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Comment by swartkrans | Hacker News Reader

The push API is pretty awesome, the key difference between it and websockets in term of what it offers is this bit:

> A push service allows a webapp server to send messages to a webapp, regardless of whether the webapp is currently active on the user agent

So you can send push notifications to a user even if they don't have a tab open to your website.

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> The push API is pretty awesome

The idea behind this is awesome (although we already have this for some platforms - e.g. https://developer.apple.com/library/mac/documentation/Networ...)

But the API looks over-engineered. e.g.

navigator.serviceWorker.ready.then(function(serviceWorkerRegistration) {

serviceWorkerRegistration.pushRegistrationManager.register().then(...

The new web APIs are promise-ified by default rather than using the callback model of the past. So rather than register(callback), it's register().then(...).

Whether this is a good thing or not is another question I don't know the answer to.

My comment was mainly about serviceWorker.ready.then. I've never seen a JS API using such pattern - the name of the event as a property which is a promise.

A manager object/class also usually rings a bell.

Not that I'm an API specialist but I would rather implement it as:

document.addEventListener("serviceready", function() {

window.pushNotification.register().then(.....

For an event that only happens once, then the

    navigator.serviceWorker.ready.then(function(){...

version is preferable to

    document.addEventListener("serviceready", function() {

because A) you don't have to worry about removing your event listener after the fact, and B) if the event has already happened, then your callback will be called immediately.

I believe this spec is aiming to standardize the service offered primarily by Google (GCM) and Apple (APN), and open/standardize it for other people like pubnub/parse/pusher/...

>The push API is pretty awesome, the key difference between it and websockets in term of what it offers is this bit:

> > A push service allows a webapp server to send messages to a webapp, regardless of whether the webapp is currently active on the user agent.

Actually, the difference you describe is what Server-Sent Events [1] already provide: one-way notifications vs bidirectional communication with websockets.

This spec, rather, would standardize an API for a single-connection (read: better battery life) push server that third party webapps can use in the same way Google Cloud Messenger is used by third-party application servers for android apps.

[1] http://www.w3.org/TR/eventsource/

I'm... not sure I want this. It sounds pretty useful/fun form a programmers perspective.

But from an end-user perspective I fear that it will lead too various "features" hogging resources. I would assume I could block them client-side, but I'm also the family-tech and quite frankly I don't expect my grandparents to do the same.

"User agents must not provide Push API access to webapps without the express permission of the use"

I share your concern. but I share a great fear that web apps will become increasingly irrelevant if they remain just documents that can't do anything when they're not explicitly in a running tab/window.

The permission requirement is the same one that allows for local storage, which could have caused great problems, but has so far held up well.

> The permission requirement is the same one that allows for local storage

Assuming this does not allow the push of UI interaction, then yes. If it would allow UI responses to be pushed then we would be one XSS vulnerability or "uneducated users" away from a new set of exploits for forcing pop-under advertising , and other potentially more insidious problems, through.

Local Storage and Index DB are storage only so the only attack routes are DoS-due-to-disk-full-errors which is generally less attractive (you can make more money pushing stuff to people than pushing people off the network).

And the Ask toolbar doesn't get installed without expressed permission, either.

We all get phone calls or text messages now when we don't have the associated binary apps open. Isn't this just the same thing for web apps?

It's the same things for web apps, with added near-infinite possibilities for spam.

It's permission based. Read the linked spec.

Are the permissions fine-grained enough to give users the power to say Yes to useful content and No to intrusive marketing messages?

Or is the option to include that choice going to be left to site designers?

I can't see that in the spec, so no. Like most things, if you don't like an app, you can revoke it's privileges and uninstall it.

The questions you keep asking are basic things solved by reading the article - you seem to have concerns, but you haven't done the minimum amount of work necessary to determine whether your concerns are valid.

Permissions are per-origin.

Safari supports push notifications from websites for a while. I've found it convenient for the news websites I often visit just to check for new content. It's like RSS integrated into OS. One can misuse it, but generally it's useful.

Is that the bit (step 1) where they install the Service Worker? I.e. regardless of whether or not the page is open, the Service Worker is active?

Yes, and it has to maintain TCP connections with every push source you've registered, including re-connecting whenever your network situation changes. IMHO, this will lead to a lot of wasted bandwidth. Might not be a problem on desktop machines, but on mobile devices…

It already happens on mobile devices through APNs, GCM, and the like. Maybe mobile web browsers will have backing cloud services that use the mobile OS's recommended push server as a frontend to the mobile device? That doesn't sound like an ideal scenario though, considering that then the cloud service would have an enormous amount of user data going through it.

APN and GCM multiplex messages from all apps on a single TCP connection. That makes a significant difference.

That is how the Push API works as well. In fact usually developers will be using APN or GCM when they use the Push API.

well how do smartphones and apps deal with push notification in general? (i mean native apps)

The OS provides a messaging service. Applications can request differing levels of latency guarantee. The default on Android is to deliver immediately unless the device is off or sleeping, in which case it'll be queued for up to 4 weeks or until the device wakes up, whichever comes first. There is also throttling functionality, where an app that sends too many messages in a short period of time will find that its messages are only delivered when the device radio has to wake up for other non-throttled messages.

With iOS, Apple provides a service that event sources push their messages to, and a single TCP connection is maintained with the device regardless of the number of event sources. Google has something similar, if not identical.

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