Extract common functions to separate module

lib/auth.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { crypto } = require('./dependencies.js');
+const { crypto, common } = require('./dependencies.js');
 
 const BYTE  = 256;
 const TOKEN = 'token';
@@ -44,12 +44,6 @@ const parseCookies = cookie => {
   return values;
 };
 
-const parseHost = host => {
-  const portOffset = host.indexOf(':');
-  if (portOffset > -1) return host.substr(0, portOffset);
-  return host;
-};
-
 module.exports = application => {
   let timer = null;
   const { db } = application;
@@ -95,7 +89,7 @@ module.exports = application => {
 
   const start = (client, userId) => {
     const token = generateToken();
-    const host = parseHost(client.req.headers.host);
+    const host = common.parseHost(client.req.headers.host);
     const ip = client.req.connection.remoteAddress;
     const cookie = `${TOKEN}=${token}; ${COOKIE_HOST}=${host}; HttpOnly`;
     const sandbox = getSandbox();
@@ -132,7 +126,7 @@ module.exports = application => {
   };
 
   const remove = (client, token) => {
-    const host = parseHost(client.req.headers.host);
+    const host = common.parseHost(client.req.headers.host);
     client.res.setHeader('Set-Cookie', COOKIE_DELETE + host);
     sessions.delete(token);
     db.delete('Session', { token });

lib/common.js

@@ -0,0 +1,15 @@
+'use strict';
+
+const parseHost = host => {
+  const portOffset = host.indexOf(':');
+  if (portOffset > -1) return host.substr(0, portOffset);
+  return host;
+};
+
+const timeout = msec => new Promise(resolve => {
+  setTimeout(resolve, msec);
+});
+
+const sample = arr => arr[Math.floor(Math.random() * arr.length)];
+
+module.exports = { parseHost, timeout, sample };

lib/dependencies.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const api = {};
+const api = { common: require('./common.js') };
 const internals = [
   'util', 'child_process', 'worker_threads', 'os', 'v8', 'vm', 'path', 'url',
   'assert', 'querystring', 'string_decoder', 'perf_hooks', 'async_hooks',

lib/server.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { http, https, path, worker } = require('./dependencies.js');
+const { http, https, path, worker, common } = require('./dependencies.js');
 
 const WebSocket = require('ws');
 const Semaphore = require('./semaphore.js');
@@ -21,10 +21,6 @@ const METHOD_OFFSET = '/api/'.length;
 
 const clients = new Map();
 
-const timeout = msec => new Promise(resolve => {
-  setTimeout(resolve, msec);
-});
-
 const receiveArgs = async req => new Promise(resolve => {
   const body = [];
   req.on('data', chunk => {
@@ -154,11 +150,9 @@ const listener = application => (req, res) => {
     });
   } else {
     if (url === '/' && !req.connection.encrypted) {
-      const { host } = req.headers;
-      const portOffset = host.indexOf(':');
-      const addr = portOffset > -1 ? host.substr(0, portOffset) : host;
-      const port = application.server.randomPort();
-      client.redirect(`https://${addr}:${port}/`);
+      const host = common.parseHost(req.headers.host);
+      const port = common.sample(application.server.ports);
+      client.redirect(`https://${host}:${port}/`);
     }
     client.static();
   }
@@ -187,15 +181,11 @@ class Server {
     this.instance.listen(port, host);
   }
 
-  randomPort() {
-    return this.ports[Math.floor(Math.random() * this.ports.length)];
-  }
-
   async close() {
     this.instance.close(err => {
       if (err) this.application.logger.error(err.stack);
     });
-    await timeout(SHUTDOWN_TIMEOUT);
+    await common.timeout(SHUTDOWN_TIMEOUT);
     closeClients();
   }
 }