// 后端Express中间件
const express = require('express');
const mongoose = require('mongoose');
const app = express();

// 连接MongoDB
mongoose.connect('mongodb://localhost:27017/mydb', {useNewUrlParser: true});

// 定义数据模型
const Item = mongoose.model('Item', { name: String, value: Number });

// 创建REST API
app.get('/api/items', async (req, res) => {
  const items = await Item.find();
  res.json(items);
});

app.post('/api/items', async (req, res) => {
  const newItem = new Item(req.body);
  await newItem.save();
  res.json(newItem);
});

app.listen(3000);

// 前端jQuery代码
$.ajax({
  url: '/api/items',
  type: 'GET',
  dataType: 'json',
  success: function(data) {
    console.log('获取数据:', data);
    // 处理数据...
  }
});

// 提交数据
$.ajax({
  url: '/api/items',
  type: 'POST',
  contentType: 'application/json',
  data: JSON.stringify({name: "New Item", value: 100}),
  success: function(data) {
    console.log('创建成功:', data);
  }
});

// 后端Express中间件
const express = require('express');
const nano = require('nano');
const app = express();

const couch = nano('http://localhost:5984');
const db = couch.db.use('mydb');

app.get('/api/docs', async (req, res) => {
  const docs = await db.list({include_docs: true});
  res.json(docs.rows.map(row => row.doc));
});

app.post('/api/docs', async (req, res) => {
  const response = await db.insert(req.body);
  res.json(response);
});

app.listen(3000);

// 在Express中间件中添加CORS支持
const cors = require('cors');
app.use(cors());

// 在中间件中添加验证
app.post('/api/items', express.json(), (req, res) => {
  if (!req.body.name || !req.body.value) {
    return res.status(400).json({error: "缺少必要字段"});
  }
  // 处理有效数据...
});

// 分页示例
app.get('/api/items', async (req, res) => {
  const page = parseInt(req.query.page) || 1;
  const limit = parseInt(req.query.limit) || 10;
  const items = await Item.find()
    .skip((page - 1) * limit)
    .limit(limit);
  res.json(items);
});