Tags: background

19

sparkline

Thursday, December 6th, 2018

Introducing Background Fetch  |  Web  |  Google Developers

I’m going to have to read through this article by Jake a few times before I begin to wrap my head around this background fetch thing, but it looks like it would be perfect for something like the dConstruct Audio Archive, where fairly large files can be saved for offline listening.

Sunday, November 11th, 2018

Push without notifications

On the first day of Indie Web Camp Berlin, I led a session on going offline with service workers. This covered all the usual use-cases: pre-caching; custom offline pages; saving pages for offline reading.

But on the second day, Sebastiaan spent a fair bit of time investigating a more complex use of service workers with the Push API.

The Push API is what makes push notifications possible on the web. There are a lot of moving parts—browser, server, service worker—and, frankly, it’s way over my head. But I’m familiar with the general gist of how it works. Here’s a typical flow:

  1. A website prompts the user for permission to send push notifications.
  2. The user grants permission.
  3. A whole lot of complicated stuff happens behinds the scenes.
  4. Next time the website publishes something relevant, it fires a push message containing the details of the new URL.
  5. The user’s service worker receives the push message (even if the site isn’t open).
  6. The service worker creates a notification linking to the URL, interrupting the user, and generally adding to the weight of information overload.

Here’s what Sebastiaan wanted to investigate: what if that last step weren’t so intrusive? Here’s the alternate flow he wanted to test:

  1. A website prompts the user for permission to send push notifications.
  2. The user grants permission.
  3. A whole lot of complicated stuff happens behinds the scenes.
  4. Next time the website publishes something relevant, it fires a push message containing the details of the new URL.
  5. The user’s service worker receives the push message (even if the site isn’t open).
  6. The service worker fetches the contents of the URL provided in the push message and caches the page. Silently.

It worked.

I think this could be a real game-changer. I don’t know about you, but I’m very, very wary of granting websites the ability to send me push notifications. In fact, I don’t think I’ve ever given a website permission to interrupt me with push notifications.

You’ve seen the annoying permission dialogues, right?

In Firefox, it looks like this:

Will you allow name-of-website to send notifications?

[Not Now] [Allow Notifications]

In Chrome, it’s:

name-of-website wants to

Show notifications

[Block] [Allow]

But in actual fact, these dialogues are asking for permission to do two things:

  1. Receive messages pushed from the server.
  2. Display notifications based on those messages.

There’s no way to ask for permission just to do the first part. That’s a shame. While I’m very unwilling to grant permission to be interrupted by intrusive notifications, I’d be more than willing to grant permission to allow a website to silently cache timely content in the background. It would be a more calm technology.

Think of the use cases:

  • I grant push permission to a magazine. When the magazine publishes a new article, it’s cached on my device.
  • I grant push permission to a podcast. Whenever a new episode is published, it’s cached on my device.
  • I grant push permission to a blog. When there’s a new blog post, it’s cached on my device.

Then when I’m on a plane, or in the subway, or in any other situation without a network connection, I could still visit these websites and get content that’s fresh to me. It’s kind of like background sync in reverse.

There’s plenty of opportunity for abuse—the cache could get filled with content. But websites can already do that, and they don’t need to be granted any permissions to do so; just by visiting a website, it can add multiple files to a cache.

So it seems that the reason for the permissions dialogue is all about displaying notifications …not so much about receiving push messages from the server.

I wish there were a way to implement this background-caching pattern without requiring the user to grant permission to a dialogue that contains the word “notification.”

I wonder if the act of adding a site to the home screen could implicitly grant permission to allow use of the Push API without notifications?

In the meantime, the proposal for periodic synchronisation (using background sync) could achieve similar results, but in a less elegant way; periodically polling for new content instead of receiving a push message when new content is published. Also, it requires permission. But at least in this case, the permission dialogue should be more specific, and wouldn’t include the word “notification” anywhere.

Thursday, January 18th, 2018

Finding Dead CSS – CSS Wizardry

Here’s a clever idea from Harry if you’re willing to play the long game in tracking down redundant CSS—add a transparent background image to the rule block and then sit back and watch your server logs for any sign of that sleeper agent ever getting activated.

If you do find entries for that particular image, you know that, somehow, the legacy feature is potentially still accessible—the number of entries should give you a clue as to how severe the problem might be.

Tuesday, March 21st, 2017

Lisbon Azulejos

When I was in Porto a few weeks back, I took lots of pictures of the beautiful tiles. They reminded me of the ubiquitous repeating background images that were so popular on the early web. I was thinking about abstracting them into a collection of reusable patterns but now it looks like I’ve been beaten to it!

Tuesday, February 21st, 2017

Send messages when you’re back online with Service Workers and Background Sync – Twilio Cloud Communications Blog

This example of using background sync looks like it’s specific to Twilio, but the breakdown of steps is broad enough to apply to many situations:

On the page we need to:

  1. Register a Service Worker
  2. Intercept the “submit” event for our message form
  3. Place the message details into IndexedDB, an in browser database
  4. Register the Service Worker to receive a “sync” event

Then, in the Service Worker we need to:

  1. Listen for sync events
  2. When a sync event is received, retrieve the messages from IndexedDB
  3. For each message, send a request to our server to send the message
  4. If the message is sent successfully, then remove the message from IndexedDB

And that’s it.

Wednesday, October 12th, 2016

Enhancing a comment form: From basic to custom error message to BackgroundSync | justmarkup

This is a truly fantastic example of progressive enhancement applied to a form.

What I love about this is that it shows how progressive enhancement isn’t a binary on/off choice: there are layers and layers of enhancements here, from simple inline validation all the way to service workers and background sync, with many options in between.

Superb!

Friday, September 30th, 2016

the new code – Even Stevens: Using Round and Space in Repeated Background Images

See, when I first heard about background-repeat: round; I thought it was something to do with making things circular. But no, it’s about tiling a background image so that nothing gets cut off. The amount of tiling required is rounded to the nearest whole number.

Now I get it.

Wednesday, August 24th, 2016

Psiu Puxa Wallpapers

Yummy wallpapers for your desktop, tablet, and phone, from NASA and ESA.

Friday, August 5th, 2016

ServiceWorker: A Basic Guide to BackgroundSync

A nice introduction to using Service Workers to enable syncing in the background: when the user is offline, tasks get queued up and then when the user is back online, those tasks execute.

Wednesday, July 23rd, 2014

The Pattern Library

Literally a library of patterns: y’know, for tiling background images. Old school!

Monday, February 25th, 2013

Protip: All browsers that support SVG background images also supports multiple background images.

A very hand tip from Ben on using SVG background images with a PNG fallback for IE8 and below.

Monday, June 11th, 2012

NoisePNG - Generate noisy PNG-images with alpha-transparency

If you’re adding some noise texture to your backgrounds, this little service might be handy. I usually base-64 encode these kinds of background images: it would be nice to see that added as an option here.

Sunday, May 22nd, 2011

JoshEmerson.co.uk · Blog · Base64 and the tiling background

Josh explains the pros and cons of embedding background images in your CSS using base 64 encoding.

Thursday, April 7th, 2011

The Cicada Principle and Why It Matters to Web Designers » HTML & CSS, Layout » Design Festival

A lovely bit of experimentation with prime numbers and multiple background images.

Monday, June 14th, 2010

Multiple Backgrounds and Borders with CSS 2.1 – Nicolas Gallagher — Blog & Ephemera

A clever technique to create the effect of multiple background images using the :before and :after pseudo-elements.

Sunday, May 31st, 2009

Meme Scenery - Waxy.org

There's something haunting about this: the physical settings of internet memes with the protagonists removed.

Tuesday, November 13th, 2007

iPhone/iTouch Backgrounds, Set 1 · Journal · AntonPeck.com

Awesome iPhone wallpaper images from the awesome Anton.

Saturday, December 2nd, 2006

Multiple CSS background images

Got Safari? Try resizing this page.

Wednesday, August 3rd, 2005

Surfin’ Safari » Multiple Backgrounds

Multiple background images (from CSS3) is implemented in Safari.... and has been for months!