Got rid of redundant copy of telnetlib.py

Demo/cwilib/telnetlib.py

-# A TELNET client class.  Based on RFC 854: TELNET Protocol
-# Specification, by J. Postel and J. Reynolds
-
-
-# Example:
-#
-# >>> from telnetlib import Telnet
-# >>> tn = Telnet('voorn.cwi.nl', 79) # connect to finger port
-# >>> tn.write('guido\r\n')
-# >>> print tn.read_all()
-# Login name: guido                       In real life: Guido van Rossum
-# Office: M353,  x4127                    Home phone: 020-6225521
-# Directory: /ufs/guido                   Shell: /usr/local/bin/esh
-# On since Oct 28 11:02:16 on ttyq1   
-# Project: Multimedia Kernel Systems
-# No Plan.
-# >>>
-#
-# Note that read() won't read until eof -- it just reads some data
-# (but it guarantees to read at least one byte unless EOF is hit).
-#
-# It is possible to pass a Telnet object to select.select() in order
-# to wait until more data is available.  Note that in this case,
-# read_eager() may return '' even if there was data on the socket,
-# because the protocol negotiation may have eaten the data.
-# This is why EOFError is needed to distinguish between "no data"
-# and "connection closed" (since the socket also appears ready for
-# reading when it is closed).
-#
-# Bugs:
-# - may hang when connection is slow in the middle of an IAC sequence
-#
-# To do:
-# - option negotiation
-
-
-# Imported modules
-import socket
-import select
-import string
-import regsub
-
-# Tunable parameters
-DEBUGLEVEL = 0
-
-# Telnet protocol defaults
-TELNET_PORT = 23
-
-# Telnet protocol characters (don't change)
-IAC  = chr(255)	# "Interpret As Command"
-DONT = chr(254)
-DO   = chr(253)
-WONT = chr(252)
-WILL = chr(251)
-
-
-# Telnet interface class
-
-class Telnet:
-
-    # Constructor
-    def __init__(self, host, *args):
-	if not args:
-	    port = TELNET_PORT
-	else:
-	    if len(args) > 1: raise TypeError, 'too many args'
-	    port = args[0]
-	    if not port: port = TELNET_PORT
-	self.debuglevel = DEBUGLEVEL
-	self.host = host
-	self.port = port
-	self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-	self.sock.connect((self.host, self.port))
-	self.rawq = ''
-	self.irawq = 0
-	self.cookedq = ''
-	self.eof = 0
-
-    # Destructor
-    def __del__(self):
-	self.close()
-
-    # Debug message
-    def msg(self, msg, *args):
-	if self.debuglevel > 0:
-	    print 'Telnet(%s,%d):' % (self.host, self.port), msg % args
-
-    # Set debug level
-    def set_debuglevel(self, debuglevel):
-	self.debuglevel = debuglevel
-
-    # Explicit close
-    def close(self):
-	if self.sock:
-	    self.sock.close()
-	self.sock = None
-	self.eof = 1
-
-    # Return socket (e.g. for select)
-    def get_socket(self):
-	return self.sock
-
-    # Return socket's fileno (e.g. for select)
-    def fileno(self):
-	return self.sock.fileno()
-
-    # Write a string to the socket, doubling any IAC characters
-    # Might block if the connection is blocked
-    # May raise socket.error if the connection is closed
-    def write(self, buffer):
-	if IAC in buffer:
-	    buffer = regsub.gsub(IAC, IAC+IAC, buffer)
-	self.sock.send(buffer)
-
-    # The following read_* methods exist:
-    # Special case:
-    # - read_until() reads until a string is encountered or a timeout is hit
-    # These may block:
-    # - read_all() reads all data until EOF
-    # - read_some() reads at least one byte until EOF
-    # These may do I/O but won't block doing it:
-    # - read_very_eager() reads all data available on the socket
-    # - read_eager() reads either data already queued or some data
-    #                available on the socket
-    # These don't do I/O:
-    # - read_lazy() reads all data in the raw queue (processing it first)
-    # - read_very_lazy() reads all data in the cooked queue
-
-    # Read until a given string is encountered or until timeout
-    # Raise EOFError if connection closed and no cooked data available
-    # Return '' if no cooked data available otherwise
-    def read_until(self, match, *args):
-	if not args:
-	    timeout = None
-	else:
-	    if len(args) > 1: raise TypeError, 'too many args'
-	    timeout = args[0]
-	n = len(match)
-	self.process_rawq()
-	i = string.find(self.cookedq, match)
-	if i >= 0:
-	    i = i+n
-	    buf = self.cookedq[:i]
-	    self.cookedq = self.cookedq[i:]
-	    return buf
-	s_reply = ([self], [], [])
-	s_args = s_reply
-	if timeout is not None:
-	    s_args = s_args + (timeout,)
-	while not self.eof and apply(select.select, s_args) == s_reply:
-	    i = max(0, len(self.cookedq)-n)
-	    self.fill_rawq()
-	    self.process_rawq()
-	    i = string.find(self.cookedq, match, i)
-	    if i >= 0:
-		i = i+n
-		buf = self.cookedq[:i]
-		self.cookedq = self.cookedq[i:]
-		return buf
-	return self.read_very_lazy()
-
-    # Read all data until EOF
-    # Block until connection closed
-    def read_all(self):
-	self.process_rawq()
-	while not self.eof:
-	    self.fill_rawq()
-	    self.process_rawq()
-	buf = self.cookedq
-	self.cookedq = ''
-	return buf
-
-    # Read at least one byte of cooked data unless EOF is hit
-    # Return '' if EOF is hit
-    # Block if no data is immediately available
-    def read_some(self):
-	self.process_rawq()
-	while not self.cookedq and not self.eof:
-	    self.fill_rawq()
-	    self.process_rawq()
-	buf = self.cookedq
-	self.cookedq = ''
-	return buf
-
-    # Read everything that's possible without blocking in I/O (eager)
-    # Raise EOFError if connection closed and no cooked data available
-    # Return '' if no cooked data available otherwise
-    # Don't block unless in the midst of an IAC sequence
-    def read_very_eager(self):
-	self.process_rawq()
-	while not self.eof and self.sock_avail():
-	    self.fill_rawq()
-	    self.process_rawq()
-	return self.read_very_lazy()
-
-    # Read readily available data
-    # Raise EOFError if connection closed and no cooked data available
-    # Return '' if no cooked data available otherwise
-    # Don't block unless in the midst of an IAC sequence
-    def read_eager(self):
-	self.process_rawq()
-	while not self.cookedq and not self.eof and self.sock_avail():
-	    self.fill_rawq()
-	    self.process_rawq()
-	return self.read_very_lazy()
-
-    # Process and return data that's already in the queues (lazy)
-    # Raise EOFError if connection closed and no data available
-    # Return '' if no cooked data available otherwise
-    # Don't block unless in the midst of an IAC sequence
-    def read_lazy(self):
-	self.process_rawq()
-	return self.read_very_lazy()
-
-    # Return any data available in the cooked queue (very lazy)
-    # Raise EOFError if connection closed and no data available
-    # Return '' if no cooked data available otherwise
-    # Don't block
-    def read_very_lazy(self):
-	buf = self.cookedq
-	self.cookedq = ''
-	if not buf and self.eof and not self.rawq:
-	    raise EOFError, 'telnet connection closed'
-	return buf
-
-    # Transfer from raw queue to cooked queue
-    # Set self.eof when connection is closed
-    # Don't block unless in the midst of an IAC sequence
-    def process_rawq(self):
-	buf = ''
-	try:
-	    while self.rawq:
-		c = self.rawq_getchar()
-		if c != IAC:
-		    buf = buf + c
-		    continue
-		c = self.rawq_getchar()
-		if c == IAC:
-		    buf = buf + c
-		elif c in (DO, DONT):
-		    opt = self.rawq_getchar()
-		    self.msg('IAC %s %d', c == DO and 'DO' or 'DONT', ord(c))
-		    self.sock.send(IAC + WONT + opt)
-		elif c in (WILL, WONT):
-		    opt = self.rawq_getchar()
-		    self.msg('IAC %s %d',
-			  c == WILL and 'WILL' or 'WONT', ord(c))
-		else:
-		    self.msg('IAC %s not recognized' % `c`)
-	except EOFError: # raised by self.rawq_getchar()
-	    pass
-	self.cookedq = self.cookedq + buf
-
-    # Get next char from raw queue
-    # Block if no data is immediately available
-    # Raise EOFError when connection is closed
-    def rawq_getchar(self):
-	if not self.rawq:
-	    self.fill_rawq()
-	    if self.eof:
-		raise EOFError
-	c = self.rawq[self.irawq]
-	self.irawq = self.irawq + 1
-	if self.irawq >= len(self.rawq):
-	    self.rawq = ''
-	    self.irawq = 0
-	return c
-
-    # Fill raw queue from exactly one recv() system call
-    # Block if no data is immediately available
-    # Set self.eof when connection is closed
-    def fill_rawq(self):
-	if self.irawq >= len(self.rawq):
-	    self.rawq = ''
-	    self.irawq = 0
-	# The buffer size should be fairly small so as to avoid quadratic
-	# behavior in process_rawq() above
-	buf = self.sock.recv(50)
-	self.eof = (not buf)
-	self.rawq = self.rawq + buf
-
-    # Test whether data is available on the socket
-    def sock_avail(self):
-	return select.select([self], [], [], 0) == ([self], [], [])
-
-
-# Test program
-# Usage: test [-d] ... [host [port]]
-def test():
-    import sys, string, socket, select
-    debuglevel = 0
-    while sys.argv[1:] and sys.argv[1] == '-d':
-	debuglevel = debuglevel+1
-	del sys.argv[1]
-    host = 'localhost'
-    if sys.argv[1:]:
-	host = sys.argv[1]
-    port = 0
-    if sys.argv[2:]:
-	portstr = sys.argv[2]
-	try:
-	    port = string.atoi(portstr)
-	except string.atoi_error:
-	    port = socket.getservbyname(portstr, 'tcp')
-    tn = Telnet(host, port)
-    tn.set_debuglevel(debuglevel)
-    while 1:
-	rfd, wfd, xfd = select.select([tn, sys.stdin], [], [])
-	if sys.stdin in rfd:
-	    line = sys.stdin.readline()
-	    tn.write(line)
-	if tn in rfd:
-	    try:
-		text = tn.read_eager()
-	    except EOFError:
-		print '*** Connection closed by remote host ***'
-		break
-	    if text:
-		sys.stdout.write(text)
-		sys.stdout.flush()
-    tn.close()