lazy-compile-webpack-plugin/lib/server.js

Lazy compile dynamic imports to boost your webpack startup time.

const detect = require('detect-port-alt');
const http = require('http');
const url = require('url');

class Server {
  constructor(plugin, port) {
    this.plugin = plugin;
    this._listenAddr = '0.0.0.0';
    this._listenPort = port;
  }

  async start() {
    try {
      this._listenPort = await detect(this._listenPort, this._listenAddr);
    } catch (err) {
      throw new Error(
        `Could not find an open port.` +
          '\n' +
          ('Network error message: ' + err.message || err) +
          '\n'
      );
    }

    // Create an HTTP server
    if (!this.server) {
      this.server = http.createServer((req, res) => {
        const userRequest = url.parse(req.url, true).query.r;
        this.plugin.activateModule(userRequest).then(() => {
          res.writeHead(200, { 'Content-Type': 'image/svg+xml' });
          res.end(
            '<?xml version="1.0" encoding="utf-8"?>\n' +
              '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n' +
              '<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><text y="20">lazy-compile-webpack-plugin</text> </svg>'
          );
        });
      });
    }
    return new Promise((resove, reject) => {
      this.server.listen(this._listenPort, this._listenAddr, err => {
        if (err) {
          return reject(
            new Error(
              `Could not start the backend.` +
                '\n' +
                ('Network error message: ' + err.message || err) +
                '\n'
            )
          );
        }

        resove();
      });
    });
  }

  close() {
    if (this.server) {
      this.server.close();
    }
  }

  createActivationUrl(userRequest) {
    return `http://{host}:${this._listenPort}?r=${encodeURIComponent(
      userRequest
    )}`;
  }
}

module.exports = Server;