakref.ref(protocol)
self.protocol().protocol_flags["SCREENWIDTH"] = {
0: DEFAULT_WIDTH
} # windowID (0 is root):width
self.protocol().protocol_flags["SCREENHEIGHT"] = {0: DEFAULT_HEIGHT} # windowID:width
self.protocol().negotiationMap[NAWS] = self.negotiate_sizes
self.protocol().do(NAWS).addCallbacks(self.do_naws, self.no_naws)
[docs] def no_naws(self, option):
"""
Called when client is not reporting NAWS. This is the normal
operation.
Args:
option (Option): Not used.
"""
self.protocol().protocol_flags["AUTORESIZE"] = False
self.protocol().handshake_done()
[docs] def do_naws(self, option):
"""
Client wants to negotiate all the NAWS information.
Args:
option (Option): Not used.
"""
self.protocol().protocol_flags["AUTORESIZE"] = True
self.protocol().handshake_done()
[docs] def negotiate_sizes(self, options):
"""
Step through the NAWS handshake.
Args:
option (list): The incoming NAWS options.
"""
if len(options) == 4:
# NAWS is negotiated with 16bit words
width = options[0] + options[1]
self.protocol().protocol_flags["SCREENWIDTH"][0] = int(codecs_encode(width, "hex"), 16)
height = options[2] + options[3]
self.protocol().protocol_flags["SCREENHEIGHT"][0] = int(codecs_encode(height, "hex"), 16)