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Python reverse listener using threading

I'm working on a project that requires me to make a Python reverse listener that can send commands to a client that connects to my server, below is my server code and i am stuck on how to get multiple connections from more than just one client at the same time.
thank you
#!/usr/bin/python3
import socket
import sys
import time
import threading
from queue import Queue
NUMBER_OF_THREADS = 2
JOB_NUMBER = [1, 2]
queue = Queue)
all_connections = []
all_addresses = []
# create socket
def socket_create():
try:
global host
global port
global s
host = '0.0.0.0'
port = 5555
s = socket.socket()
except socket.error as msg:
print("Socket creation error: " + str(msg))
# bind socket to port and wait for connection from client
def socket_bind():
try:
global host
global port
global s
print("Binding socket to port: " + str(port))
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host, port))
s.listen(5)
except socket.error as msg:
print("Socket binding error: " + str(msg))
time.sleep(5)
socket_bind()
# accept connections from multiple clients and save to list
def accept_connections():
for c in all_connections:
c.close()
del all_connections[:]
del all_addresses[:]
while 1:
try:
conn, address = s.accept()
conn.setblocking(1)
all_connections.append(conn)
all_addresses.append(address)
print("\nConnection has been established: " + address[0])
except:
print("Error accepting connections")
# interactive prompt
def start_luka():
while True:
cmd = input('luka> ')
if cmd == 'list':
list_connections()
elif 'select' in cmd:
conn = get_target(cmd)
if conn is not None:
send_target_commands(conn)
else:
print("Command not recognized")
# displays all current connections
def list_connections():
results = ''
for i, conn in enumerate(all_connections):
try:
conn.send(str.encode(' '))
conn.recv(20480)
except:
del all_connections[i]
del all_addresses[i]
continue
results += str(i) + ' ' + str(all_addresses[i][0]) + ' ' + str(all_addresses[i][1]) + '\n'
print('------ Clients -----' + '\n' + results)
def main():
socket_create()
socket_bind()
start_luka()
list_connections()
accept_connections()
main()
when i run this code it doesn't say the connection is established and it doesn't add the connection to the list i created.
and lastly i'm trying to make all of this automated, as in, the second a client connects to my server listener, these commands will automatically run (ls, pwd, IP a...ect) and a file would be created to store all the data so i can check it out later. not sure where to start on that.
thanks for helping

python broadcasting message via server

I am trying to broadcast a message to the subnet and i am giving the subnet address to the server to connect and the client throws error saying name or service unknown and not receiving the packet. Could anyone please tell me how do i broadcast message to my subnet such that client can also get that message or packet. exactly in the address area. My main doubts are about. which address is given at the client side and server side.
Error i get at client side is :
sending
Traceback (most recent call last):
File "/Threaded-server.py", line 11, in <module>
sent=s.sendto(msg.encode(),address)
socket.gaierror: [Errno -2] Name or service not known
closing socket
Process finished with exit code 1
Thanks
client
import socket
import sys
import json
connected = False
#connect to server
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect((' ',10000))
connected = True
while connected == True:
#wait for server commands to do things, now we will just display things
data = client_socket.recv(1024)
cmd = json.loads(data) #we now only expect json
if(cmd['type'] == 'bet'):
bet = cmd['value']
print('betting is: '+bet)
elif (cmd['type'] == 'result'):
print('winner is: '+str(cmd['winner']))
print('payout is: '+str(cmd['payout']))
##Server
import socket, time, sys
import threading
import pprint
TCP_IP = '192.168.1.255'
TCP_PORT = 10000
BUFFER_SIZE = 1024
clientCount = 0
class server():
def __init__(self):
self.CLIENTS = []
def startServer(self):
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((TCP_IP,TCP_PORT))
s.listen(10)
while 1:
client_socket, addr = s.accept()
print ('Connected with ' + addr[0] + ':' + str(addr[1]))
global clientCount
clientCount = clientCount+1
print (clientCount)
# register client
self.CLIENTS.append(client_socket)
threading.Thread(target=self.playerHandler, args=(client_socket,)).start()
s.close()
except socket.error as msg:
print ('Could Not Start Server Thread. Error Code : ') #+ str(msg[0]) + ' Message ' + msg[1]
sys.exit()
#client handler :one of these loops is running for each thread/player
def playerHandler(self, client_socket):
#send welcome msg to new client
client_socket.send(bytes('{"type": "bet","value": "1"}', 'UTF-8'))
while 1:
data = client_socket.recv(BUFFER_SIZE)
if not data:
break
#print ('Data : ' + repr(data) + "\n")
#data = data.decode("UTF-8")
# broadcast
for client in self.CLIENTS.values():
client.send(data)
# the connection is closed: unregister
self.CLIENTS.remove(client_socket)
#client_socket.close() #do we close the socket when the program ends? or for ea client thead?
def broadcast(self, message):
for c in self.CLIENTS:
c.send(message.encode("utf-8"))
def _broadcast(self):
for sock in self.CLIENTS:
try :
self._send(sock)
except socket.error:
sock.close() # closing the socket connection
self.CLIENTS.remove(sock) # removing the socket from the active connections list
def _send(self, sock):
# Packs the message with 4 leading bytes representing the message length
#msg = struct.pack('>I', len(msg)) + msg
# Sends the packed message
sock.send(bytes('{"type": "bet","value": "1"}', 'UTF-8'))
if __name__ == '__main__':
s = server() #create new server listening for connections
threading.Thread(target=s.startServer).start()
while 1:
s._broadcast()
pprint.pprint(s.CLIENTS)
print(len(s.CLIENTS)) #print out the number of connected clients every 5s
time.sleep(5)

how to combine server and client to work together as one program?

is their a function that i can check if there is incoming connection or not to the server ( inside While Loop )?
import socket
import sys
HOST = ''
PORT = 8888
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print 'Socket created'
try:
s.bind((HOST, PORT))
except socket.error , msg:
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
s.listen(10)
print 'Socket now listening'
while 1:
##### IF there is request to server Do #####
conn, addr = s.accept()
print 'Connected with ' + addr[0] + ':' + str(addr[1])
data = conn.recv(1024)
reply = 'OK...' + data
conn.sendall(reply)
##### Else Do something else like print for example #####
print 'Nothing yet'
conn.close()
s.close()
what i want to do is to check if there is no request to my server i will do something else.
is it possible to do that?

Yes, there's a such function.
From man accept:
In order to be notified of incoming connections on a socket, you can
use select(2), poll(2), or epoll(7). A readable event will be
delivered when a new connection is attempted and you may then call
accept() to get a socket for that connection.
In python you can use select combined with the timeout parameter:
import select
# somewhere in a while loop
timeout = 0
incoming_connections, _, __ = select.select([s], [], [], timeout)
if incoming_connections:
conn, addr = s.accept()
...
else:
...

socket is not listening for multiple request

Here is the code for server -
import socket, select,re
def getSocket( idd):
return CONNECTION_LIST[idd]
def broadcast_data (sock, message):
for socket in CONNECTION_LIST:
if socket != server_socket and socket != sock :
try :
socket.send(message)
except :
socket.close()
CONNECTION_LIST.remove(socket)
def single_client (sock , message , idd):
socket = getSocket ( idd )
if socket :
socket.send(message)
else:
print "chudap"
if __name__ == "__main__":
CONNECTION_LIST = []
RECV_BUFFER = 4096
PORT = 5000
PORTC = 2225
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.bind(("0.0.0.0", PORT))
server_socket.listen(10)
listen = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
listen.bind(("0.0.0.0" , PORTC))
#listen.listen(10)
CONNECTION_LIST.append(server_socket)
CONNECTION_LIST.append(listen)
print "Chat server started on port " + str(PORT)
idd = 1
while 1:
# Get the list sockets which are ready to be read through select
read_sockets,write_sockets,error_sockets = select.select(CONNECTION_LIST,[],[])
for sock in read_sockets:
if sock == server_socket:
sockfd, addr = server_socket.accept()
CONNECTION_LIST.append(sockfd)
#name = sockfd.recv(RECV_BUFFER)
print "connected from ip %s, id assigned is %d" % (addr[0] , idd)
broadcast_data(sockfd, "client with IP %s has entered with id = %d\n" % (addr[0] , idd))
idd += 1
elif sock == listen:
print "debugging"
data,addr = listen.recvfrom(RECV_BUFFER)
print "Received server probe request from [%s:%s]"%addr
listen.sendto("iam" , addr)#(addr[0] , 2624))
listen.close()
CONNECTION_LIST.remove(listen)
listen = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
listen.bind(("0.0.0.0" , PORTC))
CONNECTION_LIST.append(listen)
else:
try:
data = sock.recv(RECV_BUFFER)
if re.findall(r'.*/msg\d+' , data):
#print "got single client message request" + data
name = "private message from " + re.findall('([^:]+): /msg(\d+)([^"]+)' , data)[0][0] + ": "
#print name
eid = int(re.findall('([^:]+): /msg(\d+)([^"]+)' , data)[0][1])
#print eid
data = re.findall('([^:]+): /msg(\d+)([^"]+)' , data)[0][2]
#print data
data = name + data
#print "single client message sent with id = %d" %eid
single_client( sock , data , int(eid))
elif data:
broadcast_data(sock, data)
except:
broadcast_data(sock, "Client (%s, %s) is offline" % addr)
print "Client (%s, %s) is offline" % addr
sock.close()
CONNECTION_LIST.remove(sock)
continue
server_socket.close()
Here is the code for client -
import socket, select, string, sys
def prompt() :
sys.stdout.write('<You>: ')
sys.stdout.flush()
def exit(sock):
print "\n Thank you for using chat application\nBye"
sock.close()
sys.exit()
def printUsage():
print "1. By default your message will be sent to all clients sitting on the chat server"
print "2. You can send a private message to a person by starting your message as \"/msg{id}{Your message}\" for example /msg2Hi will send \"hi\" to client with id 2"
print "3. For quitting simply type \"/q\" or \"/quit\""
prompt()
PORTS = 2225
PORTC = 2624
if __name__ == "__main__":
broad = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
broad.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
broad.bind(( '0.0.0.0' , 2624) )
broad.sendto(b'whoisserver', 0, ("255.255.255.255", PORTS))
broad.settimeout(10)
print 15*"-" + "WELCOME TO CHATVILLE" + 15*"-" + "\nFinding the server"
try:
data , addr = broad.recvfrom(10)
except:
print "Can't find server ! Please ensure that server is up"
broad.close()
sys.exit()
broad.close()
if data <> "iam":
print "Can't find a valid server !"
sys.exit()
host = addr[0]
port = 5000
print addr
# host = sys.argv[1]
# port = int(sys.argv[2])
# print host,port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(2)
name = raw_input("Please Enter your name: ")
try :
s.connect((host, port))
s.send(name)
except :
print 'Unable to connect'
sys.exit()
print 'Connected to remote host. Enjoy...............................'
name = "<" + name + ">" + ": "
print " - type /h to see usage instructions any time :) - "
prompt()
while 1:
socket_list = [sys.stdin, s]
read_sockets, write_sockets, error_sockets = select.select(socket_list , [], [])
for sock in read_sockets:
if sock == s:
data = sock.recv(4096)
if not data :
print '\nDisconnected from chat server'
sys.exit()
else :
print ""
sys.stdout.write(data)
prompt()
else :
msg = sys.stdin.readline()
if str.startswith(msg, "/h") or str.startswith(msg,"/help"):
printUsage()
elif str.startswith(msg, "/quit") or str.startswith(msg,"/q"):
exit(s)
else:
msg = name + msg
s.send(msg)
prompt()
Main problem is that only one client is able to connect as soon as the first client connects are to server no other client is able to discover the server.
I tried by looking at the client's code by tcpdump and I can see the packet going at port number 2225, but the socket listen is not responding at all after the first connection.
PS - earlier I was not making instance of listen socket again and again but I tried this also and it didn't work out.

In the sever broadcast_data() does not exclude the UDP socket (listen) from the sockets to write to, and so it calls send() on that socket. This fails with exception
socket.error: [Errno 89] Destination address required
because no address is supplied (and can't be with socket.send()). The exception handler then closes the UDP socket and no further messages from new clients can be received. That's why additional clients can not connect to the server.
This is a perfect example of why it is not a good idea to use a bare except, i.e. an except statement that handles all exceptions. In this case the handler closes the UDP socket without even logging the fact. There are other instances of bare except statements in your code. I suggest that you handle specific exceptions to avoid this sort of bug. You can fix it by adding the UDP socket to the list of sockets to ignore:
def broadcast_data(sock, message):
for socket in CONNECTION_LIST:
if socket not in (server_socket, sock, listen):
try :
socket.send(message)
except socket.error as exc:
print '!!! An error occurred while writing to client. !!!'
print exc
socket.close()
CONNECTION_LIST.remove(socket)
Now no attempt will be made to send messages to the UDP listen socket, and the socket won't be closed due to error.
P.S. the code in your main loop that closes and reopens the listen socket is not necessary.

How to send a message from the server to a client using sockets

Server
import socket
import sys
HOST = ''
PORT = 9000
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print 'Socket created'
try:
s.bind((HOST, PORT))
except socket.error , msg:
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
s.listen(10)
print 'Socket now listening'
conn, addr = s.accept()
print 'Connecting from: ' + addr[0] + ':' + str(addr[1])
while 1:
message=raw_input(">")
s.sendto(message, (addr[0], addr[1]))
print(s.recv(1024))
How do I make this send a message to the client?
I can make it reply to a string the client sends to the server, but in this case I want the server to send the first message...
Can anyone help me, The solutions on google don't seem to work properly and I'm not sure what I'm doing wrong.

Since this is the 1st Google Stack Overflow result for this, I'll post a complete, working example for both a client and a server. You can start either 1st. Verified working on Ubuntu 18.04 w/ Python 3.6.9
text_send_server.py:
# text_send_server.py
import socket
import select
import time
HOST = 'localhost'
PORT = 65439
ACK_TEXT = 'text_received'
def main():
# instantiate a socket object
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print('socket instantiated')
# bind the socket
sock.bind((HOST, PORT))
print('socket binded')
# start the socket listening
sock.listen()
print('socket now listening')
# accept the socket response from the client, and get the connection object
conn, addr = sock.accept() # Note: execution waits here until the client calls sock.connect()
print('socket accepted, got connection object')
myCounter = 0
while True:
message = 'message ' + str(myCounter)
print('sending: ' + message)
sendTextViaSocket(message, conn)
myCounter += 1
time.sleep(1)
# end while
# end function
def sendTextViaSocket(message, sock):
# encode the text message
encodedMessage = bytes(message, 'utf-8')
# send the data via the socket to the server
sock.sendall(encodedMessage)
# receive acknowledgment from the server
encodedAckText = sock.recv(1024)
ackText = encodedAckText.decode('utf-8')
# log if acknowledgment was successful
if ackText == ACK_TEXT:
print('server acknowledged reception of text')
else:
print('error: server has sent back ' + ackText)
# end if
# end function
if __name__ == '__main__':
main()
text_receive_client.py
# text_receive_client.py
import socket
import select
import time
HOST = 'localhost'
PORT = 65439
ACK_TEXT = 'text_received'
def main():
# instantiate a socket object
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print('socket instantiated')
# connect the socket
connectionSuccessful = False
while not connectionSuccessful:
try:
sock.connect((HOST, PORT)) # Note: if execution gets here before the server starts up, this line will cause an error, hence the try-except
print('socket connected')
connectionSuccessful = True
except:
pass
# end try
# end while
socks = [sock]
while True:
readySocks, _, _ = select.select(socks, [], [], 5)
for sock in readySocks:
message = receiveTextViaSocket(sock)
print('received: ' + str(message))
# end for
# end while
# end function
def receiveTextViaSocket(sock):
# get the text via the scoket
encodedMessage = sock.recv(1024)
# if we didn't get anything, log an error and bail
if not encodedMessage:
print('error: encodedMessage was received as None')
return None
# end if
# decode the received text message
message = encodedMessage.decode('utf-8')
# now time to send the acknowledgement
# encode the acknowledgement text
encodedAckText = bytes(ACK_TEXT, 'utf-8')
# send the encoded acknowledgement text
sock.sendall(encodedAckText)
return message
# end function
if __name__ == '__main__':
main()

Use the returned socket object from 'accept' for sending and receiving data from a connected client:
while 1:
message=raw_input(">")
conn.send(message)
print conn.recv(1024)

You just have to use send
Server.py
import socket
s = socket.socket()
port = 65432
s.bind(('0.0.0.0', port))
s.listen(5)
while True:
c, addr = s.accept()
msg = b"Hello World!"
c.send(msg)
Client.py
import socket
s = socket.socket()
port = 65432
s.connect(('127.0.0.1', port))