I have a simple client server program and the server side works but for some reason I can't get the the client to interact to the server. I am able to launch the server and use nc -6 fe80::cbdd:d3da:5194:99be%eth1 2020 and connect to it.
Server code:
#!/usr/bin/env python3
from socket import *
from time import ctime
HOST='::'
PORT = 2020
BUFSIZ = 1024
ADDR = (HOST, PORT)
tcpSerSock = socket(AF_INET6, SOCK_STREAM)
##tcpSerSock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
tcpSerSock.bind(ADDR)
tcpSerSock.listen(5)
while True:
print('Waiting for connection...')
tcpCliSock, addr = tcpSerSock.accept()
print('...connected from:', addr)
while True:
data = tcpCliSock.recv(BUFSIZ)
if not data:
break
tcpCliSock.send(('[%s] %s'%(bytes(ctime(), 'utf-8'), data)).encode('utf-8'))
tcpCliSock.close()
tcpSerSock.close()
client code:
#!/usr/bin/python3
from socket import *
def tcp_ipv6():
HOST = 'fe80::cbdd:d3da:5194:99be%eth1'
PORT = 2020
ADDR = (HOST, PORT)
BUFSIZ = 1024
sock = socket(AF_INET6, SOCK_STREAM)
sock.connect(ADDR)
while True:
data = input('> ')
if not data:
break
sock.send(data)
response = sock.recv(BUFSIZ)
if not response:
break
print(response.decode('utf-8'))
sock.close()
tcp_ipv6()
When I run the client code I get:
Traceback (most recent call last):
File "client.py", line 44, in <module>
tcp_ipv6()
File "client.py", line 31, in tcp_ipv6
sock.connect(ADDR)
OSError: [Errno 22] Invalid argument
Edit1:
Thanks to Establishing an IPv6 connection using sockets in python
4-tuple for AF_INET6
ADDR = (HOST, PORT, 0, 0)
sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
sock.connect(ADDR)
Still having the same error
Any idea?
Thanks in advance
Some parts of your question have been asked before.
Establishing an IPv6 connection using sockets in python
However, it is not the entire reason why it is not working correctly. If you look at your IPv6 address. fe80::cbdd:d3da:5194:99be%eth1 You can see the %eth1 at the end. That is not part of the internet address. Change HOST to HOST = 'fe80::cbdd:d3da:5194:99be'. And it should work.
I would also like to point out another error in your code. You are attempting to send a string (received from input) over the socket. However, this method only accepts byte like objects. You can add data = data.encode('utf-8') to fix this.
The higher level function - create_connection , to connect to port works in such case. Sample scriptlet is given as follows. Though why sock.connect fails needs to be identified.
HOST = "xxxx::xxx:xxxx:xxxx:xxxx%en0"
PORT = 2020
ADDR = (HOST, PORT)
BUFSIZ = 1024
sock=create_connection(ADDR)
Related
I've recently been tinkering around with the python socket module and I have come across an issue.
Here is my python server side script (im using python3.8.2)
import socket
#defin socket object
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((socket.gethostname(), 0))
s.listen(5)
while True:
clientsocket, address = s.accept()
print(f"connection from client has been established")
clientsocket.send(bytes("welcome to the server!", "utf-8"))
My server side script runs fine, however when i run the client script
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((socket.gethostname(127.0.0.1), 0))
msg = s.recv(1024)
print(msg.decode("utf-8"))
i get the following:
File "client.py", line 3
s.connect((socket.gethostname(127.0.0.1), 0))
^
SyntaxError: invalid syntax
I've tried changing the IP to my computer host name and gives the following:
raceback (most recent call last):
File "client.py", line 3, in <module>
s.connect(socket.gethostname((LAPTOP-XXXXXXX), 0))
NameError: name 'LAPTOP' is not defined
There are multiple issues:
when specifying IP addresses and hostnames, they must be formatted as strings (e.g. "127.0.0.1" and "LAPTOP-XXXXXXX"). Specifying them without quotes causes Python to attempt to interpret them as other tokens, such as variable names, reserved keyword, numbers, etc., which fails causing erros such as SyntaxError and NameError.
socket.gethostname() does not take an argument
specifying port 0 in the socket.bind() call results in a random high numbered port being assigned, so you either need to hardcode the port you use or dynamically specify the correct port in your client (e.g. by specifying it as an argument when executing the program)
in the server code, socket.gethostname() may not end up using the loopback address. One option here is using an empty string, which results in accepting connections on any IPv4 address.
Here's a working implementation:
server.py
import socket
HOST = ''
PORT = 45555
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
host_addr = s.getsockname()
print("listening on {}:{}".format(host_addr[0], host_addr[1]))
s.listen(5)
while True:
client_socket, client_addr = s.accept()
print("connection from {}:{} established".format(client_addr[0], client_addr[1]))
client_socket.send(bytes("welcome to the server!", "utf-8"))
client.py
import socket
HOST = '127.0.0.1'
PORT = 45555
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
msg = s.recv(1024)
print(msg.decode("utf-8"))
Output from the server:
$ python3 server.py
listening on 0.0.0.0:45555
connection from 127.0.0.1:51188 established
connection from 127.0.0.1:51244 established
Output from client:
$ python3 client.py
welcome to the server!
$ python3 client.py
welcome to the server!
Put the 127.0.0.1 as string in gethostname
In the /etc/hosts file content, You will have an IP address mapping with '127.0.1.1' to your hostname. This will cause the name resolution to get 127.0.1.1. Just comment this line. So Every one in your LAN can receive the data when they connect with your ip (192.168.1.*). Used threading to manage multiple Clients.
Here's the Server and Client Code:
Server Code:
import socket
import os
from threading import Thread
import threading
import time
import datetime
def listener(client, address):
print ("Accepted connection from: ", address)
with clients_lock:
clients.add(client)
try:
while True:
client.send(a)
time.sleep(2)
finally:
with clients_lock:
clients.remove(client)
client.close()
clients = set()
clients_lock = threading.Lock()
host = socket.getfqdn() # it gets ip of lan
port = 10016
s = socket.socket()
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host,port))
s.listen(3)
th = []
print ("Server is listening for connections...")
while True:
client, address = s.accept()
timestamp = datetime.datetime.now().strftime("%b %d %Y,%a, %I:%M:%S %p")
a = ("Hi Steven!!!" + timestamp).encode()
th.append(Thread(target=listener, args = (client,address)).start())
s.close()
Client Code:
import socket
import os
import time
s = socket.socket()
host = '192.168.1.43' #my server ip
port = 10016
print(host)
print(port)
s.connect((host, port))
while True:
print((s.recv(1024)).decode())
s.close()
Output:
(base) paulsteven#smackcoders:~$ python server.py
Server is listening for connections...
Accepted connection from: ('192.168.1.43', 38716)
(base) paulsteven#smackcoders:~$ python client.py
192.168.1.43
10016
Hi Steven!!!Feb 19 2020,Wed, 11:13:17 AM
Hi Steven!!!Feb 19 2020,Wed, 11:13:17 AM
Hi Steven!!!Feb 19 2020,Wed, 11:13:17 AM
Simple client - server app.
#Server use decode
import socket
s = socket.socket()
host = socket.gethostname()
port = 12345
s.bind((host,port))
s.listen(5)
while True:
c,addr = s.accept()
print("Got connection from " + str(addr))
ret_val = s.send("Thank you".encode('utf-8'))
print ("ret_val={}".format(ret_val))
c.close()
Client:
#client use decode
from socket import gethostname, socket
serSocket = socket()
server = gethostname()
port = 12345
serSocket.connect((server, port))
data = serSocket.recv(1024)
msg = data.decode('utf-8')
print("Returned Msg from server: <{}>".format(msg))
serSocket.close()
when the server tries to send the following exception occurred
Traceback (most recent call last):
Got connection from ('192.168.177.1', 49755)
File "C:/Users/Oren/PycharmProjects/CientServer/ServerSide/Server2.py", line 16, in <module>
ret_val = s.send("Thank you".encode('utf-8'))
OSError: [WinError 10057] A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied
Process finished with exit code 1
As can be seen the client connects the server successfully.
But send fails.
What is the problem?
The problem is that you are sending on the listening socket, not on the connected socket. connect returns a new socket which is the one you must use for data transfer. The listening socket can never be used for sending or receiving data.
Change the send to this and your program will work fine:
ret_val = c.send("Thank you".encode('utf-8'))
(Note c.send, not s.send)
Hello so I am making a python socket server and client and I am trying to figure out how I can make it so when the server sends a message to the client using arguments(I am not good with explaining myself) but basically my issue is this
Server Console:
Command: >senddata 127.0.0.1 32
Clients Response:
Command Accepted!
Traceback (most recent call last):
File "C:\Users\Goten\Desktop\client\client.py", line 18, in <module>
ip = sys.argv[1]
IndexError: list index out of range
I am sending 32 bytes of data(I think) to 127.0.0.1 and it wont work
This is my clients code:
import socket
import sys
socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = "127.0.0.1"
port = 8888
socket.connect((host, port))
while True:
msg = socket.recv(1024)
if ">senddata".lower() in msg:
print("Command Accepted!")
ip = sys.argv[1]
datasize = sys.argv[2]
data = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
port = 80
data.sendto(datasize, (ip, port))
print("Sent")
I seriously cannot figure out what I am doing wrong
You are reading from msg, not sys.argv.
if ">senddata".lower() in msg:
print("Command Accepted!")
ip = msg.split(" ")[1]
datasize = msg.split(" ")[2]
I've got a simple client and server I found on an online tutorial
#server.py
import socket # Import socket module
s = socket.socket() # Create a socket object
host = 'localhost' # Get local machine name
port = 12345 # Reserve a port for your service.
s.bind((host, port)) # Bind to the port
s.listen(5) # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
c.send('Thank you for connecting')
c.close() # Close the connection
#client # This is client.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = 'localhost'
port = 12345 # Reserve a port for your service.
s.connect((host, port))
print s.recv(1024)
s.close # Close the socket when done
When I run my client.py all it does is print an empty string when it should print ('Thank you for connecting'). When I connect localhost 12345 from telnet it sends the message fine so I don't know why my client isn't receiving the message
Any thoughts. I'm very new to socket programming and would love to find a solution so I can move on.
While running your script as is, I got this error:
Waiting connections ...
Got connection from ('127.0.0.1', 63875)
Traceback (most recent call last):
File "serv.py", line 14, in <module>
c.send('Thank you for connecting')
TypeError: a bytes-like object is required, not 'str'
Few things here:
Ensure you're sending bytes instead of str. you could do this by replacing line 14 with:
c.send(b'Thank you for connecting')
Also, it's always useful to declare your sockets s like this:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
Further read:
Py2: https://docs.python.org/2/library/socket.html
Py3: https://docs.python.org/3/library/socket.html
Hope it works! :)
I like to have one port that first use for connect to another server and after that this port use to be a server and another clients connect to it.
I used python socket for client now I want to use it for server socket.
my code :
#!/usr/bin/python # This is server.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12349
portt = 12341 # Reserve a port for your service.
s.bind((host, portt)) # Bind to the port
s.connect((host, port))
s.listen(5) # Now wait for client connection.
c, addr = s.accept() # Establish connection with client.
print c
print 'Got connection from', addr
print s.recv(1024)
s.close
and the output is
Traceback (most recent call last):
File "client.py", line 12, in <module>
s.listen(5) # Now wait for client connection.
File "/usr/lib/python2.7/socket.py", line 224, in meth
return getattr(self._sock,name)(*args)
socket.error: [Errno 22] Invalid argument
How can I do that.
thank you for your answers!
Not sure what you are trying to do here. Seems to me that you are mixing client and server code in the same app.
For reference, you can create a simple echo server like this:
import socket
HOST = ''
PORT = 12349
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(5)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
data = conn.recv(1024)
if not data: break
conn.sendall(data)
conn.close()
And a simple echo client like this:
import socket
HOST = 'localhost'
PORT = 12349
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall('Hello, world')
data = s.recv(1024)
s.close()
print 'Received', repr(data)