added argparse class by Steven Bethard

src/brewserverblocklist/bargparse.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+
+# SPDX-FileCopyrightText: 2023 Tobias Diekershoff
+#
+# SPDX-License-Identifier: CC-BY-SA-2.5
+
+"""
+This expansion of the ArgParser class will display the --help results by
+default if an error occurs (e.g. no arguments are passed to the script).
+
+It is based on an StackOverflow answer from 2010 by unutbu who refered to
+a reply from Steven Bethard as source of the code. Postings of that time
+on StackOverflow are published under the terms of a CreativeCommons license
+specifically under the CC-BY-SA-2.5 so this module is put under the same
+license.
+
+https://stackoverflow.com/questions/4042452/display-help-message-with-python-argparse-when-script-is-called-without-any-argu/4042861#4042861
+"""
+
+import argparse
+import sys
+
+class MyParser(argparse.ArgumentParser):
+    def error(self, message):
+        sys.stderr.write('error: %s\n' % message)
+        self.print_help()
+        sys.exit(2)

src/brewserverblocklist/brewserverblocklist.py

@@ -8,11 +8,11 @@ of any number of other Friendica instances.
 
 See https://git.friendi.ca/tobias/brewserverblocklist
 """
-import argparse
 import configparser
 import sys
 from os.path import exists
 import requests
+import bargparse
 
 class BrewBlocklist():
     """
@@ -157,7 +157,7 @@ def main():
     * collect the ingredient
     * serve the result
     """
-    parser = argparse.ArgumentParser()
+    parser = bargparse.MyParser()
     parser.add_argument('-c', '--config',
                         dest='configfile',
                         required=True,