express起一个代理服务器

由于系统业务比较复杂，微前端（多页应用）实现期望用一个app一个webpack的形式，这样可以更好隔离，而且每个app的webpack config可以定制。

Nginx在前端项目中安装比较麻烦，所以考虑用nodejs来代理，社区比较成熟的node代理显然就是express的http-proxy-middleware了：

var express = require('express')
var proxy = require('http-proxy-middleware')
var rewrite = require('express-urlrewrite')

var app = express()

let options = {
    '/report/template': { 
        target: 'http://www.wenming.cn',
        pathRewrite: {
            '^/report/template': '',
        },
        headers: {
            "Host": "www.wenming.cn",
            "Connection": "keep-alive",
            "Cache-Control": "max-age=0",
            "Upgrade-Insecure-Requests": "1",
            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36",
            "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3",
            "Accept-Encoding": "gzip, deflate",
            "Accept-Language": "zh-CN,zh;q=0.9",
            "Cookie": "wdcid=118bf0416992ec45; wdlast=1553783233; Hm_lvt_3bdce7455c04dfb8cf1a26c3ac808bea=1553783233; Hm_lpvt_3bdce7455c04dfb8cf1a26c3ac808bea=1553783233",
        }
     },
     '/report':{ 
        target: 'http://localhost:8090',
        pathRewrite: {
            '^/report': '',
        },
     }
}

app.use('/app/home', (req,res,next) => {
    req.originalUrl = req.originalUrl.replace(/^\/app\/home/, '')
    next()
});
app.use(rewrite('/app/home/*', '/$1'))

function proxyFactory(source, option) {
    app.use(source, proxy(option))
}
for (let key in options) {
    proxyFactory(key, options[key])
}
app.use('/', (req, res) => {
    res.send('not found!!')
})
app.listen(3000)