Add argument checking

src/instawebhooks.py

@@ -2,31 +2,56 @@
 Placeholder
 """
 
+import re
 import logging
 import argparse
 
+
+def instagram_username(arg_value):
+    """Instagram username type"""
+    pattern = re.compile(r'^[a-zA-Z_](?!.*?\.{2})[\w.]{1,28}[\w]$')
+    if not pattern.match(arg_value):
+        raise argparse.ArgumentTypeError(
+            f"invalid value: '{arg_value}': must meet Instagram username requirements")
+    return arg_value
+
+
+def discord_webhook_url(arg_value):
+    """Discord webhook URL type"""
+    pattern = re.compile(
+        r'^.*(discord|discordapp)\.com\/api\/webhooks\/([\d]+)\/([a-zA-Z0-9_.-]*)$')
+    if not pattern.match(arg_value):
+        raise argparse.ArgumentTypeError(
+            f"invalid value: '{arg_value}': must be a valid Discord webhook URL")
+    return arg_value
+
+
+# Set up logging
 logger = logging.getLogger(__name__)
 logging.basicConfig(
     format='%(asctime)s - %(levelname)s - %(message)s',
     datefmt='%m/%d/%Y %I:%M:%S %p',
     level=logging.INFO)
 
+# Parse command line arguments
 parser = argparse.ArgumentParser(
     prog='instawebhooks',
     description='Monitor Instagram accounts for new posts and send them to a Discord webhook',
     epilog='More documentation can be found at: https://github.com/RaenLua/InstaWebhooks')
 parser.add_argument("instagram_username",
-                    help="the Instagram username to monitor for new posts")
+                    help="the Instagram username to monitor for new posts",
+                    type=instagram_username)
 parser.add_argument(
-    "discord_webhook_url", help="the Discord webhook URL to send new posts to")
+    "discord_webhook_url", help="the Discord webhook URL to send new posts to",
+    type=discord_webhook_url)
 parser.add_argument("-v", "--verbose", help="increase output verbosity",
                     action="store_true")
 args = parser.parse_args()
 
+# Set the logger to debug if verbose is enabled
 if args.verbose:
     logger.setLevel(logging.DEBUG)
     logger.debug("Verbose output enabled.")
 
-print(f"Creating webhook for {args.instagram_username}")
-
-logger.info("Starting InstaWebhooks for %s", args.instagram_username)
+logger.info("Starting InstaWebhooks for %s on %s",
+            args.instagram_username, args.discord_webhook_url)