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# Copyright (C) 2017-2024 Vanessa Sochat.
# This Source Code Form is subject to the terms of the
# Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed
# with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
import os
def setEnvVar(name, value):
"""Set or unset an environment variable
name -- Name of the variable to set
value -- Value to use or None to clear
"""
if value is None:
if name in os.environ:
del os.environ[name]
else:
os.environ[name] = value
class ScopedEnvVar:
"""Temporarily change an environment variable
Usage:
with ScopedEnvVar("FOO", "bar"):
print(os.environ["FOO"]) # "bar"
print(os.environ["FOO"]) # <oldvalue>
"""
def __init__(self, name, value):
"""Create the scoped environment variable object
name -- Name of the variable to set
value -- Value to use or None to clear
"""
self.name = name
self.value = value
self.oldValue = None
def __enter__(self):
self.oldValue = os.environ.get(self.name)
setEnvVar(self.name, self.value)
return self
def __exit__(self, ex_type, ex_value, traceback):
setEnvVar(self.name, self.oldValue)
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