81 lines
2 KiB
Markdown
81 lines
2 KiB
Markdown
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# Online/Offline Event Detection
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Online and offline event detection can be implemented in the renderer process
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using standard HTML5 APIs, as shown in the following example.
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_main.js_
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```javascript
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var app = require('app');
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var BrowserWindow = require('browser-window');
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var onlineStatusWindow;
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app.on('ready', function() {
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onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false });
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onlineStatusWindow.loadUrl('file://' + path.join(__dirname, '/online-status.html'));
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});
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```
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_online-status.html_
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```html
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<html>
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<body>
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<script>
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var alertOnlineStatus = function() {
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window.alert(navigator.onLine ? 'online' : 'offline');
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};
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window.addEventListener('online', alertOnlineStatus);
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window.addEventListener('offline', alertOnlineStatus);
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alertOnlineStatus();
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</script>
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</body>
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</html>
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```
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There may be instances where one wants to respond to these events in the
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browser process as well. The browser process however does not have a
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"navigator" object and thus cannot detect these events directly. Using
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Atom-shell's inter-process communication utilities, the events can be forwarded
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to the browser process and handled as needed, as shown in the following example.
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_main.js_
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```javascript
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var app = require('app');
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var ipc = require('ipc');
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var BrowserWindow = require('browser-window');
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var onlineStatusWindow;
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app.on('ready', function() {
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onlineStatusWindow = new BrowserWindow({ width: 0, height: 0, show: false });
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onlineStatusWindow.loadUrl('file://' + path.join(__dirname, '/online-status.html'));
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});
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ipc.on('onlineStatusMessage', function(event, status) {
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console.log(status);
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});
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```
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_online-status.html_
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```html
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<html>
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<body>
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<script>
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var ipc = require('ipc');
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var updateOnlineStatus = function() {
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ipc.send('onlineStatusMessage', navigator.onLine ? 'online' : 'offline');
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};
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window.addEventListener('online', updateOnlineStatus);
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window.addEventListener('offline', updateOnlineStatus);
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updateOnlineStatus();
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</script>
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</body>
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</html>
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```
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