```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!}
```

Sebastián Ramírez <******@****.***> 1688149516 +0200

    )
    # 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

            <label>Token: <input type="text" id="token" autocomplete="off" value="some-key-token"/></label>
            <button onclick="connect(event)">Connect</button>
            <hr>
            <label>Message: <input type="text" id="messageText" autocomplete="off"/></label>
            <button>Send</button>
        </form>
        <ul id='messages'>
        </ul>
        <script>
        var ws = null;

```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.

Sebastián Ramírez <******@****.***> 1688749933 +0200

# Advanced Middleware

In the main tutorial you read how to add [Custom Middleware](../tutorial/middleware.md){.internal-link target=_blank} to your application.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares

    page = context.new_page()
    page.goto("http://localhost:8000/docs")
    page.get_by_text("GET/items/Read Items").click()
    page.get_by_role("tab", name="Schema").click()
    page.get_by_label("Schema").get_by_role("button", name="Expand all").click()
    page.screenshot(
        path="docs/en/docs/img/tutorial/separate-openapi-schemas/image03.png"
    )

    # ---------------------
    context.close()
    browser.close()

from pydantic import BaseModel

app = FastAPI()

media_type = "application/vnd.api+json"


# NOTE: These are not valid JSON:API resources
# but they are fine for testing requestBody with custom media_type
class Product(BaseModel):
    name: str
    price: float


class Shop(BaseModel):
    name: str


@app.post("/products")