"title": "Body_login_login__post",
                    "required": ["username", "password"],
                    "type": "object",
                    "properties": {
                        "username": {"title": "Username", "type": "string"},
                        "password": {"title": "Password", "type": "string"},
                    },
                },
                "ValidationError": {

# OAuth2 实现简单的 Password 和 Bearer 验证

本章添加上一章示例中欠缺的部分，实现完整的安全流。

## 获取 `username` 和 `password`

首先，使用 **FastAPI** 安全工具获取 `username` 和 `password`。

OAuth2 规范要求使用**密码流**时，客户端或用户必须以表单数据形式发送 `username` 和 `password` 字段。

并且，这两个字段必须命名为 `username` 和 `password` ，不能使用 `user-name` 或 `email` 等其它名称。

不过也不用担心，前端仍可以显示终端用户所需的名称。

数据库模型也可以使用所需的名称。

但对于登录*路径操作*，则要使用兼容规范的 `username` 和 `password`，（例如，实现与 API 文档集成）。

        }
    }

    @Override
    public boolean changePassword(final String username, final String password) {
        if (isTargetUser(username) && StringUtil.isNotBlank(password)) {
            return executeCommand(updateCommand, username, password) == 0;
        }
        return true;
    }

    @Override
    public User load(final User user) {
        return user;
    }

## Password hashing

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

### Why use password hashing

        current_username_bytes, correct_username_bytes
    )
    current_password_bytes = credentials.password.encode("utf8")
    correct_password_bytes = b"swordfish"
    is_correct_password = secrets.compare_digest(
        current_password_bytes, correct_password_bytes
    )
    if not (is_correct_username and is_correct_password):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,

    const val PERFORMANCE_BASELINES = "performanceBaselines"
    const val PERFORMANCE_TEST_VERBOSE = "performanceTest.verbose"
    const val PERFORMANCE_DB_PASSWORD = "org.gradle.performance.db.password"
    const val PERFORMANCE_DB_PASSWORD_ENV = "PERFORMANCE_DB_PASSWORD_TCAGENT"
    const val PERFORMANCE_DB_URL = "org.gradle.performance.db.url"
    const val PERFORMANCE_DB_USERNAME = "org.gradle.performance.db.username"

If it doesn't receive it, it returns an HTTP 401 "Unauthorized" error.

And returns a header `WWW-Authenticate` with a value of `Basic`, and an optional `realm` parameter.

That tells the browser to show the integrated prompt for a username and password.

Then, when you type that username and password, the browser sends them in the header automatically.

    response = client.post(
        "/login",
        data={"username": "johndoe", "password": "secret", "grant_type": "password"},
    )
    assert response.status_code == 200, response.text
    assert response.json() == {
        "grant_type": "password",
        "username": "johndoe",
        "password": "secret",
        "scopes": [],
        "client_id": None,
        "client_secret": None,
    }

    }

    params {
        password("env.ORG_GRADLE_PROJECT_gradleS3AccessKey", "%gradleS3AccessKey%")
        password("env.ORG_GRADLE_PROJECT_gradleS3SecretKey", "%gradleS3SecretKey%")
        password("env.ORG_GRADLE_PROJECT_artifactoryUserPassword", "%gradle.internal.repository.build-tool.publish.password%")
        password("env.DOTCOM_DEV_DOCS_AWS_ACCESS_KEY", "%dotcomDevDocsAwsAccessKey%")

from docs_src.security.tutorial005 import (
    app,
    create_access_token,
    fake_users_db,
    get_password_hash,
    verify_password,
)

client = TestClient(app)


def get_access_token(username="johndoe", password="secret", scope=None):
    data = {"username": username, "password": password}
    if scope:
        data["scope"] = scope
    response = client.post("/token", data=data)