Add google.auth.crypt (#6)
diff --git a/google/auth/_helpers.py b/google/auth/_helpers.py
new file mode 100644
index 0000000..2d3b653
--- /dev/null
+++ b/google/auth/_helpers.py
@@ -0,0 +1,65 @@
+# Copyright 2015 Google Inc.
+#
+# 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
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Helper functions for commonly used utilities."""
+
+import six
+
+
+def to_bytes(value, encoding='utf-8'):
+ """Converts a string value to bytes, if necessary.
+
+ Unfortunately, ``six.b`` is insufficient for this task since in
+ Python 2 because it does not modify ``unicode`` objects.
+
+ Args:
+ value (Union[str, bytes]): The value to be converted.
+ encoding (str): The encoding to use to convert unicode to bytes.
+ Defaults to "utf-8".
+
+ Returns:
+ bytes: The original value converted to bytes (if unicode) or as
+ passed in if it started out as bytes.
+
+ Raises:
+ ValueError: If the value could not be converted to bytes.
+ """
+ result = (value.encode(encoding)
+ if isinstance(value, six.text_type) else value)
+ if isinstance(result, six.binary_type):
+ return result
+ else:
+ raise ValueError('{0!r} could not be converted to bytes'.format(value))
+
+
+def from_bytes(value):
+ """Converts bytes to a string value, if necessary.
+
+ Args:
+ value (Union[str, bytes]): The value to be converted.
+
+ Returns:
+ str: The original value converted to unicode (if bytes) or as passed in
+ if it started out as unicode.
+
+ Raises:
+ ValueError: If the value could not be converted to unicode.
+ """
+ result = (value.decode('utf-8')
+ if isinstance(value, six.binary_type) else value)
+ if isinstance(result, six.text_type):
+ return result
+ else:
+ raise ValueError(
+ '{0!r} could not be converted to unicode'.format(value))