This actually inspired updating parts of Pydantic, to support the same validation declaration style (all this functionality is now already available in Pydantic).

///

### <a href="https://github.com/hugapi/hug" class="external-link" target="_blank">Hug</a>

Hug was one of the first frameworks to implement the declaration of API parameter types using Python type hints. This was a great idea that inspired other tools to do the same.

* **Extensible**:
    * Pydantic permite que se definan tipos de datos a la medida o puedes extender la validación con métodos en un modelo decorado con el <abbr title="en inglés: validator decorator"> decorador de validación</abbr>.

{!../../docs_src/first_steps/tutorial001.py!}
```

`@app.get("/")` 告诉 **FastAPI** 在它下方的函数负责处理如下访问请求：

* 请求路径为 `/`
* 使用 <abbr title="HTTP GET 方法"><code>get</code> 操作</abbr>

/// info | "`@decorator` Info"

`@something` 语法在 Python 中被称为「装饰器」。

像一顶漂亮的装饰帽一样，将它放在一个函数的上方（我猜测这个术语的命名就是这么来的）。

装饰器接收位于其下方的函数并且用它完成一些工作。

在我们的例子中，这个装饰器告诉 **FastAPI** 位于其下方的函数对应着**路径** `/` 加上 `get` **操作**。

    * Bạn có thể có các object **JSON lồng nhau** và tất cả chúng đã validate và annotated.
* **Có khả năng mở rộng**:
    * Pydantic cho phép bạn tùy chỉnh kiểu dữ liệu bằng việc định nghĩa hoặc bạn có thể mở rộng validation với các decorator trong model.

```Python
def get_settings():
    return Settings()
```

we would create that object for each request, and we would be reading the `.env` file for each request. ⚠️

But as we are using the `@lru_cache` decorator on top, the `Settings` object will be created only once, the first time it's called. ✔️

//// tab | Python 3.9+

```Python hl_lines="1  11"
{!> ../../docs_src/settings/app03_an_py39/main.py!}
```

////

{!../../docs_src/first_steps/tutorial001.py!}
```
`@app.get("/")`は直下の関数が下記のリクエストの処理を担当することを**FastAPI**に伝えます:

* パス `/`
* <abbr title="an HTTP GET method"><code>get</code> オペレーション</abbr>

/// info | "`@decorator` について"

Pythonにおける`@something`シンタックスはデコレータと呼ばれます。

「デコレータ」は関数の上に置きます。かわいらしい装飾的な帽子のようです（この用語の由来はそこにあると思います）。

「デコレータ」は直下の関数を受け取り、それを使って何かを行います。

But in the end, they are implementing the same OAuth2 standard.

///

**FastAPI** includes utilities for all these OAuth2 authentication flows in `fastapi.security.oauth2`.

## `Security` in decorator `dependencies`

type comparable interface{ comparable }

// iota is a predeclared identifier representing the untyped integer ordinal
// number of the current const specification in a (usually parenthesized)
// const declaration. It is zero-indexed.
const iota = 0 // Untyped int.

// nil is a predeclared identifier representing the zero value for a
// pointer, channel, func, interface, map, or slice type.

                        Version.V20,
                        prefix + prefix2 + "(groupId:artifactId)",
                        null,
                        "must be unique but found duplicate declaration of plugin " + key,
                        plugin);
            } else {
                index.put(key, plugin);
            }

            Set<String> executionIds = new HashSet<>();

    /**
     * Defines a default phase to bind a mojo execution to if the user does not explicitly set a phase in the POM.
     * <i>Note:</i> This will not automagically make a mojo run when the plugin declaration is added to the POM. It
     * merely enables the user to omit the <code>&lt;phase&gt;</code> element from the surrounding
     * <code>&lt;execution&gt;</code> element.
     */
    private String phase;