Channel Messaging API Notification Tutorial

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Channel Messaging API Notification Tutorial

Channel Messaging API Notification Tutorial

In order to introduce another new Javascript API called “Channel Messaging API” …

The Channel Messaging API allows two separate scripts running in different browsing contexts attached to the same document (e.g., two IFrames, or the main document and an IFrame, two documents via a SharedWorker, or two workers) to communicate directly, passing messages between one another through two-way channels (or pipes) with a port at each end.

… into the mix, today, we wanted to combine …

… to, maybe, work towards another Broadcast (and Listen) idea. So far in its infancy is today’s “proof of concept” …

… which you can also try for yourself, below …

Stop Press

The changed channel_messaging_test.html HTML and Javascript client side parent code web application now hides any annoying “quick flash” intermediate Notification functionality popup windows. You can read more into the mechanism for this at Notification API Hidden Popup Tutorial.

Previous relevant Notification API Primer Tutorial is shown below.

Notification API Primer Tutorial

Notification API Primer Tutorial

A lot of us use notifications to tell us “what to do”, “where to go (to shop, for instance)“, “which email has arrived” etcetera etcetera etcetera. Notifications can be like SMS, as that instantaneous form of communication …

In information technology, a notification system is a combination of software and hardware that provides a means of delivering a message to a set of recipients.[1] It commonly shows activity related to an account.[2] Such systems constitute an important aspect of modern Web applications.[3]

For example, a notification system can send an e-mail announcing when a computer network will be down for a scheduled maintenance.

The complexity of the notification system may vary. Complicated notification systems are used by businesses to reach critical employees.[1] Emergency notification systems may take advantage of modern information technologies. Governments use them to inform people of upcoming danger.[1]

In mobile phones and smartphones, dedicated hardware such as a notification LED is sometimes included to deliver messages or notify users

… and so it goes without saying that a web based Notification API is interesting to us … so we’d appreciate you not trying to say “Notiflicrations” through your Rice Bubbles right now, thanks, if you don’t mind?!

You’ll be getting the gist …

  • you need permissions on behalf of your web browser (that you should programmatically ask for, as required)
  • you may need to allow “Experimental Javascript functionality” be accepted on your web browser
  • it’s quite likely you need an https: protocol URL happening
  • not all web browsers will support the API even so, and various media assumptions may not work with that underlying web browser as another issue

… but, be that as it may, it’s still worth trying this out, especially here on this macOS Google Chrome (Version 103.0.5060.53 (Official Build) (x86_64)) web browser, we reckon. And yes, thanks again to Using the Notifications API, web based notifications can happen …


<html>
<head>
<title>Notification API Usage - RJM Programming - July, 2022 ... thanks to https://developer.mozilla.org/en-US/docs/Web/API/Notifications_API/Using_the_Notifications_API</title>
<style> td { vertical-align: top; } </style>
</head>
<body>
<h2>Notification API Usage</h2>
<h3>RJM Programming - July, 2022</h3>
<h4>Thanks to <a target=_blank title='https://developer.mozilla.org/en-US/docs/Web/API/Notifications_API/Using_the_Notifications_API' href='//developer.mozilla.org/en-US/docs/Web/API/Notifications_API/Using_the_Notifications_API'>https://developer.mozilla.org/en-US/docs/Web/API/Notifications_API/Using_the_Notifications_API</a></h4><br>
<form method=GET action='./notifications_ideas.html'>
<table border=20 cellspacing=5 cellpadding=5>
<tr><th colspan=2>Notifications</th></tr>
<tr><th>Button Press</th><th>Default</th></tr>
<tr><td>
<input style='background-color:rgb(230,230,230);' placeholder='Make blank to not offer.' title='Make blank to not offer.' name=hi id=hi type=text value="Hi! " onblur="if (this.value != 'Hi! ') { document.getElementById('ifrom').value='1'; } else { document.getElementById('ifrom').value='0'; }"></input> x <input name=repeats id=repeats type=number min='1' value='9' title='Up to and including' step=1></input> from <input type=number id=ifrom min='0' max='1' step=1 value='0' title='From' readonly></input>
</td><td>
<table border=5 cellspacing=2 cellpadding=2><tr><th colspan=2>Subject and Body Notification</th></tr>
<tr><th>Subject</th><th>Body</th></tr><tr><td style='vertical-align:top;'>
<input placeholder='Make blank to not do.' title='Make blank to not do.' name=subject id=subject type=text value='To do list'></input></td><td style='vertical-align:top;'><textarea style='background-color:rgb(230,230,230);' title='Make blank to not do.' placeholder='Make blank to not do.' name=body id=body rows=5 cols=60 value='HEY! Your task document.title is now overdue.'>HEY! Your task document.title is now overdue.</textarea>
</td></tr><tr><th colspan=2>Song Notification</th></tr><tr><td colspan=2>
<input style='width:98%;background-color:rgb(230,230,230);' placeholder='Make blank to not do.' title='Make blank to not do.' name=songtext id=songtext type=text value='My Great Song'></input>
</td></tr></table>
</td>
</tr>
<tr><td colspan=2><input type=submit name=rerun value='Rerun' style='background-color:yellow;'></input></td></tr>
</table>
</form>
<br><br><br><hr><br>

<script type='text/javascript'>
document.getElementById('body').value=document.getElementById('body').value.replace('document.title', document.title);
var ris=(location.search.split('repeats=')[1] ? Math.max(1,eval('0' + location.search.split('repeats=')[1].split('&')[0])) : 9);
var vsi='[]', comis='';
for (var ii=(location.search.split('repeats=')[1] ? 1 : 0); ii<=ris; ii++) {
vsi=vsi.replace(']', comis + ii + ']');
comis=',';
}
var nondb='<button id=bhi>"' + (location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') + ' ..." + ' + vsi : 'Hi! " + ' + vsi) + '</button>&nbsp;&nbsp;';
if ((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : "Hi! ").trim() == '') {
nondb='';
}
document.write(nondb + '<button id="enable" onclick="askNotificationPermission();" style="display:none;">Enable notifications</button>');
var gv=1;

Notification.requestPermission().then(function(result) {
console.log(result);
});

Notification.requestPermission();

if (window.Notification && Notification.permission === "granted") {
gv=gv;
} else {
document.getElementById('enable').style.display='inline-block';
}

function askNotificationPermission() {
// function to actually ask the permissions
function handlePermission(permission) {
// set the button to shown or hidden, depending on what the user answers
if(Notification.permission === 'denied' || Notification.permission === 'default') {
notificationBtn.style.display = 'block';
} else {
notificationBtn.style.display = 'none';
}
}

// Let's check if the browser supports notifications
if (!('Notification' in window)) {
console.log("This browser does not support notifications.");
} else {
if(checkNotificationPromise()) {
Notification.requestPermission()
.then((permission) => {
handlePermission(permission);
})
} else {
Notification.requestPermission(function(permission) {
handlePermission(permission);
});
}
}
}

function checkNotificationPromise() {
try {
Notification.requestPermission().then();
} catch(e) {
return false;
}

return true;
}

const img = '//www.rjmprogramming.com.au/MyBusinessUnidad/Welcome_files/logo.jpg';
const text = (location.search.split('body=')[1] ? decodeURIComponent(location.search.split('body=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'HEY! Your task "' + document.title + '" is now overdue.');
if (text.trim() != '' && (location.search.split('subject=')[1] ? decodeURIComponent(location.search.split('subject=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'To do list').trim() != '') {
const notification = new Notification((location.search.split('subject=')[1] ? decodeURIComponent(location.search.split('subject=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'To do list'), { body: text, icon: img });
}
if ((location.search.split('songtext=')[1] ? decodeURIComponent(location.search.split('songtext=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'My Great Song').trim() != '') {
const n = new Notification((location.search.split('songtext=')[1] ? decodeURIComponent(location.search.split('songtext=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'My Great Song'));
document.addEventListener('visibilitychange', function() {
if (document.visibilityState === 'visible') {
// The tab has become visible so clear the now-stale Notification.
n.close();
}
});
}

window.addEventListener('load', function () {
const button = document.getElementsByTagName('button')[0];

if (window.self !== window.top) {
// Ensure that if our document is in a frame, we get the user
// to first open it in its own tab or window. Otherwise, it
// won't be able to request permission to send notifications.
button.textContent = "View live result of the example code above";
button.addEventListener('click', () => window.open(location.href));
return;
}

document.getElementById('bhi').addEventListener('click', function () {
// If the user agreed to get notified
// Let's try to send ten notifications
//alert(1);
if (window.Notification && Notification.permission === "granted") {
if ((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : "Hi! ").trim() != '') {
//alert(11);
let i = (location.search.split('repeats=')[1] ? 1 : 0);
// Using an interval cause some browsers (including Firefox) are blocking notifications if there are too much in a certain time.
const interval = window.setInterval(function () {
// Thanks to the tag, we should only see the "Hi! 9" notification
const n = new Notification((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') + ' ... ' + i : "Hi! " + i), {tag: (location.search.split('tag=')[1] ? decodeURIComponent(location.search.split('tag=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'soManyNotification')});
if (i++ == (location.search.split('repeats=')[1] ? eval(0 + Math.max(1,eval('0' + location.search.split('repeats=')[1].split('&')[0]))) : 9)) {
window.clearInterval(interval);
}
}, 700);
}
}

// If the user hasn't told if they want to be notified or not
// Note: because of Chrome, we are not sure the permission property
// is set, therefore it's unsafe to check for the "default" value.
else if (window.Notification && Notification.permission !== "denied") {
Notification.requestPermission(function (status) {
// If the user said okay
if (status === "granted") {
if ((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : "Hi! ").trim() != '') {
let i = (location.search.split('repeats=')[1] ? 1 : 0);
// Using an interval cause some browsers (including Firefox) are blocking notifications if there are too much in a certain time.
const interval = window.setInterval(function () {
// Thanks to the tag, we should only see the "Hi! 9" notification
const n = new Notification((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') + ' ... ' + i : "Hi! " + i), {tag: (location.search.split('tag=')[1] ? decodeURIComponent(location.search.split('tag=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') : 'soManyNotification')});
if (i++ == (location.search.split('repeats=')[1] ? eval(0 + Math.max(1,eval('0' + location.search.split('repeats=')[1].split('&')[0]))) : 9)) {
window.clearInterval(interval);
}
}, 700);
}
}

// Otherwise, we can fallback to a regular modal alert
else {
alert((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') + ' ... ' + i : "Hi!"));
}
});
}

// If the user refuses to get notified
else {
// We can fallback to a regular modal alert
alert((location.search.split('hi=')[1] ? decodeURIComponent(location.search.split('hi=')[1].split('&')[0]).replace(/\+/g,' ').replace(/\ \ \ /g,' + ') + ' ... ' + i : "Hi!"));
}
});
});
</script>
</body>
</html>

… used in a “proof of concept” notifications_ideas.html web Notifying application.

If this was interesting you may be interested in this too.

If this was interesting you may be interested in this too.

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