PYTHON

socket programming python

"""
UDP echo server that converts a message
received from client into uppercase and
then sends it back to client. 
"""
from socket import *
# Port number of server
server_port = 12000
# Server using IPv4 and UDP socket
server_socket = socket(AF_INET, SOCK_DGRAM)
# Bind server to port number and IP address
server_socket.bind(("127.0.0.1", server_port))
print("The server is ready to receive msg...")
while True:
    # Extract message and client address from received msg
    message, client_address = server_socket.recvfrom(2048)
    # Create response message
    modified_message = message.upper()
    server_socket.sendto(modified_message, client_address)

socket programming python

from socket import *
# Set server name and port number
server_name = "localhost"
server_port = 12000
# Create a UDP socket using IPv4
client_socket = socket(AF_INET, SOCK_DGRAM)
# Get message to send to server
message = input("Input sentence to send to server:")
# Convert it into bytes
message_bytes = bytes(message, encoding='utf-8')
client_socket.sendto(message_bytes, (server_name, server_port))
# Wait for server's response
modified_message, server_address = client_socket.recvfrom(2048)
# Display it on screen
print(modified_message.decode("utf-8"))
client_socket.close()

web socket in python

#1) Installation
#Go to your cmd and type pip install websockets

#2) Utilisation 
#Here’s how a client sends and receives messages:

import asyncio
import websockets

async def hello():
    async with websockets.connect("ws://localhost:8765") as websocket:
        await websocket.send("Hello world!")
        await websocket.recv()

asyncio.run(hello())

#And here’s an echo server:

import asyncio
import websockets

async def echo(websocket):
    async for message in websocket:
        await websocket.send(message)

async def main():
    async with websockets.serve(echo, "localhost", 8765):
        await asyncio.Future()  # run forever

asyncio.run(main())

python can socket

       import socket
       import struct
       import sys

       # CAN frame packing/unpacking (see `struct can_frame` in <linux/can.h>)
       can_frame_fmt = "=IB3x8s"

       def build_can_frame(can_id, data):
               can_dlc = len(data)
               data = data.ljust(8, b'x00')
               return struct.pack(can_frame_fmt, can_id, can_dlc, data)

       def dissect_can_frame(frame):
               can_id, can_dlc, data = struct.unpack(can_frame_fmt, frame)
               return (can_id, can_dlc, data[:can_dlc])

       if len(sys.argv) != 2:
               print('Provide CAN device name (can0, slcan0 etc.)')
               sys.exit(0)

       # create a raw socket and bind it to the given CAN interface
       s = socket.socket(socket.AF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
       s.bind((sys.argv[1],))

       while True:
               cf, addr = s.recvfrom(16)

               print('Received: can_id=%x, can_dlc=%x, data=%s' % dissect_can_frame(cf))

               try:
                       s.send(cf)
               except socket.error:
                       print('Error sending CAN frame')

               try:
                       s.send(build_can_frame(0x01, b'x01x02x03'))
               except socket.error:
                       print('Error sending CAN frame')