在REST API GET请求中定义MongoDB集合

const express = require('express');
const mongodb = require('mongodb');

const app = express();
const MongoClient = mongodb.MongoClient;
const url = 'mongodb://localhost:27017/mydatabase';

// 定义GET请求的路由处理程序
app.get('/collection', (req, res) => {
  // 连接到MongoDB数据库
  MongoClient.connect(url, (err, client) => {
    if (err) {
      console.error('Failed to connect to MongoDB:', err);
      res.status(500).send('Failed to connect to MongoDB');
      return;
    }

    // 获取数据库对象和集合对象
    const db = client.db('mydatabase');
    const collection = db.collection('mycollection');

    // 查询集合中的数据
    collection.find({}).toArray((err, result) => {
      if (err) {
        console.error('Failed to query collection:', err);
        res.status(500).send('Failed to query collection');
        return;
      }

      // 将查询结果转换为JSON格式并返回给客户端
      res.json(result);
    });
  });
});

// 启动REST API服务器
app.listen(3000, () => {
  console.log('REST API server is running on port 3000');
});