```Python hl_lines="9  11-12"
{!> ../../docs_src/response_model/tutorial004_py310.py!}
```

////

* `description: Union[str, None] = None` (⚖️ `str | None = None` 🐍 3️⃣.1️⃣0️⃣) ✔️ 🔢 `None`.
* `tax: float = 10.5` ✔️ 🔢 `10.5`.
* `tags: List[str] = []` 🔢 🛁 📇: `[]`.

✋️ 👆 💪 💚 🚫 👫 ⚪️➡️ 🏁 🚥 👫 🚫 🤙 🏪.

🖼, 🚥 👆 ✔️ 🏷 ⏮️ 📚 📦 🔢 ☁ 💽, ✋️ 👆 🚫 💚 📨 📶 📏 🎻 📨 🌕 🔢 💲.

👆 💪 ⚙️ `from starlette import status`.

**FastAPI** 🚚 🎏 `starlette.status` `fastapi.status` 🏪 👆, 👩‍💻. ✋️ ⚫️ 👟 🔗 ⚪️➡️ 💃.

///

## 🔖

👆 💪 🚮 🔖 👆 *➡ 🛠️*, 🚶‍♀️ 🔢 `tags` ⏮️ `list` `str` (🛎 1️⃣ `str`):

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="17  22  27"
{!> ../../docs_src/path_operation_configuration/tutorial002.py!}
```

////

//// tab | 🐍 3️⃣.9️⃣ & 🔛

🚥 👆 🚫 💚 🚮 🎯 💲 ✋️ ⚒ ⚫️ 📦, ⚒ 🔢 `None`.

✋️ 🕐❔ 👆 💚 ⚒ 🔢 🔢 ✔, 👆 💪 🚫 📣 🙆 🔢 💲:

```Python hl_lines="6-7"
{!../../docs_src/query_params/tutorial005.py!}
```

📥 🔢 🔢 `needy` ✔ 🔢 🔢 🆎 `str`.

🚥 👆 📂 👆 🖥 📛 💖:

```
http://127.0.0.1:8000/items/foo-item
```

...🍵 ❎ ✔ 🔢 `needy`, 👆 🔜 👀 ❌ 💖:

```JSON
{
    "detail": [
        {
            "loc": [

Fakat, bir sorgu parametresini zorunlu yapmak istiyorsanız varsayılan bir değer atamamanız yeterli olacaktır:

```Python hl_lines="6-7"
{!../../docs_src/query_params/tutorial005.py!}
```

Burada `needy` parametresi `str` tipinden oluşan zorunlu bir sorgu parametresidir.

Eğer tarayıcınızda şu bağlantıyı:

```
http://127.0.0.1:8000/items/foo-item
```

def write_action_env_to_bazelrc(var_name, var):
  write_to_bazelrc('build --action_env {}="{}"'.format(var_name, str(var)))


def write_repo_env_to_bazelrc(config_name, var_name, var):
  write_to_bazelrc(
      'build:{} --repo_env {}="{}"'.format(config_name, var_name, str(var))
  )


def run_shell(cmd, allow_non_zero=False, stderr=None):
  if stderr is None:
    stderr = sys.stdout

callback_router0 = APIRouter()


@callback_router0.get("/")
async def callback0(level0: str):
    pass  # pragma: nocover


callback_router1 = APIRouter()


@callback_router1.get("/")
async def callback1(level1: str):
    pass  # pragma: nocover


callback_router2 = APIRouter()


@callback_router2.get("/")
async def callback2(level2: str):
    pass  # pragma: nocover


callback_router3 = APIRouter()

Você pode usar `jsonable_encoder` para converter os dados de entrada em dados que podem ser armazenados como JSON (por exemplo, com um banco de dados NoSQL). Por exemplo, convertendo `datetime` em `str`.

//// tab | Python 3.10+

```Python hl_lines="28-33"
{!> ../../../docs_src/body_updates/tutorial001_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="30-35"

You can use the `jsonable_encoder` to convert the input data to data that can be stored as JSON (e.g. with a NoSQL database). For example, converting `datetime` to `str`.

//// tab | Python 3.10+

```Python hl_lines="28-33"
{!> ../../docs_src/body_updates/tutorial001_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="30-35"

* Wenn der Parameter ein **einfacher Typ** ist (wie `int`, `float`, `str`, `bool`, usw.), wird er als **Query**-Parameter interpretiert.
* Wenn der Parameter vom Typ eines **Pydantic-Modells** ist, wird er als Request**body** interpretiert.

/// note | "Hinweis"

FastAPI weiß, dass der Wert von `q` nicht erforderlich ist, wegen des definierten Defaultwertes `= None`

{!> ../../docs_src/body/tutorial004.py!}
```

////

函数参数按如下规则进行识别：

- **路径**中声明了相同参数的参数，是路径参数
- 类型是（`int`、`float`、`str`、`bool` 等）**单类型**的参数，是**查询**参数
- 类型是 **Pydantic 模型**的参数，是**请求体**

/// note | "笔记"

因为默认值是 `None`， FastAPI 会把 `q` 当作可选参数。

FastAPI 不使用 `Optional[str]` 中的 `Optional`， 但 `Optional` 可以让编辑器提供更好的支持，并检测错误。

///

## 不使用 Pydantic