///

While building an API, the "path" is the main way to separate "concerns" and "resources".

#### Operation

"Operation" here refers to one of the HTTP "methods".

One of:

* `POST`
* `GET`
* `PUT`
* `DELETE`

...and the more exotic ones:

* `OPTIONS`
* `HEAD`
* `PATCH`
* `TRACE`

    current_user: Annotated[User, Security(get_current_user, scopes=["me"])],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    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:

    current_user: Annotated[User, Security(get_current_user, scopes=["me"])],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    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:

## 使用回调的应用

示例如下。

假设要开发一个创建发票的应用。

发票包括 `id`、`title`（可选）、`customer`、`total` 等属性。

API 的用户 （外部开发者）要在您的 API 内使用 POST 请求创建一条发票记录。

（假设）您的 API 将：

* 把发票发送至外部开发者的消费者
* 归集现金
* 把通知发送至 API 的用户（外部开发者）
    * 通过（从您的 API）发送 POST 请求至外部 API （即**回调**）来完成

## 常规 **FastAPI** 应用

添加回调前，首先看下常规 API 应用是什么样子。

常规 API 应用包含接收 `Invoice` 请求体的*路径操作*，还有包含回调 URL 的查询参数 `callback_url`。

furnished to do so, subject to...

    authorization_code = request.args.get('code')

    data = {'grant_type': 'authorization_code',
            'code': authorization_code, 'redirect_uri': callback_uri}
    id_token_response = requests.post(
        token_url, data=data, verify=False,
        allow_redirects=False, auth=(client_id, client_secret))

    print('body: ' + id_token_response.text)

class Item:
    name: str
    description: Union[str, None] = None


@dataclass
class Author:
    name: str
    items: List[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)
async def create_author_items(author_id: str, items: List[Item]):  # (5)
    return {"name": author_id, "items": items}  # (6)

/**
 * @author shinsuke
 *
 */
public final class Constants {
    public static final String GET_METHOD = "GET";

    public static final String HEAD_METHOD = "HEAD";

    public static final String POST_METHOD = "POST";

    public static final int OK_STATUS = 0;

    public static final int NOT_MODIFIED_STATUS = 304;

    public static final int OK_STATUS_CODE = 200;

    public static final int NOT_MODIFIED_STATUS_CODE = 304;

    current_user: Annotated[User, Depends(get_current_user)],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user


@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
    user_dict = fake_users_db.get(form_data.username)
    if not user_dict:

    current_user: Annotated[User, Depends(get_current_user)],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user


@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
    user_dict = fake_users_db.get(form_data.username)
    if not user_dict: