from contextvars import ContextVar
from typing import Any

from fastapi import Depends, FastAPI, Request, Response
from fastapi.testclient import TestClient

legacy_request_state_context_var: ContextVar[dict[str, Any] | None] = ContextVar(
    "legacy_request_state_context_var", default=None
)

app = FastAPI()


async def set_up_request_state_dependency():
    request_state = {"user": "deadpond"}

{* ../../docs_src/query_params/tutorial005_py310.py hl[6:7] *}

Here the query parameter `needy` is a required query parameter of type `str`.

If you open in your browser a URL like:

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

...without adding the required parameter `needy`, you will see an error like:

```JSON
{

## 用 `PUT` 替换式更新 { #update-replacing-with-put }

更新数据可以使用 [HTTP `PUT`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PUT) 操作。

把输入数据转换为以 JSON 格式存储的数据（比如，使用 NoSQL 数据库时），可以使用 `jsonable_encoder`。例如，把 `datetime` 转换为 `str`。

{* ../../docs_src/body_updates/tutorial001_py310.py hl[28:33] *}

`PUT` 用于接收替换现有数据的数据。

### 关于替换的警告 { #warning-about-replacing }

用 `PUT` 把数据项 `bar` 更新为以下请求体时：

```Python
{
    "name": "Barz",

			}
		}

		str := getUserAgent(testCase.mode)
		expectedStr := testCase.expectedStr
		if IsDocker() {
			expectedStr = strings.ReplaceAll(expectedStr, "; source", "; docker; source")
		}
		if !strings.Contains(str, expectedStr) {
			t.Errorf("Test %d: expected: %s, got: %s", i+1, expectedStr, str)
		}
		os.Unsetenv("MARATHON_APP_LABEL_DCOS_PACKAGE_VERSION")

응답 모델은 아래와 같이 기본값을 가질 수 있습니다:

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (또는 Python 3.10에서 `str | None = None`)은 기본값으로 `None`을 갖습니다.
* `tax: float = 10.5`는 기본값으로 `10.5`를 갖습니다.
* `tags: List[str] = []`는 기본값으로 빈 리스트 `[]`를 갖습니다.

하지만 실제로 저장되지 않았을 경우 결과에서 이를 생략하고 싶을 수 있습니다.

    @Test
    public void testSubstitution() throws IOException {
        String str = "port = 4141" + LINE_SEPARATOR + "host = localhost"
                + LINE_SEPARATOR + "url = https://${host}:${port}/service"
                + LINE_SEPARATOR;
        MavenProperties properties = new MavenProperties();
        properties.load(new StringReader(str));
        properties.put("url", "https://localhost:4141/service");

Puedes devolverla directamente.

Acepta los siguientes parámetros:

* `content` - Un `str` o `bytes`.
* `status_code` - Un código de estado HTTP `int`.
* `headers` - Un `dict` de strings.
* `media_type` - Un `str` que da el media type. Por ejemplo, `"text/html"`.

For example, if you have a function:

```Python
@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

your program could execute like this:

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()

		if len(f) > 0 && strings.Contains(printed, "(PC)") {
			index := len(f) - 1
			suf := "(PC)"
			for !strings.HasSuffix(f[index], suf) {
				index--
				suf = "(PC),"
			}
			str := f[index]
			n, err := strconv.Atoi(str[:len(str)-len(suf)])
			if err == nil {
				f[index] = fmt.Sprintf("%d%s", seq+n, suf)
			}
		}

		if len(f) == 1 {
			printed = f[0]
		} else {

Möglicherweise stellen Sie fest, dass Sie zum Erstellen einer Instanz einer Python-Klasse die gleiche Syntax verwenden.

Zum Beispiel:

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

In diesem Fall ist `fluffy` eine Instanz der Klasse `Cat`.

Und um `fluffy` zu erzeugen, rufen Sie `Cat` auf.