For example:

```Python
from fastapi import Cookie, FastAPI, Header, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
def main(
    item_id: int = Path(default=..., gt=0),
    query: str = Query(default=..., max_length=10),
    session: str = Cookie(default=..., min_length=3),
    x_trace: str = Header(default=..., title="Tracing header"),
):
    return {"message": "Hello World"}
```

### Typannotationen und Tooling

Sehen wir uns zunächst an, wie Editor, mypy und andere Tools dies sehen würden.

`BaseUser` verfügt über die Basis-Felder. Dann erbt `UserIn` von `BaseUser` und fügt das Feld `Passwort` hinzu, sodass dass es nun alle Felder beider Modelle hat.

Wir annotieren den Funktionsrückgabetyp als `BaseUser`, geben aber tatsächlich eine `UserIn`-Instanz zurück.

# Header-параметры

Вы можете определить параметры заголовка таким же образом, как вы определяете параметры `Query`, `Path` и `Cookie`.

## Импорт `Header`

Сперва импортируйте `Header`:

=== "Python 3.10+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/header_params/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/header_params/tutorial001_an_py39.py!}
    ```

# Header 参数

定义 `Header` 参数的方式与定义 `Query`、`Path`、`Cookie` 参数相同。

## 导入 `Header`

首先，导入 `Header`：

=== "Python 3.10+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/header_params/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="3"
    {!> ../../../docs_src/header_params/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="3"

# Templating - `Jinja2Templates`

You can use the `Jinja2Templates` class to render Jinja templates.

Read more about it in the [FastAPI docs for Templates](https://fastapi.tiangolo.com/advanced/templates/).

You can import it directly from `fastapi.templating`:

```python
from fastapi.templating import Jinja2Templates
```

}

.user .title {
  text-align: center;
}

.user .count {
  font-size: 80%;
  text-align: center;
}

a.announce-link:link,
a.announce-link:visited {
  color: #fff;
}

a.announce-link:hover {
  color: var(--md-accent-fg-color);
}

.announce-wrapper {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  align-items: center;
}

.announce-wrapper div.item {

  - navigation
---

# FastAPI People

FastAPI has an amazing community that welcomes people from all backgrounds.

## Creator

Hey! 👋

This is me:

{% if people %}
<div class="user-list user-list-center">
{% for user in people.maintainers %}

У FastAPI замечательное сообщество, которое доброжелательно к людям с любым уровнем знаний.

## Создатель и хранитель

Хай! 👋

Это я:

{% if people %}
<div class="user-list user-list-center">
{% for user in people.maintainers %}

---
hide:
  - navigation
---

# FastAPI People

FastAPIには、様々なバックグラウンドの人々を歓迎する素晴らしいコミュニティがあります。

## Creator - Maintainer

こんにちは！ 👋

これが私です:

{% if people %}
<div class="user-list user-list-center">
{% for user in people.maintainers %}

<p align="center">
  <a href="https://fastapi.tiangolo.com"><img src="https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png" alt="FastAPI"></a>
</p>
<p align="center">
    FastAPI keretrendszer, nagy teljesítmény, könnyen tanulható, gyorsan kódolható, productionre kész
</p>
<p align="center">
<a href="https://github.com/tiangolo/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster" target="_blank">