I have implemented code for a server and a client using sockets, however I would like the server to send continuously and the client to receive and print the message received until I end either program. The code just prints out once "L2" on the client.
Is it ideal to reverse functionality by receiving with the server and sending with the client?
client.py
import socket
import time
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((socket.gethostname, 1223))
while True:
msg = s.recv(5)
# clientsocket.close()
print(msg.decode("utf-8"))
server.py
import socket
import time
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((socket.gethostname(), 1223))
s.listen(3)
while True:
clientsocket, address = s.accept()
clientsocket.send(bytes("L2", "utf-8"))
time.sleep(2)
Related
I'm leanring how sockets work and trying to do some simple things.
My client is NOT sending anything to the server, and the server will not receive anything. But the problem is that the server socket will be always waiting for nothing. I want it to do something else if there is no available coming data from the client side. The if statement does not help end its waiting.
Server.py:
import socket
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
hostname = socket.gethostname()
host = socket.gethostbyname(hostname)
port = 9090
server.bind((host, port))
server.listen(10)
con, addr = server.accept()
msg = con.recv(2048)
if not msg:
con.send('hello world'.encode('utf-8'))
con.close()
server.close()
else:
con.send('hi Client I received it'.encode('utf-8'))
con.close()
server.close()
Client.py:
import socket
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(('192.155.11.79', 9090))
data = client.recv(2048).decode('utf-8')
print('From server side: ', data)
client.close()
My socket sends the first message but nothing afterward.
The output in the server:
What do you want to send?
lol
The client receives:
From localhost got message:
lol
And then it doesn't want to send anything else.
I don't get the what do you want to send printed anymore.
My code:
server.py file:
#!/usr/bin/python3
import socket
# create a socket object
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# get local machine name
host = socket.gethostname()
print ("got host name:", host)
port = 9996
print("connecting on port:", port)
# bind to the port
serversocket.bind((host, port))
print("binding host and port")
# queue up to 5 requests
serversocket.listen(5)
print("Waiting for connection")
while True:
clientsocket, addr = serversocket.accept()
msg = input("what do you want to send?\n")
clientsocket.send(msg.encode('ascii'))
client.py file:
#!/usr/bin/python3
import socket # create a socket object
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # get local machine
# name
host = socket.gethostname()
port = 9996 # connection to hostname on the port.
s.connect((host, port)) # Receive no more than 1024 bytes
while True:
msg = s.recv(1024)
print(msg.decode("ascii"))
The client only connects once (OK) but the server waits for an incoming connection every start of the while loop.
Since there are no more connection requests by a client, the server will freeze on the second iteration.
If you just want to handle a single client, move clientsocket, addr = serversocket.accept() before the while loop. If you want to handle multiple clients, the standard way is to have the server accept connections inside the while loop and spawn a thread for each client.
You can also use coroutines, but that may be a bit overkill if you are just starting out.
I am creating a game in Pygame that requires a client-server part for the multiplayer.
First, I am checking if there are less than two connections. If this is the case, the client will be shown a screen that says 'waiting for connections'.
I have got the client to successfully send a '1' message to the server, which will respond with a '1' if the server is not full. Therefore, if the server does not respond with a 1, the server is full, and the client can continue.
However, I am getting this error mentioned in the title.
Server code:
import socket
import sys
import threading
from _thread import *
import time
s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host=socket.gethostname()
ip=socket.gethostbyname(host)
port=8000
connections=[]
print('Your local ip address is',ip)
s.bind((host,port))
s.listen(2)
def threaded_client(connection):
while True:
data=connection.recv(2048) #anything we receive
if not data:
break
connection.close()
def checkconnected(connections):
noofconn=len(connections)
while True:
print('Waiting for a connection...')
connection,address=s.accept()
print(address,'has connected to server hosted at port',address[1])
connections.append(address)
data=connection.recv(1024)
received=[]
counter=0
for letter in data:
received.append(data[counter])
counter+=1
received=(chr(received[0]))
if received=='1':#handling initial connections
if len(connections)!=2:
s.sendall(b'1')
if not data:
break
start_new_thread(threaded_client,(connection,))
s.close()
The client code that calls it:
host=socket.gethostname()
ip=socket.gethostbyname(host)
s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
address=address
port=8000
if address==ip:
ishost=True
else:
ishost=False
try:
s.connect((address,port))
connectionwaitingmenu()
connected=False
while connected==False:
s.sendall(b'1')
data=s.recv(1024)
received=[]
counter=0
for letter in data:
received.append(data[counter])
counter+=1
received=(chr(received[0]))
if received=='1':
connected=False
elif received!='1':
connected=True
classselection()
The error occurs on the s.sendall(b'1') line in the server code.
There are a few other problems in your code, but the cause of the error in the title is that you're using the wrong socket to send and receive data on the server side.
When a server accepts a new client (conn, addr = server.accept()) this returns a new socket, which represents the channel through which you communicate with the client. All further communication with this client happens by reading and writing on conn. You should not be calling recv() or sendall() on s, which is the server socket.
The code should look something like this:
# Assuming server is a bound/listening socket
conn, addr = server.accept()
# Send to client
conn.sendall(b'hello client')
# Receive from client
response = conn.recv(1024)
# NO
server.send(b'I am not connected')
this_wont_work = server.recv(1024)
So I have created a socket program for both client and server as a basic chat. I made it so the server accepts multiple clients with threading, so that is not the problem. I am having trouble sending messages to each client that is connected to the server. I am not trying to have the server send a message it created but rather have client1 sending a message to client2 by going through the server. For some reason it will only send it back to client1.
For example, client1 will say hello and the server will send the same message back to client1 but nothing to client2. I fixed this slightly by making sure the client doesn't receive its own message but client2 is still not receiving the message from the client1.
Any help will be appreciated.
I have tried multiple changes and nothing seems to work. You can look at my code for specifics on how I did things but ask if there are any questions.
Also, there is a question where someone has asked that is similar and I thought it would give me an answer but the responses stopped going through and a solution was never fully given, so please don't just refer me to that question. that is located here: Python 3: Socket server send to multiple clients with sendto() function.
Here's the code:
CLIENT:
import socket
import sys
import thread
#Create a socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#Enter username to identify self to others
name = raw_input("Enter username: ") + ": "
#Connect socket to ip and port
host = socket.gethostname()
#host = '192.168.1.10'
server_address = (host, 4441)
sock.connect(server_address)
#function waiting to receive and print a message
def receive(nothing):
while True:
data = sock.recv(1024)
if message != data:
print data
# Send messages
while True:
#arbitrary variable allowing us to have a thread
nothing = (0, 1)
message = name + raw_input("> ")
sock.sendall(message)
#thread to receive a message
thread.start_new_thread(receive, (nothing,))
SERVER:
import socket
import sys
import thread
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Bind the socket to the port
host = socket.gethostname()
server_address = (host, 4441)
sock.bind(server_address)
#Listen for incoming connections
sock.listen(5)
print "Waiting for connection..."
#Variable for the number of connections
numbOfConn = 0
#Name of list used for connections
addressList = []
#Function that continuosly searches for connections
def clients(connection, addressList):
while True:
message = connection.recv(1024)
print message
#connection.sendall(message)
#for loop to send message to each
for i in range(0,numbOfConn - 1):
connection.sendto(message, addressList[i])
connection.close()
while True:
#accept a connection
connection, address = sock.accept()
print 'Got connection from', address
numbOfConn += 1
addressList.append((address))
#Thread that calls the function: clients and stores them in a tuple called connection
thread.start_new_thread(clients, (connection, addressList))
sock.close()
Please help me if you can!
EDIT:
I was able to fix it to a certain extent. It is still a little buggy but I am able to send messages back and forth now. I needed to specify the connection socket as well as the address. Here's the updated code:
SERVER
import socket
import sys
import thread
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Bind the socket to the port
host = socket.gethostname()
server_address = (host, 4441)
sock.bind(server_address)
#Listen for incoming connections
sock.listen(5)
print "Waiting for connection..."
#Variable for the number of connections
numbOfConn = 0
#Name of list used for connections
addressList = []
connectionList = []
#Function that continuosly searches for connections
def clients(connectionList, addressList):
while True:
for j in range(0,numbOfConn):
message = connectionList[j].recv(1024)
print message
#for loop to send message to each
for i in range(0,numbOfConn):
connectionList[i].sendto(message, addressList[i])
connection.close()
while True:
#accept a connection
connection, address = sock.accept()
print 'Got connection from', address
numbOfConn += 1
addressList.append((address))
connectionList.append((connection))
#Thread that calls the function: clients and stores them in a tuple called connection
thread.start_new_thread(clients, (connectionList, addressList))
sock.close()
How do I get a response from the server?
Client side:
#CLIENT
import socket
import time
host = "localhost"
port = 5454
data_c = input()
c = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
c.sendto(bytes(data_c, 'utf-8'),(host,port))
print( data_c )
print( c.recv(1024).decode('utf-8'))
SERVER side:
#SERVER
import socket
import time
host = "localhost"
port = 5454
data_s = "ACKNOWLEDGMENT"
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
print(s.recv(1024).decode('utf-8'))
I can send a message from the server that the client will receive, but can not seem to get communication (like an ACK.) to make it back to the server.
(yes UDP is not a good way to be doing this i'm pretty sure, but that was a specific for the project)
for question 1: to send the ACK, you could replicate what you have in the reverse direction.
Since UDP is connection-less you don't know beforehand you receive a packet where the packet will come from, so you have to use recvfrom to get both the packet and the peer (address/port) the packet came from. Then you have to use that address to send data back.
What you're doing now in your client (but what really looks like the server) in the loop is send the same data over and over to itself. Instead in the loop you should receive packets using the previously mentions recvfrom then send replies to the peer you received the packet from.
So something like the following pseudo code
while True:
peer = recvfrom(...)
sendto(..., peer)
After many attempts to get a simple acknowledgment reply from my server this did it.
Beyond literally starting completely over each round, the time.sleep(.1) function was the only missing key. It allowed the server and client both time to close the current socket connection so that there was not an error of trying to bind multiple bodies to a single location or something.
OSError: [WinError 10048] Only one usage of each socket address (protocol/network address/port) is normally permitted
Working result:
#SERVER
import socket
import time
host = "localhost"
port = 5454
data_s = "ACKNOWLEDGMENT"
while 1:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
received = print("Client: " + s.recv(1024).decode('utf-8')) #waiting to receive
s.close
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
time.sleep(.1)
s.sendto(bytes(data_s, 'utf-8'),(host,port)) #sending acknowledgment
print("Server: " + data_s)
s.close # close out so that nothing sketchy happens
time.sleep(.1) # the delay keeps the binding from happening to quickly
Server Command Window:
>>>
Client: hello
Server: ACKNOWLEDGMENT
Client:
#CLIENT
import socket
import time
host = "localhost"
port = 5454
c = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
while 1:
data_c = input("Client: ")
c = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
c.sendto(bytes(data_c, 'utf-8'),(host,port)) #send message
c.close
# time.sleep()
c = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
c.bind((host, port))
print("Server: " + c.recv(1024).decode('utf-8')) # waiting for acknowledgment
c.close
c = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
time.sleep(.1)
Client Command Window:
>>>
Client: hello
Client: hello
Server: ACKNOWLEDGMENT
I did finally remove the redundant input("Client: ") there at the top.
A special thanks #JoachimPileborg for helping, but I have to give it to the little guy just because it was the path I ended up taking.