* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> oder
* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager" class="external-link" target="_blank">`@contextlib.asynccontextmanager`</a>

kann auch als gültige **FastAPI**-Abhängigkeit verwendet werden.

```JSON
{"item_id":3}
```

/// check | "检查"

注意，函数接收并返回的值是 `3`（ `int`），不是 `"3"`（`str`）。

**FastAPI** 通过类型声明自动<abbr title="将来自 HTTP 请求中的字符串转换为 Python 数据类型">**解析**请求中的数据</abbr>。

///

## 数据校验

# 高级安全

## 附加特性

除 [教程 - 用户指南: 安全性](../../tutorial/security/index.md){.internal-link target=_blank} 中涵盖的功能之外，还有一些额外的功能来处理安全性.

/// tip | "小贴士"

接下来的章节 **并不一定是 "高级的"**.

而且对于你的使用场景来说，解决方案很可能就在其中。

///

## 先阅读教程

接下来的部分假设你已经阅读了主要的 [教程 - 用户指南: 安全性](../../tutorial/security/index.md){.internal-link target=_blank}.

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import org.codelibs.core.lang.StringUtil;

import jakarta.validation.Constraint;
import jakarta.validation.Payload;

@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = CustomSizeValidator.class)

You can read more about this in the [Advanced User Guide](../advanced/index.md){.internal-link target=_blank}.

## Details

The first `"/static"` refers to the sub-path this "sub-application" will be "mounted" on. So, any path that starts with `"/static"` will be handled by it.

Zum Beispiel bietet **FastAPI** selbst eine alternative API-Dokumentation (verwendet ReDoc), welche Sie unter <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a> einsehen können:

## Conclusão

Com isso, você deve ter uma compreensão básica do que são **variáveis ​​de ambiente** e como usá-las em Python.

Você também pode ler mais sobre elas na <a href="https://en.wikipedia.org/wiki/Environment_variable" class="external-link" target="_blank">Wikipedia para Variáveis ​​de Ambiente</a>.

`TestClient` ⚓️ 🔛 <a href="https://www.python-httpx.org" class="external-link" target="_blank">🇸🇲</a>, &amp; ↩️, 👥 💪 ⚙️ ⚫️ 🔗 💯 🛠️.

## 🖼

🙅 🖼, ➡️ 🤔 📁 📊 🎏 1️⃣ 🔬 [🦏 🈸](../tutorial/bigger-applications.md){.internal-link target=_blank} &amp; [🔬](../tutorial/testing.md){.internal-link target=_blank}:

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

* <a href="https://cdn.jsdelivr.net/npm/swagger-ui-dist@5/swagger-ui.css" class="external-link" target="_blank">`swagger-ui.css`</a>

Und **ReDoc** verwendet diese Datei:

* <a href="https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js" class="external-link" target="_blank">`redoc.standalone.js`</a>

/// tip

The actual callback is just an HTTP request.

When implementing the callback yourself, you could use something like <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> or <a href="https://requests.readthedocs.io/" class="external-link" target="_blank">Requests</a>.

///

## Write the callback documentation code