And if the server is restarted (for example after updates, or migrations from the cloud provider) you probably **won't notice it**. And because of that, you won't even know that you have to restart the process manually. So, your API will just stay dead. 😱

### Run Automatically on Startup

* Then it detects that it has to use the worker class at `uvicorn.workers.UvicornWorker`.
* And then it starts **4 workers**, each with its own PID: `19511`, `19513`, `19514`, and `19515`.

Gunicorn would also take care of managing **dead processes** and **restarting** new ones if needed to keep the number of workers. So that helps in part with the **restart** concept from the list above.

#### Operation

„Operation“ bezieht sich hier auf eine der HTTP-„Methoden“.

Eine von diesen:

* `POST`
* `GET`
* `PUT`
* `DELETE`

... und die etwas Exotischeren:

* `OPTIONS`
* `HEAD`
* `PATCH`
* `TRACE`

Im HTTP-Protokoll können Sie mit jedem Pfad über eine (oder mehrere) dieser „Methoden“ kommunizieren.

---

...and the more exotic ones:

* `OPTIONS`
* `HEAD`
* `PATCH`
* `TRACE`

In the HTTP protocol, you can communicate to each path using one (or more) of these "methods".

---

When building APIs, you normally use these specific HTTP methods to perform a specific action.

Normally you use:

* `POST`: to create data.
* `GET`: to read data.
* `PUT`: to update data.
* `DELETE`: to delete data.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

The next sections assume you already read the main [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

接收到新的请求时，**FastAPI** 执行如下操作：

* 用正确的参数调用依赖项函数（「可依赖项」）
* 获取函数返回的结果
* 把函数返回的结果赋值给*路径操作函数*的参数

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

这样，只编写一次代码，**FastAPI** 就可以为多个*路径操作*共享这段代码 。

!!! check "检查"

    注意，无需创建专门的类，并将之传递给 **FastAPI** 以进行「注册」或执行类似的操作。

```Python hl_lines="10  12-13"
{!../../../docs_src/middleware/tutorial001.py!}
```

## Other middlewares

You can later read more about other middlewares in the [Advanced User Guide: Advanced Middleware](../advanced/middleware.md){.internal-link target=_blank}.

* `read(size)`: ✍ `size` (`int`) 🔢/🦹 📁.
* `seek(offset)`: 🚶 🔢 🧘 `offset` (`int`) 📁.
    * 🤶 Ⓜ., `await myfile.seek(0)` 🔜 🚶 ▶️ 📁.
    * 👉 ✴️ ⚠ 🚥 👆 🏃 `await myfile.read()` 🕐 & ⤴️ 💪 ✍ 🎚 🔄.
* `close()`: 🔐 📁.

🌐 👫 👩‍🔬 `async` 👩‍🔬, 👆 💪 "⌛" 👫.

🖼, 🔘 `async` *➡ 🛠️ 🔢* 👆 💪 🤚 🎚 ⏮️:

```Python
contents = await myfile.read()
```

* `write(data)`: `data`(`str` 또는 `bytes`)를 파일에 작성합니다.
* `read(size)`: 파일의 바이트 및 글자의 `size`(`int`)를 읽습니다.
* `seek(offset)`: 파일 내 `offset`(`int`) 위치의 바이트로 이동합니다.
    * 예) `await myfile.seek(0)` 를 사용하면 파일의 시작부분으로 이동합니다.
    * `await myfile.read()` 를 사용한 후 내용을 다시 읽을 때 유용합니다.
* `close()`: 파일을 닫습니다.

상기 모든 메소드들이 `async` 메소드이기 때문에 “await”을 사용하여야 합니다.

            - openapi
            - websocket
            - include_router
            - get
            - put
            - post
            - delete
            - options
            - head
            - patch
            - trace
            - on_event
            - middleware