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#!/bin/env python3
import argparse
import re
import sys
import socket
import _thread
replacements = [
["!", " !"],
["?", " ?"],
[".", " ."],
[",", " ,"],
[":", " :"],
[";", " ;"],
[")", " )"],
["(", "( "],
[">", " >"],
["<", "< "],
["]", " ]"],
["[", "[ "],
["}", " }"],
["{", "{ "],
]
class ClientState:
CLIENT_IS_SENDING_DOWNSTREAM = 1
CLIENT_IS_SENDING_UPSTREAM = 2
CLIENT_IS_CONNECTING = 3
CLIENT_IS_TERMINATING = 4
def replace_client_to_server (string):
prefix_size = (string.find(' ') + 1)
prefix = string[:prefix_size]
content = string[prefix_size:]
for entry in replacements:
content = content.replace(entry[0], entry[1])
return (prefix + content)
def replace_server_to_client (string):
prefix_size = (string.find(' ') + 1)
prefix = string[:prefix_size]
content = string[prefix_size:]
for entry in replacements:
content = content.replace(entry[1], entry[0])
return (prefix + content)
def client_main (source, params):
state = ClientState.CLIENT_IS_CONNECTING
connect = None
try:
while True:
if (state == ClientState.CLIENT_IS_SENDING_DOWNSTREAM):
try:
in_data = b""
while True:
in_char = source.recv(1)
in_data = (in_data + in_char)
if (in_char == b"\n"):
break
elif (in_char == b''):
raise Exception("Disconnected client")
up_data = in_data.decode("UTF-8")
valid = 1
except UnicodeDecodeError:
print("Could not decode UTF-8...")
valid = 0
if (valid == 1):
up_data = replace_client_to_server(up_data)
connect.sendall(up_data.encode("UTF-8"))
state = ClientState.CLIENT_IS_SENDING_UPSTREAM
else:
connect.sendall(in_data)
state = ClientState.CLIENT_IS_SENDING_UPSTREAM
elif (state == ClientState.CLIENT_IS_SENDING_UPSTREAM):
in_data = b""
matched = 0
c = b"\0"
try:
while True:
in_char = connect.recv(1)
in_data = (in_data + in_char)
if (in_char == b"\n"):
break
elif (in_char == b''):
raise Exception("Disconnected server")
if ((in_data == b"!P \n") or (in_data == b"!N \n")):
print("Sending downstream without touching...")
state = ClientState.CLIENT_IS_SENDING_DOWNSTREAM
elif ((in_data.startswith(b"!GR "))):
print("Sending downstream, after checking...")
up_data = in_data.decode("UTF-8")
up_data = replace_server_to_client(up_data)
in_data = up_data.encode("UTF-8")
except UnicodeDecodeError:
print("Could not decode UTF-8...")
source.sendall(in_data)
elif (state == ClientState.CLIENT_IS_CONNECTING):
print("Connecting to downstream...")
connect = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
connect.connect(params.destination)
print("Sending downstream...")
state = ClientState.CLIENT_IS_SENDING_DOWNSTREAM
else:
break
except:
print("Unexpected error:", sys.exc_info())
print("Closing")
source.close()
connect.close()
################################################################################
## ARGUMENTS HANDLING ##########################################################
################################################################################
parser = argparse.ArgumentParser(
description = (
"Performs replacements both ways"
)
)
parser.add_argument(
'-s',
'--socket-name',
type = str,
required = True,
help = 'Name of the UNIX socket for this filter.'
)
parser.add_argument(
'-d',
'--destination',
type = str,
help = 'UNIX socket this filter sends to when a match is found.',
)
args = parser.parse_args()
################################################################################
## MAIN ########################################################################
################################################################################
server_socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
server_socket.bind(args.socket_name)
server_socket.listen(5)
while True:
(client, client_address) = server_socket.accept()
_thread.start_new_thread(client_main, (client, args))
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