Tags: offline

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Thursday, December 14th, 2017

Progressive Web Apps - My new book is available! | Dean Hume

This looks interesting—a new book by Dean Hume all about progressive web apps. A few chapters are available to download.

Monday, November 6th, 2017

Installing Progressive Web Apps

When I was testing the dConstruct Audio Archive—which is now a Progressive Web App—I noticed some interesting changes in how Chrome on Android offers the “add to home screen” prompt.

It used to literally say “add to home screen.”

Getting the “add to home screen” prompt for https://huffduffer.com/ on Android Chrome. And there’s the “add to home screen” prompt for https://html5forwebdesigners.com/ HTTPS + manifest.json + Service Worker = “Add to Home Screen” prompt. Add to home screen.

Now it simply says “add.”

The dConstruct Audio Archive is now a Progressive Web App

I vaguely remember there being some talk of changing the labelling, but I could’ve sworn it was going to change to “install”. I’ve got to be honest, just having the word “add” doesn’t seem to provide much context. Based on the quick’n’dirty usability testing I did with some co-workers, it just made things confusing. “Add what?” “What am I adding?”

Additionally, the prompt appeared immediately on the first visit to the site. I thought there was supposed to be an added “engagement” metric in order for the prompt to appear; that the user needs to visit the site more than once.

You’d think I’d be happy that users will be presented with the home-screen prompt immediately, but based on the behaviour I saw, I’m not sure it’s a good thing. Here’s what I observed:

  1. The user types the URL archive.dconstruct.org into the address bar.
  2. The site loads.
  3. The home-screen prompt slides up from the bottom of the screen.
  4. The user immediately moves to dismiss the prompt (cue me interjecting “Don’t close that!”).

This behaviour is entirely unsurprising for three reasons:

  1. We web designers and web developers have trained users to dismiss overlays and pop-ups if they actually want to get to the content. Nobody’s going to bother to actually read the prompt if there’s a 99% chance it’s going to say “Sign up to our newsletter!” or “Take our survey!”.
  2. The prompt appears below the “line of death” so there’s no way to tell it’s a browser or OS-level dialogue rather than a JavaScript-driven pop-up from the site.
  3. Because the prompt now appears on the first visit, no trust has been established between the user and the site. If the prompt only appeared on later visits (or later navigations during the first visit) perhaps it would stand a greater chance of survival.

It’s still possible to add a Progressive Web App to the home screen, but the option to do that is hidden behind the mysterious three-dots-vertically-stacked icon (I propose we call this the shish kebab icon to distinguish it from the equally impenetrable hamburger icon).

I was chatting with Andreas from Mozilla at the View Source conference last week, and he was filling me in on how Firefox on Android does the add-to-homescreen flow. Instead of a one-time prompt, they’ve added a persistent icon above the “line of death” (the icon is a combination of a house and a plus symbol).

When a Firefox 58 user arrives on a website that is served over HTTPS and has a valid manifest, a subtle badge will appear in the address bar: when tapped, an “Add to Home screen” confirmation dialog will slide in, through which the web app can be added to the Android home screen.

This kind of badging also has issues (without the explicit text “add to home screen”, the user doesn’t know what the icon does), but I think a more persistently visible option like this works better than the a one-time prompt.

Firefox is following the lead of the badging approach pioneered by the Samsung Internet browser. It provides a plus symbol that, when pressed, reveals the options to add to home screen or simply bookmark.

What does it mean to be an App?

I don’t think Chrome for Android has any plans for this kind of badging, but they are working on letting the site authors provide their own prompts. I’m not sure this is such a good idea, given our history of abusing pop-ups and overlays.

Sadly, I feel that any solution that relies on an unrequested overlay is doomed. That’s on us. The way we’ve turned browsing the web—especially on mobile—into a frustrating chore of dismissing unwanted overlays is a classic tragedy of the commons. We blew it. Users don’t trust unrequested overlays, and I can’t blame them.

For what it’s worth, my opinion is that ambient badging is a better user experience than one-time prompts. That opinion is informed by a meagre amount of testing though. I’d love to hear from anyone who’s been doing more detailed usability testing of both approaches. I assume that Google, Mozilla, and Samsung are doing this kind of testing, and it would be really great to see the data from that (hint, hint).

But it might well be that ambient badging is just too subtle to even be noticed by the user.

On one end of the scale you’ve got the intrusiveness of an add-to-home-screen prompt, but on the other end of the scale you’ve got the discoverability problem of a subtle badge icon. I wonder if there might be a compromise solution—maybe a badge icon that pulses or glows on the first or second visit?

Of course that would also need to be thoroughly tested.

Thursday, November 2nd, 2017

The dConstruct Audio Archive works offline

The dConstruct conference is as old as Clearleft itself. We put on the first event back in 2005, the year of our founding. The last dConstruct was in 2015. It had a good run.

I’m really proud of the three years I ran the show—2012, 2013, and 2014—and I have great memories from each event. I’m inordinately pleased that the individual websites are still online after all these years. I’m equally pleased with the dConstruct audio archive that we put online in 2012. Now that the event itself is no longer running, it truly is an archive—a treasury of voices from the past.

I think that these kinds of online archives are eminently suitable for some offline design. So I’ve added a service worker script to the dConstruct archive.

Caching

To start with, there’s the no-brainer: as soon as someone hits the website, pre-cache static assets like CSS, JavaScript, the logo, and icon images. Now subsequent page loads will be quicker—those assets are taken straight from the cache.

But what about the individual pages? For something like Resilient Web Design—another site that won’t be updated—I pre-cache everything. I could do that with the dConstruct archive. All of the pages with all of the images add up to less than two megabytes; the entire site weighs less than a single page on Wired.com or The Verge.

In the end, I decided to go with a cache-as-you-go strategy. Every time a page or an image is fetched from the network, it is immediately put in a cache. The next time that page or image is requested, the file is served from that cache instead of the network.

Here’s the logic for fetch requests:

  1. First, look to see if the file is in a cache. If it is, great! Serve that.
  2. If the file isn’t in a cache, make a network request and serve the response …but put a copy of a file in the cache.
  3. The next time that file is requested, go to step one.

Save for offline

That caching strategy works great for pages, images, and other assets. But there’s one kind of file on the dConstruct archive that’s a bit different: the audio files. They can be fairly big, so I don’t want to cache those unless the user specifically requests it.

If you end up on the page for a particular talk, and your browser supports service workers, you’ll get an additional UI element in the list of options: a toggle to “save offline” (under the hood, it’s a checkbox). If you activate that option, then the audio file gets put into a cache.

Now if you lose your network connection while browsing the site, you’ll get a custom offline page with the option to listen to any audio files you saved for offline listening. You’ll also see this collection of talks on the homepage, regardless of whether you’ve got an internet connection or not.

So if you’ve got a long plane journey ahead of you, have a browse around the dConstruct archive and select some talks for your offline listening pleasure.

Or just enjoy the speediness of browsing the site.

Turning another website into a Progressive Web App.

Saturday, September 23rd, 2017

Progressive Web Apps? No, we are building Alien Web Apps | Condé Nast Technology

There’s a lot of misinformation on the internet as to how to build a PWA and how “appy” and SPA-y one must be.

Yes!

This simply isn’t true. Disappointingly, It is what most of the documentation, blog posts and public discourse seem to imply.

Preach it!

I’m so, so happy to see some pushback against the misinformation that progressive web apps automatically imply client-side rendered single page apps built from scratch. There’s so much value to be had in turbo-charging an existing site into a progressive web app.

But what we don’t need is yet another TLA like Alien Web Apps.

Friday, September 22nd, 2017

How much storage space is my Progressive Web App using? | Dean Hume

You can use navigator.storage.estimate() to get a (vague) idea of how much space is available on a device for your service worker caches.

Tuesday, September 19th, 2017

Infusion: An Inclusive Documentation Builder

Two of my favourite things together at last: pattern libraries and service workers. Infusion is a tool for generating pattern libraries that also work offline.

Thinking about it, it makes total sense that a pattern library should be a progressive web app.

Sunday, September 17th, 2017

Tame your Service Worker before your Progressive Web App go into the wild by Maxim Salnikov

There are some great service worker optimisation tips in these slides.

Monday, September 11th, 2017

Betting on the Web

Along the lines of John’s recent post, Henrik makes the business case for progressive web apps.

He also points out how they can be much better than native apps for controlling hardware.

They can be up and running in a fraction of the time whether or not they were already “installed” and unlike “apps” can be saved as an app on the device at the user’s discretion!

Essentially they’re really great for creating “ad hoc” experiences that can be “cold started” on a whim nearly as fast as if it were already installed.

Friday, September 1st, 2017

Yes, That Web Project Should Be a PWA · An A List Apart Article

A fantastic piece by Aaron who—once again—articulates what I’ve been thinking:

Your site—every site—should be a PWA.

He clearly explains the building blocks of progressive web apps—HTTPS, a manifest file, and a service worker—before describing different scenarios for different kinds of sites:

  • Informational
  • Periodical
  • Transactional
  • Social
  • Software
  • Institutional

Progressive Web Apps may seem overly technical or beyond the needs of your project, but they’re really not. They’re just a shorthand for quality web experiences—experiences that can absolutely make a difference in our users’ lives.

Highly recommended!

Thursday, August 24th, 2017

A Progressive Roadmap for your Progressive Web App - Cloud Four

Jason lists the stages of gradually turning the Cloud Four site into a progressive web app:

And you can just keep incrementally adding and tweaking:

You don’t have to wait to bundle up a binary, submit it to an app store, and wait for approval before your customers benefit.

Sunday, August 20th, 2017

Offline POSTs with Progressive Web Apps – Web Dev @ Microsoft – Medium

This is a smart way to queue up POST submissions for later if the user is offline. It’s not as powerful as background sync (because it requires the user to revisit your site) but it’s a good fallback for browsers that support service workers but don’t yet support background sync

Thursday, August 3rd, 2017

Attachment #317095 for bug #175115

I’ve never been so excited by a single diff in a JSON file.

Service workers are coming to Safari.

Wednesday, July 26th, 2017

Web Publications for the Open Web Platform: Vision And Technical Challenges

Given my experience publishing Resilient Web Design as a web book, I think I should take a good look at this nascent spec.

What we envision for Packaged Web Publications is similar to the goals and techniques of Progressive Web Apps: breaking the boundaries between web sites and mobile apps, an emphasis on “offline” paradigms, and so on. The time is right to broaden the scope and power of the web to include publications.

Friday, July 14th, 2017

You’re Offline | Max Böck - Frontend Web Developer

This looks like a sensible way to detect if the user is offline, and provide appropriate feedback, like making certain links or forms inactive.

Introducing PWAs

The slides from Calum’s presentation about progressive web apps. There are links throughout to some handy resources.

Thursday, July 13th, 2017

How to turn your website into a PWA | Max Böck - Frontend Web Developer

This primer on progressive web apps starts by dispelling some myths:

  1. Your thing does not have to be an “Application” to be a PWA.
  2. Your thing does not have to be a Javascript-powered single page app.
  3. PWAs are not specifically made for Google or Android.
  4. PWAs are ready and safe to use today.

Then it describes the three-step programme for turning your thing into a progressive web app:

  1. The Manifest.
  2. Go HTTPS.
  3. The Service Worker.

Thursday, July 6th, 2017

Your Site—Any Site—Should be a PWA | Aaron Gustafson

Tell it, brother!

PWAs don’t require you use a particular JavaScript framework or any JavaScript framework at all. You don’t need to be building a Single Page App either.

Sunday, June 25th, 2017

Service Worker gotchas

A great collection of learned lessons from implementing service workers.

I really, really like it when people share their own personal experiences and “gotchas!” like this.

Monday, June 5th, 2017

Johannes Dachsel – Making my website work offline – a service worker module for Processwire

If you use the ProcessWire Content Management System, Johannes has written a handy plug-in that allows you to specify which files should be cached by a service worker.

Wednesday, May 31st, 2017

HN PWA - Hacker News readers as Progressive Web Apps

Of all the sites to pick to demo progressive web apps, we get the cesspit that is Hacker News …I guess it is possible to polish a turd.

Anyway, here are some examples of using frameworks to create alternative Hacker News readers. So the challenge here is to display some text to read..

Four of them render absolutely no content without JavaScript.

In the Hall of Shame we have React, Preact, Angular, and Polymer.

In the Hall of Fame, we have the ones doing it right: React, Vue, and Viper.

That’s right: React appears in both. See, it’s not about the tools; it’s about how you use ‘em.