不过，仍可以验证、转换与注释（使用 Pydantic 模型的请求体等）其它正常声明的参数。

但在某些特定情况下，还是需要提取 `Request` 对象。

## 直接使用 `Request` 对象

假设要在*路径操作函数*中获取客户端 IP 地址和主机。

此时，需要直接访问请求。

```Python hl_lines="1  7-8"
{!../../../docs_src/using_request_directly/tutorial001.py!}
```

把*路径操作函数*的参数类型声明为 `Request`，**FastAPI** 就能把 `Request` 传递到参数里。

!!! tip "提示"

    注意，本例除了声明请求参数之外，还声明了路径参数。

    因此，能够提取、验证路径参数、并转换为指定类型，还可以用 OpenAPI 注释。

    This allows you to use `pytest` directly without complications.

!!! note "Technical Details"
    You could also use `from starlette.testclient import TestClient`.

    **FastAPI** provides the same `starlette.testclient` as `fastapi.testclient` just as a convenience for you, the developer. But it comes directly from Starlette.

!!! tip

# `Request` class

You can declare a parameter in a *path operation function* or dependency to be of type `Request` and then you can access the raw request object directly, without any validation, etc.

You can import it directly from `fastapi`:

```python
from fastapi import Request
```

!!! tip

* **Uvicorn**:
    * Will have the best performance, as it doesn't have much extra code apart from the server itself.

You can declare a parameter in a *path operation function* or dependency function with the type `BackgroundTasks`, and then you can use it to schedule the execution of background tasks after the response is sent.

You can import it directly from `fastapi`:

```python
from fastapi import BackgroundTasks
```

<a href="https://github.com/containous/traefik/releases" class="external-link" target="_blank">Download Traefik</a>, it's a single binary, you can extract the compressed file and run it directly from the terminal.

Then create a file `traefik.toml` with:

```TOML hl_lines="3"
[entryPoints]
  [entryPoints.http]
    address = ":9999"

[providers]
  [providers.file]

        Optional[Callable[..., Any]],
        Doc(
            """
            A "dependable" callable (like a function).

            Don't call it directly, FastAPI will call it for you, just pass the object
            directly.
            """
        ),
    ] = None,
    *,
    use_cache: Annotated[
        bool,
        Doc(
            """

### Return a Response Directly

The most common case would be [returning a Response directly as explained later in the advanced docs](../advanced/response-directly.md){.internal-link target=_blank}.

```Python hl_lines="8  10-11"
{!> ../../../docs_src/response_model/tutorial003_02.py!}
```

!!! check "**FastAPI** uses it to"
    Handle all the core web parts. Adding features on top.

    The class `FastAPI` itself inherits directly from the class `Starlette`.

    So, anything that you can do with Starlette, you can do it directly with **FastAPI**, as it is basically Starlette on steroids.

### <a href="https://www.uvicorn.org/" class="external-link" target="_blank">Uvicorn</a>

#### Check the `openapi.json`

If you are curious about how the raw OpenAPI schema looks like, FastAPI automatically generates a JSON (schema) with the descriptions of all your API.

You can see it directly at: <a href="http://127.0.0.1:8000/openapi.json" class="external-link" target="_blank">http://127.0.0.1:8000/openapi.json</a>.

It will show a JSON starting with something like:

```JSON
{
    "openapi": "3.1.0",