{
                "url": IsOneOf(
                    "http://staging.localhost.tiangolo.com:8000/",
                    # TODO: remove when deprecating Pydantic v1
                    "http://staging.localhost.tiangolo.com:8000",
                ),
                "description": "Staging but actually localhost still",
            },
            {
                "url": IsOneOf(

                    "https://stag.example.com/",
                    # TODO: remove when deprecating Pydantic v1
                    "https://stag.example.com",
                ),
                "description": "Staging environment",
            },
            {
                "url": IsOneOf(
                    "https://prod.example.com/",
                    # TODO: remove when deprecating Pydantic v1

By default, **FastAPI** will create a `server` in the OpenAPI schema with the URL for the `root_path`.

But you can also provide other alternative `servers`, for example if you want *the same* docs UI to interact with a staging and production environments.

If you pass a custom list of `servers` and there's a `root_path` (because your API lives behind a proxy), **FastAPI** will insert a "server" with this `root_path` at the beginning of the list.

Sie können aber auch andere alternative `server` bereitstellen, beispielsweise wenn Sie möchten, dass *dieselbe* Dokumentationsoberfläche mit einer Staging- und Produktionsumgebung interagiert.

from fastapi import FastAPI, Request

app = FastAPI(
    servers=[
        {"url": "https://stag.example.com", "description": "Staging environment"},
        {"url": "https://prod.example.com", "description": "Production environment"},
    ],
    root_path="/api/v1",
)


@app.get("/app")
def read_main(request: Request):

from fastapi import FastAPI, Request

app = FastAPI(
    servers=[
        {"url": "https://stag.example.com", "description": "Staging environment"},
        {"url": "https://prod.example.com", "description": "Production environment"},
    ],
    root_path="/api/v1",
    root_path_in_servers=False,
)


@app.get("/app")
def read_main(request: Request):

                    "https://stag.example.com/",
                    # TODO: remove when deprecating Pydantic v1
                    "https://stag.example.com",
                ),
                "description": "Staging environment",
            },
            {
                "url": IsOneOf(
                    "https://prod.example.com/",
                    # TODO: remove when deprecating Pydantic v1

## 附加的服务器

!!! warning "警告"

    此用例较难，可以跳过。

默认情况下，**FastAPI** 使用 `root_path` 的链接在 OpenAPI 概图中创建 `server`。

但也可以使用其它备选 `servers`，例如，需要同一个 API 文档与 staging 和生产环境交互。

如果传递自定义 `servers` 列表，并有 `root_path`（ 因为 API 使用了代理），**FastAPI** 会在列表开头使用这个 `root_path` 插入**服务器**。

例如：

```Python hl_lines="4-7"
{!../../../docs_src/behind_a_proxy/tutorial003.py!}
```

    But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations ([CORS (Cross-Origin Resource Sharing)](cors.md){.internal-link target=_blank}) using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette's CORS docs</a>.

class="external-link" target="_blank">Verwenden Sie dafür das Präfix 'X-'</a>.

    Wenn Sie jedoch benutzerdefinierte Header haben, die ein Client in einem Browser sehen soll, müssen Sie sie zu Ihrer CORS-Konfigurationen ([CORS (Cross-Origin Resource Sharing)](cors.md){.internal-link target=_blank}) hinzufügen, indem Sie den Parameter `expose_headers` verwenden, der in der <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette-CORS-Dokumentation</a>...