2.1 KiB
2.1 KiB
Online/Offline Event Detection
Online and offline event detection can be implemented in the renderer process using standard HTML5 APIs, as shown in the following example.
main.js
const electron = require('electron');
const app = electron.app;
const BrowserWindow = electron.BrowserWindow;
let onlineStatusWindow;
app.on('ready', () => {
onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false });
onlineStatusWindow.loadURL(`file://${__dirname}/online-status.html`);
});
online-status.html
<!DOCTYPE html>
<html>
<body>
<script>
const alertOnlineStatus = () => {
window.alert(navigator.onLine ? 'online' : 'offline');
};
window.addEventListener('online', alertOnlineStatus);
window.addEventListener('offline', alertOnlineStatus);
alertOnlineStatus();
</script>
</body>
</html>
There may be instances where you want to respond to these events in the
main process as well. The main process however does not have a
navigator object and thus cannot detect these events directly. Using
Electron's inter-process communication utilities, the events can be forwarded
to the main process and handled as needed, as shown in the following example.
main.js
const electron = require('electron');
const app = electron.app;
const ipcMain = electron.ipcMain;
const BrowserWindow = electron.BrowserWindow;
let onlineStatusWindow;
app.on('ready', () => {
onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false });
onlineStatusWindow.loadURL(`file://${__dirname}/online-status.html`);
});
ipcMain.on('online-status-changed', (event, status) => {
console.log(status);
});
online-status.html
<!DOCTYPE html>
<html>
<body>
<script>
const {ipcRenderer} = require('electron');
const updateOnlineStatus = () => {
ipcRenderer.send('online-status-changed', navigator.onLine ? 'online' : 'offline');
};
window.addEventListener('online', updateOnlineStatus);
window.addEventListener('offline', updateOnlineStatus);
updateOnlineStatus();
</script>
</body>
</html>