return current_user


@app.post("/token")
async def login_for_access_token(
    form_data: OAuth2PasswordRequestForm = Depends(),
) -> Token:
    user = authenticate_user(fake_users_db, form_data.username, form_data.password)
    if not user:
        raise HTTPException(status_code=400, detail="Incorrect username or password")

    return current_user


@app.post("/token")
async def login_for_access_token(
    form_data: Annotated[OAuth2PasswordRequestForm, Depends()],
) -> Token:
    user = authenticate_user(fake_users_db, form_data.username, form_data.password)
    if not user:
        raise HTTPException(status_code=400, detail="Incorrect username or password")

    Sie können mehrere `File`- und `Form`-Parameter in einer *Pfadoperation* deklarieren, aber Sie können nicht gleichzeitig auch `Body`-Felder deklarieren, welche Sie als JSON erwarten, da der Request den Body mittels `multipart/form-data` statt `application/json` kodiert.

    Das ist keine Limitation von **FastAPI**, sondern Teil des HTTP-Protokolls.

## Zusammenfassung

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.request_files.tutorial002_an import app

client = TestClient(app)


def test_post_form_no_body():
    response = client.post("/files/")
    assert response.status_code == 422, response.text
    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "missing",

                    "operationId": "login_for_access_token_token_post",
                    "requestBody": {
                        "content": {
                            "application/x-www-form-urlencoded": {
                                "schema": {
                                    "$ref": "#/components/schemas/Body_login_for_access_token_token_post"
                                }

!!! info "说明"

    `OAuth2PasswordRequestForm` 与 `OAuth2PasswordBearer` 一样，都不是 FastAPI 的特殊类。

    **FastAPI** 把 `OAuth2PasswordBearer` 识别为安全方案。因此，可以通过这种方式把它添加至 OpenAPI。

    但 `OAuth2PasswordRequestForm` 只是可以自行编写的类依赖项，也可以直接声明 `Form` 参数。

    但由于这种用例很常见，FastAPI 为了简便，就直接提供了对它的支持。

### 使用表单数据

!!! tip "提示"

    `OAuth2PasswordRequestForm` 类依赖项的实例没有以空格分隔的长字符串属性 `scope`，但它支持 `scopes` 属性，由已发送的 scope 字符串列表组成。

def test_incorrect_multipart_installed_multi_form(monkeypatch):
    monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
    with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
        app = FastAPI()

        @app.post("/")
        async def root(username: str = Form(), password: str = Form()):
            return username  # pragma: nocover

Quando você precisar receber campos de formulário ao invés de JSON, você pode usar `Form`.

!!! info "Informação"
    Para usar formulários, primeiro instale <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

    Ex: `pip install python-multipart`.

## Importe `Form`

Importe `Form` de `fastapi`:

```Python hl_lines="1"
{!../../../docs_src/request_forms/tutorial001.py!}

* `Path()`
* `Body()`
* `Cookie()`
* `Header()`
* `Form()`
* `File()`

Sie können diese alle direkt von `fastapi` importieren:

```python
from fastapi import Body, Cookie, File, Form, Header, Path, Query
```

::: fastapi.Query

::: fastapi.Path

::: fastapi.Body

::: fastapi.Cookie

::: fastapi.Header

::: fastapi.Form

Когда вам нужно получить поля формы вместо JSON, вы можете использовать `Form`.

!!! info "Дополнительная информация"
    Чтобы использовать формы, сначала установите <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

    Например, выполните команду `pip install python-multipart`.

## Импорт `Form`

Импортируйте `Form` из `fastapi`:

=== "Python 3.9+"

    ```Python hl_lines="3"