server.py

import socket
import struct
import pickle
import time

localhost_with_port_9000 = ( "127.0.0.1", 9000 )

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server_socket:

    server_socket.bind( localhost_with_port_9000 )
    server_socket.listen( 1 )

    print("\nWaiting for client connection...")

    connection, address = server_socket.accept()

    with connection as conn:

        print(f"connected by {address}")

        # 1. Test one data payload dividing into three transmission to client

        data_1 = {"message":"hello world. This is test item #1's data"}
        data_1_rawbyte = pickle.dumps(data_1)
        id = 1

        payload = data_1_rawbyte

        # definition of header
        # first field is id
        # second field is size of payload
        header = (id, len(payload) )

        # define header size as 2 * 4 Unsigne Int = 8 Bytes
        header_rawbyte_1 = struct.pack("!2I", *header)

        # divide one data payload into three transmission
        send_1_full = header_rawbyte_1 + payload
        send_1_a = send_1_full[:5]
        send_1_b = send_1_full[5:10]
        send_1_c = send_1_full[10:]

        # send 1_a to clinet
        print("\n send data 1_a to clinet ... ")
        connection.sendall( send_1_a )

        time.sleep(0.5)

        # send 1_b to clinet
        print("\n send data 1_b to clinet ... ")
        connection.sendall( send_1_b )

        time.sleep(0.5)

        # send 1_c to clinet
        print("\n send data 1_c to clinet ... ")
        connection.sendall( send_1_c )

        time.sleep(0.5)


        # ---------------------------------------------------------


        ## 2. Test merging two differnt data payload divide into one transmission to client

        data_2 = {"message":"Meow meow. This is test item #2's data"}
        data_2_rawbyte = pickle.dumps(data_2)
        id = 2

        payload = data_2_rawbyte

        # definition of header
        # first field is id
        # second field is size of payload
        header = (id, len(payload) )

        # define header size as 2 * 4 Unsigne Int = 8 Bytes
        header_rawbyte_2 = struct.pack("!2I", *header)



        data_3 = {"message":"Meow meow. This is test item #3's data", "demand":"quit connection"}
        data_3_rawbyte = pickle.dumps(data_3)
        id = 3

        payload = data_3_rawbyte

        # definition of header
        # first field is id
        # second field is size of payload
        header = (id, len(payload) )

        # define header size as 2 * 4 Unsigne Int = 8 Bytes
        header_rawbyte_3 = struct.pack("!2I", *header)

        send_2_and_3 = header_rawbyte_2 + data_2_rawbyte + header_rawbyte_3 + data_3_rawbyte

        # send 2 and 3 to clinet
        print("\n send data 2 and data 3 in one transmission to clinet ... ")
        connection.sendall( send_2_and_3 )

        time.sleep(0.5)