* `summary`: A short summary of the API.
* `description`: The description of your API, this can include markdown and will be shown in the docs.
* `routes`: A list of routes, these are each of the registered *path operations*. They are taken from `app.routes`.

!!! info
    The parameter `summary` is available in OpenAPI 3.1.0 and above, supported by FastAPI 0.99.0 and above.

## Overriding the defaults

至此，在上文创建的回调路由里就包含了*回调路径操作*（外部开发者要在外部 API 中实现）。

现在使用 API *路径操作装饰器*的参数 `callbacks`，从回调路由传递属性 `.routes`（实际上只是路由/路径操作的**列表**）：

```Python hl_lines="36"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip "提示"

    注意，不能把路由本身（`invoices_callback_router`）传递给 `callback=`，要传递 `invoices_callback_router.routes` 中的 `.routes` 属性。

### 查看文档

 *     a race in fast follow-up.
 *
 *  4. If there's no existing connection, make a list of routes (which may require blocking DNS
 *     lookups) and attempt a new connection them. When failures occur, retries iterate the list of
 *     available routes.
 *
 * If the pool gains an eligible connection while DNS, TCP, or TLS work is in flight, this finder

🔜 ⚙️ 🔢 `callbacks` *👆 🛠️ ➡ 🛠️ 👨‍🎨* 🚶‍♀️ 🔢 `.routes` (👈 🤙 `list` 🛣/*➡ 🛠️*) ⚪️➡️ 👈 ⏲ 📻:

```Python hl_lines="35"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip
    👀 👈 👆 🚫 🚶‍♀️ 📻 ⚫️ (`invoices_callback_router`) `callback=`, ✋️ 🔢 `.routes`, `invoices_callback_router.routes`.

### ✅ 🩺

   *
   * If [routes] is non-null these are the resolved routes (ie. IP addresses) for the connection.
   * This is used to coalesce related domains to the same HTTP/2 connection, such as `square.com`
   * and `square.ca`.
   */
  fun callAcquirePooledConnection(
    doExtensiveHealthChecks: Boolean,
    address: Address,
    connectionUser: ConnectionUser,
    routes: List<Route>?,

* `summary`: Eine kurze Zusammenfassung der API.
* `description`: Die Beschreibung Ihrer API. Dies kann Markdown enthalten und wird in der Dokumentation angezeigt.
* `routes`: Eine Liste von Routen, dies sind alle registrierten *Pfadoperationen*. Sie stammen von `app.routes`.

!!! info
    Der Parameter `summary` ist in OpenAPI 3.1.0 und höher verfügbar und wird von FastAPI 0.99.0 und höher unterstützt.

## Überschreiben der Standardeinstellungen

& 👈 🔢 `get_openapi()` 📨 🔢:

* `title`: 🗄 📛, 🎦 🩺.
* `version`: ⏬ 👆 🛠️, ✅ `2.5.0`.
* `openapi_version`: ⏬ 🗄 🔧 ⚙️. 🔢, ⏪: `3.0.2`.
* `description`: 📛 👆 🛠️.
* `routes`: 📇 🛣, 👫 🔠 ® *➡ 🛠️*. 👫 ✊ ⚪️➡️ `app.routes`.

## 🔑 🔢

⚙️ ℹ 🔛, 👆 💪 ⚙️ 🎏 🚙 🔢 🏗 🗄 🔗 & 🔐 🔠 🍕 👈 👆 💪.

[entryPoints]
  [entryPoints.http]
    address = ":9999"

[providers]
  [providers.file]
    filename = "routes.toml"
```

这个文件把 Traefik 监听端口设置为 `9999`，并设置要使用另一个文件 `routes.toml`。

!!! tip "提示"

    使用端口 9999 代替标准的 HTTP 端口 80，这样就不必使用管理员权限运行（`sudo`）。

接下来，创建 `routes.toml`：

```TOML hl_lines="5  12  20"
[http]
  [http.middlewares]

    [http.middlewares.api-stripprefix.stripPrefix]

    address = ":9999"

[providers]
  [providers.file]
    filename = "routes.toml"
```

This tells Traefik to listen on port 9999 and to use another file `routes.toml`.

!!! tip
    We are using port 9999 instead of the standard HTTP port 80 so that you don't have to run it with admin (`sudo`) privileges.

Now create that other file `routes.toml`:

```TOML hl_lines="5  12  20"
[http]
  [http.middlewares]

   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked prior to a proxy selection.
   *
   * This will be invoked for route selection regardless of whether the client