SSE es un estándar para hacer streaming de datos desde el servidor al cliente sobre HTTP.

Cada evento es un pequeño bloque de texto con “campos” como `data`, `event`, `id` y `retry`, separados por líneas en blanco.

Se ve así:

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

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

```

## What are Server-Sent Events? { #what-are-server-sent-events }

SSE is a standard for streaming data from the server to the client over HTTP.

Each event is a small text block with "fields" like `data`, `event`, `id`, and `retry`, separated by blank lines.

It looks like this:

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

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

```

    }

    // ===================================================================================
    //                                                             Retry Limit
    //                                                             ============

    @Test
    public void test_tryStartOperation_singleArg_delegatesToTwoArg() {

```

це означатиме, що ви використовуватимете версії `0.112.0` і вище, але менше `0.113.0`, наприклад, версія `0.112.2` все ще буде прийнятною.

Якщо ви використовуєте інший інструмент для керування встановленнями, як-от `uv`, Poetry, Pipenv чи інші, у всіх них є спосіб визначати конкретні версії для ваших пакетів.

## Доступні версії { #available-versions }

public enum RequestParam {

    /**
     * No special request parameters.
     */
    NONE,

    /**
     * Wait indefinitely for a response
     */
    NO_TIMEOUT,

    /**
     * Do not retry request on failure
     */
    NO_RETRY,

    /**
     * Save the raw payload for further inspection
     */
    RETAIN_PAYLOAD

 *  Fix: Improve `CONNECT` handling for misbehaving HTTP proxies.
 *  Fix: Don't retry requests that failed due to timeouts.
 *  Fix: Cache 302s and 308s that include appropriate response headers.
 *  Fix: Improve pooling of connections that use proxy selectors.
 *  Fix: Don't leak connections when using ALPN on the desktop.
 *  Fix: Update Jetty ALPN to `7.1.2.v20141202` (Java 7) and `8.1.2.v20141202` (Java 8).

/// info

在 FastAPI 0.135.0 新增。

///

## 什麼是 Server-Sent Events？ { #what-are-server-sent-events }

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

guava-jre = { module = "com.google.guava:guava", version.ref = "guava" }
http-client5 = { module = "org.apache.httpcomponents.client5:httpclient5", version.ref = "http-client5" }
jetty-client = { module = "org.eclipse.jetty:jetty-client", version.ref = "jetty-client" }
jnr-unixsocket = { module = "com.github.jnr:jnr-unixsocket", version.ref = "jnr-unixsocket" }
jsoup = { module = "org.jsoup:jsoup", version.ref = "jsoup" }

 */
fun interface Dns {
  /**
   * Returns the IP addresses of `hostname`, in the order they will be attempted by OkHttp. If a
   * connection to an address fails, OkHttp will retry the connection with the next address until
   * either a connection is made, the set of IP addresses is exhausted, or a limit is exceeded.
   */
  @Throws(UnknownHostException::class)

async def stream_items() -> AsyncIterable[Item]:
    yield Item(name="Plumbus", price=32.99)
    yield Item(name="Portal Gun", price=999.99)
```

For full control over SSE fields (`event`, `id`, `retry`, `comment`), yield `ServerSentEvent` instances:

```python
from collections.abc import AsyncIterable

from fastapi import FastAPI
from fastapi.sse import EventSourceResponse, ServerSentEvent

app = FastAPI()