This also means that in many cases you can pass the same object you get from a request **directly to the database**, as everything is validated automatically.

The same applies the other way around, in many cases you can just pass the object you get from the database **directly to the client**.

		uploadID        string
		PartID          int
		inputReaderData string
		inputMd5        string
		inputSHA256     string
		inputDataSize   int64
		// flag indicating whether the test should pass.
		shouldPass bool
		// expected error output.
		expectedMd5   string
		expectedError error
	}{
		// Test case  1-4.
		// Cases with invalid bucket name.

class FooBaseModel(BaseModel):
    if PYDANTIC_V2:
        model_config = ConfigDict(extra="forbid")
    else:

        class Config:
            extra = "forbid"


class Foo(FooBaseModel):
    pass


app = FastAPI()


@app.post("/")
async def post(
    foo: Union[Foo, None] = None,
):
    return foo


client = TestClient(app)


def test_call_invalid():

```Python hl_lines="1  13"
{!../../docs_src/background_tasks/tutorial001.py!}
```

**FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.

## Create a task function

Create a function to be run as the background task.

It is just a standard function that can receive parameters.

## Return a `Response`

In fact, you can return any `Response` or any sub-class of it.

/// tip

`JSONResponse` itself is a sub-class of `Response`.

///

And when you return a `Response`, **FastAPI** will pass it directly.

It won't do any data conversion with Pydantic models, it won't convert the contents to any type, etc.

The middleware function receives:

* The `request`.
* A function `call_next` that will receive the `request` as a parameter.
    * This function will pass the `request` to the corresponding *path operation*.
    * Then it returns the `response` generated by the corresponding *path operation*.
* You can then further modify the `response` before returning it.

            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header X-NginX-Proxy true;

            # This is necessary to pass the correct IP to be hashed
            real_ip_header X-Real-IP;

            proxy_connect_timeout 300;
            
            # To support websocket
            proxy_http_version 1.1;

correcte",andSpaces:" et des espaces ",badInt:"Vous n'avez pas saisi un numéro",badSecurityNumber:"Vous avez saisi un mauvais numéro de sécurité sociale",badUKVatAnswer:"Vous n'avez pas saisi un numéro de TVA au Royaume-Uni",badStrength:"Vous avez saisi un mot de passe pas assez sécurisé",badNumberOfSelectedOptionsStart:"Vous devez sélectionner au moins ",badNumberOfSelectedOptionsEnd:" réponse(s)",badAlphaNumeric:"Vous ne pouvez répondre qu'avec des caractères alphanumériques et des chiffres ",badAlphaNumericEx...

In our code example above, we don't use it directly, but we pass it to FastAPI for it to use it.

The `lifespan` parameter of the `FastAPI` app takes an **async context manager**, so we can pass our new `lifespan` async context manager to it.

```Python hl_lines="22"
{!../../docs_src/events/tutorial003.py!}
```

## Alternative Events (deprecated)

            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header X-NginX-Proxy true;

            # This is necessary to pass the correct IP to be hashed
            real_ip_header X-Real-IP;

            proxy_connect_timeout 300;
            
            # To support websocket
            proxy_http_version 1.1;