ファイル整理してたらNode.js始めたばかりの頃にリバースプロキシ風の処理を自作したコードが出てきて懐かしいので晒す

server.js

const app = require('http').createServer(handler)
const io = require('socket.io')(app)
const path = require('path')
const fs = require('fs')
const mime = require('mime-types')

io.sockets.on('connection', socket => {
  socket.on('socket', data => {
    console.log(data)
    io.sockets.emit('socket',data)
  })
})

function handler(req, res) {
  fs.readFile('./servers.json', 'utf8', (err, data) => {
    const servers = JSON.parse(data)
    for (const server of servers) {
      if (req.url.startsWith(server.url)) {
        const pathname = req.url.replace(server.url, '')
        let uri = path.join(__dirname, server.uri, pathname)
        console.log(uri)
        fs.exists(uri, exists => {
          if (!exists) {
            res.writeHead(404)
            res.write('404 Not Found\n')
            res.end()
          } else {
            if (fs.statSync(uri).isDirectory()) uri += '/index.html'
            fs.readFile(uri, 'binary', (err, file) => {
              if (err) {
                res.writeHead(500)
                res.write(err + '\n')
                res.end()
              } else {
                res.writeHead(200, {
                  'Content-Type': mime.lookup(pathname),
                })
                res.write(file, 'binary')
                res.end()
              }
            })
          }
        })
        return
      }
    }
    res.writeHead(404)
    res.write('404 Not Found\n')
    res.end()
  })
}

app.listen(80)

servers.json

[
  {
  	"url": "/nextyear",
  	"uri": "/projects/nextyear"
  },
  {
  	"url": "/musicbot",
  	"uri": "/projects/musicbot"
  },
  {
    "url": "/npsdct",
    "uri": "/projects/npsdct"
  }
]