OAuth2 的设计目标是让后端或 API 与负责用户认证的服务器解耦。

但在这个例子中，**FastAPI** 应用同时处理 API 和认证。

从这个简化的角度来看看流程：

* 用户在前端输入 `username` 和 `password`，然后按下 `Enter`。
* 前端（运行在用户浏览器中）把 `username` 和 `password` 发送到我们 API 中的特定 URL（使用 `tokenUrl="token"` 声明）。
* API 校验 `username` 和 `password`，并返回一个“令牌”（这些我们尚未实现）。
    * “令牌”只是一个字符串，包含一些内容，之后可用来验证该用户。
    * 通常，令牌会在一段时间后过期。
        * 因此，用户过一段时间需要重新登录。

        print("Oops, we didn't raise again, Britney 😱")


@app.get("/items/{item_id}")
def get_item(item_id: str, username: str = Depends(get_username)):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(

Итак, рассмотрим это с упрощенной точки зрения:

* Пользователь вводит на фронтенде `username` и `password` и нажимает `Enter`.
* Фронтенд (работающий в браузере пользователя) отправляет эти `username` и `password` на конкретный URL в нашем API (объявленный с `tokenUrl="token"`).
* API проверяет этот `username` и `password` и отвечает «токеном» (мы еще ничего из этого не реализовали).

        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        final String username = systemHelper.getUsername();
        final long currentTime = systemHelper.getCurrentTimeAsLong();
        return getEntity(form, username, currentTime).map(entity -> {
            entity.setUpdatedBy(username);
            entity.setUpdatedTime(currentTime);

        assertEquals(5, chain.deleteCalls.size());
    }

    // Helper method to create test user
    private User createTestUser(String username, String displayName) {
        User user = new User();
        user.setName(username);
        user.setDisplayName(displayName);
        return user;
    }

    // Test implementation of AuthenticationChain for testing

        print("Oops, we didn't raise again, Britney 😱")


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(

The <dfn title="specification">spec</dfn> requires the fields to be exactly named `username` and `password`, and to be sent as form fields, not JSON.

With `Form` you can declare the same configurations as with `Body` (and `Query`, `Path`, `Cookie`), including validation, examples, an alias (e.g. `user-name` instead of `username`), etc.

/// info

        try {
            userService.store(entity);
            saveInfo(messages -> messages.addSuccessCrudCreateCrudTable(GLOBAL));
        } catch (final Exception e) {
            logger.warn("Failed to create user: username={}, error={}", body.name, e.getMessage(), e);
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateCrudTable(GLOBAL, buildThrowableMessage(e)));
        }

from inline_snapshot import snapshot
from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyCookie(name="key")


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str = Security(api_key)):
    user = User(username=oauth_header)
    return user


@app.get("/users/me")
def read_current_user(current_user: User = Depends(get_current_user)):
    return current_user

from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyCookie(name="key", description="An API Cookie Key")


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str = Security(api_key)):
    user = User(username=oauth_header)
    return user


@app.get("/users/me")
def read_current_user(current_user: User = Depends(get_current_user)):
    return current_user