That's what we'll solve, let's load the model before the requests are handled, but only right before the application starts receiving requests, not while  the code is being loaded.

## Lifespan { #lifespan }

**FastAPI** provides it as a convenience for you, the developer. But it comes directly from Starlette.

///

### Before and after the `response` { #before-and-after-the-response }

You can add code to be run with the `request`,  before any *path operation* receives it.

And also after the `response` is generated, before returning it.

    public String csvFileEncoding;

    /**
     * Number of days to keep search logs before purging.
     * Set to -1 to disable automatic purging of search logs.
     */
    @Min(-1)
    @Max(100000)
    @ValidateTypeFailure
    public Integer purgeSearchLogDay;

    /**
     * Number of days to keep job logs before purging.
     * Set to -1 to disable automatic purging of job logs.
     */
    @Min(-1)

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")

Make sure you [Upgrade the FastAPI version](../deployment/versions.md#upgrading-the-fastapi-versions){.internal-link target=_blank} to at least 0.95.1 before using `Annotated`.

///

## Use `Annotated` in the type for the `q` parameter { #use-annotated-in-the-type-for-the-q-parameter }

This guide will help you to...

* maximize the chance of your changes being accepted
* work on the Gradle code base
* get help if you encounter trouble

## Before you start

Before starting to work on a feature or a bug fix, please open an issue to discuss the use case or bug with us, or post a comment in the relevant issue. 
This can save everyone a lot of time and frustration.

For example you could use it to add metadata for a frontend user interface, etc.

///

/// info

OpenAPI 3.1.0 (used since FastAPI 0.99.0) added support for `examples`, which is part of the **JSON Schema** standard.

Before that, it only supported the keyword `example` with a single example. That is still supported by OpenAPI 3.1.0, but is deprecated and is not part of the JSON Schema standard. So you are encouraged to migrate `example` to `examples`. 🤓

{* ../../docs_src/dependencies/tutorial008e_an_py39.py hl[12,16] *}

`Depends()` receives a `scope` parameter that can be:

from fastapi import Depends, FastAPI

app = FastAPI()


def get_username():
    try:
        yield "Rick"
    finally:
        print("Cleanup up before response is sent")


@app.get("/users/me")
def get_user_me(username: str = Depends(get_username, scope="function")):