Express中間件body-parser的實現方法

// lib/body-parser.js
const querystring = require('querystring');

module.exports.urlencoded = function (req, res, next) {
 let chunks = [];
 req.on('data', data => {
 chunks.push(data);
 });

 req.on('end', () => {
 // 合并Buffer。
 let buf = Buffer.concat(chunks).toString();
 // 把querystring解析過的json 放到 req.body上。
 req.body = querystring.parse(buf);
 next();
 });
}

// app.js
const express = require('express');
const bodyParser = require('./lib/body-parser');

let app = express();

app.use(bodyParser.urlencoded);


app.post('/', (req, res) => {
 res.send(req.body);
});

app.listen(8000);