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Why can't I access a specific variable inside of a threaded class

The bounty expires in 5 days. Answers to this question are eligible for a +50 reputation bounty.
Haley Mueller wants to draw more attention to this question.
I'm new to Python so this could be a simple fix.
I am using Flask and sockets for this Python project. I am starting the socket on another thread so I can actively listen for new messages. I have an array variable called 'SocketConnections' that is within my UdpComms class. The variable gets a new 'Connection' appended to it when a new socket connection is made. That works correctly. My issue is that when I try to read 'SocketConnections' from outside of the thread looking in, it is an empty array.
server.py
from flask import Flask, jsonify
import UdpComms as U
app = Flask(__name__)
#app.route('/api/talk', methods=['POST'])
def talk():
global global_server_socket
apples = global_server_socket.SocketConnections
return jsonify(message=apples)
global_server_socket = None
def start_server():
global global_server_socket
sock = U.UdpComms(udpIP="127.0.0.1", portTX=8000, portRX=8001, enableRX=True, suppressWarnings=True)
i = 0
global_server_socket = sock
while True:
i += 1
data = sock.ReadReceivedData() # read data
if data != None: # if NEW data has been received since last ReadReceivedData function call
print(data) # print new received data
time.sleep(1)
if __name__ == '__main__':
server_thread = threading.Thread(target=start_server)
server_thread.start()
app.run(debug=True,host='192.168.0.25')
UdpComms.py
import json
import uuid
class UdpComms():
def __init__(self,udpIP,portTX,portRX,enableRX=False,suppressWarnings=True):
self.SocketConnections = []
import socket
self.udpIP = udpIP
self.udpSendPort = portTX
self.udpRcvPort = portRX
self.enableRX = enableRX
self.suppressWarnings = suppressWarnings # when true warnings are suppressed
self.isDataReceived = False
self.dataRX = None
# Connect via UDP
self.udpSock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # internet protocol, udp (DGRAM) socket
self.udpSock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) # allows the address/port to be reused immediately instead of it being stuck in the TIME_WAIT state waiting for late packets to arrive.
self.udpSock.bind((udpIP, portRX))
# Create Receiving thread if required
if enableRX:
import threading
self.rxThread = threading.Thread(target=self.ReadUdpThreadFunc, daemon=True)
self.rxThread.start()
def __del__(self):
self.CloseSocket()
def CloseSocket(self):
# Function to close socket
self.udpSock.close()
def SendData(self, strToSend):
# Use this function to send string to C#
self.udpSock.sendto(bytes(strToSend,'utf-8'), (self.udpIP, self.udpSendPort))
def SendDataAddress(self, strToSend, guid):
# Use this function to send string to C#
print('finding connection: ' + guid)
if self.SocketConnections:
connection = self.GetConnectionByGUID(guid)
print('found connection: ' + guid)
if connection is not None:
self.udpSock.sendto(bytes(strToSend,'utf-8'), connection.Address)
def ReceiveData(self):
if not self.enableRX: # if RX is not enabled, raise error
raise ValueError("Attempting to receive data without enabling this setting. Ensure this is enabled from the constructor")
data = None
try:
data, _ = self.udpSock.recvfrom(1024)
print('Socket data recieved from: ', _)
if self.IsNewConnection(_) == True:
print('New socket')
self.SendDataAddress("INIT:" + self.SocketConnections[-1].GUID, self.SocketConnections[-1].GUID)
data = data.decode('utf-8')
except WindowsError as e:
if e.winerror == 10054: # An error occurs if you try to receive before connecting to other application
if not self.suppressWarnings:
print("Are You connected to the other application? Connect to it!")
else:
pass
else:
raise ValueError("Unexpected Error. Are you sure that the received data can be converted to a string")
return data
def ReadUdpThreadFunc(self): # Should be called from thread
self.isDataReceived = False # Initially nothing received
while True:
data = self.ReceiveData() # Blocks (in thread) until data is returned (OR MAYBE UNTIL SOME TIMEOUT AS WELL)
self.dataRX = data # Populate AFTER new data is received
self.isDataReceived = True
# When it reaches here, data received is available
def ReadReceivedData(self):
data = None
if self.isDataReceived: # if data has been received
self.isDataReceived = False
data = self.dataRX
self.dataRX = None # Empty receive buffer
if data != None and data.startswith('DIALOG:'): #send it info
split = data.split(':')[1]
return data
class Connection:
def __init__(self, gUID, address) -> None:
self.GUID = gUID
self.Address = address
def IsNewConnection(self, address):
for connection in self.SocketConnections:
if connection.Address == address:
return False
print('Appending new connection...')
connection = self.Connection(str(uuid.uuid4()),address)
self.SocketConnections.append(connection)
return True
def GetConnectionByGUID(self, guid):
for connection in self.SocketConnections:
if connection.GUID == guid:
return connection
return None
As mentioned above. When IsNewConnection() is called in UdpComms it does append a new object to SocketConnections. It's just trying to view the SocketConnections in the app.route that is empty. My plans are to be able to send socket messages from the app.routes

For interprocess communication you may try to use something like shared memory documented here
Instead of declaring your self.SocketConnections as a list = []
you'd use self.SocketConnections = Array('i', range(10)) (you are then limited to remembering only 10 connections though).

The publishing code below is stalling on time.sleep() how can i change this behaviour + what would be a good way to implement a thread safe cach

For refreshing skills for a new job i have been trying to implement a very simple price publisher + client + mtm_cache. In the code below in publishing.py the code stops at time.sleep() and doesnt seem to wakeup (say for example two clients connect, but they stop receiving the messages while publisher executes time.sleep()), how can i correct the behavior of the publisher.
Also there is another class MTMCache where i hope to store the MTM sent by the client, would a dictionary be a good thread safe cache which stores list of tuples (time,MTMValue) per client.
As a third point how can i change the implementation of this Publisher class using asyncio?
publishing.py
import threading
import socket
import time
import random
class Publisher(object):
def __init__(self):
self.list_subscribers = []#list of tuples with ip and port
self.mtm_cache = None
self.current_price = 50
self.listening_ports = [1100,1101,1102,1103,1104]
self.stop_threads = False
self.listening_port = 1100
self.sock = None
self.listening = False
#run listening function in another thread
def update_price(self):
tmp = random.randint(-10,10)
#print("Number generated is " + str(tmp))
self.current_price = self.current_price + tmp
def update_price_in_loop(self):
while(True):
self.update_price()
if(self.stop_threads):
break
def send_price_to_subscribers(self):
#in a parallel for loop send current price to subscribers
while(True):
#print(str(self.current_price))
if self.list_subscribers:
for cl in self.list_subscribers:
cl.send(str(self.current_price).encode())
if(self.stop_threads):
break
def start_listener_and_accept_connections(self):
if(not self.listening):
self.sock = socket.socket()
self.sock.bind(('',self.listening_port))
print("sock bound at ", self.listening_port)
while True:
if not self.listening:
print("listening for connections")
self.sock.listen(5)
#above is a blocking call, it is blocking other threads
self.listening = True # how to properly set and utilise this flag
c, addr = self.sock.accept()
print('Got connection from', addr)
self.list_subscribers.append(c)
if(self.stop_threads):
print("closing client connections")
for cl in self.list_subscribers:
cl.close()
self.sock.close()
break
class MTMCache(object):
def __init__(self,publisher):
self.publisher = publisher
self.cache = {} #subscriber token for each of the subscribers in publisher class, currenttime and mtm to be stored here, maybe some other structure besides dict could be used, explore that later
def receive_mtm(self,message):
#message could be string in json format
#have to design this method with appropriate data structures
pass
if __name__ == "__main__":
from threading import *
import time
pub = Publisher()
#pub.update_price()
#print(pub.current_price)
t = Thread(target = pub.update_price_in_loop)
t1 = Thread(target = pub.send_price_to_subscribers)
#t.start()
#t1.start()
t2 = Thread(target = pub.start_listener_and_accept_connections)
t2.start()
t.start()
t1.start()
time.sleep(5)
pub.stop_threads = True
#t2.raise_exception()
#t.raise_exception()
#t1.raise_exception()
t2.join()
t.join()
t1.join()
------
basic_client.py
import socket
s = socket.socket()
port = 1100
s.connect(('127.0.0.1', port))
while(True):
tmp = s.recv(1024).decode()
print(tmp)
if not tmp:
break
s.close()
----
in separate terminals:
python3 publishing.py
term2
python3 basic_client.py
term3
python3 basic_client.py

Python socket programming with packets

I am writing a Python based application for which I am using socket programming.
I am following below approach.
Created 1 TCP/IP server, 1 controller TCP/IP client thread and 3 TCP/IP Clients threads.
I want the application to work like this. Whenever controller sends a message it gets broadcast to all 3 TCP/IP clients. Upon received message from controller the client threads perform some task and send data to the server.
Now server has to send this data to controller thread.
The communication part for of the clients and controller is working fine.
Only problem which I am facing is server is putting all the data received from clients to controller socket together.
I want server should put 1 Client thread's data on controller socket, Wait for that data to be picked up. Then place next thread's data.
So far I am using SOCK_STREAM for sockets.
Library:-
#!/usr/bin/python
import select, socket, sys, Queue, errno
usable_port_start = 40000
Internal_ip = "127.0.0.1"
class getTCPports(object):
def __init__(self,starting_port=usable_port_start,address=Internal_ip):
super(getTCPports, self).__init__()
self.IP_address = address
i = 1
delta = 0
while i <= 1:
delta += 2
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
try_port=starting_port + delta
s.bind((self.IP_address,try_port))
self.free_port=try_port
i+=1
except socket.error as e:
if e.errno == errno.EADDRINUSE:
print("Port" , try_port , "is already in use")
else:
# something else raised the socket.error exception
print(e)
s.close()
class IPCLib(getTCPports):
server_port = 0
controller_port = 0
client_map = {}
def __init__(self):
super(IPCLib,self).__init__()
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.socket.bind((self.IP_address, self.free_port))
self.inputs = [self.socket]
self.is_alive = True
self.broadcast_list = []
#classmethod
def modify_server_port(cls,port):
cls.server_port = port
#classmethod
def modify_client_port(cls,identity,port):
if 0 <= identity.find("CONTROLLER"):
cls.controller_port = port
elif 0 <= identity.find("CLIENT"):
cls.client_map[identity] = port
def start_TCP_server(self):
self.socket.setblocking(0)
self.socket.listen(10)
self.modify_server_port(self.free_port)
while self.is_alive:
inputready,outputready,exceptready = select.select(self.inputs,[],[])
for s in inputready: #check each socket that select() said has available data
if s == self.socket: #if select returns our server socket, there is a new
#remote socket trying to connect
client, address = s.accept()
self.inputs.append(client) #add it to the socket list so we can check it now
self.broadcast_list.append(client)
#print 'new client added%s'%str(address)
else:
# select has indicated that these sockets have data available to recv
data = s.recv(4096)
if data:
#print '%s Received From Client(on server)-> %s'%(data,s.getpeername()[1])
#Uncomment below to echo the recv'd data back
#to the sender... loopback!
if s.getpeername()[1]==self.controller_port:
self.broadcast(data)
else: #if sender is monitoring clients, send data to only controller
self.send_to_controller(data)
else:#if recv() returned NULL, that usually means the sender wants
#to close the socket.
s.close()
self.inputs.remove(s)
#if running is ever set to zero, we will call this
server.close()
def start_TCP_client(self,identity):
self.modify_client_port(identity,self.free_port)
self.socket.connect((self.IP_address,self.server_port))
def stop_TCP_client(self):
self.socket.shutdown(socket.SHUT_RDWR)
self.socket.close()
def broadcast(self,message):
for client in self.broadcast_list:
if client.getpeername()[1]!=self.controller_port:
try:
client.send(message)
except:
client.close()
# if the link is broken, we remove the client
remove(clients)
def send_to_controller(self,message):
for client in self.broadcast_list:
if client.getpeername()[1]==self.controller_port:
try:
client.send(message)
except:
client.close()
# if the link is broken, we remove the client
remove(clients)
def send_data(self,data):
self.socket.send(data)
def receive_data(self):
message = self.socket.recv(4096)
return message
Driver Program:-
#!/usr/bin/python
from IPCLib import *
import threading
import os
import time
def run_server():
i1=IPCLib()
print("Task assigned to thread: {}".format(threading.current_thread().name))
print("ID of process running task: {}".format(os.getpid()))
i1.start_TCP_server()
def run_controller(identity):
i1=IPCLib()
print("Task assigned to thread: {}".format(threading.current_thread().name))
print("ID of process running task: {}".format(os.getpid()))
i1.start_TCP_client(identity)
print("server port " , i1.server_port)
print("controller port", i1.controller_port)
print("bsc info", i1.client_map)
time.sleep(1)
while i1.is_alive:
i1.send_data("hello")
print"Next Clock"
sender_map={}
sender_list = []
sender_list = i1.client_map.values()
for sender in sender_list:
sender_map[sender] = False
i=1
#print any(sender_map.values())
while any(value == False for value in sender_map.values()):
print("Loop Iteration %s"%i)
data = i1.receive_data()
temp = data.split(",")
port = temp.pop(0)
sender_map[int(port)] = True
data = ",".join(temp)
print("Data %s received from port %s"%(data,port))
print sender_map
i+=1
print sender_list
time.sleep(1)
i1.stop_TCP_client()
def run_monitors(identity):
i1=IPCLib()
print("Task assigned to thread: {}".format(threading.current_thread().name))
print("ID of process running task: {}".format(os.getpid()))
i1.start_TCP_client(identity)
print("server port " , i1.server_port)
print("controller port", i1.controller_port)
print("bsc info", i1.client_map)
while i1.is_alive:
if i1.receive_data():
output = "%d"%i1.free_port
output = output + "," + "Hello"
i1.send_data(output)
i1.stop_TCP_client()
# creating thread
t1 = threading.Thread(target=run_server, name='server')
t3 = threading.Thread(target=run_monitors, name='Client1',args=("CLIENT-1",))
t4 = threading.Thread(target=run_monitors, name='Client2',args=("CLIENT-2",))
t5 = threading.Thread(target=run_monitors, name='Client3',args=("CLIENT-3",))
t6 = threading.Thread(target=run_monitors, name='Clinet4',args=("CLIENT-4",))
#make threads deamons
t1.daemon = True
t3.daemon = True
t4.daemon = True
t5.daemon = True
t6.daemon = True
# starting threads
try:
t1.start()
time.sleep(0.1)
t3.start()
time.sleep(0.1)
t4.start()
time.sleep(0.1)
t5.start()
time.sleep(0.1)
t6.start()
time.sleep(0.1)
run_controller("CONTROLLER")
except KeyboardInterrupt:
t1.is_alive = False
t3.is_alive = False
t4.is_alive = False
t5.is_alive = False
t6.is_alive = False
How can I force server to wait till the time there is already some data on the socket?

yowsup - Integrating sending and receiving

Background:
I would like to integrate yowsup to my home automation project. I have seen a simple sample on how to receive messages and after some minor changes it is working fine.
Issue:
My problem starts when it comes to integrate the send message feature. Those are the two files I am using:
run.py
from layer import EchoLayer
from yowsup.layers.auth import YowAuthenticationProtocolLayer
from yowsup.layers.protocol_messages import YowMessagesProtocolLayer
from yowsup.layers.protocol_receipts import YowReceiptProtocolLayer
from yowsup.layers.protocol_acks import YowAckProtocolLayer
from yowsup.layers.protocol_presence import YowPresenceProtocolLayer
from yowsup.layers.network import YowNetworkLayer
from yowsup.layers.coder import YowCoderLayer
from yowsup.common import YowConstants
from yowsup.layers import YowLayerEvent
from yowsup.stacks import YowStack, YOWSUP_CORE_LAYERS
from yowsup import env
CREDENTIALS = ("phone", "pwd")
if __name__ == "__main__":
layers = (
EchoLayer,
(YowAuthenticationProtocolLayer, YowMessagesProtocolLayer, YowReceiptProtocolLayer, YowAckProtocolLayer, YowPresenceProtocolLayer)
) + YOWSUP_CORE_LAYERS
stack = YowStack(layers)
# Setting credentials
stack.setProp(YowAuthenticationProtocolLayer.PROP_CREDENTIALS, CREDENTIALS)
# WhatsApp server address
stack.setProp(YowNetworkLayer.PROP_ENDPOINT, YowConstants.ENDPOINTS[0])
stack.setProp(YowCoderLayer.PROP_DOMAIN, YowConstants.DOMAIN)
stack.setProp(YowCoderLayer.PROP_RESOURCE, env.CURRENT_ENV.getResource())
# Sending connecting signal
stack.broadcastEvent(YowLayerEvent(YowNetworkLayer.EVENT_STATE_CONNECT))
# Program main loop
stack.loop()
layer.py
from yowsup.layers.interface import YowInterfaceLayer, ProtocolEntityCallback
from yowsup.layers.protocol_messages.protocolentities import TextMessageProtocolEntity
from yowsup.layers.protocol_receipts.protocolentities import OutgoingReceiptProtocolEntity
from yowsup.layers.protocol_acks.protocolentities import OutgoingAckProtocolEntity
from yowsup.layers.protocol_presence.protocolentities import PresenceProtocolEntity
import threading
import logging
logger = logging.getLogger(__name__)
class EchoLayer(YowInterfaceLayer):
#ProtocolEntityCallback("message")
def onMessage(self, messageProtocolEntity):
#send receipt otherwise we keep receiving the same message over and over
print str(messageProtocolEntity.getFrom()) + ' - ' + str(messageProtocolEntity.getBody())
receipt = OutgoingReceiptProtocolEntity(messageProtocolEntity.getId(), messageProtocolEntity.getFrom())
self.toLower(receipt)
#ProtocolEntityCallback("send_message")
def sendMessage(self, destination, message, messageProtocolEntity):
outgoingMessageProtocolEntity = TextMessageProtocolEntity(
message,
to = destination + "#s.whatsapp.net")
self.toLower(outgoingMessageProtocolEntity)
#ProtocolEntityCallback("receipt")
def onReceipt(self, entity):
ack = OutgoingAckProtocolEntity(entity.getId(), "receipt", "delivery")
self.toLower(ack)
# List of (jid, message) tuples
PROP_MESSAGES = "org.openwhatsapp.yowsup.prop.sendclient.queue"
def __init__(self):
super(EchoLayer, self).__init__()
self.ackQueue = []
self.lock = threading.Condition()
#ProtocolEntityCallback("success")
def onSuccess(self, successProtocolEntity):
self.lock.acquire()
for target in self.getProp(self.__class__.PROP_MESSAGES, []):
phone, message = target
if '#' in phone:
messageEntity = TextMessageProtocolEntity(message, to = phone)
elif '-' in phone:
messageEntity = TextMessageProtocolEntity(message, to = "%s#g.us" % phone)
else:
messageEntity = TextMessageProtocolEntity(message, to = "%s#s.whatsapp.net" % phone)
self.ackQueue.append(messageEntity.getId())
self.toLower(messageEntity)
self.lock.release()
#ProtocolEntityCallback("ack")
def onAck(self, entity):
self.lock.acquire()
if entity.getId() in self.ackQueue:
self.ackQueue.pop(self.ackQueue.index(entity.getId()))
if not len(self.ackQueue):
logger.info("Message sent")
#raise KeyboardInterrupt()
self.lock.release()
Questions:
Where am I supposed to call the send_message method, so I can send messages wherever I need it?
Is there a regular event (triggering every second or something) which I could use to send my messages?

#ProtocolEntityCallback("send_message")
def sendMessage(self, destination, message, messageProtocolEntity):
outgoingMessageProtocolEntity = TextMessageProtocolEntity(
message,
to = destination + "#s.whatsapp.net")
self.toLower(outgoingMessageProtocolEntity)
In the avove code sendMessage to be called, protocolEntity.getTag() == "send_message" has to be True. You don't need it to send message.
layer.py
from yowsup.layers.interface import YowInterfaceLayer, ProtocolEntityCallback
from yowsup.layers.protocol_messages.protocolentities import TextMessageProtocolEntity
from yowsup.layers.protocol_receipts.protocolentities import OutgoingReceiptProtocolEntity
from yowsup.layers.protocol_acks.protocolentities import OutgoingAckProtocolEntity
from yowsup.layers.protocol_presence.protocolentities import PresenceProtocolEntity
import threading
import logging
logger = logging.getLogger(__name__)
recv_msg = []
class EchoLayer(YowInterfaceLayer):
def __init__(self):
super(EchoLayer, self).__init__()
self.ackQueue = []
self.lock = threading.Condition()
#ProtocolEntityCallback("message")
def onMessage(self, messageProtocolEntity):
if messageProtocolEntity.getType() == 'text':
recv_msg.append((messageProtocolEntity.getFrom(),messageProtocolEntity.getBody()))
#send receipt otherwise we keep receiving the same message over and over
receipt = OutgoingReceiptProtocolEntity(messageProtocolEntity.getId(), messageProtocolEntity.getFrom())
self.toLower(receipt)
#ProtocolEntityCallback("receipt")
def onReceipt(self, entity):
ack = OutgoingAckProtocolEntity(entity.getId(), "receipt", "delivery")
self.toLower(ack)
# List of (jid, message) tuples
PROP_MESSAGES = "org.openwhatsapp.yowsup.prop.sendclient.queue"
#ProtocolEntityCallback("success")
def onSuccess(self, successProtocolEntity):
self.lock.acquire()
for target in self.getProp(self.__class__.PROP_MESSAGES, []):
phone, message = target
if '#' in phone:
messageEntity = TextMessageProtocolEntity(message, to = phone)
elif '-' in phone:
messageEntity = TextMessageProtocolEntity(message, to = "%s#g.us" % phone)
else:
messageEntity = TextMessageProtocolEntity(message, to = "%s#s.whatsapp.net" % phone)
self.ackQueue.append(messageEntity.getId())
self.toLower(messageEntity)
self.lock.release()
#ProtocolEntityCallback("ack")
def onAck(self, entity):
self.lock.acquire()
if entity.getId() in self.ackQueue:
self.ackQueue.pop(self.ackQueue.index(entity.getId()))
if not len(self.ackQueue):
self.lock.release()
logger.info("Message sent")
raise KeyboardInterrupt()
self.lock.release()
To send message define a function send_message in the stack run.py. You can also import run.py and use it's function from other script.
from layer import EchoLayer, recv_msg
CREDENTIALS = ("phone", "pwd")
def send_message(destination, message):
'''
destination is <phone number> without '+'
and with country code of type string,
message is string
e.g send_message('11133434343','hello')
'''
messages = [(destination, message)]
layers = (EchoLayer,
(YowAuthenticationProtocolLayer,
YowMessagesProtocolLayer,
YowReceiptProtocolLayer,
YowAckProtocolLayer,
YowPresenceProtocolLayer)
) + YOWSUP_CORE_LAYERS
stack = YowStack(layers)
stack.setProp(EchoLayer.PROP_MESSAGES, messages)
stack.setProp(YowAuthenticationProtocolLayer.PROP_PASSIVE, True)
# Setting credentials
stack.setProp(YowAuthenticationProtocolLayer.PROP_CREDENTIALS, CREDENTIALS)
# WhatsApp server address
stack.setProp(YowNetworkLayer.PROP_ENDPOINT, YowConstants.ENDPOINTS[0])
stack.setProp(YowCoderLayer.PROP_DOMAIN, YowConstants.DOMAIN)
stack.setProp(YowCoderLayer.PROP_RESOURCE, env.CURRENT_ENV.getResource())
# Sending connecting signal
stack.broadcastEvent(YowLayerEvent(YowNetworkLayer.EVENT_STATE_CONNECT))
try:
# Program main loop
stack.loop()
except AuthError as e:
print('Authentication error %s' % e.message)
sys.exit(1)
def recv_message():
layers = ( EchoLayer,
(YowAuthenticationProtocolLayer, YowMessagesProtocolLayer,
YowReceiptProtocolLayer, YowAckProtocolLayer,
YowPresenceProtocolLayer)
) + YOWSUP_CORE_LAYERS
stack = YowStack(layers)
# Setting credentials
stack.setProp(YowAuthenticationProtocolLayer.PROP_CREDENTIALS, CREDENTIALS)
# WhatsApp server address
stack.setProp(YowNetworkLayer.PROP_ENDPOINT, YowConstants.ENDPOINTS[0])
stack.setProp(YowCoderLayer.PROP_DOMAIN, YowConstants.DOMAIN)
stack.setProp(YowCoderLayer.PROP_RESOURCE, env.CURRENT_ENV.getResource())
# Sending connecting signal
stack.broadcastEvent(YowLayerEvent(YowNetworkLayer.EVENT_STATE_CONNECT))
try:
# Program main loop
stack.loop()
except AuthError as e:
print('Authentication error %s' % e.message)
sys.exit(1)
if __name__ == '__main__':
if len(sys.argv) == 1:
print('%s send number message\nrecv\n' % sys.argv[0])
sys.exit(1)
if sys.argv[1] == 'send':
try:
send_message(sys.argv[2],sys.argv[3])
except KeyboardInterrupt:
print('closing')
sys.exit(0)
if sys.argv[1] == 'recv':
try:
recv_message()
except KeyboardInterrupt:
print('closing')
sys.exit(0)
for m in recv_msg:
print('From %s:\n%s\n' % m)
Now you can send message by calling send_message('1234567890','Howdy') and recieve message by calling recv_message().

python Client hangs when no data to receive from server and hangs in that thread w/o letting client send

I am trying to figure out how to get my client to send and receive data 'simultaneously' and am using threads. My problem is that, depending on the way I set it up, the way here it waits for data from the server in the recieveFromServer function which is in its own thread and cannot stop it when nothing will be sent. The other way it just waits for user input, and will send to the server and then I'd call the function recieveFromServer after the client sends a message to the server which doesn't allow for fluent communication, but cannot get it to alternate automatically. How do I release the thread when the client has nothing to be sent, or there is no more to be received from the server.
It would get to long if I tried to explain everything I have tried. :)
Thanks.
The client:
from socket import *
from threading import *
import thread
import time
from struct import pack,unpack
from networklingo import *
#from exception import *
HOST = '192.168.0.105'
PORT = 21567
BUFFSIZE = 1024
ADDR = (HOST,PORT)
lock = thread.allocate_lock()
class TronClient:
def __init__(self,control=None):
self.tcpSock = socket(AF_INET,SOCK_STREAM)
#self.tcpSock.settimeout(.2)
self.recvBuff = []
def connect(self):
self.tcpSock.connect(ADDR)
self.clientUID = self.tcpSock.recv(BUFFSIZE)
print 'My clientUID is ', self.clientUID
t = Thread(target = self.receiveFromSrv())
t.setDaemon(1)
t.start()
print 'going to main loop'
self.mainLoop()
#t = Thread(target = self.mainLoop())
#t.setName('mainLoop')
#t.setDaemon(1)
#t.start()
def receiveFromSrv(self):
RECIEVING = 1
while RECIEVING:
#print 'Attempting to retrieve more data'
#lock.acquire()
#print 'Lock Aquired in recieveFromSrv'
#try:
data = self.tcpSock.recv(BUFFSIZE)
#except socket.timeout,e:
#print 'Error recieving data, ',e
#continue
#print data
if not data: continue
header = data[:6]
msgType,msgLength,clientID = unpack("hhh",header)
print msgType
print msgLength
print clientID,'\n'
msg = data[6:]
while len(msg) < msgLength:
data = self.tcpSock.recv(BUFFSIZE)
dataLen = len(data)
if dataLen <= msgLength:
msg += data
else:
remLen = msgLength-len(data) #we just need to retrieve first bit of data to complete msg
msg += data[:remLen]
self.recvBuff.append(data[remLen:])
print msg
#else:
#lock.release()
# print 'lock release in receiveFromSrv'
#time.sleep(2)
#RECIEVING = 0
def disconnect(self,data=''):
self.send(DISCONNECT_REQUEST,data)
#self.tcpSock.close()
def send(self,msgType,msg):
header = pack("hhh",msgType,len(msg),self.clientUID)
msg = header+msg
self.tcpSock.send(msg)
def mainLoop(self):
while 1:
try:
#lock.acquire()
#print 'lock aquired in mainLoop'
data = raw_input('> ')
except EOFError: # enter key hit without any data (blank line) so ignore and continue
continue
#if not data or data == '': # no valid data so just continue
# continue
if data=='exit': # client wants to disconnect, so send request to server
self.disconnect()
break
else:
self.send(TRON_CHAT,data)
#lock.release()
#print 'lock released in main loop'
#self.recieveFromSrv()
#data = self.tcpSock.recv(BUFFSIZE)
#t = Thread(target = self.receiveFromSrv())
#t.setDaemon(1)
#t.start()
if __name__ == "__main__":
cli = TronClient()
cli.connect()
#t = Thread(target = cli.connect())
#t.setName('connect')
#t.setDaemon(1)
#t.start()
The server (uses a lock when incrementing or decrementing number of clients):
from socket import *
from threading import *
import thread
from controller import *
from networklingo import *
from struct import pack,unpack
HOST = ''
PORT = 21567
BUFSIZE = 1024
ADDR = (HOST,PORT)
nclntlock = thread.allocate_lock()
class TronServer:
def __init__(self,maxConnect=4,control=None):
self.servSock = socket(AF_INET,SOCK_STREAM)
# ensure that you can restart server quickly when it terminates
self.servSock.setsockopt(SOL_SOCKET,SO_REUSEADDR,1)
self.servSock.bind(ADDR)
self.servSock.listen(maxConnect)
# keep track of number of connected clients
self.clientsConnected = 0
# give each client a unique identfier for this run of server
self.clientUID = 0
# list of all clients to cycle through for sending
self.allClients = {}
# keep track of threads
self.cliThreads = {}
#reference back to controller
self.controller = control
self.recvBuff = []
def removeClient(self,clientID,addr):
if clientID in self.allClients.keys():
self.allClients[clientID].close()
print "Disconnected from", addr
nclntlock.acquire()
self.clientsConnected -= 1
nclntlock.release()
del self.allClients[clientID]
else:
print 'ClientID is not valid'
def recieve(self,clientsock,addr):
RECIEVING = 1
# loop serving the new client
while RECIEVING: # while PLAYING???
try:
data = clientsock.recv(BUFSIZE)
except:
RECIEVING = 0
continue
# if not data: break #no data was recieved
if data != '':
print 'Recieved msg from client: ',data
header = data[:6]
msgType,msgLength,clientID = unpack("hhh",header)
print msgType
print msgLength
print clientID,'\n'
if msgType == DISCONNECT_REQUEST: #handle disconnect request
self.removeClient(clientID,addr)
else: #pass message type and message off to controller
msg = data[6:]
while len(msg) < msgLength:
data = self.tcpSock.recv(BUFSIZE)
dataLen = len(data)
if dataLen <= msgLength:
msg += data
else:
remLen = msgLength-len(data) #we just need to retrieve first bit of data to complete msg
msg += data[:remLen]
self.recvBuff.append(data[remLen:])
print msg
# echo back the same data you just recieved
#clientsock.sendall(data)
self.send(TRON_CHAT,msg,-1) #send to client 0
for k in self.allClients.keys():
if self.allClients[k] == clientsock:
self.removeClient(k,addr)
print 'deleted after hard exit from clientID ', k
#self.cliThreads[k].join()
#del self.cliThreads[k]
# then tell controller to delete player with k
break
def send(self,msgType,msg,clientID=-1):
header = pack("hhh",msgType,len(msg),clientID)
msg = header+msg
if clientID in self.allClients:
self.allClients[clientID].send(msg)
elif clientID==ALL_PLAYERS:
for k in self.allClients.keys():
self.allClients[k].send(msg)
def mainLoop(self):
global nclntlock
try:
while self.controller != None and self.controller.state == WAITING:
print 'awaiting connections'
clientsock, caddy = self.servSock.accept()
nclntlock.acquire()
self.clientsConnected += 1
nclntlock.release()
print 'Client ',self.clientUID,' connected from:',caddy
clientsock.setblocking(0)
clientsock.send(str(self.clientUID))
self.allClients[self.clientUID] = clientsock
t = Thread(target = self.recieve, args = [clientsock,caddy])
t.setName('recieve-' + str(self.clientUID))
self.cliThreads[self.clientUID] = t
self.clientUID += 1
# t.setDaemon(1)
t.start()
finally:
self.servSock.close()
if __name__ == "__main__":
serv = TronServer(control = LocalController(nPlayers = 3, fWidth = 70, fHeight = 10))
t = Thread(target = serv.mainLoop())
t.setName('mainLoop')
# t.setDaemon(1)
t.start()

I think you want to try and set the socket to non-blocking mode:
http://docs.python.org/library/socket.html#socket.socket.setblocking
Set blocking or non-blocking mode of
the socket: if flag is 0, the socket
is set to non-blocking, else to
blocking mode. Initially all sockets
are in blocking mode. In non-blocking
mode, if a recv() call doesn’t find
any data, or if a send() call can’t
immediately dispose of the data, a
error exception is raised; in blocking
mode, the calls block until they can
proceed. s.setblocking(0) is
equivalent to s.settimeout(0);
s.setblocking(1) is equivalent to
s.settimeout(None).
Also, instead of using raw sockets, have you considdered using the multiprocessing module. It is a higher-level abstraction for doing network IO. The section on Pipes & Queues is specific to sending and receiving data between a client/server.