使用Postman发送JSON数据到数据库时遇500内部服务器错误

使用Postman向数据库发送JSON数据时触发500内部服务器错误，已确认数据库连接与Schema配置正常。

相关代码 #

userControllers.js #

const asyncHandler = require("express-async-handler");
const User = require("../models/userModel");
const alert = require("alert");
const generateToken = require("../config/generateToken");
const registerUsers = asyncHandler(async (req, res) => {
  const { name, email, password, pic } = req.body;

  if (!email || !name || !password) {
    res.status(400);
    throw new Error("Please Enter All fields");
  }
  const userExists = await User.findOne({
    email,
  });
  if (userExists) {
    res.status(400);
    throw new Error("User already exists");
  }
  const user = await User.create({ name, email, password, pic });
  if (user) {
    res.status(400).json({
      _id: user._id,
      name: user.name,
      email: user.email,
      password: user.password,
      pic: user.pic,
      token: generateToken(user_id),
    });
  } else {
    res.status(400);
    throw new Error("Failed to create the account, try again after some time.");
  }
});
const authUser = asyncHandler(async (req, res) => {});
module.exports = { registerUsers };

userRoutes.js #

const { registerUsers } = require("../controllers/userControllers");
const express = require("express");
const router = express.Router();

router.post("/", registerUsers);
// router.route("/login").post(authUser);

module.exports = router;

server.js #

app.use("/api/user", userRoutes);

请求数据 #

向/api/user/发送POST请求，数据如下：

{
    "name": "joseph ngatia",
    "email": "jngatia@gmail.com",
    "password": "12345"
}

错误信息 #

ValidationError: User validation failed: name: Path `name` is required., email: Path `email` is required., password: Path `password` is required.
    at Document.invalidate (C:\Users\User\MERN App\node_modules\mongoose\lib\document.js:3147:32)
    at C:\Users\User\MERN App\node_modules\mongoose\lib\document.js:2940:17
    at C:\Users\User\MERN App\node_modules\mongoose\lib\schematype.js:1350:9
    at process.processTicksAndRejections (node:internal/process/task_queues:77:11)

解决方法 #

1. 添加JSON解析中间件
   Express默认不解析JSON请求体，导致req.body为空对象，name/email/password取值均为undefined，触发Mongoose必填字段验证错误。在server.js中路由注册前添加：

   app.use(express.json());
   

2. 修正Token生成的变量名
   代码中generateToken(user_id)的user_id是未定义变量，需改为user._id：

   token: generateToken(user._id),
   

3. 修正成功响应状态码
   用户创建成功应返回201（资源创建成功）而非400（错误状态码），同时建议移除明文密码返回（存在安全风险）：

   res.status(201).json({
     _id: user._id,
     name: user.name,
     email: user.email,
     pic: user.pic,
     token: generateToken(user._id),
   });
   

内容的提问来源于stack exchange，提问作者Joseph Ngatia