from typing import Optional

import pytest
from fastapi import Depends, FastAPI, Security
from fastapi.security import OAuth2, OAuth2PasswordRequestFormStrict
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }

from .oauth2 import OAuth2PasswordBearer as OAuth2PasswordBearer
from .oauth2 import OAuth2PasswordRequestForm as OAuth2PasswordRequestForm
from .oauth2 import OAuth2PasswordRequestFormStrict as OAuth2PasswordRequestFormStrict
from .oauth2 import SecurityScopes as SecurityScopes

    HTTPBasic,
    HTTPBasicCredentials,
    HTTPBearer,
    HTTPDigest,
    OAuth2,
    OAuth2AuthorizationCodeBearer,
    OAuth2PasswordBearer,
    OAuth2PasswordRequestForm,
    OAuth2PasswordRequestFormStrict,
    OpenIdConnect,
    SecurityScopes,
)
```

## API Key Security Schemes

::: fastapi.security.APIKeyCookie

::: fastapi.security.APIKeyHeader

::: fastapi.security.APIKeyQuery

import pytest
from fastapi import Depends, FastAPI, Security
from fastapi.security import OAuth2, OAuth2PasswordRequestFormStrict
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    }
)

from typing import Optional

import pytest
from fastapi import Depends, FastAPI, Security
from fastapi.security import OAuth2, OAuth2PasswordRequestFormStrict
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }

/// tip

The OAuth2 spec actually *requires* a field `grant_type` with a fixed value of `password`, but `OAuth2PasswordRequestForm` doesn't enforce it.

If you need to enforce it, use `OAuth2PasswordRequestFormStrict` instead of `OAuth2PasswordRequestForm`.

///

* An optional `client_id` (we don't need it for our example).
* An optional `client_secret` (we don't need it for our example).

/// info

* 可选的 `grant_type`

/// tip | 提示

实际上，OAuth2 规范*要求* `grant_type` 字段使用固定值 `password`，但 `OAuth2PasswordRequestForm` 没有作强制约束。

如需强制使用固定值 `password`，则不要用 `OAuth2PasswordRequestForm`，而是用 `OAuth2PasswordRequestFormStrict`。

///

* 可选的 `client_id`（本例未使用）
* 可选的 `client_secret`（本例未使用）

/// info | 说明

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