Revamp authentication (#831)

* Implement Transport classes

* Implement authentication strategy classes

* Revamp authentication with Transport and Strategy

* Revamp strategy and OAuth so that they can use a callable dependency

* Update docstring

* Make ErrorCode a proper Enum and cleanup unused OpenAPI utils

* Remove useless check

* Tweak typing in authenticator

* Update docs

* Improve logout/destroy token logic

* Update docs

* Update docs

* Update docs and full examples

* Apply formatting to examples

* Update OAuth doc and examples

* Add migration doc

* Implement Redis session token

* Add Redis Session documentation

* RedisSession -> Redis

* Fix links in docs

examples/mongodb/sqlalchemy/app/users.py

@@ -0,0 +1,62 @@
+from typing import Optional
+
+from fastapi import Depends, Request
+from fastapi_users import BaseUserManager, FastAPIUsers
+from fastapi_users.authentication import (
+    AuthenticationBackend,
+    BearerTransport,
+    JWTStrategy,
+)
+from fastapi_users.db import SQLAlchemyUserDatabase
+
+from app.db import get_user_db
+from app.models import User, UserCreate, UserDB, UserUpdate
+
+SECRET = "SECRET"
+
+
+class UserManager(BaseUserManager[UserCreate, UserDB]):
+    user_db_model = UserDB
+    reset_password_token_secret = SECRET
+    verification_token_secret = SECRET
+
+    async def on_after_register(self, user: UserDB, request: Optional[Request] = None):
+        print(f"User {user.id} has registered.")
+
+    async def on_after_forgot_password(
+        self, user: UserDB, token: str, request: Optional[Request] = None
+    ):
+        print(f"User {user.id} has forgot their password. Reset token: {token}")
+
+    async def on_after_request_verify(
+        self, user: UserDB, token: str, request: Optional[Request] = None
+    ):
+        print(f"Verification requested for user {user.id}. Verification token: {token}")
+
+
+async def get_user_manager(user_db: SQLAlchemyUserDatabase = Depends(get_user_db)):
+    yield UserManager(user_db)
+
+
+bearer_transport = BearerTransport(tokenUrl="auth/jwt/login")
+
+
+def get_jwt_strategy() -> JWTStrategy:
+    return JWTStrategy(secret=SECRET, lifetime_seconds=3600)
+
+
+auth_backend = AuthenticationBackend(
+    name="jwt",
+    transport=bearer_transport,
+    get_strategy=get_jwt_strategy,
+)
+fastapi_users = FastAPIUsers(
+    get_user_manager,
+    [auth_backend],
+    User,
+    UserCreate,
+    UserUpdate,
+    UserDB,
+)
+
+current_active_user = fastapi_users.current_user(active=True)