Adding checkUserInput() per FaradayRF#30 to start validating user input

* Added checkUserInput()
* Checked callsign
* Checked ID
* Checked IP Address

faradayio_cli/faradayio_cli.py

@@ -7,6 +7,7 @@
 import threading
 import time
 import pytun
+import ipaddress
 
 from faradayio.faraday import Monitor
 from faradayio.faraday import SerialTestClass
@@ -47,6 +48,36 @@ def setupArgparse():
     # Parse and return arguments
     return parser.parse_args()
 
+def checkUserInput(args):
+    """Checks user input for validity
+
+    Args:
+        args: argparse arguments
+
+    """
+    # Check callsign
+    # Expect a string
+    if not isinstance(args.callsign, str):
+        raise TypeError
+    # Callsigns are at most seven characters long
+    if len(args.callsign) > 7:
+        raise ValueError
+
+    # Check ID
+    # Expect and integer
+    if not isinstance(args.id, int):
+        raise TypeError
+    # Expect a value between 0-255
+    if args.id < 0 or args.id > 255:
+        raise ValueError
+
+    # Check IP Address
+    # Expect a string
+    if not isinstance(args.addr, str):
+        raise TypeError
+    # Expect an IP address that is valid
+    ipaddress.IPv4Address(args.addr)
+
 
 def setupSerialPort(loopback, port, baud, readtimeout, writetimeout):
     """Sets up serial port by connecting to phsyical or software port.
@@ -95,6 +126,8 @@ def main():
     except argparse.ArgumentError as error:
         raise SystemExit(error)
 
+    checkUserInput(args)
+
     # Setup serial port
     try:
         serialPort = setupSerialPort(loopback=args.loopback,