Python TCP sockets 标头

Question

I need to create a communication between a client and a server with TCP. But I'd like to send and work with "headers". So from the client I'd like to send a header "COMMAND1" and the server returns me something.

I have the following code:

Server

import socket
import threading

bind_ip = '0.0.0.0'
bind_port = 9998

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((bind_ip, bind_port))
server.listen(5)  # max backlog of connections

print ('Listening on {}:{}'.format(bind_ip, bind_port))


def handle_client_connection(client_socket):
    request = client_socket.recv(1024)
    print ('Received {}'.format(request))
    client_socket.send('Response1!'.encode('utf-8'))
    client_socket.close()

while True:
    client_sock, address = server.accept()
    print ('Accepted connection from {}:{}'.format(address[0], address[1]))
    client_handler = threading.Thread(
        target=handle_client_connection,
        args=(client_sock,)  # without comma you'd get a... TypeError: handle_client_connection() argument after * must be a sequence, not _socketobject
    )
    client_handler.start()

Client

import socket

hostname, sld, tld, port = 'www', 'integralist', 'co.uk', 80
target = '{}.{}.{}'.format(hostname, sld, tld)

# create an ipv4 (AF_INET) socket object using the tcp protocol (SOCK_STREAM)
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# connect the client
# client.connect((target, port))
client.connect(('0.0.0.0', 9998))

# send some data (in this case a HTTP GET request)
client.send('hi'.encode('utf-8'))

# receive the response data (4096 is recommended buffer size)
response = client.recv(4096)

print (response)

Anyone knows the best way to return "Response1?" when the header is "COMMAND1" and "Response2!"when the header is "COMMAND2"?

I can't find examples on how to use headers

EDIT: It doesn't have to be "COMMAND1" or "COMMAND2" it can be a "0" or "1", or anything else.

Answer 1

If you want to add your own header, you just have to:

1. Make sure your programm finds the start of your message (like, every message beginns "!?&")

2. Send your own header-data just after the start-symbol of your message.

3. Maybe mark the end of your message with something or pass a length in your header.

4. Since TCP will give you a stream of data, it might come to a case, where it just gives you 2 or 3 messages at once. You have to separate these messages by yourself (eg by using "?!&" as start of every message).

You can always create your own protocoll as payload of another protocoll. Just as TCP is just payload from the ethernet point of view.

Answer 2

You can do something i have done with my program to accept such headers Use pickle library to encode a dict headers and send it through socket. Code will look something like this.

import pickle
def handleSocket(headers:dict):
   message = pickle.dumps(headers)
   socket.send(message)

For server side, you will be handling it Gonna initialise the socket recv to 100 kb

def handleReceivedSocket(socket):
    message:dict = pickle.loads(socket.recv(102400))

Another way to do this. Is sending a raw json string to the server (just change pickle.dumps , pickle.loads by json.dumps , json.loads But it will be in raw and less secure.

Last way you can do it is uri encoding. Check w3schools