express-validator 两次返回验证错误

Question

我想使用 Express-Validator 验证请求对象。假设我有两个路由，一个GET /users/:id (fetchUserById) 和POST /users (createUser) 路由

this.router = express.Router();
this.router.route('/').post(this.userRequestValidator.createUser, this.userController.createUser);
this.router.route('/:id').get(this.userRequestValidator.fetchUserById, this.userController.fetchUserById);

如您所见，我在调用控制器逻辑之前调用了验证中间件。首先，我创建了一个基本验证器来处理验证错误并在出现问题时返回 HTTP 400。

export abstract class RequestValidator {
    protected validate = async (request: Request, response: Response, next: NextFunction): Promise<void> => {
        const errors: Result<ValidationError> = validationResult(request);

        if (!errors.isEmpty()) {
            return res.status(422).json({ errors: errors.array() });
        } else {
            next();
        }
    };
}

我的验证器函数userRequestValidator.createUser和userRequestValidator.fetchUserById只需要扩展 RequestValidator 并实现验证

export class UserRequestValidator extends RequestValidator {
    public createUser = [
        body('username')
            .isString()
            .exists(),
        body('password')
            .isString()
            .exists(),
        this.validate,
    ];

    public fetchUserById = [
        param('id')
            .isString()
            .isUUID()
            .exists(),
        this.validate,
    ];
}

当我打电话时，GET localhost:3000/users/abc我得到了这个回应

{
    "errors": [
        {
            "value": "abc",
            "msg": "Invalid value",
            "param": "id",
            "location": "params"
        }
    ]
}

这是我期待的回应。但是当我POST localhost:3000/users用一个空的身体打电话时，我得到了这个回应

{
    "errors": [
        {
            "msg": "Invalid value",
            "param": "username",
            "location": "body"
        },
        {
            "msg": "Invalid value",
            "param": "username",
            "location": "body"
        },
        {
            "msg": "Invalid value",
            "param": "password",
            "location": "body"
        },
        {
            "msg": "Invalid value",
            "param": "password",
            "location": "body"
        }
    ]
}

有人知道我如何解决此行为或我的设置有什么问题吗？

Answer 1

我不知道为什么什么时候req.body是空对象 - {}，验证器将运行验证链的所有节点。您可以再次检查，为每个条件添加每条消息，如下所示：

class UserRequestValidator extends RequestValidator {
  public createUser = [
    body('username')
      .isString().withMessage('username must be a string') // you can see both error messages in the response
      .exists().withMessage('username must be exist'),
    body('password') // the same for this field
      .isString()
      .exists(),
    this.validate,
  ];

  public fetchUserById = [
    param('id') // because id is exist in `req.params`, then only one test has been executed.
      .isString().withMessage('id must be a string')
      .isUUID()
      .exists(),
    this.validate,
  ];
}

我在https://github.com/express-validator/express-validator/issues/638 中找到了针对您的情况的解决方案，在.bail()函数的第一个错误中停止链。

那么你的验证器类将是这样的：

class UserRequestValidator extends RequestValidator {
  public createUser = [
    body('username')
       // always check exists() first
      .exists().withMessage('username must be exist').bail()
      .isString().withMessage('username must be a string').bail(),
    body('password')
      .exists().bail()
      .isString().bail(),
    this.validate,
  ];

  public fetchUserById = [
    param('id')
      .isString()
      .isUUID()
      .exists(),
    this.validate,
  ];
}