from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        str | None,
        Query(
            alias="item-query",
            title="Query string",
            description="Query string for the items to search in the database that have a good match",
            min_length=3,
            max_length=50,
            pattern="^fixedquery$",

        assertThat(toDate(""), is(nullValue()));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testToDate_ShortStyle() throws Exception {
        System.out.println(((SimpleDateFormat) DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL)).toPattern());
        final Date date = toDate("10/9/7");

     * <p>
     * The pathnames used for matching will be relative to the specified base directory
     * and use {@code '/'} as separator, regardless of the hosting operating system.
     *
     * @param baseDirectory the base directory for relativizing paths during matching
     * @param includes the patterns of files to include, or null/empty for including all files

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(alias="item-query")] = None):
    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, alias="item-query")):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Path

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    q: str, item_id: Annotated[int, Path(title="The ID of the item to get")]
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Path

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: Annotated[int, Path(title="The ID of the item to get")], q: str
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

* Ihnen die erhaltenen Daten im Parameter `item` übergeben.
    * Da Sie ihn in der Funktion als vom Typ `Item` deklariert haben, erhalten Sie auch die volle Unterstützung des Editors (Autovervollständigung, usw.) für alle Attribute und deren Typen.

使用与声明路径和查询参数相同的方式声明请求体，把请求体添加至*路径操作*：

{* ../../docs_src/body/tutorial001_py310.py hl[16] *}

……此处，请求体参数的类型为 `Item` 模型。

## 结论

仅使用 Python 类型声明，**FastAPI** 就可以：

* 以 JSON 形式读取请求体
* （在必要时）把请求体转换为对应的类型
* 校验数据：
    * 数据无效时返回错误信息，并指出错误数据的确切位置和内容
* 把接收的数据赋值给参数 `item`
    * 把函数中请求体参数的类型声明为 `Item`，还能获得代码补全等编辑器支持
* 为模型生成 <a href="https://json-schema.org" class="external-link" target="_blank">JSON Schema</a>，在项目中所需的位置使用

                    "message": {
                        "title": "Message",
                        "type": "string"
                    }
                }
            },
            "Item": {
                "title": "Item",
                "required": [
                    "id",
                    "value"
                ],
                "type": "object",
                "properties": {