contrib/highlight

   1 #!/usr/bin/python3
   2 import re, sys
   3
   4 def parse(line): #-> [nick, user, host], command, arguments
   5     prefix, params  = b"", []
   6     command, arguments = None, []
   7     nick, user, host = None, None, None
   8
   9     line = line.rstrip(b"\r\n")
  10     # handle prefix:
  11     if line.startswith(b":"):
  12         prefix, line = line.split(b" ", 1)
  13     # handle command and arguments:
  14     while b" " in line and not line.startswith(b":"):
  15         word, line = line.split(b" ", 1)
  16         params += [word]
  17     # handle final parameter:
  18     params += [line.removeprefix(b":")]
  19
  20     command, *arguments = params # note: command may also be a numeric reply
  21
  22     if b"!" in prefix and b"@" in prefix:
  23         nick, rest = prefix.removeprefix(b":").split(b"!", 1)
  24         user, host = rest.split(b"@", 1)
  25     elif prefix: # server
  26         host = prefix.removeprefix(b":")
  27
  28     return [nick, user, host], command, arguments
  29
  30 DIM = b"\033[0;2m"
  31 BOLD = b"\033[0;1m"
  32 RESET = b"\033[0m"
  33 REV = b"\033[0;7m"
  34
  35 def say(*args):
  36     sys.stdout.buffer.write(b"".join(args)+b"\n")
  37     sys.stdout.buffer.flush()
  38
  39 def sanitize(s):
  40     # removes control characters so malicious actors can't mess up our terminal
  41     # with escape sequences. this also removes formatting codes.
  42     return re.sub(rb"[\001-\011\013\014\016-\037\177]", b"", s)
  43
  44 myself = None
  45 for line in sys.stdin.buffer:
  46     line = sanitize(line)
  47
  48     [nick, user, host], command, arguments = parse(line)
  49
  50     if command in (b"PRIVMSG", b"NOTICE") and len(arguments) == 2 and nick:
  51         chan, msg = arguments
  52         nick_start = len(b":")
  53         nick_end = nick_start+len(nick)
  54         cmd_start = nick_end+len(b"!")+len(user)+len(b"@")+len(host)+len(b" ")
  55         cmd_end = cmd_start+len(command)
  56         chan_start = cmd_end+len(b" ")
  57         chan_end = chan_start+len(chan)
  58         msg_start = chan_end+len(b" ")
  59         msg_end = msg_start+len(msg)
  60         if line[msg_start] == ord(':'):
  61             msg_start +=1
  62             msg_end +=1
  63
  64         hi_start, hi_end = msg_start, msg_start
  65         if m := re.search(rb"\b%s\b" % re.escape(myself), msg):
  66             hi_start = msg_start + m.start(0)
  67             hi_end = msg_start + m.end(0)
  68
  69         say(
  70             DIM,   line[:nick_start],
  71             BOLD,  line[nick_start:nick_end],
  72             DIM,   line[nick_end:chan_start],
  73             BOLD,  line[chan_start:chan_end],
  74             DIM,   line[chan_end:msg_start],
  75             RESET, line[msg_start:hi_start],
  76               REV,   line[hi_start:hi_end],
  77               RESET, line[hi_end:msg_end],
  78             REV,   line[msg_end:].rstrip(b"\r\n"),
  79         RESET)
  80     elif command in (b"PING", b"PONG"):
  81         pass # hide
  82     else:
  83         if command == b"001" and arguments:
  84             myself = arguments[0] # store own username for later highlighting it
  85
  86         say(DIM,   line.rstrip(b"\r\n"), RESET)