sudo certbot certonly --standalone -d you.keyin.me

class KoaOnHttps extends Koa {
 constructor() {
  super();
 }
 get options() {
  return {
   key: fs.readFileSync(require.resolve('/etc/letsencrypt/live/you.keyin.me/privkey.pem')),
   cert: fs.readFileSync(require.resolve('/etc/letsencrypt/live/you.keyin.me/fullchain.pem'))
  };
 }
 listen(...args) {
  const server = http2.createSecureServer(this.options, this.callback());
  return server.listen(...args);
 }
 redirect(...args) {
  const server = http.createServer(this.callback());
  return server.listen(...args);
 }
}

const app = new KoaOnHttps();
app.use(sslify());
//...
app.listen(443, () => {
logger.ok('app start at:', `https://you.keyin.cn`);
});

// receive all the http request, redirect them to https
app.redirect(80, () => {
logger.ok('http redirect server start at', `http://you.keyin.me`);
});

const send = require('koa-send');
const logger = require('../util/logger');
const { push, acceptsHtml } = require('../util/helper');
const depTree = require('../util/depTree');
module.exports = (root = '') => {
 return async function serve(ctx, next) {
  let done = false;
  if (ctx.method === 'HEAD' || ctx.method === 'GET') {
   try {
    // 當(dāng)希望收到html時(shí)，推送額外資源。
    if (/(\.html|\/[\w-]*)$/.test(ctx.path)) {
     depTree.currentKey = ctx.path;
     const encoding = ctx.acceptsEncodings('gzip', 'deflate', 'identity');
     // server push
     for (const file of depTree.getDep()) {
      // server push must before response!
      // https://huangxuan.me/2017/07/12/upgrading-eleme-to-pwa/#fast-skeleton-painting-with-settimeout-hack
      push(ctx.res.stream, file, encoding);
     }
    }
    done = await send(ctx, ctx.path, { root });
   } catch (err) {
    if (err.status !== 404) {
     logger.error(err);
     throw err;
    }
   }
  }
  if (!done) {
   await next();
  }
 };
};

const logger = require('./logger');

const db = new Map();
let currentKey = '/';

module.exports = {
  get currentKey() {
    return currentKey;
  },
  set currentKey(key = '') {
    currentKey = this.stripDot(key);
  },
  stripDot(str) {
    if (!str) return '';
    return str.replace(/index\.html$/, '').replace(/\./g, '-');
  },
  addDep(filePath, url, key = this.currentKey) {
    if (!key) return;
    key = this.stripDot(key);
    if(!db.has(key)){
      db.set(key,new Map());
    }
    const keyDb = db.get(key);

    if (keyDb.size >= 10) {
      logger.warning('Push resource limit exceeded');
      return;
    }
    keyDb.set(filePath, url);
  },
  getDep(key = this.currentKey) {
    key = this.stripDot(key);
    const keyDb = db.get(key);
    if(keyDb == undefined) return [];
    const ret = [];
    for(const [filePath,url] of keyDb.entries()){
      ret.push({filePath,url});
    }
    return ret;
  }
};

router.get(/\.(js|css)$/, async (ctx, next) => {
 let filePath = ctx.path;
 if (/\/sw-register\.js/.test(filePath)) return await next();
 filePath = path.resolve('../dist', filePath.substr(1));
 await next();
 if (ctx.status === 200 || ctx.status === 304) {
  depTree.addDep(filePath, ctx.url);
 }
});

exports.push = function(stream, file) {
 if (!file || !file.filePath || !file.url) return;
 file.fd = file.fd || fs.openSync(file.filePath, 'r');
 file.headers = file.headers || getFileHeaders(file.filePath, file.fd);

 const pushHeaders = {[HTTP2_HEADER_PATH]: file.url};

 stream.pushStream(pushHeaders, (err, pushStream) => {
  if (err) {
   logger.error('server push error');
   throw err;
  }
  pushStream.respondWithFD(file.fd, file.headers);
 });
};

exports.push = function(stream, file) {
 if (!file || !file.filePath || !file.url) return;
 file.fd = file.fd || fs.openSync(file.filePath, 'r');
 file.headers = file.headers || getFileHeaders(file.filePath, file.fd);

 const pushHeaders = {[HTTP2_HEADER_PATH]: file.url};

 stream.pushStream(pushHeaders, (err, pushStream) => {
  if (err) {
   logger.error('server push error');
   throw err;
  }
  if (shouldCompress()) {
   const header = Object.assign({}, file.headers);
   header['content-encoding'] = "gzip";
   delete header['content-length'];
   
   pushStream.respond(header);
   const fileStream = fs.createReadStream(null, {fd: file.fd});
   const compressTransformer = zlib.createGzip(compressOptions);
   fileStream.pipe(compressTransformer).pipe(pushStream);
  } else {
   pushStream.respondWithFD(file.fd, file.headers);
  }
 });
};

//...
fileStream.pipe(compressTransformer).pipe(pushStream);
pushStream.on('close', () => fileStream.destroy());
//...