如何从Express.Router.post()内部获取Mongoose.Schema属性？(+发送Firebase通知)

const express = require('express');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');

const app = express();
app.use(bodyParser.json());

// 定义Mongoose模型
const UserSchema = new mongoose.Schema({
  name: String,
  age: Number,
});

const User = mongoose.model('User', UserSchema);

// 定义Express路由
const router = express.Router();

router.post('/users', (req, res) => {
  // 从请求体中获取属性
  const { name, age } = req.body;

  // 创建新的用户
  const newUser = new User({ name, age });

  // 保存用户到数据库
  newUser.save()
    .then(() => {
      res.status(200).send('User created successfully');
    })
    .catch((error) => {
      res.status(500).send('Error creating user');
    });
});

app.use(router);

// 连接到MongoDB数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true })
  .then(() => {
    // 启动Express服务器
    app.listen(3000, () => {
      console.log('Server started on port 3000');
    });
  })
  .catch((error) => {
    console.error('Error connecting to database', error);
  });

const admin = require('firebase-admin');

// 初始化Firebase Admin SDK
const serviceAccount = require('path/to/serviceAccountKey.json');
admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
});

// 发送通知
const message = {
  notification: {
    title: 'New message',
    body: 'You have a new message',
  },
  topic: 'news',
};

admin.messaging().send(message)
  .then((response) => {
    console.log('Notification sent successfully:', response);
  })
  .catch((error) => {
    console.error('Error sending notification:', error);
  });