I can't get any response from client via socket

October 23, 2023

#Server

import socket

HOST = # Server IP
PORT = # Server Port

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    print("[+] Waiting for incoming connections")
    s.bind((HOST, PORT))
    s.listen()
    conn, addr = s.accept()
    print(f"[+] Connected by {addr}")

    while True:
        command = input(">> ")
        conn.send(command.encode('utf-8'))
        result = b""
        while True:
            data = conn.recv(4096)
            if not data:
                break
            result += data
        print(result.decode())

# Client
import socket
import subprocess

HOST = # Server IP
PORT = # Server Port

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))

    while True:
        command = s.recv(1024).decode('utf-8')
        result = subprocess.getoutput(command)
        chunk_size = 4096
        for i in range(0, len(result), chunk_size):
            s.send(result[i:i + chunk_size].encode('utf-8'))

I tried to send result of command entered in server by chunks but can’t get any result after doing it. Before adding for loop (to send result by chunks) in the client code I was able to get result of command sent by server but I want to get large results at once couldn’t find any way to achieve this.

>Solution :

One approach is to send the length of the data before sending the data itself. This way, the receiver knows how much data to expect.

Server.py:

import socket

HOST = "your_server_ip"
PORT = your_server_port

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    print("[+] Waiting for incoming connections")
    s.bind((HOST, PORT))
    s.listen()
    conn, addr = s.accept()
    print(f"[+] Connected by {addr}")

    while True:
        command = input(">> ")
        conn.send(command.encode('utf-8'))
        result = conn.recv(1024)  # Receive the data size first
        data_size = int(result.decode())
        result = b""
        while len(result) < data_size:
            data = conn.recv(4096)
            if not data:
                break
            result += data
        print(result.decode())

Client.py:

import socket
import subprocess

HOST = "your_server_ip"
PORT = your_server_port

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))

    while True:
        command = s.recv(1024).decode('utf-8')
        result = subprocess.getoutput(command)
        result_size = str(len(result)).encode('utf-8')
        s.send(result_size)  # Send the size of the data first
        chunk_size = 4096
        for i in range(0, len(result), chunk_size):
            s.send(result[i:i + chunk_size].encode('utf-8'))