fix network change + refactor - closes #2

Author: csabapalfi

main.js

@@ -1,29 +1,10 @@
-const timers = require('timers');
 const path = require('path');
-const dns = require('dns');
-const Ping = require('ping-lite');
-const { forever, timeout, parallel, waterfall } = require('async');
-const { app, dialog, BrowserWindow, Tray, Menu } = require('electron');
+const networkStatus = require('./network-status');
+const { app, BrowserWindow, Tray, Menu } = require('electron');
+const timeoutMs = 2000;
 
-const dnsLatency = (host, callback) => {
-  const dnsStartMs = +(new Date);
-  dns.resolve(host, err => {
-    if (err) return callback(err);
-    callback(null, +(new Date) - dnsStartMs);
-  });
-}
-
-const pingLatency = (ip, callback) => {
-  const ping = new Ping(ip);
-  ping.send((err, latencyMs) => {
-    if (err) return callback(err);
-    callback(null, Math.round(latencyMs));
-  });
-}
-
-let mainWindow;
 app.on('ready', () => {
-  mainWindow = new BrowserWindow({show: false});
+  new BrowserWindow({show: false});
   if (app.dock) app.dock.hide();
 
   const tray = new Tray(path.join(app.getAppPath(), 'icon.png'));
@@ -39,17 +20,12 @@ app.on('ready', () => {
   let title = `.../...ms`;
   tray.setTitle(title);
 
-  const refreshLatency = (check, arg, timeoutMs, titleRegex) =>
-    () => setInterval(() => {
-      timeout(check, timeoutMs)(arg, (err, latency) => {
-        title = title.replace(titleRegex, latency || '...');
-        tray.setTitle(title);
-      })
-    }, timeoutMs + 100);
-
-  parallel([
-    refreshLatency(dnsLatency, 'google.com', 2000, /[\d\.]+(?=\/)/),
-    refreshLatency(pingLatency, '8.8.8.8', 2000, /[\d\.]+(?=ms)/),
-  ]);
-
+  networkStatus({
+    timeoutMs: 2000,
+    intervalMs: 2000,
+    hostname: 'google.com',
+    address: '8.8.8.8'
+  }).on('latencies', ({dns, ping}) =>
+    tray.setTitle(`${dns || '...'}/${ping || '...'}ms`)
+  );
 });

network-status.js

@@ -0,0 +1,67 @@
+const timers = require('timers');
+const EventEmitter = require('events');
+const Ping = require('ping-lite');
+const dns = require('dns-socket');
+const resolv = require('resolv');
+
+const dnsLatency = (hostname, timeout) =>
+  new Promise((resolve, reject) => {
+    var socket = dns({ timeout });
+    const nameserver = resolv().nameserver[0];
+    const query = { questions: [{ type: 'A', name: hostname }] };
+    const dnsStartMs = +(new Date());
+    socket.query(query, 53, nameserver, error =>
+      error ? reject(error) : resolve(+(new Date()) - dnsStartMs));
+  }
+);
+
+const pingLatency = (address) =>
+  new Promise((resolve, reject) =>
+    new Ping(address).send((error, latencyMs) =>
+      error ? reject(error) : resolve(Math.round(latencyMs))
+    )
+);
+
+const timeout = (promise, timeoutMs) => {
+  let timer = null;
+  const clearTimeout = () => timers.clearTimeout(timer);
+  return Promise.race([
+    promise,
+    new Promise((resolve, reject) => {
+      timer = setTimeout(() => reject(new Error('timed out')), timeoutMs);
+    })
+  ])
+  .then(value => { clearTimeout(); return value; })
+  .catch(error => { clearTimeout(); throw error; });
+};
+
+const allIgnoreErrors = (promises) => Promise.all(
+  promises.map(promise => promise.catch(() => null))
+);
+
+const checkLatencies = ({ hostname, address, timeoutMs }) =>
+  allIgnoreErrors([
+    dnsLatency(hostname, timeoutMs).catch(() => null),
+    timeout(pingLatency(address), timeoutMs).catch(() => null)
+  ]);
+
+const networkStatus = (options) => {
+  const latencies = new EventEmitter();
+  setInterval(() => checkLatencies(options)
+    .then(([dns, ping]) =>
+      latencies.emit('latencies', { dns, ping })
+    )
+  , options.intervalMs);
+  return latencies;
+};
+
+if (require.main === module) {
+  networkStatus({
+    timeoutMs: 2000,
+    intervalMs: 2000,
+    hostname: 'google.com',
+    address: '8.8.8.8'
+  }).on('latencies', console.log);
+}
+
+module.exports = networkStatus;

package.json

@@ -1,10 +1,11 @@
 {
   "name": "TrayPing",
   "version": "3.0.0",
-  "description": "tray application showing google.com ping times",
+  "description": "tray application showing DNS/ping latency",
   "dependencies": {
-    "async": "^2.1.4",
-    "ping-lite": "^1.0.2"
+    "dns-socket": "^1.6.1",
+    "ping-lite": "^1.0.2",
+    "resolv": "^1.0.0"
   },
   "devDependencies": {
     "electron": "^1.4.13",