Fix #42: multiple authentication backends (#47)

* Revamp authentication to allow multiple backends

* Make router generate a login route for each backend

* Apply black

* Remove unused imports

* Complete docstrings

* Update documentation

* WIP add cookie auth

* Complete cookie auth unit tests

* Add documentation for cookie auth

* Fix cookie backend default name

* Don't make cookie return a Response

fastapi_users/authentication/base.py

@@ -1,70 +1,30 @@
-from typing import Callable
+from typing import Any, Optional
 
-from fastapi import HTTPException
-from fastapi.security import OAuth2PasswordBearer
-from starlette import status
+from starlette.requests import Request
 from starlette.responses import Response
 
 from fastapi_users.db import BaseUserDatabase
 from fastapi_users.models import BaseUserDB
 
-credentials_exception = HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)
-
 
 class BaseAuthentication:
     """
-    Base adapter for generating and decoding authentication tokens.
+    Base authentication backend.
 
-    Provides dependency injectors to get current active/superuser user.
+    Every backend should derive from this class.
 
-    :param scheme: Optional authentication scheme for OpenAPI.
-    Defaults to `OAuth2PasswordBearer(tokenUrl="/users/login")`.
-    Override it if your login route lives somewhere else.
+    :param name: Name of the backend. It will be used to name the login route.
     """
 
-    scheme: OAuth2PasswordBearer
+    name: str
 
-    def __init__(self, scheme: OAuth2PasswordBearer = None):
-        if scheme is None:
-            self.scheme = OAuth2PasswordBearer(tokenUrl="/users/login")
-        else:
-            self.scheme = scheme
+    def __init__(self, name: str = "base"):
+        self.name = name
 
-    async def get_login_response(self, user: BaseUserDB, response: Response):
+    async def __call__(
+        self, request: Request, user_db: BaseUserDatabase
+    ) -> Optional[BaseUserDB]:
         raise NotImplementedError()
 
-    def get_current_user(self, user_db: BaseUserDatabase):
+    async def get_login_response(self, user: BaseUserDB, response: Response) -> Any:
         raise NotImplementedError()
-
-    def get_current_active_user(self, user_db: BaseUserDatabase):
-        raise NotImplementedError()
-
-    def get_current_superuser(self, user_db: BaseUserDatabase):
-        raise NotImplementedError()
-
-    def _get_authentication_method(
-        self, user_db: BaseUserDatabase
-    ) -> Callable[..., BaseUserDB]:
-        raise NotImplementedError()
-
-    def _get_current_user_base(self, user: BaseUserDB) -> BaseUserDB:
-        if user is None:
-            raise self._get_credentials_exception()
-        return user
-
-    def _get_current_active_user_base(self, user: BaseUserDB) -> BaseUserDB:
-        user = self._get_current_user_base(user)
-        if not user.is_active:
-            raise self._get_credentials_exception()
-        return user
-
-    def _get_current_superuser_base(self, user: BaseUserDB) -> BaseUserDB:
-        user = self._get_current_active_user_base(user)
-        if not user.is_superuser:
-            raise self._get_credentials_exception(status.HTTP_403_FORBIDDEN)
-        return user
-
-    def _get_credentials_exception(
-        self, status_code: int = status.HTTP_401_UNAUTHORIZED
-    ) -> HTTPException:
-        return HTTPException(status_code=status_code)