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9334940 Jun 6, 2012
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###############################################################################
#
# Copyright (c) 2012 Ruslan Spivak
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
###############################################################################
"""
TCP Concurrent Server, I/O Multiplexing (select).
Single server process to handle any number of clients.
"""
__author__ = 'Ruslan Spivak <ruslan.spivak@gmail.com>'
import os
import sys
import errno
import select
import socket
import optparse
BACKLOG = 5
def serve_forever(host, port):
# create, bind. listen
lstsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# re-use the port
lstsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# put listening socket into non-blocking mode
lstsock.setblocking(0)
lstsock.bind((host, port))
lstsock.listen(BACKLOG)
print 'Listening on port %d ...' % port
# read, write, exception lists with sockets to poll
rlist, wlist, elist = [lstsock], [], []
while True:
# block in select
readables, writables, exceptions = select.select(rlist, wlist, elist)
for sock in readables:
if sock is lstsock: # new client connection, we can accept now
try:
conn, client_address = lstsock.accept()
except IOError as e:
code, msg = e.args
if code == errno.EINTR:
continue
else:
raise
# add the new connection to the 'read' list to poll
# in the next loop cycle
rlist.append(conn)
else:
# read a line that tells us how many bytes to write
bytes = sock.recv(1024)
if not bytes: # connection closed by client
sock.close()
rlist.remove(sock)
else:
print ('Got request to send %s bytes. '
'Sending them all...' % bytes)
# send them all
# XXX: this is cheating, we should use 'select' and wlist
# to determine whether socket is ready to be written to
data = os.urandom(int(bytes))
sock.sendall(data)
def main():
parser = optparse.OptionParser()
parser.add_option(
'-i', '--host', dest='host', default='0.0.0.0',
help='Hostname or IP address. Default is 0.0.0.0'
)
parser.add_option(
'-p', '--port', dest='port', type='int', default=2000,
help='Port. Default is 2000')
options, args = parser.parse_args()
serve_forever(options.host, options.port)
if __name__ == '__main__':
main()