My chat client freezes up after beginning threads - python

I made a better chat client following help from people:
They told me that if I didn't want to be blocked on .recv when waiting for messages, I would need to use threads, classes, functions, and queues to do so.
So I followed some help a specific person gave me where I created a thread from a class and then defined a function that was supposed to read incoming messages and print them.
I also created a function that allows you to enter stuff to be sent off.
Thing is, when I run the program. Nothing happens.
Can somebody help point out what is wrong? (I've asked questions and researched for 3 days, without getting anywhere, so I did try)
from socket import *
import threading
import json
import select
print("Client Version 3")
HOST = input("Connect to: ")
PORT = int(input("On port: "))
# Create Socket
s = socket(AF_INET,SOCK_STREAM)
s.connect((HOST,PORT))
print("Connected to: ",HOST,)
#-------------------Need 2 threads for handling incoming and outgoing messages--
# 1: Create out_buffer:
Buffer = []
rlist,wlist,xlist = select.select([s],Buffer,[])
class Incoming(threading.Thread):
# made a function a thread
def Incoming_messages():
while True:
for i in rlist:
data = i.recv(1024)
if data:
print(data.decode())
# Now for outgoing data.
def Outgoing():
while True:
user_input=("Your message: ")
if user_input is True:
Buffer += [user_input.encode()]
for i in wlist:
s.sendall(Buffer)
Buffer = []
Thanks for taking a look, thanks also to Tony The Lion for suggesting this

Take a look at this revised version of your code: (in python3.3)
from socket import *
import threading
import json
import select
print("client")
HOST = input("connect to: ")
PORT = int(input("on port: "))
# create the socket
s = socket(AF_INET, SOCK_STREAM)
s.connect((HOST, PORT))
print("connected to:", HOST)
#------------------- need 2 threads for handling incoming and outgoing messages--
# 1: create out_buffer:
out_buffer = []
# for incoming data
def incoming():
rlist,wlist,xlist = select.select([s], out_buffer, [])
while 1:
for i in rlist:
data = i.recv(1024)
if data:
print("\nreceived:", data.decode())
# now for outgoing data
def outgoing():
global out_buffer
while 1:
user_input=input("your message: ")+"\n"
if user_input:
out_buffer += [user_input.encode()]
# for i in wlist:
s.send(out_buffer[0])
out_buffer = []
thread_in = threading.Thread(target=incoming, args=())
thread_out = threading.Thread(target=outgoing, args=())
thread_in.start() # this causes the thread to run
thread_out.start()
thread_in.join() # this waits until the thread has completed
thread_out.join()
in your program you had various problems, namely you need to call the threads; to just define them isn't enough.
you also had forgot the function input() in the line: user_input=input("your message: ")+"\n".
the "select()" function was blocking until you had something to read, so the program didn't arrive to the next sections of the code, so it's better to move it to the reading thread.
the send function in python doesn't accept a list; in python 3.3 it accepts a group of bytes, as returned by the encoded() function, so that part of the code had to be adapted.

Related

Python Socket Programming, other programs aren't connecting to the server

I am opening the same program multiple times (10 to be exact) and i they are all trying to solve the random number first. When they solve this number they open a server which all of the other same programs are listening to on separate threads waiting to connect and when they do finally connect i want them all to shutdown.
import random
import os
import socket
import threading
import time
host = '192.168.1.139'
port = 8011
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
def verified():
print('Connection made successfuly')
time.sleep(10)
quit()
def network():
try:
s.connect(('192.168.1.135',8014))
f = s.recv(50)
finished = f.decode('utf-8')
if finished == 'completed':
quit()
except:
pass
def winner():
x = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
x.bind(('192.168.1.135', 8014))
x.listen(10)
con, address = x.accept()
con.send(bytes('completed', 'utf-8'))
def mine():
global guess
time.sleep(.000001)
guess = random.randint(0,1000)
print(guess)
tran = 500
while True:
mine()
if guess == 500:
print("Solved")
winner()
break;
else:
x = threading.Thread(target=network)
x.start()
For some reason it is connecting to the server but it isn't quitting the program, could this be because it is connecting to itself and exiting to fast? Please help, Thank You!
Actually, I was consfused, but apparently when the quit() is in a function it can't end the whole process, so what I would suggest you to do is to make the while loop with a variable that network would be able to change (or even use guess):
guessing = True
while guessing:
mine()
if guess == 500:
print("Solved")
winner()
break;
else:
x = threading.Thread(target=network)
x.start()
and change the network to:
def network():
try:
s.connect(('192.168.1.135',8014))
f = s.recv(50)
finished = f.decode('utf-8')
if finished == 'completed':
#quit()
global guessing
guessing = False
except:
pass
I saw that the two constants host and port were not used
Unfortunately the winner function is just accepting one answer
(she's a little introvert)
but we can solve that problem:
def winner():
x = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
x.bind(('192.168.1.135', 8014))
x.listen(10)
connected = 0
while connected < 10:
con, address = x.accept()
con.send(bytes('completed', 'utf-8'))
connected += 1
and yay, she is making friends
ok, but now she is in the outer world where she needs to talk to a lot of people
not just limited 10, so she goes to the bus stop (she's going home), she waits a little bit to see if someone will talk to her (for any reason), no one said anything for some time, so, she puts her airpods and starts listening to some good {insert here a music that a computer function likes to listen to}
So, to implement this:
def winner():
x = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
x.settimeout(5) # WAITS FOR FIVE SECONDS
x.bind(('192.168.1.135', 8014))
x.listen()
while True:
try:
con, address = x.accept()
con.send(bytes('completed', 'utf-8'))
except socket.timeout: # IF IN FIVE SECONDS, RECEIVES NO CONNECTION
break
the x.settimeout(5) will make the connections give an socket.timeout error if the time set (in case 5) is exceeded without any response of the other side.
now I remembered that using threading we could push clients to another function and "free" the queue of the clients, but I think that for this special case this solution is better

Python2.7 chat using sockets and select module(non-blocking code)

Hi i have an exercise to build with sockets select and msvcrt, server and clients of mltiplie chat(the server and the clients need to be built non-blocking) that every client will send message and the server will send the message to all the clients except the one who sent it, the server:
import socket
import select
IP = "192.168.1.154"
port = 123
default_buffer_size = 1024
open_client_sockets = []
messages_to_send = []
def send_waiting_messages(wlist):
for message in messages_to_send:
(client_sock, data) = message
if client_sock in wlist:
for sock in open_client_sockets:
if sock is not client_sock:
sock.send(data)
messages_to_send.remove(message)
def main():
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind((IP, port))
sock.listen(5)
print("The server is on and waiting for client...")
while True:
rlist, wlist, xlist = select.select([sock] + open_client_sockets, open_client_sockets, [])
for current_socket in rlist:
if current_socket is sock:
(new_socket, addr) = sock.accept()
open_client_sockets.append(new_socket)
else:
data = current_socket.recv(default_buffer_size)
if data == "":
open_client_sockets.remove(current_socket)
print("Connection with client closed")
else:
messages_to_send.append((current_socket, 'Hello ' + data))
send_waiting_messages(wlist)
if __name__ == '__main__':
main()
Building the server wasnt hard because it was guided(if it was not guided i would never got this code working) by the book but i have problem building the client and the main reason is that i dont understand how select.select works, couldn't find answer that will simplify enough this module for me.
this is what i did with the client:
import socket
import select
import msvcrt
IP = "192.168.1.154"
port = 123
sockets = []
def write():
pass
def main():
sock = socket.socket()
sock.connect((IP, port))
while True:
rlist, wlist, xlist = select.select(sockets, sockets, [])
for current_socket in rlist:
if current_socket is sock:
data = current_socket.recv(1024)
print(data)
else:
sockets.append(current_socket)
write()
if __name__ == '__main__':
main()
This probably shows you that I have low understanding of the module select and the exercise actually. I saw some threads that has similar question but I understand nothing from them so I realy need good explantion.
In conclusion I realy am lost...
select takes as parameters a list of sockets to wait for readablity, a list of sockets to wait for writability, and a list of sockets to wait for errors. It returns lists of ready to read, ready to write, and error sockets. From help:
>>> help(select.select)
Help on built-in function select in module select:
select(...)
select(rlist, wlist, xlist[, timeout]) -> (rlist, wlist, xlist)
Wait until one or more file descriptors are ready for some kind of I/O.
The first three arguments are sequences of file descriptors to be waited for:
rlist -- wait until ready for reading
wlist -- wait until ready for writing
xlist -- wait for an ``exceptional condition''
If only one kind of condition is required, pass [] for the other lists.
A file descriptor is either a socket or file object, or a small integer
gotten from a fileno() method call on one of those.
The optional 4th argument specifies a timeout in seconds; it may be
a floating point number to specify fractions of seconds. If it is absent
or None, the call will never time out.
The return value is a tuple of three lists corresponding to the first three
arguments; each contains the subset of the corresponding file descriptors
that are ready.
*** IMPORTANT NOTICE ***
On Windows, only sockets are supported; on Unix, all file
descriptors can be used.
So to fix your client, you need to add the socket you opened (sock) to the sockets list. Your write function can then be called if your socket is ready to be written.
In write, use msvcrt.kbhit() to test for characters typed. You can't just use input because it will block. Then read the character if one has been typed. Collect up the characters until you hit enter, then build a message and write it to the socket. Something like:
message = []
def write(sock):
if msvcrt.kbhit():
c = msvcrt.getche()
if c == '\r':
data = ''.join(message)
print 'sending:',data
sock.sendall(data)
message.clear()
else:
message.append(c)

Python Socket - Send/Receive messages at the same time

Basically I have been working on a simple chat room using socket and thread. In my client I can receive and send messages, my issue is that one comes before another in a loop, so if I am sending a message I will only receive data once I have sent a message. I want it to work like any other chat room, where I could receive a message when I am sending a message, any help will help greatly. This is my basic client:
import socket
import sys
###########
HOST = '25.0.18.52'
PORT = 9999
###########
name = input("Enter your name: ")
s = socket.socket()
s.connect((HOST,PORT))
while 1:
message = input("Message: ")
s.send("{}: {}".format(name, message).encode('utf-8'))
data = s.recv(1024)
a = data.decode("utf-8")
print(a)
You should keep 2 threads: one for listening and the other for receiving. In your while loop, you should remove the listener part, and keep the code in a different thread. This way you can receive and type on the console at the same time.
def recv():
while True:
data = s.recv(1024).decode()
if not data: sys.exit(0)
print data
Thread(target=recv).start()

Threading not working on multiple connections

I am trying to run two tcp clients from the same code using multithreading. The issue is that the second thread never runs. And main() never reaches the last 'Its here!' string print. I have the following code:
def main():
t = Thread(None,connect(),None,)
t2 = Thread(None,connect2(),None,)
t.start()
t2.start()
print "it's here!"
def connect_mktData():
# create Internet TCP socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# connect to server
s.connect(('IP', PORT))
while(1):
print 'data1'
k = 'enter a letter1:'
s.send(k) # send k to server
v = s.recv(1024) # receive v from server (up to 1024 bytes)
print v
time.sleep(1)
s.close() # close socket
def connect_mktData2():
# create Internet TCP socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# connect to server
s.connect(('IP', PORT))
while(1):
print 'data2'
# get letter
k = raw_input('enter a letter2:')
s.send(k) # send k to server
v = s.recv(1024) # receive v from server (up to 1024 bytes)
print v
time.sleep(1)
s.close() # close socket
main()
I get the following output:
data1
enter a letter1:
data1
enter a letter1:
data1
enter a letter1:
data1
enter a letter1:
data1
Even though both functions are mostly identical, ultimately I will have two different connections doing two different things 'simultaneously' and alternating between each other. Shouldn't both threads run independently? thanks for the help!
It looks like your issue is that this:
t = Thread(None,connect(),None,)
t2 = Thread(None,connect2(),None,)
Should be this:
t = Thread(None,connect,None,)
t2 = Thread(None,connect2,None,)
You want to pass the function objects connect and connect2 to the Thread object. When you use connect() instead of connect, you end up calling connect in the main thread, and then pass its return value to the Thread object, which isn't what you want.
Also, it is much more readable to create the Thread objects like this:
t = Thread(target=connect)
t2 = Thread(target=connect2)
Use the target kwarg, so you don't have to include the None for the group.
Also note that while this will make both functions run in concurrently, they will only truly being running at the same time while they're doing blocking I/O operations (meaning inside send, recv, or raw_input). Because of Python's Global Interpeter Lock (GIL), only one thread can be doing CPU-bound operations at a time. So your threads will end up doing a mixture of true concurrency (during I/O) and cooperative multitasking (during CPU-bound operations).

Client socket not receiving data correctly

I've tried looking about for an answer but I can't seem to find one that answers my specific problem.
Perhaps I don't know how to articulate the problem correctly.
I think I've pinpointed what it is, but the thing is I just don't know how to fix it.
EDIT: I was trying to use two clients on one TCP Socket. Can't do that. I'll have to think of another way. Solved, I guess.
So what I've got is are
1: Two Clients
2: One Server
The objective is this:
Have the server distribute new usernames to all the clients as they connect.
This is what happens when I run the program:
Server: Define Host, and Port, initialize it. Check
Client 1: Connects to the server. Check
Client 1: Once connected, sends a string to the server. Check
Server: Receives a string, checks if the string is in a list is created. If it is: Pass, if it's not, send to everyone the new string. Check
Client 1: [Now waiting to receive data] Recieves data, checks if the string received matches the one it sent. If it does, print("It's one of ours!"), else, make the new string = to Client 2 Username. Check
Client 2: Connects to server: Check
Server: [If it receives a string, prints it.] (Works) Checks if the new string is in the list. [It isn't] So It sends the new username to everyone, and then prints ("Sent to everyone") Check
But, when client 2 receives the string, it prints it. However, client 1 never recives the string.
And when running client one in IDLE, I noticed something went wrong as Client 1 tried to receive the data. (The while loop that the data = s.recv began looping real fast, instead of waiting)
I've asked around in chat, but it seems nobody's around right now. I've tried looking this up but I really can't find an answer. What I suspect is happening is that when my server sends to 'connection' the second time, it somehow overrides the original client connection.
Here's my server code:
from socket import *
import threading
import os
import csv
Username_List = []
host = input("Host: ")
port = input("Port: ")
ss = socket(AF_INET,SOCK_STREAM)
ss.bind((host,int(port)))
ss.listen(2)
while True:
try:
connection,address = ss.accept()
data = connection.recv(1024)
if data:
translated_data = data.decode()
print(translated_data)
if translated_data in Username_List:
pass
else:
Username_List.append(translated_data)
connection.sendall(translated_data.encode())
print("Sent new username to everyone")
except IOError:
connection.close()
print("An exception with a connected user occured")
break
And here is my client code: [The only difference between client 1 and 2 is I changed the username variable]
# Sample Username Client Service Handler.
from socket import *
import threading
import os
import csv
Username = ("Owatch")
host = input("Host: ")
port = input("Port: ")
try:
ss = socket(AF_INET,SOCK_STREAM)
ss.connect((host,int(port)))
except IOError:
print("Aw no man")
ss.send(Username.encode())
while True:
try:
print("Waiting to Recieve Data")
data = ss.recv(1024)
if data:
translated_data = data.decode()
print(translated_data)
if translated_data == Username:
print("It's one of ours!")
else:
Client_Username = translated_data
print (Client_Username)
except Exception as e:
print (vars(e))
If you could please help I'd be grateful.
If you know of an answer to my question that's already been asked, please tell me and I'll remove this post to avoid breaking rules. Thanks!
Right then I started with what you had then changed it till it worked what I've done is created a client class which starts a thread with each connection and adds it to a list of threads (please if I'm doing something horribly wrong smarter people correct me), the thread runs gets some data checks if that's in the list of user names if its not sends out a message to all the clients in the thread list with that name then the thread just chills out. Anyway on to the code.
SERVER!!!
import csv
class client(threading.Thread):
Username_List = []
def __init__(self, conn):
super(client, self).__init__()
self.conn = conn
def run(self):
print "Client thread started"
data = self.conn.recv(1024)
print "Received: {0}".format(data)
if data in client.Username_List:
self.send_msg("Welcome Back!")
else:
for cnt in threadz:
cnt.send_msg(data)
print("Sent new username to everyone")
client.Username_List.append(data)
while True:
# dont need nothing now
pass
def send_msg(self,msg):
self.conn.send(msg)
host = input("Host: ")
port = input("Port: ")
ss = socket() #AF_INET,SOCK_STREAM)
ss.bind((host,int(port)))
print "Server Opening on port: {0}".format(port)
ss.listen(2)
threadz = []
print "Begining Wait for connections"
while True:
try:
connection, address = ss.accept()
print "Got ONE!"
c = client(connection)
print "Recevied connection from:{0} On port:{1}".format(address[0],address[1])
c.start()
threadz.append(c)
print "Client appended to threadz, currently {0} threadz active".format(len(threadz))
except IOError,KeyboardInterrupt:
connection.close()
print("An exception with a connected user occured")
break
The CLIENT:
# Sample Username Client Service Handler.
from socket import *
import threading
import os
import csv
Username = ("ShyGuy")
host = input("Host: ")
port = input("Port: ")
try:
ss = socket() #AF_INET,SOCK_STREAM)
ss.connect((host,int(port))) #I was using ("localhost",1234) for testing
ss.send(Username)
except IOError:
print("Aw no man")
print("Waiting to Recieve Data")
while True:
try:
data = ss.recv(1024)
if data:
translated_data = data.decode()
print(translated_data)
if translated_data == Username:
print"Name: {0} has been registered on server!".format(translated_data)
else:
Client_Username = translated_data
print "New client name received: {0}".format(Client_Username)
except Exception as e:
print (vars(e))
That works on python 2.7 with two clients locally. Needs to use a semaphore to stop the threads printing at the same time as the main server loop prints: http://en.wikipedia.org/wiki/Semaphore_(programming)
This code does nothing graceful with client disconnects, but once you can work with the exceptions that a raised when that happens I'm sure you'll learn some more.

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