- media_type
            - body
            - background
            - raw_headers
            - render
            - init_headers
            - headers
            - set_cookie
            - delete_cookie

::: fastapi.responses.PlainTextResponse
    options:
        members:
            - charset
            - status_code
            - media_type
            - body

@app.post("/shops")
async def create_shop(
    data: Shop = Body(media_type=media_type),
    included: list[Product] = Body(default=[], media_type=media_type),
):
    pass  # pragma: no cover


client = TestClient(app)


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == snapshot(
        {

from typing import Any

import orjson
from fastapi import FastAPI, Response

app = FastAPI()


class CustomORJSONResponse(Response):
    media_type = "application/json"

    def render(self, content: Any) -> bytes:
        assert orjson is not None, "orjson must be installed"
        return orjson.dumps(content, option=orjson.OPT_INDENT_2)


@app.get("/", response_class=CustomORJSONResponse)
async def main():

@app.get("/")
def main():
    def iterfile():  # (1)
        with open(some_file_path, mode="rb") as file_like:  # (2)
            yield from file_like  # (3)

            "description": "Return the JSON item or an image.",
        }
    },
)
async def read_item(item_id: str, img: bool | None = None):
    if img:
        return FileResponse("image.png", media_type="image/png")
    else:

from fastapi import APIRouter, FastAPI
from fastapi.responses import HTMLResponse, JSONResponse, PlainTextResponse
from fastapi.testclient import TestClient


class OverrideResponse(JSONResponse):
    media_type = "application/x-override"


app = FastAPI()
router_a = APIRouter()
router_a_a = APIRouter()
router_a_b_override = APIRouter()  # Overrides default class
router_b_override = APIRouter()  # Overrides default class

    with protocols like MCP that stream SSE over `POST`.

    The actual encoding logic lives in the FastAPI routing layer. This class
    serves mainly as a marker and sets the correct `Content-Type`.
    """

    media_type = "text/event-stream"


def _check_id_no_null(v: str | None) -> str | None:
    if v is not None and "\0" in v:
        raise ValueError("SSE 'id' must not contain null characters")
    return v

For example, you can create a `PNGStreamingResponse` that sets the `Content-Type` header to `image/png` using the `media_type` attribute:

{* ../../docs_src/stream_data/tutorial002_py310.py ln[6,19:20] hl[20] *}

Then you can use this new class in `response_class=PNGStreamingResponse` in your *path operation function*:

在上述範例中，雖然串流了資料位元組，但回應沒有 `Content-Type` 標頭，因此用戶端不知道接收到的是哪種資料型別。

你可以建立 `StreamingResponse` 的自訂子類別，將 `Content-Type` 標頭設定為你要串流的資料型別。

例如，你可以建立 `PNGStreamingResponse`，透過 `media_type` 屬性把 `Content-Type` 設為 `image/png`：

{* ../../docs_src/stream_data/tutorial002_py310.py ln[6,19:20] hl[20] *}

接著在路徑操作函式中用 `response_class=PNGStreamingResponse` 使用這個新類別：

在上面的示例中，虽然按字节流式传输了数据，但响应没有 `Content-Type` 头，因此客户端不知道接收到的数据类型。

你可以创建 `StreamingResponse` 的自定义子类，将 `Content-Type` 头设置为你要流式传输的数据类型。

例如，你可以创建一个 `PNGStreamingResponse`，通过 `media_type` 属性把 `Content-Type` 头设置为 `image/png`：

{* ../../docs_src/stream_data/tutorial002_py310.py ln[6,19:20] hl[20] *}

然后你可以在*路径操作函数*中通过 `response_class=PNGStreamingResponse` 使用这个新类：