Why my program freezing while I am listening socket

Question

So, here is some code:

obj.HOST = ""
obj.PORT = int(port.get()) # it's 100% correct PORT number
obj.srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
obj.srv.bind((obj.HOST, obj.PORT))
obj.srv.listen(1)
obj.sock, obj.addr = obj.srv.accept()

class Client(threading.Thread):
     def __init__(self,from_):
        if from_.ip.get() == '':
            obj.HOST = 'localhost' # I am starting both programs from 1 computer, so it's 'localhost'
        else:
            obj.HOST = from_.ip.get()
        obj.PORT = int(from_.port.get()) # it's 100% correct PORT number (the same as previous)
        obj.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        obj.sock.connect((obj.HOST, obj.PORT))
        threading.Thread.__init__(self)
     def run(self):
        command = obj.sock.recv(1024)
        print command
        if command == 'confirm':
            print 'confirm'
        elif command == 'start':
            print 'start'

client = Client(cl) # cl is class, where I get port. It's works 100% correct
client.start()

I start the same program on my computer. One is host, second is client.

Question 1: while I'm waiting to connect, my server script is freezing. How it repair? After connection both programs work correctly, but when server send some information(string), client script freezing.

Question 2: so how it can be repaired?

Answer 1

Not sure what the obj is. But you are not sending anything from the server to client. on the server side, you could do some thing like this :

conn, addr = srv.accept()
print 'Connected by', addr
conn.send("confirm")
conn.close()

This will accept a single connection, send some data "confirm", close connection and exit.

Same with client side:

def run(self):
        command = self.sock.recv(1024)
        print command
        print "Recieved : ", command
        self.sock.close()

This will connect to server, receive some data, print and close connection.

recv is a blocking call and will block till it receives some data from the server. This might be the cause of your freeze up.