I have got tcp server on python with asyncore:
class AsyncClientHandler(asyncore.dispatcher_with_send):
def __init__(self,sock):
asyncore.dispatcher_with_send.__init__(self,sock)
self.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
self.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
self.message=""
self.protocol=Protocol(DBSession, logger)
def handle_read(self):
data = self.recv(8192)
if data:
self.message+=data
while TERMINATOR in self.message:
index=self.message.index(TERMINATOR)
msg=self.message[:index]
self.message=self.message[index+len(TERMINATOR):]
answer=self.protocol.process_msg(msg, DBSession, tarif_dict)
if answer:
msg = HEADER+answer+TERMINATOR
self.send(msg)
def handle_close(self):
self.close()
class AsyncServer(asyncore.dispatcher):
def __init__(self, host, port):
asyncore.dispatcher.__init__(self)
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
self.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
self.set_reuse_addr()
self.bind((host, port))
self.listen(5)
def handle_accept(self):
pair = self.accept()
if pair is None:
pass
else:
sock, addr = pair
logging.info("Incoming connection from %s",repr(addr))
AsyncClientHandler(sock)
Some clients do not close the connection, so at some point the server crashes due to the large number of sockets.
How can I close an inactive socket after some time? settimeout not work.
To achieve this you could use TCP's Keepalive (like you already did) and set its delay, pings... But this apporach should only be used for long-lasting connections and is only available on Unixes. Have some read here.
You can also make some scheduling of sockets, closing them when some time passes or delay them when they're active. I made an example working with your code:
import sched, time
class SocketSched(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.daemon = True
self.to_run = []
self.scheds = {}
self.start()
def add(self, what):
self.to_run.append(what.values()[0])
self.scheds.update(what)
def run(self):
while True:
if self.to_run:
run = self.to_run.pop()
if not run.empty(): run.run()
else: self.to_run.append(run)
Here we define new class of scheduler in different thread - this is important, sched module would continuously block, like asyncore.loop().
This needs modificating your code a bit:
class AsyncClientHandler(asyncore.dispatcher_with_send):
def __init__(self,sock, sch_class):
...
self.delay = 10
self.sch_class = sch_class
self.sch = sched.scheduler(time.time, time.sleep)
self.sch_class.add({self.fileno(): self.sch})
self.event = self.sch_class.scheds[self.fileno()].enter(self.delay, 1, self.handle_close, ())
...
def delay_close(self):
self.sch_class.scheds[self.fileno()].cancel(self.event)
self.event = self.sch_class.scheds[self.fileno()].enter(self.delay, 1, self.handle_close, ())
...
def handle_close(self):
try:
self.sch_class.scheds[self.fileno()].cancel(self.event)
except:
pass
...
self.delay is a timeout in seconds. After this time passes, and no action delays it, socket will be closed. Line in handle_close() ensures it won't be called twice due to task in scheduler.
Now you have to add self.delay_close() to the beginning of every method that ensures socket is active, eg. handle_read().
Server class (gets instance of SocketSched and passes it to new channels):
class AsyncServer(asyncore.dispatcher):
def __init__(self, host, port, sch_class):
...
self.sch_class = sch_class
...
def handle_accept(self):
...
AsyncClientHandler(sock, self.sch_class)
Ready. Using this:
server = AsyncServer('', 1337, SocketSched())
asyncore.loop()
This solution works, but can be error-prone on some close events. Anyway, sockets will read, delay, and close when given timeout occurs. Unfortunately running such scheduling loop uses some CPU.
Related
In the below code, although the thread seems to be stopping the socket does not seem to be freed. Not sure what mistake I am making.
When I try to start the second time it is throwing an error 'Address already in use'. I looked up a lot of stack overflow suggestions, did not help much.
Here is my code:
import threading
import time
import socket
class TCPServer(object):
def __init__(self):
self.stop_thread = threading.Event()
def startServer(self, ip="localhost", port=12345):
self.ip = ip
self.port = port
t = threading.Thread(target=self.server, args=(self.stop_thread,
"stop_event"))
t.daemon = True
t.start()
def server(self, stop_event, arg):
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((self.ip, self.port))
sock.listen(5)
connection = ""
while not stop_event.is_set():
connection, addr = self.sock.accept()
data = connection.recv(50000)
if data:
connection.send(self.response)
connection.close()
#Tried with below statements - still fails
#self.sock.shutdown(socket.SHUT_RDWR)
#self.sock.close()
def stopServer(self):
self.stop_thread.set()
if __name__ == "__main__":
server = TCPServer()
server.startServer("localhost", 12345)
time.sleep(5)
server.stopServer()
time.sleep(15)
server.startServer("localhost", 12345)
time.sleep(5)
server.stopServer()
I found a work around by forcefully shutting down the socket in stopServer() like below:
def stopServer(self):
self.stop_thread.set()
self.sock.shutdown(socket.SHUT_RDWR)
self.sock.close()
But I dont think this is a good solution. Any suggestions?
import threading
import time
import socket
class TCPServer(object):
def __init__(self):
self.stop_thread = threading.Event()
def startServer(self, ip="localhost", port=12345):
self.ip = ip
self.port = port
t = threading.Thread(target=self.server, args=(self.stop_thread,
"stop_event"))
t.daemon = True
t.start()
def server(self, stop_event, arg):
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.bind((self.ip, self.port))
self.sock.listen(5)
connection, addr = self.sock.accept()
while not stop_event.is_set():
data = connection.recv(50000)
if data:
connection.send(self.response)
connection.close()
self.sock.close()
def stopServer(self):
self.stop_thread.set()
so mostly minor things that accumulated. You needed to check if event is set, not just if event was true. You can read more on that in event-object docs. That meant you never left the inner loop. Once you leave the inner loop you need to close both connection and the socket explicitly.
I have a socketserver in Python which has to handle multiple clients using the select.select method, as seen in the code below:
import socket
import select
class Server:
def __init__(self):
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.bind(('localhost', 2000))
self.socket_list = [self.server]
self.addresses = ['localhost']
self.commands = [""]
self.running = True
self.server.listen(10)
def listen(self):
while self.running:
read, write, error = select.select(self.socket_list, [], self.socket_list, 0)
for sock in read:
if sock == self.server and self.running:
try:
conn, address = self.server.accept()
conn.settimeout(30)
self.socket_list.append(conn)
self.addresses.append(address[0])
self.commands.append("")
except:
self.shutdown()
break
elif self.running:
try:
packet = sock.recv(60)
if not packet:
self.close_conn(sock)
index = self.socket_list.index(sock)
self.commands[index] += packet
if '\n' in self.commands[index]:
#handle command
except:
self.close_conn(sock)
def close_conn(self, conn):
#close client conn
def shutdown(self):
#shutdown server
if __name__ == "__main__":
Server().listen()
The problem i currently have is that the client's connection should be closed after 30 seconds, but that doesn't happen, even though i declared that by using conn.settimeout(30). I haven't found any explanation yet as to why this happens.
Note: comments were used to replace parts of the code that didn't mater to the problem.
From my understanding python can only run 1 thread at a time so if I were to do something like this
import socket, select
from threading import Thread
import config
class Source(Thread):
def __init__(self):
self._wait = False
self._host = (config.HOST, config.PORT + 1)
self._socket = socket.socket()
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._sock = None
self._connections = []
self._mount = "None"
self._writers = []
self._createServer()
Thread.__init__(self)
def _createServer(self):
self._socket.bind(self._host)
self._socket.listen(2)
self._connections.append(self._socket)
self._audioPackets=[]
def _addPacket(self, packet):
self._audioPackets.append(packet)
def _removePacket(self, packet):
self._audioPackets.remove(packet)
def _getPacket(self):
if len(self._audioPackets) > 0:
return self._audioPackets[0]
else:
return None
def _sendOK(self, sock):
sock.send("OK")
def _sendDenied(self, sock):
sock.send("DENIED")
def _sendMount(self, sock):
sock.send("mount:{0}".format(self._mount))
def _sendBufPacket(self, sock, packet):
packet = "buffer:%s" % packet
sock.send(packet)
def recv(self, sock, data):
data = data.split(":", 1)
if data[0] == "WAIT": self._wait = True
elif data[0] == "STOP_WAITING": self._wait = False
elif data[0] == "LOGIN":
if data[1] == config.SOURCE_AUTH:
self._source = sock
self._sendOK(sock)
else:
self._sendClose(sock)
elif data[0] == "MOUNT":
if self._source == sock:
self._mount = data[1]
else:
self._sendClose(sock)
elif data[0] == "CLIENT":
self._sendMount(sock)
self._writers.append(sock)
def _sendCloseAll(self):
for sock in self._connections:
sock.send("CLOSE")
sock.close()
def _sendClose(self, sock):
sock.send("CLOSE")
sock.close()
def main(self):
while True:
rl, wl, xl = select.select(self._connections, self._writers, [], 0.2)
for sock in rl:
if sock == self._socket:
con, ip = sock.accept()
self._connections.append(con)
else:
data = sock.recv(config.BUFFER)
if data:
self.recv(sock, data)
else:
if sock in self._writers:
self._writers.remove(sock)
if sock in self._connections:
self._connections.remove(sock)
for sock in wl:
packet = self._getPacket()
if packet != None:
self._sendBufPacket(sock, packet)
def run(self):
self.main()
class writeThread(Thread):
def __init__(self):
self.running = False
def make(self, client):
self.client = client
self.running = True
def run(self):
host = (config.HOST, config.PORT+1)
sock = socket.socket()
sock.connect(host)
sock.send("CLIENT")
sock.send("MOUNT:mountpoint")
while self.running:
data = sock.recv(config.BUFFER)
if data:
data = data.split(":", 1)
if data[0] == "buffer":
self.client.send(data[1])
elif data[0] == "CLOSE":
self.client.close()
break
if __name__=="__main__":
source = Source()
source.start()
webserver = WebServer()
webserver.runloop()
if I need to build the webserver part I will. But, I'll explain it.
Okay, so basically when someone connects to the websever under the mountpoint that was set, They will get there own personal thread that then grabs the data from Source() and sends it to them. Now say another person connects to the mount point and the last client as well as the source is still going. Wouldn't the new client be blocked from getting the Source data considering there are two active threads?
Your understanding of how Threads work in Python seems to be incorrect, based on the question you are asking. If used correctly, threads will not be blocking: you can instantiate multiple thread with Python. The limitation is that, due to the Global Interpreter Lock (GIL), you cannot get the full parallelism expected in thread programming (e.g. simultaneous execution and thus, reduced runtime).
What is going to happen in your case is that the two threads will take, together, the same amount of time that they would take if they were executed sequentially (although that is not necessarily what happens in practice).
Okay, I have copy and pasted some Python3 code that I have already written for a project that I am currently working on. With modification, you can make this code serve your purposes.
The code uses multiprocessing and multithreading. For my purposes, I am using multiprocessing so that sockets will run on one processor, and I can run a GUI program on another processor. You can remove the multiprocessor part if you prefer. The code below runs a socket message server. The server will listen for clients one at a time. Once a client has connected, a new thread will be initiated to handle all the communications between the server and each client. The server will then continue to search for for clients. At the moment however, the server only listens to data being sent from each client, and then it prints it to the terminal. With a small amount of effort, you can modify my code to send information from the server to each client individually.
import multiprocessing
import threading
from threading import Thread
class ThreadedServer(object):
def __init__(self, host, port):
self.host = host
self.port = port
self.sock = socket(AF_INET, SOCK_STREAM)
self.sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
self.sock.bind((self.host, self.port))
def listen(self):
self.sock.listen(3) #Allow 3 Clients to connect to this server
while True:
#The program will search for one client at a time
print("Searching for Client")
client, address = self.sock.accept()
print(address, " is connected")
#client.settimeout(60)
#Once a client has been found, start a individual client thread
d = threading.Thread(target = self.listenToClient, args=(client, address))
d.daemon = True
d.start()
def listenToClient(self, client, address):
size = 1024
while True:
try:
data = client.recv(size)
if not data:
break
if data:
print(data)
#client.send(response)
else:
raise error('Client disconnected')
except:
client.close()
return False
def dataSharingHost():
#Using Sockets to send information between Processes
#This is the server Function
#ThreadServer(Host_IP, Port_Number), for LocalHost use ''
ThreadedServer('', 8000).listen()
def Main():
commServer = multiprocessing.Process(target=dataSharingHost, args=())
commServer.daemon = True
commServer.start()
if __name__== '__main__':
Main()
And to be fair, my code is modified from https://www.youtube.com/watch?v=qELZAi4yra8 . The client code is covered in those videos. I think the 3rd video covers the multiple client connects.
I am working on a simple HTTP server in Python. I am taking bits and pieces from here: http://hg.python.org/cpython/file/3.3/Lib/socketserver.py to see how Python's standard library handles it.
My problem is that as soon as I try to accept requests my program hangs. Here is my code its only 100 lines so I'll just post it directly here.
I have a process() function which is in a loop that loops forever and it's suppose to handle new connections. Inside I have a print statement that only gets printed once.
print('processing') in TCPServer.process()
I have tried threading off process() but I get the same result.
"""."""
import socket
import select
from abc import abstractmethod, ABCMeta
class BaseServer(metaclass=ABCMeta):
def __init__(self, server_address, server_port, RequestHandlerClass):
self._server_address = server_address
self._server_port = server_port
self._RequestHandlerClass = RequestHandlerClass
self._running = False
def serve_forever(self):
self._running = True
while self._running:
self.process()
#abstractmethod
def process(self):
pass
def shutdown(self):
self._running = False
class TCPServer(BaseServer):
def __init__(self,
server_address,
server_port,
RequestHandlerClass,
address_family=socket.AF_INET,
socket_type=socket.SOCK_STREAM,
request_queue_size=1,
bind=True):
super(TCPServer, self).__init__(server_address,
server_port,
RequestHandlerClass)
self._address_family = address_family
self._socket_type = socket_type
self._request_queue_size = request_queue_size
self._socket = socket.socket(self._address_family, self._socket_type)
self._read_list = [self._socket]
if bind:
self.bind()
def bind(self):
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._socket.bind((self._server_address, self._server_port))
self._socket.listen(self._request_queue_size)
def shutdown(self):
super().shutdown()
self._socket.close()
def process(self):
print('processing')
readable, writeable, errored = select.select(self._read_list, [], [])
for socket in readable:
if socket is self._socket:
client_socket, client_address = self._socket.accept()
self._read_list.append(client_socket)
print('connection from: ', client_address)
else:
self._RequestHandlerClass(client_socket)
self._read_list.remove(client_socket)
class BaseRequestHandler(metaclass=ABCMeta):
def __init__(self, client_socket):
self._client_socket = client_socket
self.setup()
try:
self.handle()
finally:
self.finish()
#abstractmethod
def setup(self):
pass
#abstractmethod
def handle(self):
pass
#abstractmethod
def finish(self):
pass
class HTTPRequestHandler(BaseRequestHandler):
def setup(self):
print('REQUEST SETUP')
print(self._client_socket.recv(2048))
def handle(self):
print('REQUEST HANDLE')
def finish(self):
print('REQUEST FINISH')
self._client_socket.close()
if __name__ == '__main__':
tcp_server = TCPServer(server_address='',
server_port=9000,
RequestHandlerClass=HTTPRequestHandler)
tcp_server.serve_forever()
I ran your code but couldn't make it hang. However, there is a fatal error in your process() function where you refer to client_socket in the else: branch, but client_socket is not defined at that point. You probably meant to refer to socket.
I was able to make two connections to the server on port 9000, and get "connection from:" lines for each. As soon as one of those connections sent something, your server would crash for the above reason.
Good evening, This is my 1st time on this site, I have been programming a python based user monitoring system for my work for the past 3 months and I am almost done with my 1st release. However I have run into a problem controlling what computer I want to connect to.
If i run the two sample code I put in this post I can receive the client and send commands to client with the server, but only one client at a time, and the server is dictating which client I can send to and which one is next. I am certain the problem is "server side but I am not sure how to fix the problem and a Google search does not turn up anyone having tried this.
I have attached both client and server base networking code in this post.
client:
import asyncore
import socket
import sys
do_restart = False
class client(asyncore.dispatcher):
def __init__(self, host, port=8000):
serv = open("srv.conf","r")
host = serv.read()
serv.close()
asyncore.dispatcher.__init__(self)
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.connect((host, port))
def writable(self):
return 0
def handle_connect(self):
pass
def handle_read(self):
data = self.recv(4096)
#Rest of code goes here
serv = open("srv.conf","r")
host = serv.read()
serv.close()
request = client(host)
asyncore.loop()
server:
import asyncore
import socket
import sys
class soc(asyncore.dispatcher):
def __init__(self, port=8000):
asyncore.dispatcher.__init__(self)
self.port = port
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.bind(('', port))
self.listen(5)
def handle_accept(self):
channel, addr = self.accept()
while 1:
j = raw_input(addr)
#Rest of my code is here
server = soc(8000)
asyncore.loop()
Here is a fast and dirty idea that I threw together.
The use of raw_input has been replaced with another dispatcher that is asyncore compatable, referencing this other question here
And I am expanding on the answer given by #user1320237 to defer each new connection to a new dispatcher.
You wanted to have a single command line interface that can send control commands to any of the connected clients. That means you need a way to switch between them. What I have done is created a dict to keep track of the connected clients. Then we also create a set of available commands that map to callbacks for your command line.
This example has the following:
list: list current clients
set <client>: set current client
send <msg>: send a msg to the current client
server.py
import asyncore
import socket
import sys
from weakref import WeakValueDictionary
class Soc(asyncore.dispatcher):
CMDS = {
'list': 'cmd_list',
'set': 'cmd_set_addr',
'send': 'cmd_send',
}
def __init__(self, port=8000):
asyncore.dispatcher.__init__(self)
self._conns = WeakValueDictionary()
self._current = tuple()
self.port = port
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.set_reuse_addr()
self.bind(('', port))
self.listen(5)
self.cmdline = Cmdline(self.handle_input, sys.stdin)
self.cmdline.prompt()
def writable(self):
return False
def handle_input(self, i):
tokens = i.strip().split(None, 1)
cmd = tokens[0]
arg = ""
if len(tokens) > 1:
arg = tokens[1]
cbk = self.CMDS.get(cmd)
if cbk:
getattr(self, cbk)(arg)
self.cmdline.prompt(self._addr_to_key(self._current))
def handle_accept(self):
channel, addr = self.accept()
c = Conn(channel)
self._conns[self._addr_to_key(addr)] = c
def _addr_to_key(self, addr):
return ':'.join(str(i) for i in addr)
def cmd_list(self, *args):
avail = '\n'.join(self._conns.iterkeys())
print "\n%s\n" % avail
def cmd_set_addr(self, addr_str):
conn = self._conns.get(addr_str)
if conn:
self._current = conn.addr
def cmd_send(self, msg):
if self._current:
addr_str = self._addr_to_key(self._current)
conn = self._conns.get(addr_str)
if conn:
conn.buffer += msg
class Cmdline(asyncore.file_dispatcher):
def __init__(self, cbk, f):
asyncore.file_dispatcher.__init__(self, f)
self.cbk = cbk
def prompt(self, msg=''):
sys.stdout.write('%s > ' % msg)
sys.stdout.flush()
def handle_read(self):
self.cbk(self.recv(1024))
class Conn(asyncore.dispatcher):
def __init__(self, *args, **kwargs):
asyncore.dispatcher.__init__(self, *args, **kwargs)
self.buffer = ""
def writable(self):
return len(self.buffer) > 0
def handle_write(self):
self.send(self.buffer)
self.buffer = ''
def handle_read(self):
data = self.recv(4096)
print self.addr, '-', data
server = Soc(8000)
asyncore.loop()
Your main server is now never blocking on stdin, and always accepting new connections. The only work it does is the command handling which should either be a fast operation, or signals the connection objects to handle the message.
Usage:
# start the server
# start 2 clients
>
> list
127.0.0.1:51738
127.0.0.1:51736
> set 127.0.0.1:51736
127.0.0.1:51736 >
127.0.0.1:51736 > send foo
# client 127.0.0.1:51736 receives "foo"
To me
while 1:
j = raw_input(addr)
seems to be the problem:
you only accept a socket an then do something with it until end.
You should create e new dispatcher for every client connecting
class conn(asyncore.dispatcher):
...
def handle_read(self):
...
class soc(asyncore.dispatcher):
def handle_accept(self):
...
c = conn()
c.set_socket(channel)
Asyncore will call you back for every read operation possible.
Asyncore uses only one thread. This is its strength. every dispatcher that has a socket is called one after an other with those handle_* functions.