# Security Tools

When you need to declare dependencies with OAuth2 scopes you use `Security()`.

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.

---

## Instala FastAPI

El primer paso es instalar FastAPI.

Para el tutorial, es posible que quieras instalarlo con todas las dependencias y características opcionales:

<div class="termy">

```console
$ pip install "fastapi[all]"

---> 100%
```

</div>

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-11"
    {!> ../../../docs_src/dependencies/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9-12"
    {!> ../../../docs_src/dependencies/tutorial001_an.py!}
    ```

=== "Python 3.10+ nicht annotiert"

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-11"
    {!> ../../../docs_src/dependencies/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9-12"
    {!> ../../../docs_src/dependencies/tutorial001_an.py!}
    ```

=== "Python 3.10+ non-Annotated"

そして、これらの値を含む`dict`を返します。

### `Depends`のインポート

```Python hl_lines="3"
{!../../../docs_src/dependencies/tutorial001.py!}
```

### "dependant"での依存関係の宣言

*path operation関数*のパラメータに`Body`や`Query`などを使用するのと同じように、新しいパラメータに`Depends`を使用することができます:

```Python hl_lines="13  18"
{!../../../docs_src/dependencies/tutorial001.py!}
```

関数のパラメータに`Depends`を使用するのは`Body`や`Query`などと同じですが、`Depends`の動作は少し異なります。

You can define dependencies that in turn can define dependencies themselves.

In the end, a hierarchical tree of dependencies is built, and the **Dependency Injection** system takes care of solving all these dependencies for you (and their sub-dependencies) and providing (injecting) the results at each step.

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-11"
    {!> ../../../docs_src/dependencies/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9-12"
    {!> ../../../docs_src/dependencies/tutorial001_an.py!}
    ```

=== "Python 3.10+ Annotated가 없는 경우"

➡️ 🥇 🎯 🔛 🔗.

⚫️ 🔢 👈 💪 ✊ 🌐 🎏 🔢 👈 *➡ 🛠️ 🔢* 💪 ✊:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="8-11"
    {!> ../../../docs_src/dependencies/tutorial001.py!}
    ```

=== "🐍 3️⃣.1️⃣0️⃣ & 🔛"

    ```Python hl_lines="6-7"
    {!> ../../../docs_src/dependencies/tutorial001_py310.py!}
    ```

👈 ⚫️.

**2️⃣ ⏸**.

& ⚫️ ✔️ 🎏 💠 & 📊 👈 🌐 👆 *➡ 🛠️ 🔢* ✔️.

Para entender más al respecto revisa la sección <a href="https://fastapi.tiangolo.com/benchmarks/" class="internal-link" target="_blank">Benchmarks</a>.

## Dependencias Opcionales

Usadas por Pydantic:

* <a href="https://github.com/JoshData/python-email-validator" target="_blank"><code>email_validator</code></a> - para validación de emails.

Usados por Starlette:

When you install `fastapi` it comes these standard dependencies.

## `fastapi-slim`

If you don't want the extra standard optional dependencies, install `fastapi-slim` instead.

When you install with:

```bash
pip install fastapi
```

...it includes the same code and dependencies as:

```bash
pip install "fastapi-slim[standard]"
```