I am new to python and trying to code. I want to create simple echo server ie whatever I input to the client will simply be echo back by the server and if the client user press enter without writing anything then the server will disconnects. It may be very simple but I lacks logic here, any help??
here is my code
#!/usr/bin/env python
import socket
import sys
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #create socket
s.bind(("0.0.0.0",12345)) #binding port
s.listen(1) #listening for only one client
print "I am listening..."
conn,addr=s.accept() #accept the connection
conn.send("\nEnter your name.\n")
data = conn.recv(2048)
print "Client name is : ",data
conn.send("Now each word you typed will be echo back to you.\n")
while len(data)>0:
data=conn.recv(2048)
if data == '':
sys.exit()
else:
conn.send(data)
The result will contain a newline, but you can simply call str.strip to filter that out:
conn.send("\nEnter your name.\n")
data = conn.recv(2048)
if not data.strip():
print('Please enter a name')
return 1
print("Client name is : ", data)
Related
This is a python chat room that I've been working on and it enables to you to chat to other people on the same network through python
Host:
import socket
import sys
import time
s = socket.socket()
host = socket.gethostname()
port = 8080
s.bind((host,port))
print("")
print("Sever adress is", host)
print("")
name = input(str("Please enter your username : "))
s.listen(1)
print("")
print("Waiting for any incoming connections ... ")
print("")
conn, addr = s.accept()
print("Recieved connection")
#connection done ###
s_name = conn.recv(1024)
s_name = s_name.decode()
print("")
print(s_name, "has connected to the chat room")
print("")
conn.send(name.encode())
## messaging loop ##
while 1:
message = input(str("Please enter enter your message : "))
print("")
conn.send(message.encode())
message = conn.recv(1024)
message = message.decode()
print("")
print(name,": ",message)
print("")
Client:
import socket
import sys
import time
print("Welcome to python chat ")
print("")
print("Initiallsing....")
time.sleep(1)
s = socket.socket()
print("")
host = input(str("Please enter server adress : "))
print("")
name = input(str("Please enter your name : "))
port = 8080
print("")
time.sleep(1)
s.connect((host,port))
print("Connected...")
## Conection done ##
s.send(name.encode())
s_name = s.recv(1024)
s_name = s_name.decode()
print("")
print( s_name, "has joined the chat room ")
while 1:
message = s.recv(1024)
message = message.decode()
print("")
print(name,": ",message)
print("")
message = input(str("Please enter your enter message : "))
print("")
s.send(message.encode())
I have 2 problems, the first problem is that it only allows one person to speak at a time, what I mean by this say that if you send a message first you won't be allowed to send another message until the other person has responded. The second problem is that this code only works for 2 users, I want it so it works for multiple users
Edit:
Also could some one acutually give a proper solution instead of telling me to start all over again please because it took me so long to figure out how to make this system in the place.
Thank you
You need to create two separate threads for sending and receiving. The way you have written the loop will not work for both way communication simultaneously. Because after sending a message the loop is waiting to receive something. [If you want to run the code over internet, replace localhost with the desired IP address in the line HOST = 'localhost'] Let me share a solution (this is a sample solution I have done while TAing an undergraduate class on networking):
I have tested the code on a Linux machine (Ubuntu 18.04). I have got students who have successfully ran this on their Mac. I am not sure if it runs on a windows machine. Even if it does not work on a Windows machine, a few minor modifications should do the trick.
Server sider code (you need to run this first): chatServerDuplex.py
# Import socket module
from socket import *
import threading
import sys # In order to terminate the program
FLAG = False # this is a flag variable for checking quit
# function for receiving message from client
def recv_from_client(conn):
global FLAG
try:
# Receives the request message from the client
while True:
if FLAG == True:
break
message = conn.recv(1024).decode()
# if 'q' is received from the client the server quits
if message == 'q':
conn.send('q'.encode())
print('Closing connection')
conn.close()
FLAG = True
break
print('Client: ' + message)
except:
conn.close()
# function for receiving message from client
def send_to_client(conn):
global FLAG
try:
while True:
if FLAG == True:
break
send_msg = input('')
# the server can provide 'q' as an input if it wish to quit
if send_msg == 'q':
conn.send('q'.encode())
print('Closing connection')
conn.close()
FLAG = True
break
conn.send(send_msg.encode())
except:
conn.close()
# this is main function
def main():
threads = []
global FLAG
# TODO (1) - define HOST name, this would be an IP address or 'localhost' (1 line)
HOST = 'localhost'
# TODO (2) - define PORT number (1 line) (Google, what should be a valid port number)
# make sure the ports are not used for any other application
serverPort = 6789
# Create a TCP server socket
#(AF_INET is used for IPv4 protocols)
#(SOCK_STREAM is used for TCP)
# TODO (3) - CREATE a socket for IPv4 TCP connection (1 line)
serverSocket = socket(AF_INET, SOCK_STREAM)
# Bind the socket to server address and server port
# TODO (4) - bind the socket for HOSR and serverPort (1 line)
serverSocket.bind((HOST, serverPort))
# Listen to at most 1 connection at a time
# TODO (5) - listen and wait for request from client (1 line)
serverSocket.listen(1)
# Server should be up and running and listening to the incoming connections
print('The chat server is ready to connect to a chat client')
# TODO (6) - accept any connection request from a client (1 line)
connectionSocket, addr = serverSocket.accept()
print('Sever is connected with a chat client\n')
t_rcv = threading.Thread(target=recv_from_client, args=(connectionSocket,))
t_send = threading.Thread(target=send_to_client, args=(connectionSocket,))
# call the function to receive message server
#recv_from_server(clientSocket)
threads.append(t_rcv)
threads.append(t_send)
t_rcv.start()
t_send.start()
t_rcv.join()
t_send.join()
# closing serverScoket before exiting
print('EXITING')
serverSocket.close()
#Terminate the program after sending the corresponding data
sys.exit()
# This is where the program starts
if __name__ == '__main__':
main()
Client side code: chatClientDuplex.py
from socket import *
import threading
import sys
FLAG = False # this is a flag variable for checking quit
# function for receiving message from client
def send_to_server(clsock):
global FLAG
while True:
if FLAG == True:
break
send_msg = input('')
clsock.sendall(send_msg.encode())
# function for receiving message from server
def recv_from_server(clsock):
global FLAG
while True:
data = clsock.recv(1024).decode()
if data == 'q':
print('Closing connection')
FLAG = True
break
print('Server: ' + data)
# this is main function
def main():
threads = []
# TODO (1) - define HOST name, this would be an IP address or 'localhost' (1 line)
HOST = 'localhost' # The server's hostname or IP address
# TODO (2) - define PORT number (1 line) (Google, what should be a valid port number)
PORT = 6789 # The port used by the server
# Create a TCP client socket
#(AF_INET is used for IPv4 protocols)
#(SOCK_STREAM is used for TCP)
# TODO (3) - CREATE a socket for IPv4 TCP connection (1 line)
clientSocket = socket(AF_INET, SOCK_STREAM)
# request to connect sent to server defined by HOST and PORT
# TODO (4) - request a connection to the server (1 line)
clientSocket.connect((HOST, PORT))
print('Client is connected to a chat sever!\n')
# call the function to send message to server
#send_to_server(clientSocket)
t_send = threading.Thread(target=send_to_server, args=(clientSocket,))
# call the function to receive message server
#recv_from_server(clientSocket)
t_rcv = threading.Thread(target=recv_from_server, args=(clientSocket,))
threads.append(t_send)
threads.append(t_rcv)
t_send.start()
t_rcv.start()
t_send.join()
t_rcv.join()
print('EXITING')
sys.exit()
# This is where the program starts
if __name__ == '__main__':
main()
Your first problem is likely due to the fact that python sockets are blocking by default.
What this means is that, for example, on the line message = s.recv(1024), your program will keep listening and won't move on to the rest of your script until it receives something.
If you want two people to be able to receive and send at the same time, you might want to look into non-blocking sockets and some asynchronous programming.
This how-to from the official documentation might help you: https://docs.python.org/2/howto/sockets.html#non-blocking-sockets
System123456 the problem is that you built a client-server system when the server listens and the client connects to it. Try looking at peer-to-peer systems instead where each node is an equal. For building a chat room you might review DHT nodes.
I'm currently working on a project for a class. It consists in code a simple chat client (protocol given by the teacher) to do (at first) some simple tasks.
My problem is that after I send a mensage on the globlal channel or in other channel that doesn't require the use of a command, and try to send any command, the server replies with an error, saying something like: "msgbeforemsgbeforeCOMMAND" is not a valid command. I just cannot figure it out why this is happening...
(another thing, note that my dictionary is not printing the right why, I dont know why to)
ex:
chat running
import socket, select, string, sys
import threading
import time
def prompt():
sys.stdout.write('<You>: ')
sys.stdout.flush()
tLock = threading.Lock()
shutdown = False
def receber(sock):
while not shutdown:
try:
tLock.acquire()
while True:
data = sock.recv(1024)
if not data:
print ('Disconnected from server\n')
sys.exit()
else:
print ('<server>: %s' % (data.decode()))
sys.stdout.write(data)
except:
pass
finally:
tLock.release()
#Main Function
if __name__ == "__main__":
host = 'mini.alunos.di.uevora.pt'
port = 143
#IP do servidor
try:
busca_ip = socket.gethostbyname( host )
print ('Chat server IP: %s Port: %d \nNow connecting...\n' %(busca_ip, port))
except socket.gaierror:
#Não conseguiu o IP do servidor
print ('Hostname could not be resolved. Exiting.')
sys.exit()
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(3)
# connectar ao host
try :
s.connect((busca_ip, port))
s.setblocking(0)
except :
print ('Unable to connect to the server.')
sys.exit()
print ('Connected to chat server. You may start chatting\n')
COM_ARG = {'_Comando_': '_Argumentos_',
'NICK': '<nickname> [\<password>]',
'MSG': '<recipient> \<message>',
'ENTER': '<room>',
'LEAVE': '<room> [\<message>]',
'RLIST':'',
'ULIST':''}
for chave, valor, in COM_ARG.items():
print (("%s %s") % (chave,valor))
print ('\n')
comandos = COM_ARG.keys()
#criar thread para o socket
t = threading.Thread(target = receber, args=(s,))
t.start()
while True:
msg = input('<You>: ')
msg = msg.strip()
msg12 = msg.upper()
msg12 = msg12.split()
try:
if msg12[0] in comandos:
msg = msg + '\n'
except:
pass
s.send(msg.encode())
time.sleep(0.25)
btw, sys.stdout.write(data) is doing something there?
Hope you could help me out.
(another thing, note that my dictionary is not printing the right why, I dont know why to)
Dictionary doesn't respect order.
My problem is that after I send a mensage on the globlal channel or in other channel that doesn't require the use of a command, and try to send any command, the server replies with an error, saying something like: "msgbeforemsgbeforeCOMMAND" is not a valid command. I just cannot figure it out why this is happening...
It's not just a problem with the code, the server recives the msgs, and keeps them until a '\n' appears, just then interprets the command. It's a "problem" with the protocol, but the code must be changed.
btw, sys.stdout.write(data) is doing something there?
Supposedly does the samething that print (data.decode()) does, but doesn't work in my case. I'm not sure.
I am creating a simple chat in python 3 using socket
here are the code
CLIENT
#!/bin/python
import socket
import threading
import time
tLock = threading.Lock()
poweroff = False
def receving(name, sock):
while not poweroff:
try:
tLock.acquire()
while True:
data, addr = sock.recvfrom(1024)
print (str(data))
except:
pass
finally:
tLock.release()
host = '127.0.0.1'
port = 0
server = ('127.0.0.1', 5000)
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((host, port))
s.setblocking(0)
rT = threading.Thread(target=receving, args=("RecvThread", s))
rT.start()
alias = input("Username: ")
time.sleep(0.2)
message = input(alias + ">>> ")
while message != 'q':
if message != "":
s.sendto(str(alias + ": " + message).encode('utf-8'), server)
tLock.acquire()
message = input(alias + ">>> ")
tLock.release()
time.sleep(0.2)
poweroff = True
rT.join()
s.close()
SERVER
#!/bin/python
import socket
import time
hostname = '127.0.0.1'
port = 5000
clients = []
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((hostname, port))
s.setblocking(0)
iQuit = False
print ("Server Started.")
while not iQuit:
try:
data, addr = s.recvfrom(1024)
if addr not in clients:
clients.append(addr)
print (time.ctime(time.time()) + str(addr) + ": :" + str(data))
for client in clients:
s.sendto(data, client)
except:
pass
s.close()
How do i print a string to the server when a user connect?
I have tried to add this string after you have insert the name
s.sendto(str(alias + " Connected").encode('utf-8'), server)
but the output is orrible for me
Another Question:
Why i get something like this when seding a message?
Username: User_A
User_A>>> Hello
User_A>>> How Are you?
b'User:A: Hello'
User_A>>>
b'User_A: How Are you?'
b'User_B: Hi'
Concerning your second question: You are printing binary strings, see here for more information.
Use str(data.decode('utf-8')) instead of str(data) when printing the message on the server or the client.
Concerning the first question: This should work if you send the "Connected" string just after asking for the user name.
The string is decoded the same way as a common message if you include the decode('utf-8') and looks normal to me.
i have to press enter to see if user_B send something to me.
You enforced this behavior by locking out the receiving thread during the input of a message. You have to make up your mind whether you want this or want incoming data to be printed while typing.
You might want to cf. Simultaneous input and output for network based messaging program.
I attempted to find an answer for this, but most examples out there are for purely echo base Socket Servers.
Basically I have the following code:
import socket
import sys
from thread import *
HOST = '' # Symbolic name meaning all available interfaces
PORT = 8888 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print 'Socket created'
#Bind socket to local host and port
try:
s.bind((HOST, PORT))
except socket.error as msg:
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
#Start listening on socket
s.listen(10)
print 'Socket now listening'
#Function for handling connections. This will be used to create threads
def clientthread(conn):
#Sending message to connected client
conn.send('Welcome to the server. Type something and hit enter\n') #send only takes string
#infinite loop so that function do not terminate and thread do not end.
while True:
#Receiving from client
data = conn.recv(1024)
if data == "hello":
reply = 'OK...Hello back to you'
else:
reply = '01:OK - ' + data
if not data:
break
conn.sendall(reply)
#came out of loop
conn.close()
#now keep talking with the client
while 1:
#wait to accept a connection - blocking call
conn, addr = s.accept()
print 'Connected with ' + addr[0] + ':' + str(addr[1])
#start new thread takes 1st argument as a function name to be run, second is the tuple of arguments to the function.
start_new_thread(clientthread ,(conn,))
s.close()
Everything works great until I try to use a conditional statement. I am very new to python and I am using this as a way to learn it a little better, but when the following line runs it skips the if each time.
#Receiving from client
data = conn.recv(1024)
if data == "hello":
reply = 'Why hello there!'
else:
reply = '01:OK - ' + data
if not data:
break
conn.sendall(reply)
From the telnet client I am connecting to it just echos everything I send it including the 'hello' I send it rather than the phrase.
I have a feeling that it is something simple, but I am not sure the format of the data variable.
Very close!
Telnet will send whatever EOL delimiter you gave it, along with the text. So if you type "data" and press enter, data is actually something like hello\r\n.
You can effectively ignore this whitespace by doing something like changing
data = conn.recv(1024)
to
data = conn.recv(1024).strip()
And you should be good to go.
EDIT:
As noted in the comments, the network may split up the message into multiple packets. To work around this, you can use use the socket.makefile() method and get a file-like object and then use readline() which will block until a complete line is available. For example, changing clientthread to:
def clientthread(conn):
#Sending message to connected client
conn.send('Welcome to the server. Type something and hit enter\n') #send only takes string
sfh = conn.makefile("r+b", bufsize=0)
#infinite loop so that function do not terminate and thread do not end.
while True:
#Receiving from client
data = sfh.readline().strip()
if data == "hello":
reply = 'OK...Hello back to you'
else:
reply = '01:OK - ' + data
if not data:
break
conn.sendall(reply)
#came out of loop
conn.close()
== PYTHON ==
Socket created
Socket bind complete
Socket now listening
Connected with 192.168.1.10:42749
== TELNET ==
$ telnet 192.168.1.106 8888
Trying 192.168.1.106...
Connected to 192.168.1.106.
Escape character is '^]'.
Welcome to the server. Type something and hit enter
hello
OK...Hello back to you
I have a Blender code which takes sets of data from a csv file and uses them to rotate a robot arm and a human model in the Game Engine. This code works fine, but now I want to send data across a wireless connection to Blender.
I have a server code set up in Blender (which runs on Python 3)
# Server Program
# Make sure the client is being run on the data generation computer
SERVER_LOOP = True
import socket
import sys
import json
import bge
cont = bge.logic.getCurrentController()
owner = cont.owner
print ('INFO: Starting up')
# Create a TCP/IP socket to listen on
print ('INFO: Creating TCP/IP Socket')
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Prevent from 'ADDRESS ALREADY IN USE' upon restart
print ('INFO: Housekeeping...')
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# Bind the socket to port 8081 on all interfaces
server_address = ('localhost', 8081)
print ('INFO: Binding and starting up on %s port %s' % server_address)
server.bind(server_address)
print ('INFO: Server bound')
def send_welcome(cont):
cont.send('SERVER: Welcome'.encode('utf8'))
# Listen for connectons for 5 seconds
server.listen(5)
# Connection is the SOCKET OBJECT for the connection
# Client_address is the connected peer(the client)
connection, client_address = server.accept()
print ('INFO: Connection from', connection.getpeername())
print ('INFO: Sending welcome msg')
send_welcome(connection)
print ()
while SERVER_LOOP:
# Receive data
try:
data = connection.recv(10000)
# Unless there's an error
except OSError:
print (connection)
# Decode the data into usable lists
if type(data) != type(''):
data = data.decode()
# If we want to end the client stream but keep the server running
if data=='end' or data=='End' or data=='END':
print ('INFO: Closing connection with ',connection.getpeername())
connection.shutdown(socket.SHUT_RD | socket.SHUT_WR)
print ()
connection.close()
connection, client_address = server.accept()
print ('INFO: Connection from', connection.getpeername())
print ('INFO: Sending welcome msg')
send_welcome(connection)
print ()
# If we want to stop running the server
elif data=='end server' or data=='End server' or data=='End Server':
print ()
print ('SERVER SHUT DOWN')
SERVER_LOOP = False
# Display when data is loaded back on the client side
else:
# gives feedback in server command line
data = json.loads(data)
owner['test'] = data
print ('CLIENT: %s' % data)
message = 'ping'
connection.send(('SERVER: %s' % message).encode('utf-8'))
print ('SERVER: %s' % message)
And the client code to run with it (this one runs on Python 2.7)
# Client Program
# Make sure the server is being run in Blender
import socket
import time
import json
print 'INFO: Creating Socket'
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ip_addr = raw_input('IP: ')
port_addr = raw_input('PORT: ')
# Type 'localhost' in the IP field
# Type '8081' in the PORT field
print 'INFO: Connecting to server'
s.settimeout(5) # Times out if 5 seconds without connecting to client
s.connect((ip_addr, int(port_addr)))
# Listen for welcome
data = s.recv(10000)
print data
print ''
while 1:
message = raw_input('CLIENT: ')
if message=='end' or message=='End' or message=='END':
print ''
print 'SHUTTING DOWN CLIENT, SERVER STILL RUNNING'
s.send(message)
break
elif message=='end server' or message=='End server' or message=='End Server':
print ''
print 'SHUTTING DOWN SERVER'
s.send(message)
break
else:
s.send(message)
data = s.recv(10000)
print data
print 'INFO: Closing socket'
s.close()
print 'INFO: Quitting'
Now, obviously this doesn't do the rotations; it's just a test script to make sure that the data transfer between the two works. And it does - in Blender's system console, the data is displayed just as I want it. However, I have a string debug property in Blender titled "test", which is supposed to display the current number just typed in the client, and it's not until I close the whole program down.
For example:
I run the server script in Blender
I run the client script in IDLE
I type in numbers on the client side
They appear in the system console on the server side, but they do NOT appear in the Game Engine
I close the server from the client side
Now, the last number I typed finally appears on the server side
So the problem is that Blender runs my script and then the Game Engine after it's done, but I want them to run concurrently.
Let me know if my explanation doesn't make sense; I can provide downloads to my stuff if need be.
I don't know if this is still a problem - you posted in February and it's now August, but I was just searching for the answer of a similar problem. Your problem is that Blender doesn't update its frames until a script has finished running. Your game is literally stuck on the first frame it plays because it starts a script as soon as that frame hits, and because of the nature of your script, never ends.
Currently, you use server.listen(5) to mean that it listens to five seconds, but the number 5 in that function refers to the backlog instead of the length of time [source]. socket.listen() will stall your game indefinitely (as far as I understand) just like an infinite loop would.
This may not be the answer you were looking for, but it's definitely an answer.