add_event_handler() — fastapi Function Reference

Architecture documentation for the add_event_handler() function in routing.py from the fastapi codebase.

Function python FastAPI Routing called by 2

Entity Profile

FastAPI→ Routing→ add_event_handler() — fastapi Function Reference

Dependency Diagram

graph TD
  4bbb96be_c308_9252_9434_46c4b5112bf3["add_event_handler()"]
  ecadd3bc_0c58_b4e5_06d8_57da79199adc["APIRouter"]
  4bbb96be_c308_9252_9434_46c4b5112bf3 -->|defined in| ecadd3bc_0c58_b4e5_06d8_57da79199adc
  c1d02f65_9a84_123a_bdd4_304e5732f35a["include_router()"]
  c1d02f65_9a84_123a_bdd4_304e5732f35a -->|calls| 4bbb96be_c308_9252_9434_46c4b5112bf3
  a27c576c_fb92_8398_f37e_212c576404a2["on_event()"]
  a27c576c_fb92_8398_f37e_212c576404a2 -->|calls| 4bbb96be_c308_9252_9434_46c4b5112bf3
  style 4bbb96be_c308_9252_9434_46c4b5112bf3 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

fastapi/routing.py lines 4583–4600

    def add_event_handler(
        self,
        event_type: str,
        func: Callable[[], Any],
    ) -> None:
        """
        Add an event handler function for startup or shutdown.

        This method is kept for backward compatibility after Starlette removed
        support for on_startup/on_shutdown handlers.

        Ref: https://github.com/Kludex/starlette/pull/3117
        """
        assert event_type in ("startup", "shutdown")
        if event_type == "startup":
            self.on_startup.append(func)
        else:
            self.on_shutdown.append(func)