yield item


@app.get("/items/stream-raw", response_class=EventSourceResponse)
async def sse_items_raw():
    yield ServerSentEvent(raw_data="plain text without quotes")
    yield ServerSentEvent(raw_data="<div>html fragment</div>", event="html")
    yield ServerSentEvent(raw_data="cpu,87.3,1709145600", event="csv")


router = APIRouter()


@router.get("/events", response_class=EventSourceResponse)

    def _check_data_exclusive(self) -> "ServerSentEvent":
        if self.data is not None and self.raw_data is not None:
            raise ValueError(
                "Cannot set both 'data' and 'raw_data' on the same "
                "ServerSentEvent. Use 'data' for JSON-serialized payloads "
                "or 'raw_data' for pre-formatted strings."
            )
        return self


def format_sse_event(
    *,

 */
class HpackRoundTripTest : HpackDecodeTestBase() {
  internal class StoriesTestProvider : SimpleProvider() {
    override fun arguments(): List<Any> = createStories(RAW_DATA)
  }

  private val bytesOut = Buffer()
  private val hpackWriter = Hpack.Writer(out = bytesOut)

  @ParameterizedTest
  @ArgumentsSource(StoriesTestProvider::class)
  fun testRoundTrip(story: Story) {

    yield ServerSentEvent(data={"status": "started"}, event="status", id="1")
    yield ServerSentEvent(data={"progress": 50}, event="progress", id="2")
```

Use `raw_data` instead of `data` to send pre-formatted strings without JSON encoding:

```python
yield ServerSentEvent(raw_data="plain text line", event="log")
```

## Stream bytes

If you need to send data **without** JSON encoding, use `raw_data` instead of `data`.

This is useful for sending pre-formatted text, log lines, or special <dfn title="A value used to indicate a special condition or state">"sentinel"</dfn> values like `[DONE]`.

{* ../../docs_src/server_sent_events/tutorial003_py310.py hl[17] *}

/// note

`data` and `raw_data` are mutually exclusive. You can only set one of them on each `ServerSentEvent`.

        "2025-01-01 INFO  Application started",
        "2025-01-01 DEBUG Connected to database",
        "2025-01-01 WARN  High memory usage detected",
    ]
    for log_line in logs:

async def stream_chat(prompt: Prompt) -> AsyncIterable[ServerSentEvent]:
    words = prompt.text.split()
    for word in words:
        yield ServerSentEvent(data=word, event="token")

`data` 欄位一律會以 JSON 編碼。你可以傳入任何可序列化為 JSON 的值，包括 Pydantic 模型。

## 原始資料 { #raw-data }

如果你需要在**不**進行 JSON 編碼的情況下傳送資料，請使用 `raw_data` 取代 `data`。

這對於傳送已格式化的文字、日誌行或特殊的 <dfn title="用於表示特殊條件或狀態的值">"哨兵"</dfn> 值（例如 `[DONE]`）很有用。

{* ../../docs_src/server_sent_events/tutorial003_py310.py hl[17] *}

/// note

`data` 與 `raw_data` 互斥。每個 `ServerSentEvent` 只能設定其中一個。

///

## 使用 `Last-Event-ID` 繼續 { #resuming-with-last-event-id }

`data` 字段始终会被编码为 JSON。你可以传入任何可被序列化为 JSON 的值，包括 Pydantic 模型。

## 原始数据 { #raw-data }

如果你需要发送**不**进行 JSON 编码的数据，请使用 `raw_data` 而不是 `data`。

这对于发送预格式化文本、日志行或特殊的 <dfn title="用于指示特殊条件或状态的值">"哨兵"</dfn> 值（例如 `[DONE]`）很有用。

{* ../../docs_src/server_sent_events/tutorial003_py310.py hl[17] *}

/// note | 注意

`data` 和 `raw_data` 是互斥的。每个 `ServerSentEvent` 上只能设置其中一个。

///

## 使用 `Last-Event-ID` 恢复 { #resuming-with-last-event-id }

## 원시 데이터 { #raw-data }

JSON 인코딩 없이 데이터를 보내야 한다면, `data` 대신 `raw_data`를 사용하세요.

미리 포맷된 텍스트, 로그 라인, 또는 `[DONE]`과 같은 특수한 <dfn title="특수한 조건이나 상태를 나타내는 데 사용되는 값">"센티널"</dfn> 값을 보낼 때 유용합니다.

{* ../../docs_src/server_sent_events/tutorial003_py310.py hl[17] *}

/// note | 참고

`data`와 `raw_data`는 상호 배타적입니다. 각 `ServerSentEvent`에는 이 둘 중 하나만 설정할 수 있습니다.

///