mirror of
https://github.com/uhi22/pyPLC.git
synced 2024-11-20 01:13:58 +00:00
220 lines
8.3 KiB
Python
220 lines
8.3 KiB
Python
|
|
# Server and client on a non-blocking socket
|
|
#
|
|
# explanation of socket handling:
|
|
# https://docs.python.org/3/howto/sockets.html
|
|
# https://realpython.com/python-sockets/
|
|
# https://stackoverflow.com/questions/5308080/python-socket-accept-nonblocking
|
|
#
|
|
|
|
|
|
import socket
|
|
import select
|
|
import sys # for argv
|
|
import time # for time.sleep()
|
|
import errno
|
|
|
|
class pyPlcTcpClientSocket():
|
|
def __init__(self):
|
|
self.sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
|
|
self.isConnected = False
|
|
self.rxData = []
|
|
|
|
def connect(self, host, port):
|
|
try:
|
|
print("connecting...")
|
|
# for connecting, we are still in blocking-mode because
|
|
# otherwise we run into error "[Errno 10035] A non-blocking socket operation could not be completed immediately"
|
|
# We set a shorter timeout, so we do not block too long if the connection is not established:
|
|
self.sock.settimeout(0.5)
|
|
self.sock.connect((host, port))
|
|
self.sock.setblocking(0) # make this socket non-blocking, so that the recv function will immediately return
|
|
self.isConnected = True
|
|
except socket.error as e:
|
|
print("connection failed", e)
|
|
self.isConnected = False
|
|
|
|
def transmit(self, msg):
|
|
if (self.isConnected == False):
|
|
# if not connected, just ignore the transmission request
|
|
return -1
|
|
totalsent = 0
|
|
MSGLEN = len(msg)
|
|
while (totalsent < MSGLEN) and (self.isConnected):
|
|
try:
|
|
sent = self.sock.send(msg[totalsent:])
|
|
if sent == 0:
|
|
self.isConnected = False
|
|
print("socket connection broken")
|
|
return -1
|
|
totalsent = totalsent + sent
|
|
except:
|
|
self.isConnected = False
|
|
return -1
|
|
return 0 # success
|
|
|
|
def isRxDataAvailable(self):
|
|
# check for availability of data, and get the data from the socket into local buffer.
|
|
if (self.isConnected == False):
|
|
return False
|
|
blDataAvail=False
|
|
try:
|
|
msg = self.sock.recv(4096)
|
|
except socket.error as e:
|
|
err = e.args[0]
|
|
if err == errno.EAGAIN or err == errno.EWOULDBLOCK:
|
|
# this is the normal case, if no data is available
|
|
# print('No data available')
|
|
pass
|
|
else:
|
|
# a "real" error occurred
|
|
# print("real error")
|
|
# print(e)
|
|
self.isConnected = False
|
|
else:
|
|
if len(msg) == 0:
|
|
# print('orderly shutdown on server end')
|
|
self.isConnected = False
|
|
else:
|
|
# we received data. Store it.
|
|
self.rxData = msg
|
|
blDataAvail=True
|
|
return blDataAvail
|
|
|
|
def getRxData(self):
|
|
# provides the received data, and clears the receive buffer
|
|
d = self.rxData
|
|
self.rxData = []
|
|
return d
|
|
|
|
class pyPlcTcpServerSocket():
|
|
def __init__(self):
|
|
self.ipAdress = 'fe80::e0ad:99ac:52eb:85d3'
|
|
self.tcpPort = 15118 # The port for CCS
|
|
self.BUFFER_SIZE = 1024 # Normally 1024
|
|
# Concept explanation:
|
|
# We create a socket, that is just listening for incoming connections.
|
|
# Later in the cyclic loop, we use the "select" to wait for activity on this socket.
|
|
# In case there is a connection request, we create a NEW socket, which will handle the
|
|
# data exchange. The original socket is still listening for further incoming connections.
|
|
# This would allow to handle multiple connections.
|
|
self.ourSocket = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
|
|
self.ourSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
|
|
self.ourSocket.bind((self.ipAdress, self.tcpPort))
|
|
self.ourSocket.listen(1)
|
|
print("pyPlcTcpSocket listening on port " + str(self.tcpPort))
|
|
self.read_list = [self.ourSocket]
|
|
self.rxData = []
|
|
|
|
def isRxDataAvailable(self):
|
|
return (len(self.rxData)>0)
|
|
|
|
def getRxData(self):
|
|
# provides the received data, and clears the receive buffer
|
|
d = self.rxData
|
|
self.rxData = []
|
|
return d
|
|
|
|
def transmit(self, txMessage):
|
|
numberOfSockets = len(self.read_list)
|
|
if (numberOfSockets<2):
|
|
# print("we have " + str(numberOfSockets) + ", we should have 2, one for accepting and one for data transfer. Will not transmit.")
|
|
return -1
|
|
# Simplification: We will send to the FIRST open connection, even we would have more connections open. This is
|
|
# ok, because in our use case we have exactly one client.
|
|
totalsent = 0
|
|
MSGLEN = len(txMessage)
|
|
while totalsent < MSGLEN:
|
|
sent = self.read_list[1].send(txMessage[totalsent:])
|
|
if sent == 0:
|
|
print("socket connection broken")
|
|
return -1
|
|
totalsent = totalsent + sent
|
|
return 0 # success
|
|
|
|
def mainfunction(self):
|
|
# The select() function will block until one of the socket states has changed.
|
|
# We specify a timeout, to be able to run it in the main loop.
|
|
timeout_s = 0.05 # 50ms
|
|
readable, writable, errored = select.select(self.read_list, [], [], timeout_s)
|
|
for s in readable:
|
|
if s is self.ourSocket:
|
|
# We received a connection request at ourSocket.
|
|
# -> we create a new socket (named client_socket) for handling this connection.
|
|
client_socket, address = self.ourSocket.accept()
|
|
# and we append this new socket to the list of sockets, which in the next loop will be handled by the select.
|
|
self.read_list.append(client_socket)
|
|
print("Connection from", address)
|
|
else:
|
|
# It is not the "listener socket", it is an above created "client socket" for talking with a client.
|
|
# Let's take the data from it:
|
|
try:
|
|
data = s.recv(1024)
|
|
except:
|
|
# The client closed the connection in the meanwhile.
|
|
#print("The client closed the connection in the meanwhile.")
|
|
data = None
|
|
if data:
|
|
# print("received data:", data)
|
|
self.rxData = data
|
|
else:
|
|
print("connection closed")
|
|
s.close()
|
|
self.read_list.remove(s)
|
|
|
|
|
|
|
|
|
|
def testServerSocket():
|
|
print("Testing the pyPlcTcpServerSocket...")
|
|
s = pyPlcTcpServerSocket()
|
|
print("Press Ctrl-Break for aborting")
|
|
nLoops = 0
|
|
while True:
|
|
s.mainfunction()
|
|
nLoops+=1
|
|
if ((nLoops % 10)==0):
|
|
print(str(nLoops) + " loops")
|
|
if (s.isRxDataAvailable()):
|
|
d = s.getRxData()
|
|
print("received " + str(d))
|
|
msg = "ok, you sent " + str(d)
|
|
print("responding " + msg)
|
|
s.transmit(bytes(msg, "utf-8"))
|
|
if ((nLoops % 50)==0):
|
|
print("trying to send something else")
|
|
msg = "ok, something else..."
|
|
s.transmit(bytes(msg, "utf-8"))
|
|
|
|
|
|
def testClientSocket():
|
|
print("Testing the pyPlcTcpClientSocket...")
|
|
c = pyPlcTcpClientSocket()
|
|
c.connect('fe80::e0ad:99ac:52eb:85d3', 15118)
|
|
print("connected="+str(c.isConnected))
|
|
print("sending something to the server")
|
|
c.transmit(bytes("Test", "utf-8"))
|
|
for i in range(0, 10):
|
|
print("waiting 1s")
|
|
time.sleep(1)
|
|
if (c.isRxDataAvailable()):
|
|
d = c.getRxData()
|
|
print("received " + str(d))
|
|
if ((i % 3)==0):
|
|
print("sending something to the server")
|
|
c.transmit(bytes("Test", "utf-8"))
|
|
|
|
print("end")
|
|
|
|
|
|
if __name__ == "__main__":
|
|
if (len(sys.argv) == 1):
|
|
print("Use command line argument c for clientSocket or s for serverSocket")
|
|
exit()
|
|
if (sys.argv[1] == "c"):
|
|
testClientSocket()
|
|
exit()
|
|
if (sys.argv[1] == "s"):
|
|
testServerSocket()
|
|
exit()
|
|
print("Use command line argument c for clientSocket or s for serverSocket")
|