I'm building a game-server in Python. The functionality is pretty well-defined. The server will listen on the port 6000 and a remote client will send a request. Then the server will establish a connection to the client's port 7000. From then on, the client will keep sending 'requests' (basically, strings such as "UP#", "DOWN#", "SHOOT#" etc.) to server's port 6000.
This is the problem. I have made a 'server' who listens on the port 6000. This means I cannot bind a client to the same port. Is there a way that I can get the data string of an incoming request in a server? So far, I only have this.
What am I doing wrong here? Any workarounds for this issue? In short, can I read the incoming request string from a client in the server code?
Thanks in advance.
def receive_data(self):
errorOccured = False
connection = None
try:
listener = socket.socket() # Create a socket object.
host = socket.gethostname()
port = 6000 # The port that the server keeps listening to.
listener.bind(('', port))
# Start listening
listener.listen(5)
statement = ("I:P0:7,6;8,1;0,4;3,8;3,2;1,6:5,4;9,3;8,7;2,6;1,4;2,7;6,1;6,3:2,1;8,3;5,8;9,8;7,2;0,3;9,4;4,8;7,1;6,8#\n","S:P0;0,0;0#","G:P0;0,0;0;0;100;0;0:4,3,0;5,4,0;3,8,0;2,7,0;6,1,0;5,8,0;1,4,0;1,6,0#", "C:0,5:51224:824#","G:P0;0,0;0;0;100;0;0:4,3,0;5,4,0;3,8,0;2,7,0;6,1,0;5,8,0;1,4,0;1,6,0#","G:P0;0,1;2;0;100;0;0:4,3,0;5,4,0;3,8,0;2,7,0;6,1,0;5,8,0;1,4,0;1,6,0#")
# This is just game specific test data
while True:
c, sockadd = listener.accept() # Establish connection with client.
print 'incoming connection, established with ', sockadd
i = 0 # Just a counter.
while i<len(statement):
try:
self.write_data(statement[i], sockadd[0])
time.sleep(1) # The game sends updates every second to the clients
i = i + 1
#print listener.recv(1024) -- this line doesn't work. gives an error
except:
print "Error binding client"
c.close() # Close the connection
return
except:
print "Error Occurred"
I'm going to answer it because I got some help and figured it out.
The most basic thing I can do is to use the client connection which is c for this purpose. In here, instead of the commented line data=listener.recv(1024) I should have used data= c.recv(1024). Now it works.
Another way is to use SocketServers with a StreamingRequestHandler. While this is ideal for usage of typical servers, if a lot of objects are involved it could reduce the flexibility.
Related
i need to send a data each every X seconds from a client to a server with SOCKET, so i try this code:
for i in range(100):
localip = '127.0.0.1'
port = 5010
bufferSize = 1024
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR,1)
client.connect((localip, port))
pacote = '2B4F08FE0F3B'
client.send(bytes(pacote, "utf-8"))
client.close()
time.sleep(10)
But in the serv i recive a package with nothing (' '). I need send 100x the same message to the serv, each 10 seconds. Somebody knows where is the mistake?
I have other Client.py where i put manually the data (with the input() ) and he works perfect, but now i need to do this automatically.
The client need to open a new connection to send each data.
But in the serv i recive a package with nothing (' ').
This is because the socket gets closed after sending the message, i.e. client.close().
I need send 100x the same message to the serv, each 10 seconds. Somebody knows where is the mistake?
If the server expects the client to create a single connection and then send many data over this connection before closing it, then the client should do exactly this. Instead your client opens a new connection for each new message and then closes the connection immediately after the message.
This means either you must fix the server to match the clients behavior or fix the client to match the servers behavior.
hi i make model server client which works fine and i also create separate GUI which need to two input server IP and port it only check whether server is up or not. But when i run server and then run my GUI and enter server IP and port it display connected on GUI but on server side it throw this error. The Server Client working fine but integration of GUI with server throw below error on server side.
conn.send('Hi'.encode()) # send only takes string BrokenPipeError: [Errno 32] Broken pip
This is server Code:
from socket import *
# Importing all from thread
import threading
# Defining server address and port
host = 'localhost'
port = 52000
data = " "
# Creating socket object
sock = socket()
# Binding socket to a address. bind() takes tuple of host and port.
sock.bind((host, port))
# Listening at the address
sock.listen(5) # 5 denotes the number of clients can queue
def clientthread(conn):
# infinite loop so that function do not terminate and thread do not end.
while True:
# Sending message to connected client
conn.send('Hi'.encode('utf-8')) # send only takes string
data =conn.recv(1024)
print (data.decode())
while True:
# Accepting incoming connections
conn, addr = sock.accept()
# Creating new thread. Calling clientthread function for this function and passing conn as argument.
thread = threading.Thread(target=clientthread, args=(conn,))
thread.start()
conn.close()
sock.close()
This is part of Gui Code which cause problem:
def isOpen(self, ip, port):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
s.connect((ip, int(port)))
data=s.recv(1024)
if data== b'Hi':
print("connected")
return True
except:
print("not connected")
return False
def check_password(self):
self.isOpen('localhost', 52000)
Your problem is simple.
Your client connects to the server
The server is creating a new thread with an infinite loop
The server sends a simple message
The client receives the message
The client closes the connection by default (!!!), since you returned from its method (no more references)
The server tries to receive a message, then proceeds (Error lies here)
Since the connection has been closed by the client, the server cannot send nor receive the next message inside the loop, since it is infinite. That is the cause of the error! Also there is no error handling in case of closing the connection, nor a protocol for closing on each side.
If you need a function that checks whether the server is online or not, you should create a function, (but I'm sure a simple connect is enough), that works like a ping. Example:
Client function:
def isOpen(self, ip, port):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
s.connect((str(ip), int(port)))
s.send("ping".encode('utf-8'))
return s.recv(1024).decode('utf-8') == "pong" # return whether the response match or not
except:
return False # cant connect
Server function:
def clientthread(conn):
while True:
msg = conn.recv(1024).decode('utf-8') #receiving a message
if msg == "ping":
conn.send("pong".encode('utf-8')) # sending the response
conn.close() # closing the connection on both sides
break # since we only need to check whether the server is online, we break
From your previous questions I can tell you have some problems understanding how TCP socket communication works. Please take a moment and read a few articles about how to communicate through sockets. If you don't need live communications (continous data stream, like a video, game server, etc), only login forms for example, please stick with well-known protocols, like HTTP. Creating your own reliable protocol might be a little complicated if you just got into socket programming.
You could use flask for an HTTP back-end.
In trying to familiarize myself with the socket library, I have a simple server and client setup. Basically I've stumbled through and am able to set up connection and get the server and client to talk to each other. To make it more interactive, I have client.py able to send text through the command line. Everything appears to be working properly (with the exception of the server side tearing down connection properly if client input is blank), if I type a message from the client side, it spits it right back out to me. In this example, I have it set up for the server side to print the text as well. What I noticed was, that the server side doesn't alway 'register' what it being sent from the client. I am trying to figure out why this is the case. For being a test, it doesn't really affect anything, I just can't figure out what is taking place behind the scenes.
EDIT:
Actually, after playing around with it for a bit, it appears every other message is being printed out to the server console. I've still yet to figure out why this is the case
Server side:
#server.py
import socket
ss = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ss.bind(('127.0.0.1',5000))
ss.listen(5)
while True:
conn, addr = ss.accept()
with conn:
print ('Connected by', addr)
while True:
data = conn.recv(4096)
print (data)
if not data:
print ("nothing received from client")
ss.close()
break
Client side:
#client.py
import socket
server = 'localhost'
port = 5000
s = socket. socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.1', 5000))
s.send(bytes(b'Client has connected'))
while True:
msg = input()
s.send(bytes(input(msg),'utf-8'))
if not msg:
print ("Server should tear down connection...")
# s.close()
break
In sockets you there are no methods __exit__ implemented, so you can't use the with conn:
you need to remove this part of code.
I am using TCP sockets to communicate between my server and clients. The server code and socket code are as below:
server:
from socket import *
HOST = 'xx.xx.xx.xx'
PORT = 1999
serversocket = socket(AF_INET,SOCK_STREAM)
serversocket.bind((HOST,PORT))
print 'bind success'
serversocket.listen(5)
print 'listening'
while True:
(clientsocket, address) = serversocket.accept()
print ("Got client request from",address)
#clientsocket.send('True')
data = clientsocket.recv(1024)
print data
clientsocket.send('True')
clientsocket.close()
client:
import socket
import sys
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Connect the socket to the port on the server given by the caller
server_address = ('xx.xx.xx.xx', 1999)
print >>sys.stderr, 'connecting to %s port %s' % server_address
sock.connect(server_address)
try:
message = 'This is the message. It will be repeated.'
print >>sys.stderr, 'sending'
for x in range (0,1):
name=raw_input ('what is ur name')
print type(name)
sock.send(name)
print sock.recv(1024)
finally:
sock.close()
I am able to communicate with the server from client and able to send and receive data. But the problem I am facing is that I am not able to send and receive data continuously from the server. I have to restart my client code on my laptop to send and receive data again from the server. The way the above client code is working is that when I give a keyboard input, then the socket sends data to server and server responds back. But in the client code, in the for loop if I do two iterations, for the second iteration the data I enter from keyboard is not reaching server. I need to restart my client code to send data again. How do I fix this ?
Also, when once client is connected to the server, the other cannot connect to the server. Any ideas on how to do this ?
You need to design and implement a protocol that specifies what each side is supposed to do and then implement that protocol. You're expecting it to work by magic.
For example:
data = clientsocket.recv(1024)
I suspect you are expecting this to receive a "message". But TCP has no notion of messages. If you need to send and receive messages, you need to define precisely what a "message" is for your protocol and write code to send and receive them.
It may be helpful to look at the specifications for other protocols that use TCP such as HTTP, FTP, or IRC. It really is worth the time to write out a specification of your protocol before you write any code. It will save a lot of pain.
I have been self-learning python since few months now , and finally learning Socket programming. As an text book exercise, I am supposed to design a half-duplex chat system . Below is the code. The first request and response are just fine , but everytime I try sending a second message from client, the server seems to be hanging. The program is TCP based.
I am suspecting that since ss.accept() is being called everytime a new message has to be sent, a new thread is being created but since I have made only 1 call to sc.connect() from client , may be my new connection at the server end is hanging there for infinite time.
As a trail : I called ss.accept() outside the while loop, ie making only 1 connection and listening to data over and over on while loop, the conversations works just fine
Can someone please have a look a the code and help me understand where exactly is the issue.
Since, I am learning, I have not moved to twisted yet. I want to learn all the basics first before I move to frameworks.
!bin/usr/env python
import socket, sys
HOST =''
PORT = 1060
ADDR =(HOST,PORT)
def userinput(sock):
usermessage = input('>')
sock.sendall(str(len(usermessage)))
return usermessage
def server():
s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind(ADDR)
s.listen(1)
print 'the server is listening at',s.getsockname()
while True:
ss,sockname = s.accept()
#listen to determine the bytes sent by client
msglen = ss.recv(4096)
#accept the complete message
msg = ss.recv(int(msglen))
print 'client:', repr(msg)
servermsg = userinput(ss)
ss.sendall(servermsg)
print " ---------------"
ss.close()
def client():
sc = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
sc.connect(ADDR)
while True:
message = userinput(sc)
sc.sendall(message)
replylen = sc.recv(4096)
reply = sc.recv(int(replylen))
print "reply:",reply
print "----------------"
sc.close()
if sys.argv[1:] == ['server']:
server()
elif sys.argv[1:] == ['client']:
client()
else:
print >> sys.stderr,'usage:tcp_2_7.py server|client[host]'
Your trial - accepting once and then receiving multiple messages - is how you should do this. Calling accept is waiting for a new connection - you don't need to do this every time you want to send or receive a message, just as you don't want to call connect every time you want to send or receive.
Think of it this way:
When you connect to a chat server, do you connect, send a message, then disconnect immediately? No - you have a constant open connection which messages are sent through, and the connection is only closed at the end of a chat session.
From the docs on accept:
socket.accept()
Accept a connection. The socket must be bound to an
address and listening for connections. The return value is a pair
(conn, address) where conn is a new socket object usable to send and
receive data on the connection, and address is the address bound to
the socket on the other end of the connection.