```Python hl_lines="13  15"
{!../../../docs_src/custom_request_and_route/tutorial002.py!}
```

发生异常时，`Request` 实例仍在作用域内，因此处理错误时可以读取和使用请求体：

```Python hl_lines="16-18"
{!../../../docs_src/custom_request_and_route/tutorial002.py!}
```

## 在路由中自定义 `APIRoute` 类

您还可以设置 `APIRoute` 的 `route_class` 参数：

```Python hl_lines="26"
{!../../../docs_src/custom_request_and_route/tutorial003.py!}
```

    )
    # Get custom optional dependencies name to always include in this (non-slim) package
    include_optional_dependencies: List[str] = config.get(
        "include-optional-dependencies", []
    )
    # Override main [project] configs with custom configs for this package
    for key, value in project_config.items():
        metadata[key] = value
    # Get custom build config for the current package

```Python hl_lines="8-9  11  14"
{!../../../docs_src/middleware/tutorial001.py!}
```

!!! tip
    Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

### Custom Generate Unique ID Function

FastAPI uses a **unique ID** for each *path operation*, it is used for the **operation ID** and also for the names of any needed custom models, for requests or responses.

You can customize that function. It takes an `APIRoute` and outputs a string.

            data["client_secret"] = form_data.client_secret
        return data
    ```

    Note that for OAuth2 the scope `items:read` is a single scope in an opaque string.
    You could have custom internal logic to separate it by colon caracters (`:`) or
    similar, and get the two parts `items` and `read`. Many applications do that to
    group and organize permissions, you could do it as well in your application, just

It used custom types in its declarations instead of standard Python types, but it was still a huge step forward.

It also was one of the first frameworks to generate a custom schema declaring the whole API in JSON.

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.

For example:

```Python hl_lines="4-7"

                                }
                            },
                        },
                    },
                },
                "put": {
                    "tags": ["items", "custom"],
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {

                                }
                            },
                        },
                    },
                },
                "put": {
                    "tags": ["items", "custom"],
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {

Sebastián Ramírez <******@****.***> 1706435625 +0100