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_DefaultLifespan Class — fastapi Architecture

Architecture documentation for the _DefaultLifespan class in routing.py from the fastapi codebase.

Class python FastAPI

Entity Profile

Dependency Diagram

graph TD
  867570c5_b33e_95c7_0468_a87f8aae6ca1["_DefaultLifespan"]
  de395a51_26f8_3424_1af0_2f5bef39c893["routing.py"]
  867570c5_b33e_95c7_0468_a87f8aae6ca1 -->|defined in| de395a51_26f8_3424_1af0_2f5bef39c893
  d3c3984c_0be8_b8a8_e206_e5bf01ce1530["__init__()"]
  867570c5_b33e_95c7_0468_a87f8aae6ca1 -->|method| d3c3984c_0be8_b8a8_e206_e5bf01ce1530
  02d6cbe5_9949_3a5f_4f41_ee05399bd61e["__aenter__()"]
  867570c5_b33e_95c7_0468_a87f8aae6ca1 -->|method| 02d6cbe5_9949_3a5f_4f41_ee05399bd61e
  0bcce1e6_c4c6_e1ff_31ae_19d689ccec1d["__aexit__()"]
  867570c5_b33e_95c7_0468_a87f8aae6ca1 -->|method| 0bcce1e6_c4c6_e1ff_31ae_19d689ccec1d
  4cf8e38d_9a32_29bb_8e5e_a7062495ed3b["__call__()"]
  867570c5_b33e_95c7_0468_a87f8aae6ca1 -->|method| 4cf8e38d_9a32_29bb_8e5e_a7062495ed3b

Relationship Graph

Source Code

fastapi/routing.py lines 213–234

class _DefaultLifespan:
    """
    Default lifespan context manager that runs on_startup and on_shutdown handlers.

    This is a copy of the Starlette _DefaultLifespan class that was removed
    in Starlette. FastAPI keeps it to maintain backward compatibility with
    on_startup and on_shutdown event handlers.

    Ref: https://github.com/Kludex/starlette/pull/3117
    """

    def __init__(self, router: "APIRouter") -> None:
        self._router = router

    async def __aenter__(self) -> None:
        await self._router._startup()

    async def __aexit__(self, *exc_info: object) -> None:
        await self._router._shutdown()

    def __call__(self: _T, app: object) -> _T:
        return self

Domain

Defined In

Source

Frequently Asked Questions

What is the _DefaultLifespan class?
_DefaultLifespan is a class in the fastapi codebase, defined in fastapi/routing.py.
Where is _DefaultLifespan defined?
_DefaultLifespan is defined in fastapi/routing.py at line 213.

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