File size: 7,330 Bytes
096c926 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 |
# 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 base64
import calendar
import datetime
import sys
import six
from six.moves import urllib
from google.auth import exceptions
# Token server doesn't provide a new a token when doing refresh unless the
# token is expiring within 30 seconds, so refresh threshold should not be
# more than 30 seconds. Otherwise auth lib will send tons of refresh requests
# until 30 seconds before the expiration, and cause a spike of CPU usage.
REFRESH_THRESHOLD = datetime.timedelta(seconds=20)
def copy_docstring(source_class):
"""Decorator that copies a method's docstring from another class.
Args:
source_class (type): The class that has the documented method.
Returns:
Callable: A decorator that will copy the docstring of the same
named method in the source class to the decorated method.
"""
def decorator(method):
"""Decorator implementation.
Args:
method (Callable): The method to copy the docstring to.
Returns:
Callable: the same method passed in with an updated docstring.
Raises:
google.auth.exceptions.InvalidOperation: if the method already has a docstring.
"""
if method.__doc__:
raise exceptions.InvalidOperation("Method already has a docstring.")
source_method = getattr(source_class, method.__name__)
method.__doc__ = source_method.__doc__
return method
return decorator
def utcnow():
"""Returns the current UTC datetime.
Returns:
datetime: The current time in UTC.
"""
return datetime.datetime.utcnow()
def datetime_to_secs(value):
"""Convert a datetime object to the number of seconds since the UNIX epoch.
Args:
value (datetime): The datetime to convert.
Returns:
int: The number of seconds since the UNIX epoch.
"""
return calendar.timegm(value.utctimetuple())
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:
google.auth.exceptions.InvalidValue: 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 exceptions.InvalidValue(
"{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:
google.auth.exceptions.InvalidValue: 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 exceptions.InvalidValue(
"{0!r} could not be converted to unicode".format(value)
)
def update_query(url, params, remove=None):
"""Updates a URL's query parameters.
Replaces any current values if they are already present in the URL.
Args:
url (str): The URL to update.
params (Mapping[str, str]): A mapping of query parameter
keys to values.
remove (Sequence[str]): Parameters to remove from the query string.
Returns:
str: The URL with updated query parameters.
Examples:
>>> url = 'http://example.com?a=1'
>>> update_query(url, {'a': '2'})
http://example.com?a=2
>>> update_query(url, {'b': '3'})
http://example.com?a=1&b=3
>> update_query(url, {'b': '3'}, remove=['a'])
http://example.com?b=3
"""
if remove is None:
remove = []
# Split the URL into parts.
parts = urllib.parse.urlparse(url)
# Parse the query string.
query_params = urllib.parse.parse_qs(parts.query)
# Update the query parameters with the new parameters.
query_params.update(params)
# Remove any values specified in remove.
query_params = {
key: value for key, value in six.iteritems(query_params) if key not in remove
}
# Re-encoded the query string.
new_query = urllib.parse.urlencode(query_params, doseq=True)
# Unsplit the url.
new_parts = parts._replace(query=new_query)
return urllib.parse.urlunparse(new_parts)
def scopes_to_string(scopes):
"""Converts scope value to a string suitable for sending to OAuth 2.0
authorization servers.
Args:
scopes (Sequence[str]): The sequence of scopes to convert.
Returns:
str: The scopes formatted as a single string.
"""
return " ".join(scopes)
def string_to_scopes(scopes):
"""Converts stringifed scopes value to a list.
Args:
scopes (Union[Sequence, str]): The string of space-separated scopes
to convert.
Returns:
Sequence(str): The separated scopes.
"""
if not scopes:
return []
return scopes.split(" ")
def padded_urlsafe_b64decode(value):
"""Decodes base64 strings lacking padding characters.
Google infrastructure tends to omit the base64 padding characters.
Args:
value (Union[str, bytes]): The encoded value.
Returns:
bytes: The decoded value
"""
b64string = to_bytes(value)
padded = b64string + b"=" * (-len(b64string) % 4)
return base64.urlsafe_b64decode(padded)
def unpadded_urlsafe_b64encode(value):
"""Encodes base64 strings removing any padding characters.
`rfc 7515`_ defines Base64url to NOT include any padding
characters, but the stdlib doesn't do that by default.
_rfc7515: https://tools.ietf.org/html/rfc7515#page-6
Args:
value (Union[str|bytes]): The bytes-like value to encode
Returns:
Union[str|bytes]: The encoded value
"""
return base64.urlsafe_b64encode(value).rstrip(b"=")
def is_python_3():
"""Check if the Python interpreter is Python 2 or 3.
Returns:
bool: True if the Python interpreter is Python 3 and False otherwise.
"""
return sys.version_info > (3, 0)
|