/// info | "说明"

`Form` 是直接继承自 `Body` 的类。

///

/// tip | "提示"

声明表单体要显式使用 `Form` ，否则，FastAPI 会把该参数当作查询参数或请求体（JSON）参数。

///

## 关于 "表单字段"

与 JSON 不同，HTML 表单（`<form></form>`）向服务器发送数据通常使用「特殊」的编码。

**FastAPI** 要确保从正确的位置读取数据，而不是读取 JSON。

/// note | "技术细节"

表单数据的「媒体类型」编码一般为 `application/x-www-form-urlencoded`。

但包含文件的表单编码为 `multipart/form-data`。文件处理详见下节。

from datetime import datetime, timedelta, timezone
from typing import Union

import jwt
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from jwt.exceptions import InvalidTokenError
from passlib.context import CryptContext
from pydantic import BaseModel
from typing_extensions import Annotated

# to get a string like this run:
# openssl rand -hex 32

from typing import Optional

import pytest
from dirty_equals import IsDict
from fastapi import APIRouter, Depends, FastAPI
from fastapi.testclient import TestClient

app = FastAPI()

router = APIRouter()


async def common_parameters(q: str, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/main-depends/")
async def main_depends(commons: dict = Depends(common_parameters)):

但与此同时，必须"等待"通过 `async def` 定义的函数。因此，带 `async def` 的函数也只能在 `async def` 定义的函数内部调用。

那么，这关于先有鸡还是先有蛋的问题，如何调用第一个 `async` 函数？

如果您使用 **FastAPI**，你不必担心这一点，因为"第一个"函数将是你的路径操作函数，FastAPI 将知道如何做正确的事情。

但如果您想在没有 FastAPI 的情况下使用 `async` / `await`，则可以这样做。

### 编写自己的异步代码

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.query_params.tutorial005 import app

client = TestClient(app)


def test_foo_needy_very():
    response = client.get("/items/foo?needy=very")
    assert response.status_code == 200
    assert response.json() == {"item_id": "foo", "needy": "very"}


def test_foo_no_needy():
    response = client.get("/items/foo")

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.dependencies.tutorial001 import app

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        ("/items", 200, {"q": None, "skip": 0, "limit": 100}),
        ("/items?q=foo", 200, {"q": "foo", "skip": 0, "limit": 100}),

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.extra_data_types.tutorial001_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_extra_types(client: TestClient):
    item_id = "ff97dd87-a4a5-4a12-b412-cde99f33e00e"
    data = {

import pytest
from dirty_equals import IsDict, IsOneOf
from fastapi.testclient import TestClient

from ...utils import needs_py310


@pytest.fixture(name="client")
def get_client():
    from docs_src.response_model.tutorial005_py310 import app

    client = TestClient(app)
    return client


@needs_py310
def test_read_item_name(client: TestClient):
    response = client.get("/items/bar/name")

from typing import Annotated, Union

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"

/// tip | "Dica"

Prefira utilizar a versão `Annotated` se possível.

///

```Python hl_lines="10"
{!> ../../docs_src/dependencies/tutorial011.py!}
```

////

Neste caso, o `__call__` é o que o **FastAPI** utilizará para verificar parâmetros adicionais e sub dependências, e isso é o que será chamado para passar o valor ao parâmetro na sua *função de operação de rota* posteriormente.

## Parametrizar a instância