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Why does my Python P2P client works over LAN but not the Internet and how can I fix this

Why does my Python P2P client works over LAN but not the Internet and how can I fix this!
I would like to make a p2p messenger and I just don't know why the p2p functionality with UDP Hole Punching is not working. Please help!
Server:
This server holds peers ips and ports for the client.
The ping function pings the peers to check if they are still alive.
'''
import threading
import socket
import time
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind(("IP_ADDRESS", 8081))
addrs = []
print('Server started...')
def ping(addr):
try:
sock.sendto(b'ping', addr)
sock.settimeout(1)
data, addr = sock.recvfrom(1024)
sock.settimeout(None)
return True
except Exception as ex:
sock.settimeout(None)
return False
while True:
data, addr = sock.recvfrom(1024)
print(addr)
sock.sendto((addr[0]+' '+str(addr[1])).encode(), addr)
for a in addrs:
p = ping(a)
print(p, a)
if p:
sock.sendto((a[0]+' '+str(a[1])).encode(), addr)
addrs.append(addr)
sock.sendto(b'DONE', addr)
'''
Client:
import threading
import socket
import time
self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self.addrs = []
self.chat_logs = ''
self.peers = ''
self.self_data = ('0.0.0.0', 0)
def recv_thread(self):
while True:
try:
data, addr = self.sock.recvfrom(1024)
if data == b'ping':
self.sock.sendto(b'pong', addr)
else:
data = data.decode()
new_user = True
for a in self.addrs:
if a == addr:
new_user = False
if new_user == False:
self.chat_logs += addr[0]+':'+str(addr[1])+' - '+data+'\n'
else:
self.chat_logs += addr[0]+':'+str(addr[1])+' joined the p2p network... \n'
self.addrs.append(addr)
except Exception as ex:
print(ex)
def send_msg(self):
message = self.messageBox.text()
if len(message) > 0:
self.chat_logs += 'You - '+message+'\n'
self.chatBox.setPlainText(self.chat_logs)
for a in self.addrs:
try:
self.sock.sendto(message.encode(), a)
except:
self.addrs.remove(a)
def get_peers(self, host):
host = host.split(':')
host = (host[0], int(host[1]))
self.sock.sendto(b'PEERS', host)
self.self_data, addr = self.sock.recvfrom(512)
self.self_data = self.self_data.decode().split()
self.self_data = (self.self_data[0], int(self.self_data[1]))
while True:
data, addr = self.sock.recvfrom(512)
if data == b'DONE':
break
else:
data = data.decode().split()
self.addrs.append((data[0], int(data[1])))
print(self.addrs)
for a in self.addrs:
try:
self.sock.sendto(b'join', a)
except:
self.addrs.remove(a)
t = threading.Thread(target=self.recv_thread)
t.start()
def connect_to_pears_network(self):
dlg = CustomDialog()
if dlg.exec():
text = dlg.message.text()
if len(text) > 6:
self.get_peers(text)
else:
pass
I hope I did this post right this is my first time making a post.

How to receive all data after TCP connection has been closed by the peer?

Running some production code I faced the following problem:
When sending HTTP requests to some server, server immediately closes the connection after sending response, which, for some reason, results in data loss.
Analyzing TCP dumps i can see that conversation goes as this:
client request
server ack
server push
server fin, ack (sent after ~0.000020 secs after previous push)
As the result my code can't get data sent by the server, (i'm guessing because of the small delay after push POLLHUP event might go before POLLIN?)
Trying to mimic the problem I've written the following code:
(It mimics the client behaviour on my side)
client:
import time
import socket
from errno import EAGAIN
from select import poll, POLLIN, POLLPRI, POLLERR, POLLHUP, POLLNVAL
def main(buf=""):
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.setblocking(False)
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
client.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
polling_object = poll()
polling_object.register(client, POLLPRI | POLLIN | POLLERR | POLLHUP)
in_buf = ""
sock_closed = False
try:
client.connect(("127.0.0.1", 8877))
except socket.error, e:
pass
while True and not sock_closed:
events = polling_object.poll(0)
for _, e in events:
if e & (POLLIN | POLLPRI):
while True:
try:
data = client.recv(1024)
if data:
in_buf += data
elif data == "":
client.close()
sock_closed = True
break
except socket.error, e:
if e.args[0] == EAGAIN:
break
else:
raise
elif e & (POLLERR|POLLHUP|POLLNVAL):
client.close()
sock_closed = True
if buf and not sock_closed:
try:
b_sent = client.send(buf)
if b_sent == len(buf):
buf = ""
else:
buf = buf[b_sent:]
except socket.error, e:
if e.args[0] != EAGAIN:
client.close()
sock_closed = True
time.sleep(0.5)
if sock_closed:
return in_buf
if __name__ == '__main__':
import sys
if len(sys.argv) > 1:
buf = sys.argv[1]
else:
buf = 'hello'
print main(buf)
server
import datetime
import time
import socket
def main():
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(("127.0.0.1", 8877))
server.listen(0)
client, _ = server.accept()
t1 = time.time()
data = ""
while not data:
data += client.recv(1024)
print "recv data %s" % data
client.sendall('{"ok": 1}')
t2 = time.time()
client.close()
t3 = time.time()
server.close()
return t1, t2, t3
if __name__ == '__main__':
c_r, d_s, c_c = main()
print "Connection received at ", datetime.datetime.fromtimestamp(c_r)
print "All Data sent after %.12f secs" % (d_s - c_r)
print "Connection closed after %.12f secs" % (c_c - d_s)
Running this code won't help me reproduce the problem because my client still can get data from socket buffer, which is kind of obviously by just following the code. The only difference is that in tcp dump it goes like this:
client request
server ack
server push
client ack
server fin, ack
I'm wondering is there a way to send fin, ack right after push without "letting" client to sent ack? Can it be done using python?

Thread a server to accept more than one client doesn't work properly

Well, I'm trying to make a simple Network TCP chatting program to dive deeper in python, threading and networking. The program worked but with just one user, I looked this up, I found that I need threading to make the server accept more than one user. I threaded the server but now when you connect the second user it disconnect the first one. Source code may not be that good..
#!/usr/bin/python
import socket, sys, threading
from time import sleep
# Global Stuff
localhost = socket.gethostbyname(socket.gethostname())
#localhost = '192.168.x.x'
serverPort = 5003
buffer = 1024 #Bytes
backlog = 5
userThread= []
count = 0
class server(object):
''' Constructor to Establish Bind server once an object made'''
def __init__(self, localhost, serverPort): # Connect Tcp
global backlog, count
self.servSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
self.servSock.bind((localhost, serverPort))# bind((host,Port))
self.servSock.listen(backlog)
print count
except Exception, e:
print "[Bind ]", e
sys.exit()
def accept(self):
global userThread, conn, addr, count
"""
- PROBLEM IS IN HERE SOMEWHERE SERVER DOESN'T ADD THE OTHER CLIENT EXCEPT ONCE.
- THREAD DOEN'T KEEP THE CLIENT.
- THE SECOND CLIENT FREEZES WHILE SENDING THE VERY FIRST MESSAGE TILL THE FIRST
CLIENT SEND A MESSAGE THEN IT CAN SEND MESSAGES AND THE FIRST CLIENT CAN'T SEND SHIT.
"""
count+=1
while True:
print count
self.conn, self.addr = self.servSock.accept()
conn = self.conn
print("This is a connection: ", conn)
#acceptThread = threading.start_new_thread(target=serverObj.accept, args=(conn))
#addr = self.addr
print "[Listening..]"
if(self.addr not in userThread):
userThread.append(self.addr)
print "Client's added Successfully"
else:
pass
def redirect(self):
global buffer, userThread, conn, count
count+=1
while True:
try:
print "Redirecting " + str(count)
self.data = conn.recv(buffer)
if self.data:
for user in userThread:
#conn.send(b'Recieved by server!\n')
conn.sendto("Sent!\n"+self.data+"\n", user)
print "Server: Data sent[" +self.data+"] to ["+str(user)+"]"
else:
self.data = conn.recv(buffer)
print "No dataa found"
except Exception, e:
print "[Redirect ] ",e
sleep(7)
print "OUT"# testing if it's getting out this infinite loop.
def exit(self):
self.server.close()
def main():
global localhost, serverPort, conn
try:
serverObj = server(localhost, serverPort)
print("[+] Server is UP!")
except Exception, e:
print "[Main ] ",e
exit()
acceptThread = threading.Thread(name = "Accepting Connections", target=serverObj.accept)
redirThread = threading.Thread(name = "Redirecting Data", target=serverObj.redirect)
acceptThread.start()
redirThread.start()
print userThread
main()
######################################### Client ##########################################
#!/usr/bin/python
# This is client file
"""
http://eli.thegreenplace.net/2011/05/18/code-sample-socket-client-thread-in-python
https://docs.python.org/2/library/threading.html
"""
import socket
import threading
from time import sleep
# Client Info
#clientSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#localhost = '192.168.x.x'
# Global Stuff
serverIP = socket.gethostbyname(socket.gethostname())
#serverIP = '192.168.x.x'
serverPort, MsgSendError, MsgSendSucc, clientPort, data, buffer =\
5003, False, True, 12345, '',1024 #Bytes
class client(object):
global MsgSendError, MsgSendSucc, buffer, data
''' Constructor to Establish Connection once client is up'''
def __init__(self, serverIP, serverPort): # Connect Tcp
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
self.sock.connect((serverIP, serverPort))
except Exception, e:
return "[Connecting to Server]", e
def send(self, data):
try:
self.sock.send(data) # covnert it from string into byte streams to be in proper format.
#print str(data)
return MsgSendSucc
except:
return MsgSendError
def receive2(self):
try:
data = self.sock.recv(buffer)
#print "Function: Receive2."# testing
#print(str(data))# testing
#print "Received!"# testing
return str(data)
except Exception, e:
return "[In receive2]", e
def main():
global serverIP, serverPort, data#, sock
clientObj = client(serverIP, serverPort)
alias = raw_input("Your Name USER! ")
sentData = ''
while sentData is not 'Quit':
sentData = raw_input("Data>> ")
data = alias + ": "+sentData
if clientObj.send(data) == MsgSendSucc:
#print "Sent!"
#print "Fetching..\n"# testing
print(clientObj.receive2())
# testing
main()

How to make the server side socket code run continuously

I have a server/client socket program that is used to transfer a file from the client to the server. The issue is that the code stops running once the file is transferred. I want to change it such that the server side code is continuously running so that I can transfer a file multiple times without having to run the code again and again
Server code:
import socket
host = ''
port = 5560
def setupServer():
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print("Socket created.")
try:
s.bind((host, port))
except socket.error as msg:
print(msg)
print("Socket bind comlete.")
return s
def setupConnection():
s.listen(1) # Allows one connection at a time.
conn, address = s.accept()
print("Connected to: " + address[0] + ":" + str(address[1]))
return conn
def storeFile(filePath):
picFile = open(filePath, 'wb')
print(filePath)
print("Opened the file.")
pic = conn.recv(1024)
#print(pic)
while pic:
print("Receiving picture still.")
picFile.write(pic)
pic = conn.recv(1024)
picFile.close()
def dataTransfer(conn):
# A big loop that sends/receives data until told not to.
while True:
# Receive the data
data = conn.recv(1024) # receive the data
data = data.decode('utf-8')
# Split the data such that you separate the command
# from the rest of the data.
dataMessage = data.split(' ', 1)
command = dataMessage[0]
if command == 'GET':
reply = GET()
elif command == 'REPEAT':
reply = REPEAT(dataMessage)
elif command == 'STORE':
print("Store command received. Time to save a picture")
storeFile(dataMessage[1])
reply = "File stored."
elif command == 'LED_ON':
callLED()
reply = 'LED was on'
else:
reply = 'Unknown Command'
# Send the reply back to the client
conn.sendall(str.encode(reply))
#print("Data has been sent!")
conn.close()
s = setupServer()
while True:
try:
conn = setupConnection()
dataTransfer(conn)
except:
break
The client side code is below:
import socket
from time import sleep
from time import time
host = '192.168.0.17'
port = 5560
data = "hi"
filepath = "/var/www/html/unknown.txt"
def setupSocket():
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
return s
def sendPic(s, filePath):
print(filePath)
pic = open(filePath, 'rb')
chunk = pic.read(1024)
s.send(str.encode("STORE " + filePath))
t = time()
while chunk:
print("Sending Picture")
s.send(chunk)
#print(chunk)
chunk = pic.read(1024)
pic.close()
print("Done sending")
print("Elapsed time = " + str(time() - t) + 's')
#s.close()
return "Done sending"
def sendReceive(s, message):
s.send(str.encode(message))
reply = s.recv(1024)
print("We have received a reply")
print("Send closing message.")
s.send(str.encode("EXIT"))
#s.close()
reply = reply.decode('utf-8')
return reply
def transmit(message):
s = setupSocket()
response = sendReceive(s, message)
return response
def backup(filePath):
s = setupSocket()
response = sendPic(s, filePath)
return response
while True:
backup(filepath)
print("Backup Complete!")
break
I do not own the code. I have made some change to the code that I got from a YouTube video.

Have you had a look at the SocketServer module?
You could setup your dataTransfer() function as the handle() method of a RequestHandler class, then start your server with the serve_forever() method.

How can I make multiclient server in python using multithreading?

This is the code that I have used.But I don't get actual result that I want.When I execute code ChatServer file works properly,but ChatClient gives only one line(Usage : python telnet.py hostname port).Please Help me.I am new in python.
The server code:
#!/usr/bin/env python
#!/usr/bin/env python
"""
A basic, multiclient 'chat server' using Python's select module
with interrupt handling.
Entering any line of input at the terminal will exit the server.
"""
import select
import socket
import sys
import signal
from communication import send, receive
BUFSIZ = 1024
class ChatServer(object):
""" Simple chat server using select """
def __init__(self, port=3490, backlog=5):
self.clients = 0
# Client map
self.clientmap = {}
# Output socket list
self.outputs = []
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.server.bind(('',port))
print 'Listening to port',port,'...'
self.server.listen(backlog)
# Trap keyboard interrupts
signal.signal(signal.SIGINT, self.sighandler)
def sighandler(self, signum, frame):
# Close the server
print 'Shutting down server...'
# Close existing client sockets
for o in self.outputs:
o.close()
self.server.close()
def getname(self, client):
# Return the printable name of the
# client, given its socket...
info = self.clientmap[client]
host, name = info[0][0], info[1]
return '#'.join((name, host))
def serve(self):
inputs = [self.server,sys.stdin]
self.outputs = []
running = 1
while running:
try:
inputready,outputready,exceptready = select.select(inputs, self.outputs, [])
except select.error, e:
break
except socket.error, e:
break
for s in inputready:
if s == self.server:
# handle the server socket
client, address = self.server.accept()
print 'chatserver: got connection %d from %s' % (client.fileno(), address)
# Read the login name
cname = receive(client).split('NAME: ')[1]
# Compute client name and send back
self.clients += 1
send(client, 'CLIENT: ' + str(address[0]))
inputs.append(client)
self.clientmap[client] = (address, cname)
# Send joining information to other clients
msg = '\n(Connected: New client (%d) from %s)' % (self.clients, self.getname(client))
for o in self.outputs:
# o.send(msg)
send(o, msg)
self.outputs.append(client)
elif s == sys.stdin:
# handle standard input
junk = sys.stdin.readline()
running = 0
else:
# handle all other sockets
try:
# data = s.recv(BUFSIZ)
data = receive(s)
if data:
# Send as new client's message...
msg = '\n#[' + self.getname(s) + ']>> ' + data
# Send data to all except ourselves
for o in self.outputs:
if o != s:
# o.send(msg)
send(o, msg)
else:
print 'chatserver: %d hung up' % s.fileno()
self.clients -= 1
s.close()
inputs.remove(s)
self.outputs.remove(s)
# Send client leaving information to others
msg = '\n(Hung up: Client from %s)' % self.getname(s)
for o in self.outputs:
# o.send(msg)
send(o, msg)
except socket.error, e:
# Remove
inputs.remove(s)
self.outputs.remove(s)
self.server.close()
if __name__ == "__main__":
ChatServer().serve()
The chat client:
#! /usr/bin/env python
"""
Simple chat client for the chat server. Defines
a simple protocol to be used with chatserver.
"""
import socket
import sys
import select
from communication import send, receive
BUFSIZ = 1024
class ChatClient(object):
""" A simple command line chat client using select """
def __init__(self, name, host='127.0.0.1', port=3490):
self.name = name
# Quit flag
self.flag = False
self.port = int(port)
self.host = host
# Initial prompt
self.prompt='[' + '#'.join((name, socket.gethostname().split('.')[0])) + ']> '
# Connect to server at port
try:
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.connect((host, self.port))
print 'Connected to chat server#%d' % self.port
# Send my name...
send(self.sock,'NAME: ' + self.name)
data = receive(self.sock)
# Contains client address, set it
addr = data.split('CLIENT: ')[1]
self.prompt = '[' + '#'.join((self.name, addr)) + ']> '
except socket.error, e:
print 'Could not connect to chat server #%d' % self.port
sys.exit(1)
def cmdloop(self):
while not self.flag:
try:
sys.stdout.write(self.prompt)
sys.stdout.flush()
# Wait for input from stdin & socket
inputready, outputready,exceptrdy = select.select([0, self.sock], [],[])
for i in inputready:
if i == 0:
data = sys.stdin.readline().strip()
if data: send(self.sock, data)
elif i == self.sock:
data = receive(self.sock)
if not data:
print 'Shutting down.'
self.flag = True
break
else:
sys.stdout.write(data + '\n')
sys.stdout.flush()
except KeyboardInterrupt:
print 'Interrupted.'
self.sock.close()
break
if __name__ == "__main__":
import sys
if len(sys.argv)<3:
sys.exit('Usage: %s chatid host portno' % sys.argv[0])
client = ChatClient(sys.argv[1],sys.argv[2], int(sys.argv[3]))
client.cmdloop()
###############################################################################
# The communication module (communication.py)
###############################################################################
import cPickle
import socket
import struct
marshall = cPickle.dumps
unmarshall = cPickle.loads
def send(channel, *args):
buf = marshall(args)
value = socket.htonl(len(buf))
size = struct.pack("L",value)
channel.send(size)
channel.send(buf)
def receive(channel):
size = struct.calcsize("L")
size = channel.recv(size)
try:
size = socket.ntohl(struct.unpack("L", size)[0])
except struct.error, e:
return ''
buf = ""
while len(buf) < size:
buf = channel.recv(size - len(buf))
return unmarshall(buf)[0]