from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(
        default=None,
        title="Query string",
        description="Query string for the items to search in the database that have a good match",
        min_length=3,
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Union[str, None] = Query(
        default=None,
        title="Query string",
        description="Query string for the items to search in the database that have a good match",
        min_length=3,
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:

            op.setRefreshPolicy(Constants.TRUE);
        });

    }

    /**
     * Sets up the query conditions for retrieving job logs based on the pager configuration.
     * Configures filtering and ordering for the database query.
     *
     * @param cb the condition bean for building the query
     * @param jobLogPager the pager containing filter and search criteria
     */

而且你不需要为该参数声明任何其他内容，所以实际上你并不需要使用 `Query`。

但是你仍然需要使用 `Path` 来声明路径参数 `item_id`。

如果你将带有「默认值」的参数放在没有「默认值」的参数之前，Python 将会报错。

但是你可以对其重新排序，并将不带默认值的值（查询参数 `q`）放到最前面。

对 **FastAPI** 来说这无关紧要。它将通过参数的名称、类型和默认值声明（`Query`、`Path` 等）来检测参数，而不在乎参数的顺序。

因此，你可以将函数声明为：

{* ../../docs_src/path_params_numeric_validations/tutorial002.py hl[7] *}

## 按需对参数排序的技巧

    response = client.get("/main-depends/")
    assert response.status_code == 422
    assert response.json() == {
        "detail": [
            {
                "type": "missing",
                "loc": ["query", "q"],
                "msg": "Field required",
                "input": None,
            }
        ]
    }


def test_main_depends_q_foo():
    response = client.get("/main-depends/?q=foo")

                    "type": "less_than_equal",
                    "loc": ["query", "limit"],
                    "msg": "Input should be less than or equal to 100",
                    "input": "150",
                    "ctx": {"le": 100},
                },
                {
                    "type": "greater_than_equal",
                    "loc": ["query", "offset"],
                    "msg": "Input should be greater than or equal to 0",

        // Default constructor
    }

    /** The parameter for negative query. */
    public static final String AS_NQ = "nq";

    /** The parameter for OR query. */
    public static final String AS_OQ = "oq";

    /** The parameter for exact phrase query. */
    public static final String AS_EPQ = "epq";

    /** The parameter for query. */
    public static final String AS_Q = "q";

`Header` es una clase "hermana" de `Path`, `Query` y `Cookie`. También hereda de la misma clase común `Param`.

Pero recuerda que cuando importas `Query`, `Path`, `Header`, y otros de `fastapi`, en realidad son funciones que retornan clases especiales.

///

/// info | Información

Para declarar headers, necesitas usar `Header`, porque de otra forma los parámetros serían interpretados como parámetros de query.

///

    assert response.json() == {
        "detail": [
            {
                "type": "missing",
                "loc": ["query", "needy"],
                "msg": "Field required",
                "input": None,
            },
            {
                "type": "int_parsing",
                "loc": ["query", "skip"],
                "msg": "Input should be a valid integer, unable to parse string as an integer",

쿠키 매개변수를 `Query`와 `Path` 매개변수들과 같은 방식으로 정의할 수 있습니다.

## `Cookie` 임포트

먼저 `Cookie`를 임포트합니다:

{* ../../docs_src/cookie_params/tutorial001_an_py310.py hl[3] *}

## `Cookie` 매개변수 선언

그런 다음, `Path`와 `Query`처럼 동일한 구조를 사용하는 쿠키 매개변수를 선언합니다.

첫 번째 값은 기본값이며, 추가 검증이나 어노테이션 매개변수 모두 전달할 수 있습니다:

{* ../../docs_src/cookie_params/tutorial001_an_py310.py hl[9] *}

/// note | 기술 세부사항