setstatus.py: changes by code review

better english in comments. the command line arguments are now processed by
argparse. reading vom cli removed. fix bug in exception handling.

setstatus.py

@@ -5,52 +5,22 @@
 # 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.
+# client, that connects to the statusserver at port 10001 to update the
+# krautspace door status. allowed arguments are 0 or 1.
 
+import argparse
 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
+import sys
 
 
 def main():
+    parser = argparse.ArgumentParser(description="Set door status of 
+                                     Krautspace.")
+    parser.add_argument("status_code", help="status to set", type=int,
+                        choices=(0, 1))
+    args = parser.parse_args()
+    print("Status set to {}".format(bytes([args.status_code])))
 
     HOST = 'localhost'
     PORT = 10001
@@ -61,10 +31,6 @@ def main():
     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
@@ -80,7 +46,7 @@ def main():
             print('Connection wrapped with ssl.context')
             conn.settimeout(5.0)
         except Exception as e:
-            print('Context wrapper failed: [}'.format(e))
+            print('Context wrapper failed: {}'.format(e))
         try:
             conn.connect((HOST, PORT))
             print('Connection established: {}'.format(conn.getpeercert()))
@@ -88,13 +54,15 @@ def main():
             print('Connection timeout')
         except Exception as e:
             print('Connection failed: {}'.format(e))
-            exit(1)
+            sys.exit(1)
+
         try:
             print('Send new status: {}'.format(STATUS))
             conn.send(STATUS)
         except Exception as e:
             print('Error: {}'.format(e))
-            exit(2)
+            sys.exit(2)
+
         try:
             RESPONSE = conn.recv(1)
             print('Server returns: {}'.format(RESPONSE))
@@ -105,7 +73,7 @@ def main():
             print('Disconnect from server')
         except Exception as e:
             print('Error: {}'.format(e))
-            exit(3)
+            sys.exit(3)
 
 
 if __name__ == '__main__':