Security() — fastapi Function Reference

Architecture documentation for the Security() function in param_functions.py from the fastapi codebase.

Function python FastAPI Routing

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FastAPI→ Routing→ Security() — fastapi Function Reference

Dependency Diagram

graph TD
  1e2e2816_ce84_abc1_4e93_2eabfb48a792["Security()"]
  24a9a43e_697f_81ce_6a7c_28a423a6f93b["param_functions.py"]
  1e2e2816_ce84_abc1_4e93_2eabfb48a792 -->|defined in| 24a9a43e_697f_81ce_6a7c_28a423a6f93b
  style 1e2e2816_ce84_abc1_4e93_2eabfb48a792 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

fastapi/param_functions.py lines 2373–2461

def Security(  # noqa: N802
    dependency: Annotated[
        Optional[Callable[..., Any]],
        Doc(
            """
            A "dependable" callable (like a function).

            Don't call it directly, FastAPI will call it for you, just pass the object
            directly.

            Read more about it in the
            [FastAPI docs for Dependencies](https://fastapi.tiangolo.com/tutorial/dependencies/)
            """
        ),
    ] = None,
    *,
    scopes: Annotated[
        Optional[Sequence[str]],
        Doc(
            """
            OAuth2 scopes required for the *path operation* that uses this Security
            dependency.

            The term "scope" comes from the OAuth2 specification, it seems to be
            intentionally vague and interpretable. It normally refers to permissions,
            in cases to roles.

            These scopes are integrated with OpenAPI (and the API docs at `/docs`).
            So they are visible in the OpenAPI specification.

            Read more about it in the
            [FastAPI docs about OAuth2 scopes](https://fastapi.tiangolo.com/advanced/security/oauth2-scopes/)
            """
        ),
    ] = None,
    use_cache: Annotated[
        bool,
        Doc(
            """
            By default, after a dependency is called the first time in a request, if
            the dependency is declared again for the rest of the request (for example
            if the dependency is needed by several dependencies), the value will be
            re-used for the rest of the request.

            Set `use_cache` to `False` to disable this behavior and ensure the
            dependency is called again (if declared more than once) in the same request.

            Read more about it in the
            [FastAPI docs about sub-dependencies](https://fastapi.tiangolo.com/tutorial/dependencies/sub-dependencies/#using-the-same-dependency-multiple-times)
            """
        ),
    ] = True,
) -> Any:
    """
    Declare a FastAPI Security dependency.

    The only difference with a regular dependency is that it can declare OAuth2
    scopes that will be integrated with OpenAPI and the automatic UI docs (by default
    at `/docs`).

    It takes a single "dependable" callable (like a function).

    Don't call it directly, FastAPI will call it for you.

    Read more about it in the
    [FastAPI docs for Security](https://fastapi.tiangolo.com/tutorial/security/) and
    in the
    [FastAPI docs for OAuth2 scopes](https://fastapi.tiangolo.com/advanced/security/oauth2-scopes/).

    **Example**

    ```python
    from typing import Annotated

    from fastapi import Security, FastAPI

    from .db import User
    from .security import get_current_active_user

    app = FastAPI()