Python script that checks plans with finger

planmon.py

#!/usr/bin/env python3

import sys
import os
import socket
import hashlib
import subprocess

CONFIG=os.path.expanduser("~/.config/planmon/config")
CACHEDIR=os.path.expanduser("~/.cache/planmon")

def finger(address):
    user, host = address.split("@")
    server = ( host, 79 )
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    data = ""
    try:
        sock.connect(server)
        sock.sendall((user + "\n").encode())
        data = sock.recv(8192)
        data = data.decode()
    except Exception as ex:
        print(f"error: {ex}")

    return data

def checkdiff(address, text):

    if not os.path.exists(CACHEDIR):
        os.makedirs(CACHEDIR)

    texthash = hashlib.sha1(text.encode())
    digest = texthash.hexdigest()
    if os.path.exists(CACHEDIR + "/" + address):
        fp = open(CACHEDIR + "/" + address)
        if digest == fp.read():
            fp.close()
            return False
        else: # plan has changed
            fp = open(CACHEDIR + "/" + address, "w")
            fp.write(digest) #update hash
            fp.close()
            subprocess.run(['notify-send',
                            f'Plan update from {address}', f'{text}'],
                           check=True)
            return True
    else: # new entry!
        fp = open(CACHEDIR + "/" + address, "w")
        fp.write(digest) #update hash
        fp.close()
        subprocess.run(['notify-send',
                        f'Plan cached from {address}', f'{text}'],
                       check=True)
        return True


def main():
    try:
        config = open(CONFIG, "r")
    except Exception as ex:
        print(f"Can't open config {ex}")

    for address in config.readlines():
        address = address.strip()
        text = finger(address)
        if checkdiff(address,text):
            print("Something changed...")

if __name__ == "__main__":
    sys.exit(main())