在Python中通过Telnet运行脚本

Question

so I have some normal Python scripts that you can access through your terminal normally. Like the script works with your terminal (it is a game).

Now I want to somehow make a script that creates a telnet server, and when a user telnet's to the ip, the script will run in their terminal.

How do I go about this?

Answer 1

You can use xinetd to add a service starting your python script. The standard input and output will be transmitted over the network on desired port, so you do not need to modify your scripts ( input / raw_input and print methods will work fine).

Brief tutorial: http://linuxpoison.blogspot.com/2010/01/how-to-add-custom-new-service-under.html

Answer 2

I won't create whole code for this problem. I will just give you a brief example.

This is the part of the telnet server :

list_of_the_connections = []
for connection in list_of_the_connections:
    user_command = connection.read()
    if user_command = 'name_of_the_script':
        stdout = catch_stdout(os.system('python name_of_the_script'))
    connection.send(stdout)

Line stdout = catch_stdout(os.system('python name_of_the_script')) is using os.system to run the bash command and function catch_stdout catches the output of that command. Later on, all you have to do is to send this output to the user.

Answer 3

I had a similar problem that I solved by calling the program that I was trying to connect to over telnet in a pexpect spawn class and the telnet project miniboa . By wrapping the program in pexpect you can the read and write to stdin/stdout safely.

To use the input function, pexpect uses regular expressions to know when to stop reading and get input, so I added '>' to the end of my read from stdin function.

class Client(object):
    def __init__(self, client):
        self.client = client
        self.process = pexpect.spawnu(PROGRAM)

def on_connect(client):
    clients.append(Client(client))

def process_clients():
    """
    Check each client, if client.cmd_ready == True then there is a line of
    input available via client.get_command().
    """
    for client in clients:
        if client.active and client.cmd_ready:
            # If the client sends input echo it to the chat room
            interact(client)

def interact(client):
    choice = client.process.expect([re.compile('\n*/>$'), '\n'])
    if choice == 1: # not an input prompt
        if len(client.process.before) == 0:
            return
        client.client.send(client.process.before+'\n')
    else: #input
        msg = client.client.get_command().strip()
        client.process.sendline(msg)

if __name__ == "__main__":
    tn = miniboa.TelnetServer(
        port=7000, 
        address='127.0.0.1', 
        on_connect = on_connect
    )
    while True:
        tn.poll()
        if len(clients) > 0:
            process_clients()

PROGRAM is the program to be called. This is mostly gleaned from the miniboa examples.