Demo/pysvr/pysvr.py

#! /usr/bin/env python

"""A multi-threaded telnet-like server that gives a Python prompt.

This is really a prototype for the same thing in C.

Usage: pysvr.py [port]

"""

import sys, os, string, getopt, thread, socket, traceback

OK_DOMAINS = [".cnri.reston.va.us", ".python.org"]

PORT = 7585892 % 0xFFFF			# == 49367

def main():
    try:
	opts, args = getopt.getopt(sys.argv[1:], "")
	if len(args) > 1:
	    raise getopt.error, "Too many arguments."
    except getopt.error, msg:
	usage(msg)
    for o, a in opts:
	pass
    if args:
	try:
	    port = string.atoi(args[0])
	except ValueError, msg:
	    usage(msg)
    else:
	port = PORT
    main_thread(port)

def usage(msg=None):
    sys.stdout = sys.stderr
    if msg:
	print msg
    print "\n", __doc__,
    sys.exit(2)

def main_thread(port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.bind(("", port))
    sock.listen(5)
    while 1:
	(conn, addr) = sock.accept()
	thread.start_new_thread(service_thread, (conn, addr))
	del conn, addr

def service_thread(conn, addr):
    (caddr, cport) = addr
    try:
	host, aliases, ipaddrs = socket.gethostbyaddr(caddr)
    except socket.error:
	print "Don't know hostname for", caddr
	return
    if '.' not in host:
	for a in aliases:
	    if '.' in a:
		host = a
		break
	else:
	    print "Only a local name (%s) for %s" % (host, caddr)
	    return
    i = string.find(host, '.')
    domain = string.lower(host[i:])
    if domain not in OK_DOMAINS:
	print "Connection from", host, "not accepted"
	return
    print "Thread %s has connection from %s.\n" % (str(thread.get_ident()),
						   host),
    stdin = conn.makefile("r")
    stdout = conn.makefile("w", 0)
    run_interpreter(stdin, stdout)
    print "Thread %s is done.\n" % str(thread.get_ident()),

def run_interpreter(stdin, stdout):
    globals = {}
    try:
	str(sys.ps1)
    except:
	sys.ps1 = ">>> "
    source = ""
    while 1:
	stdout.write(sys.ps1)
	line = stdin.readline()
	if line[:2] == '\377\354':
	    line = ""
	if not line and not source:
	    break
	if line[-2:] == '\r\n':
	    line = line[:-2] + '\n'
	source = source + line
	try:
	    code = compile_command(source)
	except SyntaxError, err:
	    source = ""
	    traceback.print_exception(SyntaxError, err, None, file=stdout)
	    continue
	if not code:
	    continue
	source = ""
	try:
	    run_command(code, stdin, stdout, globals)
	except SystemExit, how:
	    if how:
		try:
		    how = str(how)
		except:
		    how = ""
		stdout.write("Exit %s\n" % how)
	    break
    stdout.write("\nGoodbye.\n")

def run_command(code, stdin, stdout, globals):
	save = sys.stdin, sys.stdout, sys.stderr
	try:
	    sys.stdout = sys.stderr = stdout
	    sys.stdin = stdin
	    try:
		exec code in globals
	    except SystemExit, how:
		raise SystemExit, how, sys.exc_info()[2]
	    except:
		type, value, tb = sys.exc_info()
		if tb: tb = tb.tb_next
		traceback.print_exception(type, value, tb)
		del tb
	finally:
	    sys.stdin, sys.stdout, sys.stderr = save

from code import compile_command

main()