Python code after sockets connection executed only once - sockets

Question

What are the intentions of this program:
I want to send some commands from a client to a server using sockets, the server then send these command to an Arduino using serial. And another thing that I want the server to do in the future is that periodically sends other commands to the Arduino without getting any input from the client, so the sockets needs to be non-blocking or there needs to be another way to run the code separately from the sockets code.
The problem is that the part that is supposed to send the command to the Arduino only runs once.
What I have come up with after playing with the debugger in Pycharm, is that the problem is that the following line blocks after a connection has been established, and thus not allowing the rest of the code to be run.
conn, addr = s.accept()
Is this correct, or is there something else wrong?
I have tried to set the socket to non-blocking but when I do this I get an error.
"BlockingIOError: [WinError 10035] A non-blocking socket operation could not be completed immediately"
I have some basic knowledge of C/C++ and C# and am new to Python.
server.py
import socket
import serial
import sys
from _thread import *
import threading
import queue
# command that the client sends are "ON" and "OFF"
class serialConnect:
comPort =' '
baudrate = 115200
myserial = serial.Serial('COM5', baudrate)
def serialstart(self):
# self.comPort = input('Comport: ')
try:
self.myserial.open()
except IOError:
print('Port is already open!')
def serialRead(self):
data = self.myserial.read(16)
data.decode('UTF-8')
return data
def serialWrite(self, data):
data += '\n' #the arduino needs a \n after each command.
databytes = data.encode('UTF-8')
self.myserial.write(databytes)
print('send data: ', databytes)
def threaded_client(conn, dataqueue):
data = {bytes}
conn.send(str.encode('welcome, type your info \n'))
while True:
data = conn.recv(2048)
if not data:
break
reply = 'server output: ' + data.decode('UTF-8')
dataqueue.put(data.decode('UTF-8'))
print("Items in queue: ",dataqueue.qsize())
#conn.sendall(str.encode(reply))
print("Recieved data in threaded_client: ", data.decode('UTF-8') + '\n')
conn.close()
def Main():
ser = serialConnect()
host = ''
port = 5555
dataRecieved = 'hello'
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(2)
s.setblocking(1) #when set to non-blocking error occurs : "BlockingIOError: [WinError 10035] A non-blocking socket operation could not be completed immediately"
workQueue = queue.Queue(10)
try:
s.bind((host,port))
except socket.error as e:
print(str(e))
s.listen(5)
print('waiting for a connection')
while True:
try:
conn, addr = s.accept() #once connection is established it blocks?
print('connected to: ' + addr[0] + ':' + str())
t = threading.Thread(target=threaded_client, args=(conn, workQueue))
t.daemon = True
t.start()
except:
e = sys.exc_info()
print('Error:', e)
# This section of code is only run once, doesn't matter if put inside try block or not. :(
dataRecieved = workQueue.get()
print('The recieved data: ', dataRecieved)
ser.serialstart()
ser.serialWrite(dataRecieved)
if __name__ == '__main__':
Main()
client.py
import socket
def Main():
host = '127.0.0.1'
port = 5555
message = "<,R,G,B,>"
mySocket = socket.socket()
mySocket.connect((host, port))
while message != 'q':
message = input(" -> ")
mySocket.send(message.encode())
mySocket.close()
if __name__ == '__main__':
Main()
Arduino Code
String inputString = ""; // a string to hold incoming data
boolean stringComplete = false; // whether the string is complete
int LEDpin = 10;
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin 13 as an output.
pinMode(10, OUTPUT);
Serial.begin(19200);
}
// the loop function runs over and over again forever
void loop() {
serialEvent();
if(stringComplete){
Serial.println(inputString);
if(inputString == "ON\n"){
digitalWrite(LEDpin, HIGH); // turn the LED on (HIGH is the voltage level)
}
if(inputString == "OFF\n"){
digitalWrite(LEDpin, LOW); // turn the LED off by making the voltage LOW
}
inputString = "";
stringComplete = false;
}
}
void serialEvent()
{
while (Serial.available()) {
// get the new byte:
char inChar = (char)Serial.read();
// add it to the inputString:
inputString += inChar;
// if the incoming character is a newline, set a flag
// so the main loop can do something about it:
if (inChar == '\n') {
stringComplete = true;
}
}
}

Answer 1

Refactored server code for anyone that is interested in it.
I am not sure if this is up to standard, but it is working.
import serial
import socket
import queue
import sys
import threading
class serialConnect:
comPort = 'COM5'
baudrate = 115200
myserial = serial.Serial(comPort, baudrate)
def serial_run(self):
# self.comPort = input('Comport: ')
try:
if not self.myserial.isOpen():
self.myserial.open()
else:
print('Port is already open!')
except IOError as e:
print('Error: ', e)
def serial_read(self):
data = self.myserial.read(16)
data.decode('UTF-8')
return data
def serial_write(self, data):
data += '\n' #the arduino needs a \n after each command.
databytes = data.encode('UTF-8')
self.myserial.write(databytes)
print('send data: ', databytes)
class socketServer:
host = ''
port = 5555
soc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
soc.setblocking(1)
data_queue = queue.Queue(1)
def __init__(self):
try:
self.soc.bind((self.host, self.port))
except:
print('Bind error: ', sys.exc_info())
self.soc.listen(5)
def socket_accept_thread(self):
while True:
try:
print('Waiting for a new connection')
conn, addr = self.soc.accept()
client_thread = threading.Thread(target=self.threaded_client, args=(conn, self.data_queue))
client_thread.daemon = True
client_thread.start()
except:
print('Accept thread Error: ', sys.exc_info())
def threaded_client(self, conn, data_queue):
# conn.send(str.encode('welcome, type your info \n'))
try:
while True:
data = conn.recv(2048)
if not data:
break
# reply = 'server output: ' + data.decode('UTF-8')
data_queue.put(data.decode('UTF-8'))
print("Items in queue: ", data_queue.qsize())
# conn.sendall(str.encode(reply))
print("Received data in threaded_client: ", data.decode('UTF-8'))
except:
print("Error: ", sys.exc_info())
conn.close()
def get_data(self):
data = self.data_queue.get()
return data
def Main():
server = socketServer()
arduino_conn = serialConnect()
accept_thread = threading.Thread(target=server.socket_accept_thread)
data_received = 'Nothing received'
while True:
if not accept_thread.is_alive():
accept_thread.daemon = True
accept_thread.start()
arduino_conn.serial_run()
data_received = server.get_data()
arduino_conn.serial_write(data_received)
if __name__ == '__main__':
Main()