extra.put("reloadable_ja_stop", JapaneseStopTokenFilterFactory::new);
        extra.put("kanji_number", KanjiNumberFilterFactory::new);
        extra.put("kuromoji_pos_concat", PosConcatenationFilterFactory::new);
        extra.put("char_type", CharTypeFilterFactory::new);
        extra.put("number_concat", NumberConcatenationFilterFactory::new);

There's a whole chapter here in the documentation about it, you can read it at [Additional Responses in OpenAPI](additional-responses.md){.internal-link target=_blank}.

## OpenAPI Extra

When you declare a *path operation* in your application, **FastAPI** automatically generates the relevant metadata about that *path operation* to be included in the OpenAPI schema.

/// note | "Technical details"

	ctx := newContext(r, w, "ListObjectsV2")
	api.listObjectsV2Handler(ctx, w, r, false)
}

// listObjectsV2Handler performs listing either with or without extra metadata.
func (api objectAPIHandlers) listObjectsV2Handler(ctx context.Context, w http.ResponseWriter, r *http.Request, metadata bool) {
	defer logger.AuditLog(ctx, w, r, mustGetClaimsFromToken(r))

	vars := mux.Vars(r)

again.  The Mock Turtle went on.

  `We had the best of educations--in fact, we went to school
every day--'

  `I'VE been to a day-school, too,' said Alice; `you needn't be
so proud as all that.'

  `With extras?' asked the Mock Turtle a little anxiously.

  `Yes,' said Alice, `we learned French and music.'

  `And washing?' said the Mock Turtle.

  `Certainly not!' said Alice indignantly.

            # TODO: remove when deprecating Pydantic v1
            {
                "detail": [
                    {
                        "type": "value_error.extra",
                        "loc": ["cookie", "extra"],
                        "msg": "extra fields not permitted",
                    }
                ]
            }
        )
    )


def test_openapi_schema(client: TestClient):

// must be extracted from the header.
var userMetadataKeyPrefixes = []string{
	"x-amz-meta-",
	"x-minio-meta-",
}

// extractMetadataFromReq extracts metadata from HTTP header and HTTP queryString.
func extractMetadataFromReq(ctx context.Context, r *http.Request) (metadata map[string]string, err error) {

        "/login/", data={"username": "Foo", "password": "secret", "extra": "extra"}
    )
    assert response.status_code == 422
    assert response.json() == {
        "detail": [
            {
                "type": "extra_forbidden",
                "loc": ["body", "extra"],
                "msg": "Extra inputs are not permitted",
                "input": "extra",
            }
        ]
    }


@needs_pydanticv2

///

## Add extra information

You can declare extra information in `Field`, `Query`, `Body`, etc. And it will be included in the generated JSON Schema.

You will learn more about adding extra information later in the docs, when learning to declare examples.

/// warning

Extra keys passed to `Field` will also be present in the resulting OpenAPI schema for your application.

        "parameters": [
            {
                "required": False,
                "schema": {"title": "Extra Param 1"},
                "name": "extra_param_1",
                "in": "query",
            },
            {
                "required": True,
                "schema": {"title": "Extra Param 2"},
                "name": "extra_param_2",
                "in": "query",
            },
        ]
    },

Stefan Wolf <******@****.***> 1633938695 +0200