I am writing a code where an arduino reads data from an accelerometer, passes it to a python script and then that computer running python sends the data to another computer over a socket conneciton. I have written code which can send and recieve one message at a time, slowly, but as soon as I do it bascially as fast as I can (about 100Hz) then the server side only prints the first message, but no more.
Here is the code for my server side:
import socket
class server:
def __init__(self, PORT=9077, MAX_CONNECTIONS=1000, BUFF_SIZE=1024):
self.s = socket.socket()
self.HOST = socket.gethostbyname(socket.gethostname())
self.PORT = PORT
self.MAX_CONNECTIONS = MAX_CONNECTIONS
self.BUFF_SIZE = BUFF_SIZE
self.s.bind((self.HOST, self.PORT))
self.s.listen(self.MAX_CONNECTIONS)
self.recievingData = False
print("Starting a server")
print("IP: " + str(self.HOST))
print("Port: " + str(self.PORT))
def recieveData(self):
self.recievingData = True
while self.recievingData:
print("Waiting for data")
c, addr = self.s.accept()
print(addr)
data = b''
part = c.recv(self.BUFF_SIZE)
data += part
while len(part) > self.BUFF_SIZE:
# print("looping")
part = c.recv(self.BUFF_SIZE)
print(len(part))
data += part
print(data)
c.close()
def stopRecieving(self):
self.revievingData = False
new_server = server()
new_server.recieveData()
and the client side:
class client:
def __init__(self, HOST="192.168.0.51", PORT=9077):
self.s = socket.socket()
self.HOST = HOST
self.PORT = PORT
self.s.connect((self.HOST, self.PORT))
def send_message(self, message):
message = message.encode()
sent = self.s.sendall(message)
print(sent)
and I basically just call send_message every time there is new data to send.
Is there a way to increase the speed at which the server can recieve messages from the same client? Do I need to create multiple threads for recieving data?
My solution to this was using UDP protocol, where you send messages without checking if the data has been recieved. This is achieved using socket.socket(type=SOCK_DGRAM)
on the client and server side and using self.s.recvfrom(self.BUFF_SIZE)
for recieving data from a client and self.s.sendto(str(message).encode(), (host, port))
for sending data. This way, there is no handshake between the client and the server and it runs much faster.
You just need some error checking from your input data.
For reference, this is my full updated code:
import socket
from socket import SOCK_DGRAM, SO_REUSEADDR
import numpy as np
import threading
class client:
def __init__(self, HOST="192.168.0.51", PORT=9077):
self.s = socket.socket(type=SOCK_DGRAM)
self.HOST = HOST
self.PORT = PORT
def send_message(self, message):
self.s.sendto(str(message).encode(), (host, port))
class server:
def __init__(self, PORT=9077, BUFF_SIZE=1024):
self.s = socket.socket(type=SOCK_DGRAM)
self.HOST = socket.gethostbyname(socket.gethostname())
self.PORT = PORT
self.MAX_CONNECTIONS = MAX_CONNECTIONS
self.BUFF_SIZE = BUFF_SIZE
self.s.bind((self.HOST, self.PORT))
# self.s.listen(self.MAX_CONNECTIONS)
self.recievingData = False
self.recievedData = np.zeros((1,4))
self.thread = threading.Thread(target=self.recieveData)
self.thread.start()
# self.s.setblocking(0)
self.startRecieving()
print("Starting a server")
print("IP: " + str(self.HOST))
print("Port: " + str(self.PORT))
def startRecieving(self):
self.recievingData = True
self.recievedData = np.zeros((1,4))
self.thread = threading.Thread(target=self.recieveData)
self.thread.start()
print("Started reading data")
def stopRecieving(self):
self.recievingData = False
self.thread.join()
print("Stopped reading data")
def recieveData(self):
self.recievingData = True
while self.recievingData:
# print("Waiting for data")
part, addr = self.s.recvfrom(self.BUFF_SIZE)
# print(part, addr)
data = b''
data += part
while len(part) > self.BUFF_SIZE:
# print("looping")
part = self.s.recvfrom(self.BUFF_SIZE)
# print(len(part))
data += part
self.lastData = data
print(data)
as_float = np.array([[float(x.strip()) for x in data.decode().split(',')]])
self.recievedData = np.vstack((self.recievedData, as_float))