Pure node js server where routes represents your directories

server.js

const { createServer } = require('http')
const { createReadStream } = require('fs')
const { parse } = require('url')
const { extname, resolve } = require('path')
const PORT = 9000
const HOST = '0.0.0.0'
const DOC_HANDLER = process.env.J2S_DOC_HANDLER || '_doc'
const DOC_CHECK = process.env.J2S_DOC_CHECK
const BASE_PATH = process.env.J2S_BASE_PATH || '/v0'

createServer((req, res) => {
  const parsed = parse(req.url, true)
  req.query = parsed.query
  const reqMethod = req.method.toLowerCase()
  if (!(parsed.pathname.startsWith(BASE_PATH))) {
    res.writeHead(404, { 'Content-Type': 'application/json' });
    return res.end('{"error":"Service not found"}')
  }
  const paths = parsed.pathname.slice(BASE_PATH.length + 1).split('/')
  const pathLength = paths.length;

  async function resolveResponse() {
    const jsonRes = {}
    for (let ind = 0; ind < pathLength; ind++) {
      let module;
      const pathParams = {}
      if (ind % 2 === 1) {
        pathParams[paths[ind-1].slice(0,-1) + 'Id'] = paths[ind]
        if (DOC_CHECK === '1') {
          try {
            module = require(resolve(...(paths.slice(0, ind+1))))
          } catch (er) {
            if (er.code === 'MODULE_NOT_FOUND') {
              module = require(resolve(...(paths.slice(0, ind).concat([DOC_HANDLER]))))
            } else {
              throw er
            }
          }
        } else {
          module = require(resolve(...(paths.slice(0, ind).concat([DOC_HANDLER]))))
        }
      } else {
        module = require(resolve(...(paths.slice(0, ind+1))))
      }
      await module[reqMethod](req, jsonRes, pathParams)
    }
    return jsonRes
  }

  resolveResponse().then((jsonRes) => {
    if (jsonRes.hasOwnProperty('_file')) {
      const fileExt = String(extname(jsonRes._file)).toLowerCase();
      res.writeHead(jsonRes._statusCode || 200, {
        'Content-disposition': `attachment; filename=${jsonRes._file}`,
        'Content-Type': `application/${fileExt}`
      });
      const filestream = createReadStream(jsonRes._file);
      filestream.pipe(res);
    } else {
      res.writeHead(jsonRes._statusCode || 200, { 'Content-Type': 'application/json' });
      const toSend = jsonRes.data;
      if (typeof toSend === 'string') {
        res.end(`{"message":"${toSend}"}`)
      } else {
        res.end(JSON.stringify(toSend))
      }
    }
  }).catch((er) => {
    // console.error(er)
    if (er.code == 'MODULE_NOT_FOUND') {
      er._statusCode = 404
      er.message = 'Route not found.'
    } else if (er.message === 'module[reqMethod] is not a function') {
      er._statusCode = 405
      er.message = 'Route method not found.'
    }
    res.writeHead(er._statusCode || 400, { 'Content-Type': 'application/json' })
    res.end(`{"error":"${er.message}"}`)
  });

}).listen(PORT, HOST, () => {
  console.log(`Server running at http://${HOST}:${PORT}`)
})