# Copyright (C) 2016-2019 Virgil Security Inc.
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# Lead Maintainer: Virgil Security Inc. <support@virgilsecurity.com>
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from functools import partial
from virgil_sdk.jwt import Jwt
from virgil_sdk.jwt.abstractions.access_token_provider import AccessTokenProvider
[docs]class CachingCallbackProvider(AccessTokenProvider):
"""
The CachingCallbackProvider class provides an opportunity to get cached access token
or renew it using callback mechanism.
"""
TOKEN_TTL = 5 # 5 seconds
def __init__(
self,
renew_jwt_callback, # type: function
token_ttl=TOKEN_TTL, # type: int
initial_token=None # type Jwt
):
self._token_ttl = token_ttl
self.__renew_jwt_callback = partial(renew_jwt_callback, token_ttl=token_ttl)
self.__access_token = initial_token
[docs] def get_token(self, token_context):
# type: (TokenContext) -> Jwt
"""
Gets access token from cache or renew by provided callback if expired.
Args:
token_context: Access token context.
Returns:
Instance of access token.
"""
if self.__access_token:
if not self.__access_token.is_expired() and not token_context.force_reload:
return self.__access_token
self.__access_token = Jwt.from_string(self.__renew_jwt_callback(token_context))
return self.__access_token