Python. Redirect stdout to a socket

python, redirect, sockets, stdout

Solution

There is the `makefile` function in Python's socket class:

socket.makefile(mode='r', buffering=None, *, encoding=None, errors=None, newline=None)

Return a file object associated with the socket. The exact returned type depends on the arguments given to makefile(). These arguments are interpreted the same way as by the built-in open() function.

Closing the file object won’t close the socket unless there are no remaining references to the socket. The socket must be in blocking mode; it can have a timeout, but the file object’s internal buffer may end up in a inconsistent state if a timeout occurs.

You can read how to use it in Mark Lutz's book (chapter 12, "Making Sockets Look Like Files and Streams").

An example from the book (the idea is simple: make a file object from a socket with `socket.makefile` and link `sys.stdout` with it):

def redirectOut(port=port, host=host):
    """
    connect caller's standard output stream to a socket for GUI to listen
    start caller after listener started, else connect fails before accept
    """
    sock = socket(AF_INET, SOCK_STREAM)
    sock.connect((host, port))                # caller operates in client mode
    file = sock.makefile('w')                 # file interface: text, buffered
    sys.stdout = file                         # make prints go to sock.send
    return sock                               # if caller needs to access it raw

Problem

I run my script on computer "A". Then I connect to computer "A" from computer "B" through my script. I send my message to computer "A" and my script runs it with an `exec()` instruction. I want to see the result of executing my message on computer "A", through a socket on computer "B". I tried to change `sys.stdout = socket_response` but had a error: "Socket object has no attribute write()" So, how can I redirect standard output (for `print` or `exec()`) from computer "A" to computer "B" through socket connection? It will be some kind of 'python interpreter' into my script. SORRY, I CAN'T ANSWER MY OWN QUESTION WITHOUT REPUTATION Thanks to all! I use a simple way, which @Torxed advised me of. Here's my pseudo-code (it's just an example, not my real script) ``` #-*-coding:utf-8-*- import socket import sys class stdout_(): def __init__(self, sock_resp): self.sock_resp = sock_resp def write(self, mes): self.sock_resp.send(mes) MY_IP = 'localhost' MY_PORT = 31337 srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM) print("Start server") old_out = sys.stdout srv.bind((MY_IP, MY_PORT)) srv.listen(0) sock_resp, addr_resp = srv.accept() new_out = stdout_(sock_resp) sys.stdout = new_out #sys.stdout = sock_resp ### sock_object has no attribute 'write' while 1: try: a = sock_resp.recv(1024) exec(a) except socket.timeout: #print('server timeout!!' + '\n') continue ``` I connected to script with Putty and sent "print 'abc'" and then I received the answer 'abc'.

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