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conn.send('Hi'.encode()) BrokenPipeError: [Errno 32] Broken pipe (SOCKET)

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.

Only one usage of each socket address (protocol/network address/port) is normally permitted,

I have a server that uses a thread to listen for new connections and then starts one thread for every client to serve him. Now, the server runs perfectly, but when a client connects it gives me the error in the title. I think because both client and server are trying to use the same port.
Here's the server code:
class ThreadedTCPRequestHandler(SocketServer.BaseRequestHandler):
def __init__(self, conne):
initialization
def handle(self):# "run"
does something
class ThreadedTCPServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
pass
HOST = '' # Symbolic name meaning all available interfaces
PORT = 1000 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(5)
n=1
while 1:
conn, addr = s.accept() # wait for a new connection. Get a new socket (conn) for each new connection
print 'Connected by', addr
server = ThreadedTCPServer((HOST, PORT), ThreadedTCPRequestHandler) #this line gives me the error
ip, port = server.server_address
server_thread = threading.Thread(target=server.serve_forever)
server_thread.setDaemon(True)
server_thread.setName('Client '+str(n))
server_thread.start() # Start the new thread
n+=1
server.shutdown()
server.server_close()
And here's the client:
import socket
HOST, PORT = "localhost", 1000
data = "0"
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
sock.connect((HOST, PORT))
sock.sendall(data)
received = sock.recv(1024)
finally:
sock.close()
print "Sent: {}".format(data)
print "Received: {}".format(received)

First you create server socket and bind it to port 1000. Then when client connects you receive a socket connected with client (conn, addr = s.accept()) that should be used to communicate with client but you completely ignore it. Instead you create another server that tried to bind again to port 1000. This results in "already used" error as expected.
I'd suggest you check this example of TcpServer threading and forking. Here a custom class derived from SocketServer.TCPServer is created initially (not a simple server socket as you do). It internally loops over accepting incoming client connections and for each connection calls specified SocketServer.BaseRequestHandler from a new thread or process (in case of forking) so you don't need to deal with them explicitly. Custom request handler just needs to, well, handle the request, potentially in a loop if communication with client is multi-step.
Be aware that thread/process per client approach doesn't scale well on large number of simultaneous client connections.

Python Socket, how do i choose between s.send and conn.send?

def send_Button():
try:
myMsg = "ME: " + text.get()
msg = text.get()
conn.send(msg) ###
textBox.insert(END, myMsg + "\n")
textEntry.delete(0, END)
textBox.yview_pickplace("end")
except NameError:
myMsg = "ME: " + text.get()
msg = text.get()
conn.send(msg) ###
textBox.insert(END, myMsg + "\n")
textEntry.delete(0, END)
textBox.yview_pickplace("end")
This program uses the tkinter module with socket in python2.7. My program allows for you to either connect to a server to chat with or host a server for others to connect to you, but whenever I try and test it out then the lines with the '###' on always bring up an error and it doesn't work, the error which comes up is: "NameError: global name 'conn' is not defined" OR "error: [Errno 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".
Any help please?

I think that you are trying to get the program to act as a Client or as a Server just changing s.send() to conn.send() saddly it isn't that simple.
Socket Initializzation
The socket have to be initialized before sending or receiving data.
For a client usually it's something like this.
send_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM) # Create the socket
send_socket.connect((serverIp, serverPort)) # Connect to the server
send_socket.send(data) # Send the data to the server
And like this for a Server:
listen_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM) # Create the socket
listen_socket.bind(("0.0.0.0", port)) # Set the socket to accept client from every interface on the port port
listen_socket.listen(1) # Put the server on listen on the port setted before
accept_socket, addr = self.listen_socket.accept() # when a client connect return the socket to talk with it
data = self.accept_socket.recv(buffer_size) # Receive data form the client of max size buffer_size
Docs examples
From your question I guess that with s.send() and conn.send() you are talking about
this example from the python 2.7 socket docs
Here are four minimal example programs using the TCP/IP protocol: a server that echoes all data that it receives back (servicing only one client), and a client using it. Note that a server must perform the sequence socket(), bind(), listen(), accept() (possibly repeating the accept() to service more than one client), while a client only needs the sequence socket(), connect(). Also note that the server does not sendall()/recv() on the socket it is listening on but on the new socket returned by accept().
Client
Echo client program
import socket
HOST = 'daring.cwi.nl' # The remote host
PORT = 50007 # The same port as used by the server
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)
the client is pretty stright forward, it create the socket s and then after using s.connect() it just send data through it.
Server
The server one is where there there are both s and conn
Echo server program
import socket
HOST = '' # Symbolic name meaning all available interfaces
PORT = 50007 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)
conn.close()
in this one first of all we create a socket s on which the server will listen and then using s.accept() it will wait till a client connect to the server and then return the conn which is the socket of the connected client.
So to receive or send data to the client you have to use conn.
Notes
As said in the documentation in these two example the server accept only one client. So if you want to deal with multiple clients you have to repeat the accept step and possibly generate a new Thread for each client so that other clients don't have to wait for each others.

Python Sockets Peer to Peer

I'm trying to make a simple Peer to Peer Network in Python 2.7. The problem is, I can't seem to be able to create a connection between two machines in which they both act as a server and a client. I can get it to work when one is a server and the other is a client but not when they are both, both. Do I need to create 2 sockets? Also I'm using TCP to connect.
UPDATE:
import socket, sys # 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
if sys.argv[1] == "connect":
host = sys.argv[2]
s.connect((host, port))
s.close
else:
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()
The codes not very good because for someone to connect as a client they have to use the argument "connect" followed by the hostname or IP of the second machine. I can't get the two to connect and serve to each other simultaneously.

Yes, two sockets are necessary. The listening socket should open on a constant port, and the client port should be opened on a different (potentially dynamic) port, usually higher in the port range. As an example:
Server sockets on port 1500, client sockets on port 1501.
Peer1: 192.168.1.101
Peer2: 192.168.1.102
When peer1 connects to peer2 it looks like this: 192.168.1.101:1501 -> 192.168.1.102:1500.
When peer2 connects to peer1 it looks like this: 192.168.1.102:1501 -> 192.168.1.101:1500.
Listening TCP sockets are also generally run on a separate thread since they are blocking.

Yes, you'll need to use two sockets, one for accepting connections (server) and one for initiating connections (client). However, you can bind both sockets to the same local port, using that port number as both the source and destination port and thereby ensuring that you'll end up with only a single connection between each pair of peers. If both peers try to connect simultaneously (e.g. because they discovered each other at the same time), one of the client connection attempts will fail (where the peer's server socket accepted the connection), you'll have to handle (ignore) that.
To bind two sockets on the same port, you'll need to set the SO_REUSEPORT/SO_REUSEADDR flags on both.
Here is an example program demonstrating this technique (using the excellent trio on Python 3):
from errno import EADDRNOTAVAIL
from functools import partial
from itertools import count
import trio
import socket
async def peer(SRC, DEST):
counter = count(start=1)
async def sender(stream, n):
print(f"sender{n}#{SRC}: started!")
while True:
data = bytes(f"Hello from {n}#{SRC}", "utf8")
print(f"sender{n}#{SRC}: sending {data!r}")
await stream.send_all(data)
await trio.sleep(1)
async def receiver(stream, n):
print(f"receiver{n}#{SRC}: started!")
async for data in stream:
print(f"receiver{n}#{SRC}: got data {data!r}")
print(f"receiver{n}#{SRC}: connection closed")
async with trio.open_nursery() as nursery:
async def run(connection: trio.SocketStream):
count = next(counter)
print(f"peer#{SRC} got connection{count} from {method}() with {connection.socket.getpeername()}")
async with connection:
async with trio.open_nursery() as nursery:
print(f"peer#{SRC}: spawning sender...")
nursery.start_soon(sender, connection, count)
print(f"peer#{SRC}: spawning receiver...")
nursery.start_soon(receiver, connection, count)
print(f"peer: listening at {SRC}")
servers = await trio.open_tcp_listeners(SRC[1], host=SRC[0])
servers[0].socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
servers[0].socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
await nursery.start(trio.serve_listeners, partial(run, "listen"), servers)
print(f"peer: connecting from {SRC} to {DEST}")
client = trio.socket.socket()
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
await client.bind(address=SRC)
try:
await client.connect(address=DEST)
except OSError as err:
if err.errno != EADDRNOTAVAIL:
raise
# the other client was faster than us
print(f"peer#{SRC}: {err.strerror}")
else:
await run('connect', trio.SocketStream(client))
async def main():
async with trio.open_nursery() as nursery:
a = ("127.0.0.1", 12345)
b = ("127.0.0.1", 54321)
nursery.start_soon(peer, a, b)
nursery.start_soon(peer, b, a)
trio.run(main)
In this small demonstration, the two peers run within the same program on different ports on the same host, but it works just the same with two programs using the same ports but different hosts. Notice that if you comment out the client.bind(address=SRC) bit, they will use ephemeral source ports, and create two separate connections not just a single one.

Python TCP socket doesn't close?

Maybe someone here will have a response for this thing which is just driving me insane.
To make it simple, I'm making a kind of proxy. Whenever it receives something, it forwards everything to a server, and sends back the response. So there is one socket always listening on port 4557 for clients, and for each incoming connection, there is a new socket created on a random port to connect to the server port 4556.
Clients <==> Proxy <==> Server
Also, there another socket which is instantiated and listening for requests coming from the server and to be forwarded to the corresponding client.
Here is an example:
Client A connects to proxy on port 4557
Proxy creates a socket to Server on port 4556
Along with that, it creates a socket listening on port 40100
Client sends stuff, forwarded to Server
Client disconnects. Close client connection and socket to server
Some time later, Server sends stuff to proxy on port 40100
Everything's forwarded to Client A (port 40100 corresponding to Client A)
And so on..
So far in my tests, I use a simple python script for sending a unique tcp packet to the proxy, along with a dump server showing received data and echoing back.
So the issue is that when a connection to the proxy is closed, the connection to the Server should also be closed with "sock.close()". However it just seems to be completely ignored. The socket remains as ESTABLISHED.
About the code now.
A few notes.
DTN and Node are respectively Server and Clients.
runCallback is called in a loop until thread dies.
finalCallback is called when the thread is dying.
Associations between remote hosts (Client), proxy ports (to Server) and proxies are kept in the dictionaries: TCPProxyHostRegister (RemoteHost => Proxy), TCPProxyPortRegister (Port => Proxy), TCPPortToHost (Port => RemoteHost).
The first class is TCPListenerThread.
It just listen on a specific port and instantiate proxies (one for each Client=>Server couple and Server=>Client couple) and forward them connections.
class TCPListenerThread(StoppableThread):
def __init__(self, tcp_port):
StoppableThread.__init__(self)
self.tcp_port = tcp_port
self.sock = socket.socket( socket.AF_INET, # Internet
socket.SOCK_STREAM ) # tcp
self.sock.bind( (LOCAL_ADDRESS, self.tcp_port) )
self.sock.listen(1)
def runCallback(self):
print "Listen on "+str(self.tcp_port)+".."
conn, addr = self.sock.accept()
if isFromDTN(addr):
tcpProxy = getProxyFromPort(tcp_port)
if not tcpProxy:
tcpProxy = TCPProxy(host, True)
else:
host = addr[0]
tcpProxy = getProxyFromHost(host)
if not tcpProxy:
tcpProxy = TCPProxy(host, False)
tcpProxy.handle(conn)
def finalCallback(self):
self.sock.close()
Now comes the TCP Proxy:
It associates a remote host (Client) with a port connecting to Server.
If it's a connection coming from a new Client, it will create a new listener (see above) for the Server and create a socket ready to forward everything to Server.
class TCPProxy():
def __init__(self, remote, isFromDTN):
#remote = port for Server or Remote host for Client
self.isFromDTN = isFromDTN
self.conn = None
#add itself to proxy registries
#If listening from a node
if not isFromDTN:
#Set node remote host
self.remoteHost = remote
TCPProxyHostRegister[self.remoteHost] = self
#Set port to DTN interface + listener
self.portToDTN = getNewTCPPort()
TCPPortToHost[self.portToDTN] = self.remoteHost
newTCPListenerThread(self.portToDTN)
#Or from DTN
else:
self.portToDTN = remote
TCPProxyPortRegister[self.portToDTN] = self
self.remoteHost = getRemoteHostFromPortTCP(self.portToDTN)
def handle(self, conn):
print "New connection!"
#shouldn't happen, but eh
if self.conn != None:
self.closeConnections()
self.conn = conn
#init socket with remote
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
if self.isFromDTN:
self.sock.connect((self.remoteHost, 4556)) #TODO: handle dynamic port..
else:
self.sock.connect((DTN_Address, DTN_TCPPort))
#handle connection in a thread
self.handlerThread = newTCPHandlerThread(self)
#handle reply in a therad
self.replyThread = newTCPReplyThread(self)
def closeConnections(self):
try:
if self.conn != None:
print "Close connections!"
self.sock.close()
self.conn.close()
self.conn = None
self.handlerThread.kill()
self.replyThread.kill()
except Exception, err:
print str(err)
#pass
def forward(self, data):
print "TCP forwarding data: "+data
self.sock.send(data)
def forwardBack(self, data):
print "TCP forwarding data back: "+data
self.conn.send(data)
In this proxy class, I instantiate two classes, TCPHandlerThread and TCPReplyThread. They are responsible for forwarding to Server, and forwarding back to Client, respectively.
class TCPHandlerThread(StoppableThread):
def __init__(self, proxy):
StoppableThread.__init__(self)
self.proxy = proxy
def runCallback(self):
test = False
while 1:
data = self.proxy.conn.recv(BUFFER_SIZE)
if test:
self.proxy.sock.close()
test = True
if not data:
break
print "TCP received data:", data
self.proxy.forward(data)
self.kill()
def finalCallback(self):
self.proxy.closeConnections()
class TCPReplyThread(StoppableThread):
def __init__(self, proxy):
StoppableThread.__init__(self)
self.proxy = proxy
def runCallback(self):
while 1:
data = self.proxy.sock.recv(BUFFER_SIZE)
if not data:
break
print "TCP received back data: "+data
self.proxy.forwardBack(data)
self.kill()
def finalCallback(self):
self.proxy.closeConnections()
You see that whenever a connection is closed, the thread dies and the other connection (Client/Server to proxy or Proxy to Server/Client) should be closed in Proxy.closeConnections()
I noticed that when closeConnections() is "data = self.proxy.conn.recv(BUFFER_SIZE)", it goes well, but when it's called even right after the latter statement, it goes wrong.
I wiresharked TCP, and the proxy doesn't send any "bye signal". The socket state doesn't go to TIME_WAIT or whatever, it just remains ESTABLISHED.
Also, I tested it on Windows and Ubuntu.
On Windows it goes exactly as I explained
On Ubuntu, it works well for usually (not always), 2 connections, and the third time I connect with the same client in exactly the same way to the proxy, it goes wrong again exactly as explained.
Here are the three files i'm using so that you can have a look at the whole code. I'm sorry the proxy file might not be really easy to read. Was SUPPOSED to be a quick dev.
http://hognerud.net/stackoverflow/
Thanks in advance..
It's surely something stupid. Please don't hit me too hard when you see it :(

First I'm sorry that I currently have not the time to actually run and test your code.
But the idea came to my mind, that your problem might actually have something todo with using blocking mode vs. non-blocking mode on the socket. In that case you should checkout the "socket" module help in the python documentation, especially socket.setblocking().
My guess is, that the proxy.conn.recv() function only returns, when actually BUFFER_SIZE bytes where received by the socket. Because of this the thread is blocked until enough data was received and therefore the socket doesn't get closed.
As I said first, this is currently just a guess, so please don't vote me down if it doesn't solve the problem...