出于方便，**FastAPI** 会提供与 `starlette.responses` 相同的 `fastapi.responses` 给开发者。但是大多数可用的响应都直接来自 Starlette。

///

## 返回自定义 `Response`

上面的例子展示了需要的所有部分，但还不够实用，因为你本可以只是直接返回 `item`，而**FastAPI** 默认帮你把这个 `item` 放到 `JSONResponse` 中，又默认将其转换成了 `dict`等等。

现在，让我们看看你如何才能返回一个自定义的响应。

假设你想要返回一个 <a href="https://en.wikipedia.org/wiki/XML" class="external-link" target="_blank">XML</a> 响应。

    projectId = AbsoluteId("Gradle_Master")
    settingsRootId = AbsoluteId("GradleMaster")
    settingsRoot.name = "GradleMaster"
    addParameters("branch" to "master")
}

                    "properties": {
                        "errors": {
                            "title": "Errors",
                            "type": "array",
                            "items": {"$ref": "#/components/schemas/Error"},
                        }
                    },
                },
            }
        },

	for len(r.current) <= r.recordsRead {
		if r.err != nil {
			return nil, r.err
		}
		// Move to next block
		item, ok := <-r.queue
		if !ok {
			r.err = io.EOF
			return nil, r.err
		}
		r.kvDstPool.Put(r.current)
		r.current = <-item.dst
		r.err = item.err
		r.recordsRead = 0
	}
	kvRecord := r.current[r.recordsRead]
	r.recordsRead++

	dstRec, ok := dst.(*Record)
	if !ok {

def query_or_cookie_extractor(
    q: str = Depends(query_extractor),
    last_query: Union[str, None] = Cookie(default=None),
):
    if not q:
        return last_query
    return q


@app.get("/items/")
async def read_query(query_or_default: str = Depends(query_or_cookie_extractor)):

    limit: int = Field(100, gt=0, le=100)
    offset: int = Field(0, ge=0)
    order_by: Literal["created_at", "updated_at"] = "created_at"
    tags: list[str] = []


@app.get("/items/")
async def read_items(filter_query: Annotated[FilterParams, Query()]):

app = FastAPI()


async def common_parameters(
    q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
    return commons


@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):

        "size": len(raw_body),
        "content": {
            "name": "Maaaagic",
            "price": 42,
            "description": "Just kiddin', no magic here. ✨",
        },
    }


@app.post(
    "/items/",
    openapi_extra={
        "requestBody": {
            "content": {
                "application/json": {
                    "schema": {
                        "required": ["name", "price"],

from datetime import datetime, time, timedelta
from typing import Union
from uuid import UUID

from fastapi import Body, FastAPI

app = FastAPI()


@app.put("/items/{item_id}")
async def read_items(
    item_id: UUID,
    start_datetime: datetime = Body(),
    end_datetime: datetime = Body(),
    process_after: timedelta = Body(),
    repeat_at: Union[time, None] = Body(default=None),
):

    * `url` (**obrigatório**): uma `str` com a URL da documentação externa.

### Criar Metadados para tags { #create-metadata-for-tags }

Vamos tentar isso em um exemplo com tags para `users` e `items`.

Crie metadados para suas tags e passe-os para o parâmetro `openapi_tags`:

{* ../../docs_src/metadata/tutorial004_py39.py hl[3:16,18] *}