But you still need to define what is the dependable, the callable that you pass as a parameter to `Depends()` or `Security()`.

There are multiple tools that you can use to create those dependables, and they get integrated into OpenAPI so they are shown in the automatic docs UI, they can be used by automatically generated clients and SDKs, etc.

You can import them from `fastapi.security`:

```python

```

</div>

<details markdown="1">
<summary><code>uvicorn main:app --reload</code> 명령에 관하여...</summary>

명령 `uvicorn main:app`은 다음을 나타냅니다:

* `main`: `main.py` 파일 (파이썬 "모듈").
* `app`: the object created inside of `main.py` with the line `app = FastAPI()`.
* `--reload`: 코드가 변경된 후 서버 재시작하기. 개발환경에서만 사용하십시오.

</details>

### 확인하기

Integrations and "plug-ins" can be built using the **Dependency Injection** system. But in fact, there is actually **no need to create "plug-ins"**, as by using dependencies it's possible to declare an infinite number of integrations and interactions that become available to your *path operation functions*.

Verás la respuesta de JSON cómo:

```JSON
{"item_id": 5, "q": "somequery"}
```

Ya creaste una API que:

* Recibe HTTP requests en los _paths_ `/` y `/items/{item_id}`.
* Ambos _paths_ toman operaciones `GET` (también conocido como HTTP _methods_).

## Installation

<div class="termy">

```console
$ pip install fastapi

---> 100%
```

</div>

## Example

### Create it

* Create a file `main.py` with:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}

<div style="text-align: right; margin-right: 10%;">Timothy Crosley - <strong><a href="https://www.hug.rest/" target="_blank">Hug</a> creator</strong> <a href="https://news.ycombinator.com/item?id=19455465" target="_blank"><small>(ref)</small></a></div>

---

<div style="text-align: right; margin-right: 10%;">Timothy Crosley - <strong><a href="https://www.hug.rest/" target="_blank">Hug</a> creator</strong> <a href="https://news.ycombinator.com/item?id=19455465" target="_blank"><small>(ref)</small></a></div>

---

<div class="termy">

```console
$ pip install uvicorn[standard]

---> 100%
```

</div>

## Esempio

### Crea un file

* Crea un file `main.py` con:

```Python
from fastapi import FastAPI
from typing import Optional

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}