# ------------------------------------
# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.
# ------------------------------------
from typing import Any, Optional, cast
from azure.core.credentials import AccessToken, AccessTokenInfo, TokenRequestOptions
from ..._internal.aad_client import AadClientBase
from ... import CredentialUnavailableError
from ..._constants import DEVELOPER_SIGN_ON_CLIENT_ID
from ..._internal.shared_token_cache import NO_TOKEN, SharedTokenCacheBase
from .._internal import AsyncContextManager
from .._internal.aad_client import AadClient
from .._internal.decorators import log_get_token_async
[docs]
class SharedTokenCacheCredential(SharedTokenCacheBase, AsyncContextManager):
"""Authenticates using tokens in the local cache shared between Microsoft applications.
:param str username:
Username (typically an email address) of the user to authenticate as. This is required because the local cache
may contain tokens for multiple identities.
:keyword str authority: Authority of a Microsoft Entra endpoint, for example 'login.microsoftonline.com',
the authority for Azure Public Cloud (which is the default). :class:`~azure.identity.AzureAuthorityHosts`
defines authorities for other clouds.
:keyword str tenant_id: a Microsoft Entra tenant ID. Used to select an account when the cache contains
tokens for multiple identities.
:keyword cache_persistence_options: configuration for persistent token caching. If not provided, the credential
will use the persistent cache shared by Microsoft development applications
:paramtype cache_persistence_options: ~azure.identity.TokenCachePersistenceOptions
"""
async def __aenter__(self) -> "SharedTokenCacheCredential":
if self._client:
await self._client.__aenter__() # type: ignore
return self
[docs]
async def close(self) -> None:
"""Close the credential's transport session."""
if self._client:
await self._client.__aexit__() # type: ignore
[docs]
@log_get_token_async
async def get_token(
self,
*scopes: str,
claims: Optional[str] = None,
tenant_id: Optional[str] = None,
enable_cae: bool = False,
**kwargs: Any,
) -> AccessToken:
"""Get an access token for `scopes` from the shared cache.
If no access token is cached, attempt to acquire one using a cached refresh token.
This method is called automatically by Azure SDK clients.
:param str scopes: desired scopes for the access token. This method requires at least one scope.
For more information about scopes, see
https://learn.microsoft.com/entra/identity-platform/scopes-oidc.
:keyword str claims: additional claims required in the token, such as those returned in a resource provider's
claims challenge following an authorization failure.
:keyword str tenant_id: optional tenant to include in the token request.
:keyword bool enable_cae: indicates whether to enable Continuous Access Evaluation (CAE) for the requested
token. Defaults to False.
:return: An access token with the desired scopes.
:rtype: ~azure.core.credentials.AccessToken
:raises ~azure.identity.CredentialUnavailableError: the cache is unavailable or contains insufficient user
information
:raises ~azure.core.exceptions.ClientAuthenticationError: authentication failed. The error's ``message``
attribute gives a reason. Any error response from Microsoft Entra ID is available as the error's
``response`` attribute.
"""
options: TokenRequestOptions = {}
if claims:
options["claims"] = claims
if tenant_id:
options["tenant_id"] = tenant_id
options["enable_cae"] = enable_cae
token_info = await self._get_token_base(*scopes, options=options, base_method_name="get_token", **kwargs)
return AccessToken(token_info.token, token_info.expires_on)
[docs]
@log_get_token_async
async def get_token_info(self, *scopes: str, options: Optional[TokenRequestOptions] = None) -> AccessTokenInfo:
"""Get an access token for `scopes` from the shared cache.
If no access token is cached, attempt to acquire one using a cached refresh token.
This is an alternative to `get_token` to enable certain scenarios that require additional properties
on the token. This method is called automatically by Azure SDK clients.
:param str scopes: desired scope for the access token. This method requires at least one scope.
For more information about scopes, see https://learn.microsoft.com/entra/identity-platform/scopes-oidc.
:keyword options: A dictionary of options for the token request. Unknown options will be ignored. Optional.
:paramtype options: ~azure.core.credentials.TokenRequestOptions
:rtype: AccessTokenInfo
:return: An AccessTokenInfo instance containing information about the token.
:raises ~azure.identity.CredentialUnavailableError: the cache is unavailable or contains insufficient user
information
:raises ~azure.core.exceptions.ClientAuthenticationError: authentication failed. The error's ``message``
attribute gives a reason. Any error response from Microsoft Entra ID is available as the error's
``response`` attribute.
"""
return await self._get_token_base(*scopes, options=options, base_method_name="get_token_info")
async def _get_token_base(
self,
*scopes: str,
options: Optional[TokenRequestOptions] = None,
base_method_name: str = "get_token_info",
**kwargs: Any,
) -> AccessTokenInfo:
if not scopes:
raise ValueError(f"'{base_method_name}' requires at least one scope")
if not self._client_initialized:
self._initialize_client()
options = options or {}
claims = options.get("claims")
tenant_id = options.get("tenant_id")
is_cae = options.get("enable_cae", False)
token_cache = self._cae_cache if is_cae else self._cache
# Try to load the cache if it is None.
if not token_cache:
token_cache = self._initialize_cache(is_cae=is_cae)
# If the cache is still None, raise an error.
if not token_cache:
raise CredentialUnavailableError(message="Shared token cache unavailable")
account = self._get_account(self._username, self._tenant_id, is_cae=is_cae)
token = self._get_cached_access_token(scopes, account, is_cae=is_cae)
if token:
return token
# try each refresh token, returning the first access token acquired
for refresh_token in self._get_refresh_tokens(account, is_cae=is_cae):
token = await cast(AadClient, self._client).obtain_token_by_refresh_token(
scopes, refresh_token, claims=claims, tenant_id=tenant_id, enable_cae=is_cae, **kwargs
)
return token
raise CredentialUnavailableError(message=NO_TOKEN.format(account.get("username")))
def _get_auth_client(self, **kwargs: Any) -> AadClientBase:
return AadClient(client_id=DEVELOPER_SIGN_ON_CLIENT_ID, **kwargs)