AttributeError in python code with socket - python

I'm having an AttributeError that says "AttributeError: 'socket' object has no attribute 'upper'". I'm pretty sure I created and established the connection properly, and am still unsure what to do after consulting the socket documentation.
Thank you.
import socket
from _thread import *
import threading
print_lock = threading.Lock()
list_of_clients = []
def threaded(data, addr, s):
s.sendto(data.upper(), addr)
while True:
message = s.recv(1024)
if not message:
print('Bye')
print_lock.release()
break
message = message.upper()
print("Sending message to " + addr[0])
s.sendto(message, addr)
data.close()
def Main():
list_of_clients = []
serverName = 'localhost'
serverPort = 12000
with socket.socket(socket.AF_INET , socket.SOCK_STREAM) as serverSocket:
serverSocket.connect((serverName, serverPort))
while True :
print('Ready to ping...')
data, addr = serverSocket.accept()
print(type(data))
print_lock.acquire()
print("Client connected ip:<" + str(addr) + ">")
start_new_thread(threaded, (data, addr, serverSocket))
print("Continue")
if __name__ == '__main__':
Main()

The problem is this line:
s.sendto(data.upper(), addr)
data is defined here:
data, addr = serverSocket.accept()
The accept method returns a 2-tuple, where the first element is a socket object capable of sending and receiving data.
Therefore, instead of passing serverSocket to threaded, you should pass the first element of the 2-tuple, as well as whatever data you want to send.

Related

python socket programming TypeError: bytes like object is required not str

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.

How can I receive multiple messages from one connection?

I have a server and I need it to receive multiple connections and messages.
The server receives new connections without problems but it doesn't get multiple messages from one connection.
import socket
import select
HEADER_LENGTH = 1024
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
try:
server_socket.bind((HOST, PORT))
except socket.error as e:
print(str(e))
print("Server is connected")
server_socket.listen(5)
sockets_list = [server_socket]
clients = {}
print("Server is listening")
def receive_message(conn):
try:
data = conn.recv(HEADER_LENGTH)
if not len(data):
return False
strdata = data.decode('utf-8')
print(strdata)
return strdata
except Exception as e:
print(e)
return False
def handle_client():
conn, addr = server_socket.accept()
print(f"Accepted new connection from {addr[0]}:{addr[1]}")
sockets_list.append(conn)
while True:
read_sockets, _, exception_sockets = select.select(sockets_list, [], [], 0)
for i in read_sockets:
if i == server_socket:
handle_client()
else:
print("received message")
message = receive_message(i)
if message is False:
sockets_list.remove(i)
try:
del clients[i]
except KeyError:
pass
continue
if message is not None:
clients[i] = message
if message is not None:
for client_socket in clients:
if client_socket != i:
client_socket.send(str.encode(message))
print("sent to all players")
What happens it that after receiving the first message, the server stops receiving messages from that connection.
And of course there is a lot more code but I showed you the relevant code.
I'll be very happy if someone helps me with that, I've surfed the web so much but haven't seen a solution for my problem.
updates:
I've tried to put socket.close() on my client side(written in Java) and then server gets maximum 2 messages and the problems with it are:
1. The server gets maximum 2 messages.
2. the connection changes(I need that the connection will stay static if possible)
try this code block
#-*- coding:utf-8 -*-
import socket
import sys
#get machine ip address
server_ip = socket.gethostbyname(socket.gethostname())
#create socket object
s = socket.socket()
#define port number
port = 6666
#bind ip and port to server
s.bind((server_ip,port))
#now waiting for clinet to connect
s.listen(5)
print("Enter this ip to connect your clinet")
print(server_ip)
clients = []
flag = True
recv_data = ""
if not clients:
c, addr = s.accept()
print("this is c ",c," this is Addr ",addr)
clients.append(c)
recv_data = c.recv(1024)
print(recv_data.decode("utf-8"))
if flag == True:
while recv_data.decode("utf-8") != "EX":
recv_data = c.recv(1024)
recv_data.decode("utf-8")
if recv_data.decode("utf-8") == "EX":
s.close()
print("check false")
break
s.close()

Empty string is appended to the deque

I have a deque on a host. Each String that is received through TCP socket is appended to this deque. When each data is received, I print the data and the deque. Here is the code:
from __future__ import print_function
import commands
import socket
import select
from collections import deque
host = commands.getoutput("hostname -I")
port = 5005
backlog = 5
BUFSIZE = 4096
BUFFER_SIZE = 1024
q = deque()
def read_tcp(s):
conn, addr = s.accept()
print('Connected with', *addr)
while 1:
data = conn.recv(BUFFER_SIZE)
if not data: break
print("received data:", data)
conn.send(data) # echo
if (data == 'sample.jpg'):
print("start processing")
#processP(q)
else:
print("appended")
q.append(data)
print(q)
conn.close()
def read_udp(s):
data,addr = s.recvfrom(1024)
print("received message:", data)
def run():
# create tcp socket
tcp = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcp.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
try:
tcp.bind((host,port))
except socket.error as err:
print('Bind failed', err)
return
tcp.listen(1)
# create udp socket
udp = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # UDP
udp.bind((host,port))
print('***Socket now listening at***:', host, port)
input = [tcp,udp]
try:
while True:
#print("select.select")
inputready,outputready,exceptready = select.select(input,[],[], 0.1)
for s in inputready:
if s == tcp:
read_tcp(s)
elif s == udp:
read_udp(s)
else:
print("unknown socket:", s)
# Hit Break / Ctrl-C to exit
except KeyboardInterrupt:
print('\nClosing')
raise
tcp.close()
udp.close()
if __name__ == '__main__':
run()
The problem is that when I print the received data and deque in these lines print("received data:", data) and print(q), the received data is print correctly, but the deque content is printed like these in each step:
deque([''])
deque(['',''])
deque(['','',''])
What's wrong? Here is the sender code which doesn't seem to have any problem:
from __future__ import print_function
import socket
from struct import pack
import commands
import select
#HOST = '10.0.0.2'
PORT = 5005
BUFSIZE = 4096
def tcp_send(s, ip):
TCP_IP = ip
BUFFER_SIZE = 1024
MESSAGE = s
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, PORT))
s.send(MESSAGE)
data = s.recv(BUFFER_SIZE)
s.close()
print ("sent data:", data)
fnames = [
'90.jpg','91.jpg','92.jpg','93.jpg','94.jpg','95.jpg','96.jpg','97.jpg','98.jpg','99.jpg','100.jpg','sample.jpg'
]
def main():
for fname1 in fnames:
tcp_send(fname1,'10.0.0.2')
if __name__ == '__main__':
main()
replace your read_tcp(s) with
def read_tcp(s):
conn, addr = s.accept()
print('Connected with', *addr)
while 1:
data = conn.recv(BUFFER_SIZE)
if not data: break
print("received data:", data)
conn.send(data) # echo
print(data)
if (data == 'sample.jpg'):
print("start processing")
#processP(q)
else:
print("appended", data)
q.append(data)
print(q)
conn.close()
you are trying to access data outside while that's why it is empty
It looks like indentation problem. You will brake out of the while loop (in read_tcp()) only when data is evaluated False. Only then, already out of the loop you append current value of data to to the deque q. In the loop you print every chunck of data you get. I think the if block needs to be indented one level to be part of the loop.
Also in read_udp() I don't see that you add anything to deque

Server Loop Using Python Sockets and Threading module

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()

UDP TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

I'm completely newbie to python and computer networking. While working on Uni project I have faced a problem. What am I doing wrong? Any help will me much appreciated.
Here is server side:
import socket
def Main():
host = "127.0.0.1"
port = 5000
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
print ("Server Started.")
while True:
data, addr = s.recvfrom(1024)
print ("message from: ") + str(addr)
print ("from connected user: ") + str(data.decode('utf-8'))
data = str(data).upper()
print ("sending: ") + str(data)
s.sendto(data, addr)
s.close()
if __name__ == '__main__':
Main()
Here is my client side:
import socket
def Main():
host = "127.0.0.1"
port = 5000
server = ('127.0.0.1', 5000)
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
message = input('->')
while message != 'q':
s.sendto(message.encode('utf-8'), server)
data, addr = s.recvfrom(1024)
print ('Received from server: ') + str(data)
message = input('->')
s.close()
if __name__ == '__main__' :
Main()
There were a couple of issues; mostly with the printing.
You had a few instances of print('some text') + str(data); this won't work, because while print() outputs to the screen (STDOUT) it returns None, so what you were actually doing was trying to concatenate None + str(data)
What you need is print('some text' + str(data)).
Additionally, there was as issue on the server-side where you echo the data received from the client back to the client- it needed to be re-encoded as a bytearray (it comes in as a bytearray, gets converted to a utf-8 string for display, it needs to go back to bytearray before replying).
In summary, server:
import socket
def Main():
host = "127.0.0.1"
port = 5000
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
print("Server Started.")
while True:
try:
data, addr = s.recvfrom(1024)
print("message from: " + str(addr)) # moved string concatenation inside print method
print("from connected user: " + str(data.decode('utf-8'))) # moved string concatenation inside print method
data = str(data).upper()
print("sending: " + str(data)) # moved string concatenation inside print method
s.sendto(data.encode('utf-8'), addr) # needed to re-encode data into bytearray before sending
except KeyboardInterrupt: # added for clean CTRL + C exiting
print('Quitting')
break
s.close()
if __name__ == '__main__':
Main()
And the client:
import socket
def Main():
host = "127.0.0.1"
port = 5001
server = ('127.0.0.1', 5000)
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
message = input('->')
while message != 'q':
try:
s.sendto(message.encode('utf-8'), server)
data, addr = s.recvfrom(1024)
print('Received from server: ' + str(data)) # moved string concatenation inside print method
message = input('->')
except KeyboardInterrupt: # added for clean CTRL + C exiting
print('Quitting')
break
s.close()
if __name__ == '__main__':
Main()

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