SSE 是一種透過 HTTP 從伺服器向用戶端串流傳送資料的標準。

每個事件都是一個小型文字區塊，包含 `data`、`event`、`id` 和 `retry` 等「欄位」，並以空白行分隔。

看起來像這樣：

```
data: {"name": "Portal Gun", "price": 999.99}

data: {"name": "Plumbus", "price": 32.99}

```

SSE 常用於 AI 聊天串流、即時通知、日誌與可觀察性，以及其他由伺服器主動推送更新給用戶端的情境。

/// tip

如果你要串流二進位資料，例如影片或音訊，請參考進階指南：[串流資料](../advanced/stream-data.md)。

///

## 使用 FastAPI 串流 SSE { #stream-sse-with-fastapi }

 * Callback interface for handling index update operations during data store processing.
 * This interface provides methods for storing documents, tracking processing metrics,
 * and committing changes to the search index.
 */
public interface IndexUpdateCallback {

    /**
     * Stores a document in the search index with the specified parameters and data.
     *
     * @param paramMap the data store parameters containing configuration and metadata

        }
        resultData.setEncoding(fessConfig.getCrawlerCrawlingDataEncoding());

        return resultData;
    }

    /**
     * Generate the data.
     * @param responseData The response data.
     * @return The data.
     */
    protected Map<String, Object> generateData(final ResponseData responseData) {
        final CrawlingConfigHelper crawlingConfigHelper = ComponentUtil.getCrawlingConfigHelper();

				ModTime:   timeSentinel1970,
			}, nil
		}
		inData = xlMeta.data
		fi, err = xlMeta.ToFileInfo(volume, path, versionID, opts.InclFreeVersions, true)
	}
	if !opts.Data || err != nil {
		return fi, err
	}
	versionID = fi.VersionID
	if versionID == "" {
		versionID = nullVersionID
	}

	fi.Data = inData.find(versionID)
	if len(fi.Data) == 0 {
		// PR #11758 used DataDir, preserve it

        SMBUtil.writeInt2(17, buffer, bodyStart);
        // Data offset (byte - offset from header start)
        buffer[bodyStart + 2] = (byte) dataOffsetFromHeader;
        // Reserved
        buffer[bodyStart + 3] = 0;
        // Data length
        SMBUtil.writeInt4(dataLength, buffer, bodyStart + 4);
        // Data remaining
        SMBUtil.writeInt4(dataRemaining, buffer, bodyStart + 8);

The files and form fields will be uploaded as form data and you will receive the files and form fields.

And you can declare some of the files as `bytes` and some as `UploadFile`.

/// warning

You can declare multiple `File` and `Form` parameters in a *path operation*, but you can't also declare `Body` fields that you expect to receive as JSON, as the request will have the body encoded using `multipart/form-data` instead of `application/json`.

@app.get("/events", response_class=EventSourceResponse)
async def stream_events() -> AsyncIterable[ServerSentEvent]:
    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")
```

                passedData.set(data);
                return false;
            }
        };

        helper.tryStartOperation("test_op");
        assertNull(passedData.get());
    }

    @Test
    public void test_tryStartOperation_twoArg_usesConfigRetry() {
        // tryStartOperation(name, data) should read maxRetry from FessConfig

from fastapi.testclient import TestClient

app_default = FastAPI()


@app_default.post("/items/")
async def app_default_post(data: dict):
    return data


app_lax = FastAPI(strict_content_type=False)


@app_lax.post("/items/")
async def app_lax_post(data: dict):
    return data


client_default = TestClient(app_default)
client_lax = TestClient(app_lax)

    void testReadWireFormat() throws IOException {
        byte[] data = new byte[50];
        data[0] = (byte) 0x85; // SESSION_KEEP_ALIVE
        data[1] = 0x00;
        data[2] = 0x00;
        data[3] = 0x0A; // Length = 10

        ByteArrayInputStream bais = new ByteArrayInputStream(data);

        int totalRead = packet.readWireFormat(bais, data, 0);

        assertEquals(14, totalRead); // 4 header + 10 trailer