Now it's the time to use it with FastAPI. 🚀

We had this type annotation:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.9+

```Python
q: Union[str, None] = None
```

////

from fastapi import FastAPI, Form
from fastapi.testclient import TestClient

app = FastAPI()


@app.post("/form/python-list")
def post_form_param_list(items: list = Form()):
    return items


@app.post("/form/python-set")
def post_form_param_set(items: set = Form()):
    return items


@app.post("/form/python-tuple")
def post_form_param_tuple(items: tuple = Form()):
    return items


client = TestClient(app)

```
.
├── app                  # "app" is a Python package
│   ├── __init__.py      # this file makes "app" a "Python package"
│   ├── main.py          # "main" module, e.g. import app.main
│   ├── dependencies.py  # "dependencies" module, e.g. import app.dependencies
│   └── routers          # "routers" is a "Python subpackage"
│   │   ├── __init__.py  # makes "routers" a "Python subpackage"

> Requests, tüm zamanların en çok indirilen Python  <abbr title="Paket: Package">paketlerinden</abbr> biridir.

Kullanım şekli oldukça basit. Örneğin bir `GET` isteği yapmak için aşağıdaki yeterli:

```Python
response = requests.get("http://example.com/some/url")
```

Bunun FastAPI'deki API <abbr title="Yol İşlemi: Path Operation">*yol işlemi*</abbr> şöyle görünür:

```Python hl_lines="1"
@app.get("/some/url")
def read_url():

### 总结

总的来说，你就像声明函数的参数类型一样只声明了**一次**请求参数、请求体等的类型。

你使用了标准的现代 Python 类型来完成声明。

你不需要去学习新的语法、了解特定库的方法或类，等等。

只需要使用标准的 **Python 及更高版本**。

举个例子，比如声明 `int` 类型：

```Python
item_id: int
```

或者一个更复杂的 `Item` 模型：

```Python
item: Item
```

......在进行一次声明之后，你将获得：

* 编辑器支持，包括：
    * 自动补全
    * 类型检查
* 数据校验：

### Faite en python moderne

Tout est basé sur la déclaration de type standard de **Python 3.8** (grâce à Pydantic). Pas de nouvelles syntaxes à apprendre. Juste du Python standard et moderne.

Si vous souhaitez un rappel de 2 minutes sur l'utilisation des types en Python (même si vous ne comptez pas utiliser FastAPI), jetez un oeil au tutoriel suivant: [Python Types](python-types.md){.internal-link target=_blank}.

</div>

////

## Umgebungsvariablen in Python lesen { #read-env-vars-in-python }

Sie können auch Umgebungsvariablen **außerhalb** von Python erstellen, im Terminal (oder mit jeder anderen Methode) und sie dann **in Python** lesen.

Zum Beispiel könnten Sie eine Datei `main.py` haben mit:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip | Tipp

因此，如果使用如下方式创建 Pydantic 对象 `user_in`：

```Python
user_in = UserIn(username="john", password="secret", email="******@****.***")
```

就能以如下方式调用：

```Python
user_dict = user_in.dict()
```

现在，变量 `user_dict`中的就是包含数据的**字典**（变量 `user_dict` 是字典，不是 Pydantic 模型对象）。

以如下方式调用：

```Python
print(user_dict)
```

输出的就是 Python **字典**：

```Python
{
    'username': 'john',

      - changes
    runs-on: ubuntu-latest
    outputs:
      langs: ${{ steps.show-langs.outputs.langs }}
    steps:
      - uses: actions/checkout@v6
      - name: Set up Python
        uses: actions/setup-python@v6
        with:
          python-version: "3.11"
      - name: Setup uv
        uses: astral-sh/setup-uv@v7
        with:
          version: "0.4.15"
          enable-cache: true
          cache-dependency-glob: |

The key factor is that a dependency should be a "callable".

A "**callable**" in Python is anything that Python can "call" like a function.

So, if you have an object `something` (that might _not_ be a function) and you can "call" it (execute it) like:

```Python
something()
```

or

```Python
something(some_argument, some_keyword_argument="foo")
```

then it is a "callable".