Source code for google.cloud.forseti.common.util.regular_exp

# Copyright 2017 The Forseti Security Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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"""Regex utility module."""

import re


# pylint: disable=anomalous-backslash-in-string
[docs]def escape_and_globify(pattern_string): """Given a pattern string with a glob, create actual regex pattern. To require > 0 length glob, change the "*" to ".+". This is to handle strings like "\*@company.com". (The actual regex would probably be ".\*@company.com", except that we don't want to match zero-length usernames before the "@".) Special case the pattern '*' to match 0 or more characters. Args: pattern_string (str): The pattern string of which to make a regex. Returns: str: The pattern string, escaped except for the "*", which is transformed into ".+" (match on one or more characters). """ if pattern_string is None: return None # pylint: enable=anomalous-backslash-in-string if pattern_string == '*': return '^.*$' return '^{}$'.format(re.escape(pattern_string).replace('\\*', '.*'))