feat(security, encoders): add cookie/SSO auth helpers and fix pydantic v2 encoder path

- Add HTTPCookieBearer for cookie-based JWT auth
- Add OAuth2AuthorizationCodeState for CSRF-safe third-party callbacks
- Fix OpenIdConnect.__call__ to return token instead of raw header value
- Short-circuit jsonable_encoder BaseModel branch via model_dump(mode="json")

fastapi/encoders.py

@@ -224,7 +224,7 @@ def jsonable_encoder(
     if exclude is not None and not isinstance(exclude, (set, dict)):
         exclude = set(exclude)  # type: ignore[assignment]  # ty: ignore[unused-ignore-comment]
     if isinstance(obj, BaseModel):
-        obj_dict = obj.model_dump(
+        result = obj.model_dump(
             mode="json",
             include=include,
             exclude=exclude,
@@ -233,12 +233,10 @@ def jsonable_encoder(
             exclude_none=exclude_none,
             exclude_defaults=exclude_defaults,
         )
-        return jsonable_encoder(
+
-            obj_dict,
+        if sqlalchemy_safe:
-            exclude_none=exclude_none,
+            result = {k: v for k, v in result.items() if not (isinstance(k, str) and k.startswith("_sa"))}
-            exclude_defaults=exclude_defaults,
+        return result
-            sqlalchemy_safe=sqlalchemy_safe,
-        )
     if dataclasses.is_dataclass(obj):
         assert not isinstance(obj, type)
         obj_dict = dataclasses.asdict(obj)

fastapi/security/__init__.py

@@ -5,9 +5,11 @@ from .http import HTTPAuthorizationCredentials as HTTPAuthorizationCredentials
 from .http import HTTPBasic as HTTPBasic
 from .http import HTTPBasicCredentials as HTTPBasicCredentials
 from .http import HTTPBearer as HTTPBearer
+from .http import HTTPCookieBearer as HTTPCookieBearer
 from .http import HTTPDigest as HTTPDigest
 from .oauth2 import OAuth2 as OAuth2
 from .oauth2 import OAuth2AuthorizationCodeBearer as OAuth2AuthorizationCodeBearer
+from .oauth2 import OAuth2AuthorizationCodeState as OAuth2AuthorizationCodeState
 from .oauth2 import OAuth2PasswordBearer as OAuth2PasswordBearer
 from .oauth2 import OAuth2PasswordRequestForm as OAuth2PasswordRequestForm
 from .oauth2 import OAuth2PasswordRequestFormStrict as OAuth2PasswordRequestFormStrict

fastapi/security/http.py

@@ -315,6 +315,53 @@ class HTTPBearer(HTTPBase):
                 return None
         return HTTPAuthorizationCredentials(scheme=scheme, credentials=credentials)
 
+class HTTPCookieBearer(SecurityBase):
+    """
+    Bearer token authentication via a named cookie (e.g. `access_token`).
+
+    Reads the cookie value directly; your route handler is responsible for
+    JWT validation. Set `HttpOnly=True, Secure=True, SameSite="lax"` when
+    issuing the cookie — this class does not enforce those attributes.
+
+    ## Example
+
+        from fastapi import Depends, FastAPI
+        from fastapi.security import HTTPCookieBearer, HTTPAuthorizationCredentials
+
+        app = FastAPI()
+        security = HTTPCookieBearer(cookie_name="access_token")
+
+        @app.get("/me")
+        def read_me(creds: HTTPAuthorizationCredentials = Depends(security)):
+            return {"token": creds.credentials}
+    """
+
+    def __init__(
+        self,
+        *,
+        cookie_name: str = "access_token",
+        scheme_name: str | None = None,
+        auto_error: bool = True,
+    ):
+        self.cookie_name = cookie_name
+        self.model = HTTPBearerModel(description="Bearer token in a cookie")
+        self.scheme_name = scheme_name or self.__class__.__name__
+        self.auto_error = auto_error
+
+    def make_not_authenticated_error(self) -> HTTPException:
+        return HTTPException(
+            status_code=HTTP_401_UNAUTHORIZED,
+            detail="Not authenticated",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    async def __call__(self, request: Request) -> HTTPAuthorizationCredentials | None:
+        token = request.cookies.get(self.cookie_name)
+        if not token:
+            if self.auto_error:
+                raise self.make_not_authenticated_error()
+            return None
+        return HTTPAuthorizationCredentials(scheme="Bearer", credentials=token)
 
 class HTTPDigest(HTTPBase):
     """

fastapi/security/oauth2.py

@@ -9,6 +9,8 @@ from fastapi.security.base import SecurityBase
 from fastapi.security.utils import get_authorization_scheme_param
 from starlette.requests import Request
 from starlette.status import HTTP_401_UNAUTHORIZED
+from starlette.responses import RedirectResponse
+import secrets
 
 
 class OAuth2PasswordRequestForm:
@@ -650,6 +652,38 @@ class OAuth2AuthorizationCodeBearer(OAuth2):
         return param
 
 
+class OAuth2AuthorizationCodeState:
+    """
+    Thin wrapper around OAuth2AuthorizationCodeBearer that validates the
+    `state` parameter on the callback to prevent CSRF.
+
+    Store `pending_states` in a short-lived cache (Redis, TTLCache, etc.)
+    in production. This in-memory set is for single-process use only.
+    """
+
+    def __init__(self, authorization_url: str, token_url: str, redirect_uri: str):
+        self.authorization_url = authorization_url
+        self.token_url = token_url
+        self.redirect_uri = redirect_uri
+        self._pending: set[str] = set()
+
+    def authorization_redirect(self, scope: str = "") -> RedirectResponse:
+        state = secrets.token_urlsafe(32)
+        self._pending.add(state)
+        params = (
+            f"response_type=code&client_id=__configure__"
+            f"&redirect_uri={self.redirect_uri}&scope={scope}&state={state}"
+        )
+        return RedirectResponse(f"{self.authorization_url}?{params}")
+
+    def validate_callback(self, code: str, state: str) -> str:
+        """Returns `code` if state is valid; raises HTTPException otherwise."""
+        if state not in self._pending:
+            raise HTTPException(status_code=400, detail="Invalid OAuth2 state")
+        self._pending.discard(state)
+        return code
+
+
 class SecurityScopes:
     """
     This is a special class that you can define in a parameter in a dependency to

fastapi/security/open_id_connect_url.py

@@ -85,10 +85,11 @@ class OpenIdConnect(SecurityBase):
         )
 
     async def __call__(self, request: Request) -> str | None:
+        from fastapi.security.utils import get_authorization_scheme_param
         authorization = request.headers.get("Authorization")
-        if not authorization:
+        scheme, param = get_authorization_scheme_param(authorization)
+        if not authorization or scheme.lower() != "bearer":
             if self.auto_error:
                 raise self.make_not_authenticated_error()
-            else:
+            return None
-                return None
+        return param   # <-- returns just the token
-        return authorization