doorstatus/setstatus.py

#!/usr/bin/python3
# -*- coding: utf-8 -*-

# file: setstatus.py
# date: 26.07.2019
# email: berhsi@web.de

# client, who connects to the statusserver at port 10001 to update the
# krautspace door status. If no status is given as argument, he reads from
# stdin until input is 0 or 1.

import socket
import ssl
from sys import exit, argv


def check_arguments(argv):
    '''
    Checks length and validity of command line argument vectors. If there is
    no argument or argument is not valid, it returns None. Otherwise it
    converts the string value into a byte value.
    param 1: array of strings
    return: None or byte value
    '''
    if len(argv) == 1:
        byte_value = None
    else:
        if argv[1].strip() == '0' or argv[1].strip() == '1':
            i = int(argv[1].strip())
            print('Set value to {}'.format(i))
            byte_value = bytes([i])
        else:
            byte_value = None
    return byte_value


def read_argument():
    '''
    Reads from stdin until the given value is valid. Convert the given
    string to a byte value and return this value.
    return: byte value
    '''
    status = None

    while status is None:
        buf = input('Enter new status (0/1): ')
        if buf == '0' or buf == '1':
            status = bytes([int(buf)])
            print('Read status: {}'.format(status))
    return status


def main():

    HOST = 'localhost'
    PORT = 10001
    SERVER_NAME = 'server.status.kraut.space'
    CLIENT_CERT = './certs/client.crt'
    CLIENT_KEY = './certs/client.key'
    SERVER_CERT = './certs/server.crt'
    STATUS = None
    RESPONSE = None

    STATUS = check_arguments(argv)
    while STATUS is None:
        STATUS = read_argument()

    context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH,
                                         cafile=SERVER_CERT)
    context.set_ciphers('EECDH+AESGCM')   # only ciphers for tls 1.2 and 1.3
    context.options |= getattr(ssl._ssl, 'OP_NO_COMPRESSION', 0)
    context.load_cert_chain(certfile=CLIENT_CERT, keyfile=CLIENT_KEY)
    print('SSL context created')

    with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as mySocket:
        print('Socket created')
        try:
            conn = context.wrap_socket(mySocket, server_side=False,
                                       server_hostname=SERVER_NAME)
            print('Connection wrapped with ssl.context')
            conn.settimeout(5.0)
        except Exception as e:
            print('Context wrapper failed: [}'.format(e))
        try:
            conn.connect((HOST, PORT))
            print('Connection established: {}'.format(conn.getpeercert()))
        except socket.timeout:
            print('Connection timeout')
        except Exception as e:
            print('Connection failed: {}'.format(e))
            exit(1)
        try:
            print('Send new status: {}'.format(STATUS))
            conn.send(STATUS)
        except Exception as e:
            print('Error: {}'.format(e))
            exit(2)
        try:
            RESPONSE = conn.recv(1)
            print('Server returns: {}'.format(RESPONSE))
            if RESPONSE == STATUS:
                print('Status sucessfull updated')
            else:
                print('Failed to update status')
            print('Disconnect from server')
        except Exception as e:
            print('Error: {}'.format(e))
            exit(3)


if __name__ == '__main__':
    main()