def main(sysargs=None):
# Assign sysargs if not set
sysargs = sys.argv[1:] if sysargs is None else sysargs
# Create a top level parser
parser = argparse.ArgumentParser(
description="{0} command".format(COMMAND_NAME)
)
# Generate a list of verbs available
verbs = list_verbs(VERBS_ENTRY_POINT)
# Create the subparsers for each verb and collect the arg preprocessors
argument_preprocessors, verb_subparsers = create_subparsers(
parser,
COMMAND_NAME,
verbs,
VERBS_ENTRY_POINT,
sysargs,
)
# Determine the verb, splitting arguments into pre and post verb
verb, pre_verb_args, post_verb_args = split_arguments_by_verb(sysargs)
# Short circuit -h and --help
if '-h' in pre_verb_args or '--help' in pre_verb_args:
parser.print_help()
sys.exit(0)
# Error on no verb provided
if verb is None:
print(parser.format_usage())
sys.exit("Error: No verb provided.")
# Error on unknown verb provided
if verb not in verbs:
print(parser.format_usage())
sys.exit("Error: Unknown verb '{0}' provided.".format(verb))
# Short circuit -h and --help for verbs
if '-h' in post_verb_args or '--help' in post_verb_args:
verb_subparsers[verb].print_help()
sys.exit(0)
# First allow the verb's argument preprocessor to strip any args
# and return any "extra" information it wants as a dict
processed_post_verb_args, extras = \
argument_preprocessors[verb](post_verb_args)
# Then allow argparse to process the left over post-verb arguments along
# with the pre-verb arguments and the verb itself
args = parser.parse_args(pre_verb_args + [verb] + processed_post_verb_args)
# Extend the argparse result with the extras from the preprocessor
for key, value in extras.items():
setattr(args, key, value)
# Finally call the subparser's main function with the processed args
# and the extras which the preprocessor may have returned
sys.exit(args.main(args) or 0)
def test_split_arguments_by_verb(self):
args = ['--cmd-arg1', 'verb', '--verb-arg1', '--verb-arg2']
expected = ('verb', ['--cmd-arg1'], ['--verb-arg1', '--verb-arg2'])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['verb', '--verb-arg1', '--verb-arg2']
expected = ('verb', [], ['--verb-arg1', '--verb-arg2'])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['--cmd-arg1', 'verb']
expected = ('verb', ['--cmd-arg1'], [])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['verb']
expected = ('verb', [], [])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['--cmd-arg1']
expected = (None, ['--cmd-arg1'], [])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
def test_split_arguments_by_verb(self):
args = ['--cmd-arg1', 'verb', '--verb-arg1', '--verb-arg2']
expected = ('verb', ['--cmd-arg1'], ['--verb-arg1', '--verb-arg2'])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['verb', '--verb-arg1', '--verb-arg2']
expected = ('verb', [], ['--verb-arg1', '--verb-arg2'])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['--cmd-arg1', 'verb']
expected = ('verb', ['--cmd-arg1'], [])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['verb']
expected = ('verb', [], [])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
args = ['--cmd-arg1']
expected = (None, ['--cmd-arg1'], [])
self.assertEqual(verb_pattern.split_arguments_by_verb(args), expected)
