How to use client socket as a server socket python - python

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)

Related

ConnectionRefusedError when trying to host python socket server on raspberry pi

I'm trying to make a basic python networking program. All I'm trying to do is send strings of text back and forth between the server and the client. I'm trying to host the server on my Raspberry Pi, and connect with a client on Windows 10. The program works great locally on my computer, but when I try to connect to my server, it gives me ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it. My server code is as follows:
import socket # Import socket module
import netifaces as ni
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
s.bind((host, port))
#host_ip = ni.ifaddresses('wlan0')[ni.AF_INET][0]['addr']
host_ip = "bruh?"
print("Server started! \nHostname: " + host + " \nIP: " + host_ip + " \nPort: " + str(port))
s.listen() # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print('Got connection from', addr)
output = "Welcome to the server!".encode()
c.send(output)
c.close()
Client code:
import socket
s = socket.socket()
host = 192.168.1.21
port = 12345
s.connect((host, int(port)))
noResponse = False
serverResponse = s.recv(1024).decode()
print(serverResponse)
s.close()
Does anyone know what my problem is? Thanks.
There may be a few reasons you are getting a ConnectionRefusedError, please try the following:
Check that no firewall is blocking your connection.
Double-check the server IP, if it is wrong you may get this error.
Try to use Hercules to check the connection.
Also, I would change the code as follow:
Server:
import socket
HOST = '' # localhost
PORT = # IMPORTANT !! Do not use reserved ports
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.bind((HOST, PORT))
sock.listen()
conn, addr = sock.accept()
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024)
if not data:
break
print('Data: ',data)
conn.sendall('RT')
Client:
import socket
HOST = '' # server IP address
PORT = # server port
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.connect((HOST, PORT))
sock.sendall('Hello, I am the Client')
data = sock.recv(1024)
print('Received', data)
By doing this you are using a TCP connection and you can test your code with different TCP server and client emulators.

Socket Error : No connection could be made because targeted machine actively refused it

Note : This problem has been completely solved, as was am running client.py before server.py
Just got started with socket programming, I have created the below code and expecting to print some byte message, but it isn't doing that.
I just want to make the message available for any person on any
machine. But it's refusing by the machine to do that.
Here is my code:
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = 12048
s.bind((socket.gethostname(), port))
s.listen()
while True:
c, addr = s.accept()
print("Got connection from", addr)
c.send(bytes("Thank you", "utf-8"))
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = 12048
s.connect(('192.168.0.1', port))
msg = s.recv(1024)
print(msg.decode("utf-8"))
Some images to better explain my errors:
Any help would be appreciated!!!
It looks like in the server.py script you use s.bind((socket.gethostname(), port)) where socket.gethostname() is a hostname, but in the client.py script you use s.connect(('192.168.0.1', port)) where '192.168.0.1' is the hostname you are trying to connect.
I think there you have socket.gethostname() != '192.168.0.1' and that's the problem.
Also, you can bind to all available IP addresses on the host using this solution Python socket bind to any IP?
Let's use listen_ip = socket.gethostbyname(socket.gethostname()) for connection since socket.gethostname() may return hostname instead of IP and it will not be solved by python dns resolver in local network if it was local name, not DNS.
and use it later as s.bind((listen_ip, port)) and s.connect((listen_ip, port))
After some debugging I've got a working solution for you
There are the scripts required.
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname(socket.gethostname())
port = 12_048
s.bind((host, port))
s.listen()
print("Server listening # {}:{}".format(host, port))
while True:
c, addr = s.accept()
print("Got connection from", addr)
c.send(bytes("Thank you", "utf-8"))
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '192.168.1.162' # The IP printed by the server must be set here
# or we can set it using env variable named SERVER_IP
if 'SERVER_IP' in os.environ:
host = os.environ['SERVER_IP']
port = 12048
print("Connecting to {}:{}".format(host, port))
s.connect((host, port))
msg = s.recv(1024)
print(msg.decode("utf-8"))
In a chat conversation we concluded that the hardcoded IP in the question is not the correct one. This solution does have the IP he needed but it will be different in each case. Remeber that server.py needs to be launched first, and when you see the printed Server listening # IP:12048, write that IP in client.py and launch it. Client does need to be launched after seeing that line even if you already know the IP, as the server needs some time to be ready and the client will crash if it tries to connect to the server while it is not ready.
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname(socket.gethostname())
port = 12048
s.bind((host, port))
s.listen()
print("Server listening # {}:{}".format(host, port))
while True:
c, addr = s.accept()
print("Got connection from", addr)
c.send(bytes("Thank you", "utf-8"))
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '192.168.1.162' # The IP printed by the server must be set here
port = 12048
print("Connecting to {}:{}".format(host, port))
s.connect((host, port))
msg = s.recv(1024)
print(msg.decode("utf-8"))

Bad file descriptor when trying to send message from client to server

I need to be able to send a message as client to the server and get the message back from the server in my client's console.
However when I try to implement this I keep getting the error:
line 64, in <module>
s.send(message.encode('utf-8'))
OSError: [Errno 9] Bad file descriptor
My client:
import socket
HOST = 'localhost' # The server's hostname or IP address
PORT = 12000 # The port used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
while True:
message = input("write something:")
s.send(message.encode('utf-8'))
data = s.recv(1024).decode('utf-8')
print("Recieved from server: " + data)
My server:
import socket
HOST = 'localhost' # Standard loopback interface address (localhost)
PORT = 12000 # Port to listen on (non-privileged ports are > 1023)
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)

Python s.recv() returns empty string

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! :)

How to send a message from client to server in python

I'm reading two programs in Python 2.7.10 with client and server. How can I modify these programs in order to send a message from client to server?
server.py:
#!/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 = 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.py:
#!/usr/bin/python # This is client.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 80 # Reserve a port for your service.
s.connect((host, port))
print s.recv(1024)
s.close # Close the socket when done
TCP sockets are bi-directional. So, after connection, there is no difference between server and client, you only have two ends of a stream:
import socket # Import socket module
s = socket.socket() # Create a socket object
s.bind(('0.0.0.0', 12345)) # 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
print c.recv(1024)
c.close() # Close the connection
and the client:
import socket # Import socket module
s = socket.socket() # Create a socket object
s.connect(('localhost', 12345))
s.sendall('Here I am!')
s.close() # Close the socket when done
The above answer throws an error: TypeError: a bytes-like object is required, not 'str'
However, the following code worked for me:
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = 3125
s.bind(('0.0.0.0', port))
print ('Socket binded to port 3125')
s.listen(3)
print ('socket is listening')
while True:
c, addr = s.accept()
print ('Got connection from ', addr)
print (c.recv(1024))
c.close()
client.py:
import socket
s = socket.socket()
port = 3125
s.connect(('localhost', port))
z = 'Your string'
s.sendall(z.encode())
s.close()

Categories

Resources