include_in_schema: bool = True,
        json_schema_extra: dict[str, Any] | None = None,
        **extra: Any,
    ):
        self.embed = embed
        self.media_type = media_type
        if example is not _Unset:
            warnings.warn(
                "`example` has been deprecated, please use `examples` instead",
                category=FastAPIDeprecationWarning,

```python
from fastapi import FastAPI
from fastapi.responses import StreamingResponse
from app.utils import read_image

app = FastAPI()


class PNGStreamingResponse(StreamingResponse):
    media_type = "image/png"

@app.get("/image", response_class=PNGStreamingResponse)
def stream_image_no_async_no_annotation():
    with read_image() as image_file:
        yield from image_file
```

binary_image = base64.b64decode(image_base64)


def read_image() -> BytesIO:
    return BytesIO(binary_image)


app = FastAPI()


class PNGStreamingResponse(StreamingResponse):
    media_type = "image/png"


@app.get("/image/stream", response_class=PNGStreamingResponse)
async def stream_image() -> AsyncIterable[bytes]:
    with read_image() as image_file:
        for chunk in image_file:

* `content` - A `str` or `bytes`.
* `status_code` - An `int` HTTP status code.
* `headers` - A `dict` of strings.
* `media_type` - A `str` giving the media type. E.g. `"text/html"`.

FastAPI (actually Starlette) will automatically include a Content-Length header. It will also include a Content-Type header, based on the `media_type` and appending a charset for text types.

{* ../../docs_src/response_directly/tutorial002_py310.py hl[1,18] *}

            """
        ),
    ],
) -> Any:
    return params.Body(
        default=default,
        default_factory=default_factory,
        embed=embed,
        media_type=media_type,
        alias=alias,
        alias_priority=alias_priority,
        validation_alias=validation_alias,
        serialization_alias=serialization_alias,
        title=title,

你也可以直接回傳它。

它接受以下參數：

- `content` - `str` 或 `bytes`。
- `status_code` - `int` 類型的 HTTP 狀態碼。
- `headers` - 由字串組成的 `dict`。
- `media_type` - 描述 media type 的 `str`。例如 `"text/html"`。

FastAPI（實際上是 Starlette）會自動包含 Content-Length 標頭。也會根據 `media_type`（並為文字型別附加 charset）包含 Content-Type 標頭。

{* ../../docs_src/response_directly/tutorial002_py310.py hl[1,18] *}

### `HTMLResponse` { #htmlresponse }

                        )
                        media_type = route_response_media_type or "application/json"
                        additional_schema = (
                            process_response.setdefault("content", {})
                            .setdefault(media_type, {})
                            .setdefault("schema", {})
                        )

    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：