I am ttrying to implement a multithread TCP server using Python. When I run the following code I obtain the following error:
Error
Incoming message: how are you
Unhandled exception in thread started by <function client_thread at 0x00000000024499 E8>
Traceback (most recent call last):
File "tcp_test2.py", line 32, in client_thread
message = recv_msg(conn)
File "tcp_test2.py", line 24, in recv_msg
raw_msglen = recvall(sock, 4)
File "tcp_test2.py", line 13, in recvall
raise EOFError('was expecting %d bytes but only received %d bytes before socket closed' % (length, len(data)))
EOFError: was expecting 4 bytes but only received 0 bytes before socket closed
Not sure where I am going wrong with implementing the threading function. Any help would be greatly appreciated.
Code
import argparse
import socket
import struct
from thread import start_new_thread
def recvall(sock, length):
data = b''
while len(data) < length:
packet = sock.recv(length - len(data))
if not packet:
raise EOFError('was expecting %d bytes but only received %d bytes before socket closed' % (length, len(data)))
data += packet
return data
def send_msg(sock, msg):
msg = struct.pack('>I', len(msg)) + msg
sock.sendall(msg)
def recv_msg(sock):
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
return recvall(sock, msglen)
def client_thread(conn):
while True:
message = recv_msg(conn)
print('Incoming message: {}'.format(message))
conn.sendall(b'Message Received') #send data to the socket
conn.close() #mark the socket closed
print('\tReply sent, socket closed')
Server
def server(interface, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((interface, port)) # the socket to address
sock.listen(1) #listen for connections made to the socket.
while True:
conn, sockname = sock.accept()
start_new_thread(client_thread,(conn,))
sock.close()
Client
def client(host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
print('Client has been assigned socket name', sock.getsockname())
message = raw_input("Type your message: ")
send_msg(sock, message)
reply = recvall(sock, 16)
print('Server Response: {}'.format(reply))
print('\nSocket closed')
sock.close()
if __name__ == '__main__':
choices = {'client': client, 'server': server}
parser = argparse.ArgumentParser(description='Send and receive over TCP')
parser.add_argument('role', choices=choices, help='which role to play')
parser.add_argument('host', help='interface the sever listens at:' 'host the client sends to')
parser.add_argument('-p', metavar='PORT', type=int, default=1060, help='TCP port(default 1060)')
args = parser.parse_args()
function = choices[args.role]
function(args.host, args.p)
This is my previous code which did not have any unhandled exceptions
import argparse
import socket
import struct
def recvall(sock, length):
data = b''
while len(data) < length:
packet = sock.recv(length - len(data))
if not packet:
raise EOFError('was expecting %d bytes but only received %d bytes before socket closed' % (length, len(data)))
data += packet
return data
def send_msg(sock, msg):
msg = struct.pack('>I', len(msg)) + msg
sock.sendall(msg)
def recv_msg(sock):
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
return recvall(sock, msglen)
def server(interface, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((interface, port)) # the socket to address
sock.listen(1) #listen for connections made to the socket.
print('Listening at {}'.format(sock.getsockname())) #returns the socket's own address
while True:
conn, sockname = sock.accept()
print('Connection accepted from {}'.format(sockname))
print('\tServer Socket: {}'.format(conn.getsockname()))
print('\tClient Socket: {}'.format(conn.getpeername())) # return remote address to which socket is connected
message = recv_msg(conn)
print('Incoming message: {}'.format(message))
conn.sendall(b'Message Received') #send data to the socket
conn.close() #mark the socket closed
print('\tReply sent, socket closed')
def client(host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
print('Client has been assigned socket name', sock.getsockname())
message = raw_input("Type your message: ")
send_msg(sock, message)
reply = recvall(sock, 16)
print('Server Response: {}'.format(reply))
print('\nSocket closed')
sock.close()
if __name__ == '__main__':
choices = {'client': client, 'server': server}
parser = argparse.ArgumentParser(description='Send and receive over TCP')
parser.add_argument('role', choices=choices, help='which role to play')
parser.add_argument('host', help='interface the sever listens at:' 'host the client sends to')
parser.add_argument('-p', metavar='PORT', type=int, default=1060, help='TCP port(default 1060)')
args = parser.parse_args()
function = choices[args.role]
function(args.host, args.p)
Nothing is wrong. Your client closes the socket. The server detects this when it tries to read the next message. This should have been exactly what you expected.
Related
I am attempting to piece together a secure socket client server communication solution. I do not have experience in doing so, so have cobbled together what I believe are relevant sections. The idea is that the Server waits for connections, the client creates a connection that is secure and then communication can take place.
The code also utilizes secure communication in authorization with client and server keys and certificates.
client code:
class Client:
def __init__(self):
try:
self.host, self.port = "127.0.0.1", 65416
self.client_cert = os.path.join(os.path.dirname(__file__), "client.crt")
self.client_key = os.path.join(os.path.dirname(__file__), "client.key")
self._context = ssl.SSLContext()
self._context.load_cert_chain(self.client_cert, self.client_key)
self._sock = None
self._ssock = None
except Exception as e:
print("Error in Initializing")
def checkvalidclient(self):
# ---- Client Communication Setup ----
HOST = self.host # The server's hostname or IP address
PORT = self.port # The port used by the server
try:
self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._ssock = self._context.wrap_socket(self._sock,)
self._ssock.connect((HOST, PORT))
print ("Socket successfully created")
except socket.error as err:
print ("socket creation failed with error %s" %(err))
print('Waiting for connection')
Response = self._ssock.recv(1024)
while True:
Input = input('Say Something: ')
# s.send(str.encode(Input))
send_msg(self._ssock, str.encode(Input))
# Response = s.recv(1024)
Response = recv_msg(self._ssock)
if Response is not None:
print(Response.decode('utf-8'))
def closesockconnection(self):
self._ssock.close()
# ---- To Avoid Message Boundary Problem on top of TCP protocol ----
def send_msg(sock: socket, msg): # ---- Use this to send
# Prefix each message with a 4-byte length (network byte order)
msg = struct.pack('>I', len(msg)) + msg
sock.sendall(msg)
def recv_msg(sock: socket): # ---- Use this to receive
# Read message length and unpack it into an integer
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
# Read the message data
return recvall(sock, msglen)
def recvall(sock: socket, n: int):
# Helper function to receive n bytes or return None if EOF is hit
data = bytearray()
while len(data) < n:
packet = sock.recv(n - len(data))
if not packet:
return None
data.extend(packet)
return data
client = Client()
client.checkvalidclient()
Server code:
import socket
import os
import ssl
from os import path
from _thread import *
import struct # Here to convert Python data types into byte streams (in string) and back
# ---- To Avoid Message Boundary Problem on top of TCP protocol ----
def send_msg(sock: socket, msg): # ---- Use this to send
# Prefix each message with a 4-byte length (network byte order)
msg = struct.pack('>I', len(msg)) + msg
sock.sendall(msg)
def recv_msg(sock: socket): # ---- Use this to receive
# Read message length and unpack it into an integer
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
# Read the message data
return recvall(sock, msglen)
def recvall(sock: socket, n: int):
# Helper function to receive n bytes or return None if EOF is hit
try:
data = bytearray()
while len(data) < n:
packet = sock.recv(n - len(data))
if not packet:
return None
data.extend(packet)
return data
except Exception as e:
print("Exception in recvall : " + str(e))
# ---- Server Communication Setup
class Server:
def __init__(self):
self.HOST = '127.0.0.1' # Standard loopback interface address (localhost)
self.PORT = 65416 # Port to listen on (non-privileged ports are > 1023)
self.ThreadCount = 0
self.server_cert = path.join(path.dirname(__file__), "server.crt")
self.server_key = path.join(path.dirname(__file__), "server.key")
self.client_cert = path.join(path.dirname(__file__), "client.crt")
self._context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
self._context.verify_mode = ssl.CERT_REQUIRED
self._context.load_cert_chain(self.server_cert, self.server_key)
self._context.load_verify_locations(self.client_cert)
self.sock = None
def connect(self):
try: # create socket
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
print ("Socket successfully created")
except socket.error as err:
print ("socket creation failed with error %s" %(err))
try: # bind socket to an address
self.sock.bind((self.HOST, self.PORT))
except socket.error as e:
print(str(e))
print('Waiting for a Connection..')
self.sock.listen(3)
def threaded_client(self, conn: socket):
conn.send(str.encode('Welcome to the Server'))
while True:
# data = conn.recv(2048) # receive message from client
data = recv_msg(conn)
print(data)
if data is not None:
reply = 'Server Says: ' + data.decode('utf-8')
if not data:
break
# conn.sendall(str.encode(reply))
send_msg(conn, str.encode(reply))
#conn.close()
def waitforconnection(self):
while True:
Client, addr = self.sock.accept()
self._context.wrap_socket(Client, server_side=True)
print('Connected to: ' + addr[0] + ':' + str(addr[1]))
start_new_thread(self.threaded_client, (Client, )) # Calling threaded_client() on a new thread
self.ThreadCount += 1
print('Thread Number: ' + str(self.ThreadCount))
#self.sock.close()
server = Server()
server.connect()
server.waitforconnection()
The lines:
def threaded_client(self, conn: socket):
conn.send(str.encode('Welcome to the Server'))
result in the error:
[WinError 10038] An operation was attempted on something that is not a socket
When I removed the certificate related lines in client:
self.client_cert = os.path.join(os.path.dirname(__file__), "client.crt")
self.client_key = os.path.join(os.path.dirname(__file__), "client.key")
self._context = ssl.SSLContext()
self._context.load_cert_chain(self.client_cert, self.client_key)
and the certificate related lines in the server:
self.server_cert = path.join(path.dirname(__file__), "server.crt")
self.server_key = path.join(path.dirname(__file__), "server.key")
self.client_cert = path.join(path.dirname(__file__), "client.crt")
self._context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
self._context.verify_mode = ssl.CERT_REQUIRED
self._context.load_cert_chain(self.server_cert, self.server_key)
self._context.load_verify_locations(self.client_cert)
self.sock = None
and a couple of small changes to remove the certificate related functionality, everything seemed to work, the client could send messages to the server and the server could respond (and the client displayed the response).
When however I added the context related certificates I start getting the error:
An operation was attempted on something that is not a socket
The server waits at:
Client, addr = self.sock.accept()
and continues to run once the client has called (in the client.py file):
self._ssock.connect((HOST, PORT))
The server then reaches the lines:
def threaded_client(self, conn: socket):
conn.send(str.encode('Welcome to the Server'))
where it fails on this error.
Printing the terminal, a traceback and exception error results in:
Socket successfully created
Waiting for a Connection..
Connected to: 127.0.0.1:57434
Thread Number: 1
Traceback (most recent call last):
File "c:\testcode\Server.py", line 71, in threaded_client
conn.send(str.encode('Welcome to the Server'))
OSError: [WinError 10038] An operation was attempted on something that is not a socket
My knowledge is limited and I cannot find more examples of secure multi threaded two way communication client to server socket code. The idea is to ensure the client is authorized to communicate with the server before transmission happens.
Any ideas on where I am failing?
Thanks
Ok, It seems like I was close, but had a couple of tweaks to do.
The solution of:
SSL/TLS client certificate verification with Python v3.4+ SSLContext
and the commenters here, helped me get over the finish line.
Server code:
import socket
import os
from socket import AF_INET, SOCK_STREAM, SO_REUSEADDR, SOL_SOCKET, SHUT_RDWR
import ssl
from os import path
from _thread import *
import struct # Here to convert Python data types into byte streams (in string) and back
import traceback
# ---- To Avoid Message Boundary Problem on top of TCP protocol ----
def send_msg(sock: socket, msg): # ---- Use this to send
# Prefix each message with a 4-byte length (network byte order)
msg = struct.pack('>I', len(msg)) + msg
sock.sendall(msg)
def recv_msg(sock: socket): # ---- Use this to receive
# Read message length and unpack it into an integer
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
# Read the message data
return recvall(sock, msglen)
def recvall(sock: socket, n: int):
# Helper function to receive n bytes or return None if EOF is hit
try:
data = bytearray()
while len(data) < n:
packet = sock.recv(n - len(data))
if not packet:
return None
data.extend(packet)
return data
except Exception as e:
print("Exception in recvall : " + str(e))
# ---- Server Communication Setup
class Server:
def __init__(self):
self.HOST = '127.0.0.1' # Standard loopback interface address (localhost)
self.PORT = 65416 # Port to listen on (non-privileged ports are > 1023)
self.ThreadCount = 0
self.server_cert = path.join(path.dirname(__file__), "server.crt")
self.server_key = path.join(path.dirname(__file__), "server.key")
self.client_cert = path.join(path.dirname(__file__), "client.crt")
self._context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
self._context.verify_mode = ssl.CERT_REQUIRED
self._context.load_cert_chain(certfile=self.server_cert, keyfile=self.server_key)
self._context.load_verify_locations(cafile=self.client_cert)
self.sock = None
def connect(self):
try: # create socket
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) ###<-- socket.socket() ???
print ("Socket successfully created")
except socket.error as err:
print ("socket creation failed with error %s" %(err))
try: # bind socket to an address
self.sock.bind((self.HOST, self.PORT))
except socket.error as e:
print(str(e))
print('Waiting for a Connection..')
self.sock.listen(3)
def threaded_client(self, conn: socket):
try:
conn.send(str.encode('Welcome to the Server'))
while True:
data = recv_msg(conn)
print("data")
print(data)
if data is not None:
reply = 'Server Says: ' + data.decode('utf-8')
if not data:
break
send_msg(conn, str.encode(reply))
except Exception as e:
print(traceback.format_exc())
print(str(e))
finally:
print("Closing connection")
conn.shutdown(socket.SHUT_RDWR)
conn.close()
#conn.close()
def waitforconnection(self):
while True:
Client, addr = self.sock.accept()
conn = self._context.wrap_socket(Client, server_side=True)
print('Connected to: ' + addr[0] + ':' + str(addr[1]))
print("SSL established. Peer: {}".format(conn.getpeercert()))
start_new_thread(self.threaded_client, (conn, )) # Calling threaded_client() on a new thread
self.ThreadCount += 1
print('Thread Number: ' + str(self.ThreadCount))
#self.sock.close()
server = Server()
server.connect()
server.waitforconnection()
Client code:
import socket
import struct # Here to convert Python data types into byte streams (in string) and back
import sys
import ssl
import socket
import selectors
import types
import io
import os
import time
import requests
from pathlib import Path
import mysql.connector as mysql
from loguru import logger as log
from utils.misc import read_py_config
import json
import rsa
import base64
class Client:
def __init__(self):
self.host, self.port = "127.0.0.1", 65416
self.client_cert = os.path.join(os.path.dirname(__file__), "client.crt")
self.client_key = os.path.join(os.path.dirname(__file__), "client.key")
self.server_crt = os.path.join(os.path.dirname(__file__), "server.crt")
self.sni_hostname = "example.com"
self._context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH, cafile=self.server_crt)
self._context.load_cert_chain(certfile=self.client_cert, keyfile=self.client_key)
self._sock = None
self._ssock = None
def checkvalidclient(self):
# ---- Client Communication Setup ----
HOST = self.host # The server's hostname or IP address
PORT = self.port # The port used by the server
try:
self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._ssock = self._context.wrap_socket(self._sock, server_side=False, server_hostname=self.sni_hostname)
self._ssock.connect((HOST, PORT))
print ("Socket successfully created")
except socket.error as err:
print ("socket creation failed with error %s" %(err))
print('Waiting for connection')
Response = self._ssock.recv(1024)
if Response is not None:
print(Response.decode('utf-8'))
while True:
Input = input('Say Something: ')
send_msg(self._ssock, str.encode(Input))
Response = recv_msg(self._ssock)
if Response is not None:
print(Response.decode('utf-8'))
def closesockconnection(self):
self._ssock.close()
# ---- To Avoid Message Boundary Problem on top of TCP protocol ----
def send_msg(sock: socket, msg): # ---- Use this to send
# Prefix each message with a 4-byte length (network byte order)
msg = struct.pack('>I', len(msg)) + msg
sock.sendall(msg)
def recv_msg(sock: socket): # ---- Use this to receive
# Read message length and unpack it into an integer
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
# Read the message data
return recvall(sock, msglen)
def recvall(sock: socket, n: int):
# Helper function to receive n bytes or return None if EOF is hit
data = bytearray()
while len(data) < n:
packet = sock.recv(n - len(data))
if not packet:
return None
data.extend(packet)
return data
Also ensure (as per the link) that the certificate creation is correct.
There is also another useful link at:
Exploring HTTPS With Python
Which covers HTTPS, specifically the Wireshark section allows you to monitor the traffic from client to server. After completing the above and deploying Wireshark I see that the data is encrypted. Any editing of the certificates (manually) causes the app to fail.
There still needs to be additions of try and except if the communication is halted midway etc. But hoping it will smooth the journey for others.
Thanks to the commenters, helped lead me on the way to solution.
I have a Python server running that listen to data that is sent by the Python client. The client takes input from the user and sends it to the server which prints it. However, I get the error that says "TyperError: a byte-like object is required, not 'str'". It is on line number 8 of the client code.
SERVER CODE:
import socket
def server(interface, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((interface, port))
sock.listen(1)
print('Listening at', sock.getsockname())
while True:
sc, sockname = sock.accept()
print('We have accepted a connection from', sockname)
print(' Socket name:', sc.getsockname())
print(' Socket peer:', sc.getpeername())
message = sc.recv(1024)
print(' Incoming sixteen-octet message:', repr(message))
sc.sendall(b'Farewell, client')
sc.close()
print(' Reply sent, socket closed')
if __name__ == '__main__':
server('0.0.0.0', 9999)
CLIENT CODE:
import socket
def client(host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
print('Client has been assigned socket name', sock.getsockname())
command = input("message > ")
sock.sendall(command)
reply = sock.recv(1024)
print('The server said', repr(reply))
sock.close()
if __name__ == '__main__':
client('localhost', 9999)
TyperError: a byte-like object is required, not 'str'
socket.sendall expects bytes, but you have passed in the result of input("message > "), which is a str. So, you need to somehow convert the str from the input into bytes. You can use encode to do this:
command = input("message > ").encode()
encode, well, encodes a str into bytes.
While communicating in Python, you should encode the parameter you send as a byte and decode the parameter you received from the byte format. You can understand what I want to say from the code below.
Server Code:
import socket
def server(interface, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((interface, port))
sock.listen(1)
print('Listening at', sock.getsockname())
while True:
sc, sockname = sock.accept()
print('We have accepted a connection from', sockname)
print(' Socket name:', sc.getsockname())
print(' Socket peer:', sc.getpeername())
message = sc.recv(1024).decode('utf-8')
print(' Incoming sixteen-octet message:', repr(message))
sc.sendall(bytes('Farewell, client','utf-8'))
sc.close()
print(' Reply sent, socket closed')
if __name__ == '__main__':
server('0.0.0.0', 9999)
Client Code:
import socket
def client(host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
print('Client has been assigned socket name', sock.getsockname())
command = input("message > ")
sock.sendall(bytes(command,'utf-8'))
reply = sock.recv(1024).decode('utf-8)
print('The server said', repr(reply))
sock.close()
if __name__ == '__main__':
client('localhost', 9999)
If you edit your code this way, I think you will correct the error you received. I hope it helps as I am new to this. Sorry for my entry-level English.
I have to make a simple udp echo client and server, currently my problem is that the client hangs itself up at the code "data, address = sock.recvfrom(dataSize)". Here is my client and server code (I removed some api functions, so it aint long). I tried same ports and different ports and the same goes with the ip's but i dont get any message back. I tried the original file from a friend and his version works, I have the same port and ip and the same methods on both files, but it still keeps hanging at the echoClient method receiveMSG at the first line.
echoServerUDP.py
0<0# : ^
'''
#echo off
python "%~f0" %*
pause
exit /b 0
'''
#!/usr/bin/env python
import socket
import json
host = '0.0.0.0'
sport = 11111 # own port
dataSize = 1024
ip_adresses = {}
def echo_server():
receiveSock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
receiveSock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
receiveSock.bind((host,sport))
print("Starting up echo server on %s port %s" % (host, sport))
while True:
print("Waiting to receive message")
print("Generate a Session ...")
data, address = receiveSock.recvfrom(dataSize)
data = data.decode("utf-8")
if data:
print("receive data: %s from %s" % (data,address))
json_object = json.loads(data)
operation=json_object["operation"]
if operation == "register":
register(json_object["name"],json_object["value"],json_object["sid"])
json_message={"ergebnis":"ok"}
dump = json.dumps(json_message)
sendMSG(bytes(dump,encoding="utf-8"),address)
print("er")
if operation == "unregister":
unregister(json_object["name"],json_object["sid"])
if operation == "query":
query(json_object["sid"])
if operation == "reset":
reset(json_object["sid"])
print("sent %s bytes back to %s" % (data,address))
def sendMSG(data,address):
sendSock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sendSock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sendSock.sendto(data,address)
sendSock.close()
if __name__ == '__main__':
echo_server()
and here the echoClientUDP.py
0<0# : ^
'''
#echo off
python "%~f0" %*
pause
exit /b 0
'''
#!/usr/bin/env python
import socket
import time
import json
from random import randint
host = '127.0.0.1'
sport = 11111
dataSize = 1024
sid= randint(1,10000)
name=socket.gethostname()
own_ip = socket.gethostbyname(name)
def echo_client():
sendSock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
try:
json_message = {"operation":"register","name":name,"value":own_ip,"sid":sid}
dump = json.dumps(json_message)
print("Sending %s to %s:%s" % (dump,host,sport))
sendMSG(sendSock, dump)
data = receiveMSG(sendSock)
if data:
print("Received: %s" % data)
except Exception as err:
print("Socket error: %s" %str(err))
finally:
print("Closing connection to the server")
sendSock.close()
def sendMSG(sendSock, data):
sendSock.connect((host, sport))
sendSock.sendall(bytes(data,encoding="utf-8"))
def receiveMSG(sock):
data, address = sock.recvfrom(dataSize)
print(data)
return data
if __name__ == '__main__':
echo_client()
Please put more effort in some areas like you have not added any headers and you have gone more complicated i have also created a similar working script see and observe that script and make changes to your script
client.py :-
import socket
import sys
HEADER = 64
PORT = 65432
FORMAT = 'utf-8'
DISCONNECT_MESSAGE = "!DISCONNECT"
SERVER = socket.gethostbyname(socket.gethostname())
ADDR = (SERVER, PORT)
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(ADDR)
def send(msg):
message = msg.encode(FORMAT)
msg_length = len(message)
send_length = str(msg_length).encode(FORMAT)
send_length += b' ' * (HEADER - len(send_length))
client.send(send_length)
client.send(message)
print(client.recv(2048).decode(FORMAT))
def chat():
while True:
try:
a = input()
if 'quit' in a:
sys.exit()
else:
send(a)
except Exception as e:
print(e)
sys.exit()
chat()
server.py :-
import socket
import threading
HEADER = 64
PORT = 65432
SERVER = socket.gethostbyname(socket.gethostname())
ADDR = (SERVER, PORT)
FORMAT = 'utf-8'
DISCONNECT_MESSAGE = "Bye"
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(ADDR)
def handle_client(conn, addr):
print(f"[NEW CONNECTION] {addr} connected.")
connected = True
while connected:
msg_length = conn.recv(HEADER).decode(FORMAT)
if msg_length:
msg_length = int(msg_length)
msg = conn.recv(msg_length).decode(FORMAT)
if msg == DISCONNECT_MESSAGE:
connected = False
print(f"[{addr}] left")
print(f"[{addr}] {msg}")
conn.send("Msg received".encode(FORMAT))
conn.close()
def start():
server.listen()
print(f"[LISTENING] Server is listening on {SERVER}")
while True:
conn, addr = server.accept()
thread = threading.Thread(target=handle_client, args=(conn, addr))
thread.start()
print(f"[ACTIVE CONNECTIONS] {threading.activeCount() - 1}")
print("[STARTING] server is starting...")
start()
and i have used threading here to make the process more fast.
First run the server.py in background and then run client.py to connect to the server.
I'm trying to make a small multiplayer game and thus need to send objects. Have created server and client and everything is working for sending bytes e.g. (str("").encode(utf-8)).
But when I tried to use pickle I've started bumping into issues. Have I made any mistakes below?
Server.py:
import socket
import threading
import pickle
HEADER = 8 #Contains info about incoming msg SIZE! first 8 bytes contains size
FORMAT = "utf-8"
PORT = 5558
SERVER = socket.gethostbyname(socket.gethostname())
ADDR = (SERVER, PORT)
DISCONNECT_MSG = "!Disconnect"
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(ADDR)
def handle_client(client_socket, client_addr):
print(f"[NEW CONNECTION] {client_addr} connected!")
while True:
try:
msg = pickle.loads(client_socket.recv(2048))
print(f"[RECEIVED] {client_addr} - {msg}")
if msg == DISCONNECT_MSG:
print(f"[DISCONNECTED] client {client_addr} has disconnected")
client_socket.close()
return False
except socket.error as e:
print(e)
def start_server(server):
server.listen()
print("[STARTED] server is online!")
while True:
client_socket, client_addr = server.accept()
thread = threading.Thread(target=handle_client, args=(client_socket, client_addr))
thread.start()
print(f"[ACTIVE CONNECTIONS] {threading.activeCount() - 1}")
print("[STARTING] server is starting...")
start_server(server_socket)
Client.py
import socket
import pickle
HEADER = 8
FORMAT = "utf-8"
PORT = 5558
SERVER = socket.gethostbyname(socket.gethostname())
ADDR = (SERVER, PORT)
DISCONNECT_MSG = "!Disconnect"
class Client:
def __init__(self):
self.client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
def connect_to_server(self, server_address):
"""
:param server_address: tuple(IP, PORT)
:return:
"""
self.get_client_socket().connect(server_address)
def get_client_socket(self):
return self.client_socket
def send_object(self, object):
msg = pickle.dumps(object)
self.get_client_socket().sendall(msg)
client = Client()
client.connect_to_server(ADDR)
d = "1"
client.send_object(d)
#client.send_object(DISCONNECT_MSG)
I've also tried to put while loop into send_object() but then after couple of successful receivements I get:
msg = pickle.loads(client_socket.recv(2048))
_pickle.UnpicklingError: invalid load key, '\x00'.
After some research it appears that before trying to unpickle an object you first need to check if received message is not None. Because server is constantly trying to receive message from client, but that is another issue.
Code modification in server.py:
def handle_client(client_socket, client_addr):
print(f"[NEW CONNECTION] {client_addr} connected!")
while True:
try:
msg = client_socket.recv(2048)
if msg:
new_msg = pickle.loads(msg[HEADER:])
print(f"[RECEIVED] {client_addr} - {new_msg}")
if msg == DISCONNECT_MSG:
print(f"[DISCONNECTED] client {client_addr} has disconnected")
client_socket.close()
return False
except socket.error as e:
print(e)
Note -> Until DISCONNECT message is not sent from client it will use much processor time (issue mentioned above)
I am making server-client communication in python using sockets and threading module. I connect client to server, send some data, receive some data, but the problem is, I can send only two messages. After those, the server is not reciving my packets. Can someone tell me what's wrong? Thanks in advance.
Server.py:
import socket
from threading import Thread
class Server:
def __init__(self):
self.host = '127.0.0.1'
self.port = 9999
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.bind((self.host, self.port))
self.server.listen(5)
self.threads = []
self.listen_for_clients()
def listen_for_clients(self):
print('Listening...')
while True:
client, addr = self.server.accept()
print('Accepted Connection from: '+str(addr[0])+':'+str(addr[1]))
self.threads.append(Thread(target=self.handle_client, args=(client, addr)))
for thread in self.threads:
thread.start()
def handle_client(self, client_socket, address):
client_socket.send('Welcome to server'.encode())
size = 1024
while True:
message = client_socket.recv(size)
if message.decode() == 'q^':
print('Received request for exit from: '+str(address[0])+':'+str(address[1]))
break
else:
print('Received: '+message.decode()+' from: '+str(address[0])+':'+str(address[1]))
client_socket.send('Received request for exit. Deleted from server threads'.encode())
client_socket.close()
if __name__=="__main__":
main = Server()
Client.py
import socket
import sys, time
def main():
target_host = '127.0.0.1'
target_port = 9999
try:
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except socket.error:
print('Could not create a socket')
time.sleep(1)
sys.exit()
try:
client.connect((target_host, target_port))
except socket.error:
print('Could not connect to server')
time.sleep(1)
sys.exit()
while True:
data = input()
client.send(data.encode())
message = client.recv(4096)
print('[+] Received: '+ message.decode())
main()
You have to send exit message 'q^' to client too to close client.
Warning:
Using Unicode as encoding for string is not recommended in socket. A partial Unicode character may be received in server/client resulting in UnicodeDecodeError being raised.
Code for server using threads is:
server.py:
import socket
from threading import Thread
class Server:
def __init__(self, host, port):
self.host = host
self.port = port
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.bind((self.host, self.port))
self.server.listen(5)
def listen_for_clients(self):
print('Listening...')
while True:
client, addr = self.server.accept()
print(
'Accepted Connection from: ' + str(addr[0]) + ':' + str(addr[1])
)
Thread(target=self.handle_client, args=(client, addr)).start()
def handle_client(self, client_socket, address):
size = 1024
while True:
try:
data = client_socket.recv(size)
if 'q^' in data.decode():
print('Received request for exit from: ' + str(
address[0]) + ':' + str(address[1]))
break
else:
# send getting after receiving from client
client_socket.sendall('Welcome to server'.encode())
print('Received: ' + data.decode() + ' from: ' + str(
address[0]) + ':' + str(address[1]))
except socket.error:
client_socket.close()
return False
client_socket.sendall(
'Received request for exit. Deleted from server threads'.encode()
)
# send quit message to client too
client_socket.sendall(
'q^'.encode()
)
client_socket.close()
if __name__ == "__main__":
host = '127.0.0.1'
port = 9999
main = Server(host, port)
# start listening for clients
main.listen_for_clients()
client.py:
import socket
import sys, time
def main():
target_host = '127.0.0.1'
target_port = 9999
try:
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except socket.error:
print('Could not create a socket')
time.sleep(1)
sys.exit()
try:
client.connect((target_host, target_port))
except socket.error:
print('Could not connect to server')
time.sleep(1)
sys.exit()
online = True
while online:
data = input()
client.sendall(data.encode())
while True:
message = client.recv(4096)
if 'q^' in message.decode():
client.close()
online = False
break
print('[+] Received: ' + message.decode())
break # stop receiving
# start client
main()