Tags: ads

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Saturday, August 3rd, 2019

Standard Ebooks: Free and liberated ebooks, carefully produced for the true book lover.

Books in the public domain, lovingly designed and typeset, available in multiple formats for free. Great works of fiction from Austen, Conrad, Stevenson, Wells, Hardy, Doyle, and Dickens, along with classics of non-fiction like Darwin’s The Origin of Species and Shackleton’s South!

Thursday, August 1st, 2019

Navigation preloads in service workers

There’s a feature in service workers called navigation preloads. It’s relatively recent, so it isn’t supported in every browser, but it’s still well worth using.

Here’s the problem it solves…

If someone makes a return visit to your site, and the service worker you installed on their machine isn’t active yet, the service worker boots up, and then executes its instructions. If those instructions say “fetch the page from the network”, then you’re basically telling the browser to do what it would’ve done anyway if there were no service worker installed. The only difference is that there’s been a slight delay because the service worker had to boot up first.

  1. The service worker activates.
  2. The service worker fetches the file.
  3. The service worker does something with the response.

It’s not a massive performance hit, but it’s still a bit annoying. It would be better if the service worker could boot up and still be requesting the page at the same time, like it would do if no service worker were present. That’s where navigation preloads come in.

  1. The service worker activates while simultaneously requesting the file.
  2. The service worker does something with the response.

Navigation preloads—like the name suggests—are only initiated when someone navigates to a URL on your site, either by following a link, or a bookmark, or by typing a URL directly into a browser. Navigation preloads don’t apply to requests made by a web page for things like images, style sheets, and scripts. By the time a request is made for one of those, the service worker is already up and running.

To enable navigation preloads, call the enable() method on registration.navigationPreload during the activate event in your service worker script. But first do a little feature detection to make sure registration.navigationPreload exists in this browser:

if (registration.navigationPreload) {
  addEventListener('activate', activateEvent => {
    activateEvent.waitUntil(
      registration.navigationPreload.enable()
    );
  });
}

If you’ve already got event listeners on the activate event, that’s absolutely fine: addEventListener isn’t exclusive—you can use it to assign multiple tasks to the same event.

Now you need to make use of navigation preloads when you’re responding to fetch events. So if your strategy is to look in the cache first, there’s probably no point enabling navigation preloads. But if your default strategy is to fetch a page from the network, this will help.

Let’s say your current strategy for handling page requests looks like this:

addEventListener('fetch', fetchEvent => {
  const request = fetchEvent.request;
  if (request.headers.get('Accept').includes('text/html')) {
    fetchEvent.respondWith(
      fetch(request)
      .then( responseFromFetch => {
        // maybe cache this response for later here.
        return responseFromFetch;
      })
      .catch( fetchError => {
        return caches.match(request)
        .then( responseFromCache => {
          return responseFromCache || caches.match('/offline');
        });
      })
    );
  }
});

That’s a fairly standard strategy: try the network first; if that doesn’t work, try the cache; as a last resort, show an offline page.

It’s that first step (“try the network first”) that can benefit from navigation preloads. If a preload request is already in flight, you’ll want to use that instead of firing off a new fetch request. Otherwise you’re making two requests for the same file.

To find out if a preload request is underway, you can check for the existence of the preloadResponse promise, which will be made available as a property of the fetch event you’re handling:

fetchEvent.preloadResponse

If that exists, you’ll want to use it instead of fetch(request).

if (fetchEvent.preloadResponse) {
  // do something with fetchEvent.preloadResponse
} else {
  // do something with fetch(request)
}

You could structure your code like this:

addEventListener('fetch', fetchEvent => {
  const request = fetchEvent.request;
  if (request.headers.get('Accept').includes('text/html')) {
    if (fetchEvent.preloadResponse) {
      fetchEvent.respondWith(
        fetchEvent.preloadResponse
        .then( responseFromPreload => {
          // maybe cache this response for later here.
          return responseFromPreload;
        })
        .catch( preloadError => {
          return caches.match(request)
          .then( responseFromCache => {
            return responseFromCache || caches.match('/offline');
          });
        })
      );
    } else {
      fetchEvent.respondWith(
        fetch(request)
        .then( responseFromFetch => {
          // maybe cache this response for later here.
          return responseFromFetch;
        })
        .catch( fetchError => {
          return caches.match(request)
          .then( responseFromCache => {
            return responseFromCache || caches.match('/offline');
          });
        })
      );
    }
  }
});

But that’s not very DRY. Your logic is identical, regardless of whether the response is coming from fetch(request) or from fetchEvent.preloadResponse. It would be better if you could minimise the amount of duplication.

One way of doing that is to abstract away the promise you’re going to use into a variable. Let’s call it retrieve. If a preload is underway, we’ll assign it to that variable:

let retrieve;
if (fetchEvent.preloadResponse) {
  retrieve = fetchEvent.preloadResponse;
}

If there is no preload happening (or this browser doesn’t support it), assign a regular fetch request to the retrieve variable:

let retrieve;
if (fetchEvent.preloadResponse) {
  retrieve = fetchEvent.preloadResponse;
} else {
  retrieve = fetch(request);
}

If you like, you can squash that into a ternary operator:

const retrieve = fetchEvent.preloadResponse ? fetchEvent.preloadResponse : fetch(request);

Use whichever syntax you find more readable.

Now you can apply the same logic, regardless of whether retrieve is a preload navigation or a fetch request:

addEventListener('fetch', fetchEvent => {
  const request = fetchEvent.request;
  if (request.headers.get('Accept').includes('text/html')) {
    const retrieve = fetchEvent.preloadResponse ? fetchEvent.preloadResponse : fetch(request);
    fetchEvent.respondWith(
      retrieve
      .then( responseFromRetrieve => {
        // maybe cache this response for later here.
       return responseFromRetrieve;
      })
      .catch( fetchError => {
        return caches.match(request)
        .then( responseFromCache => {
          return responseFromCache || caches.match('/offline');
        });
      })
    );
  }
});

I think that’s the least invasive way to update your existing service worker script to take advantage of navigation preloads.

Like I said, preload navigations can give a bit of a performance boost if you’re using a network-first strategy. That’s what I’m doing here on adactio.com and on thesession.org so I’ve updated their service workers to take advantage of navigation preloads. But on Resilient Web Design, which uses a cache-first strategy, there wouldn’t be much point enabling navigation preloads.

Jeff Posnick made this point in his write-up of bringing service workers to Google search:

Adding a service worker to your web app means inserting an additional piece of JavaScript that needs to be loaded and executed before your web app gets responses to its requests. If those responses end up coming from a local cache rather than from the network, then the overhead of running the service worker is usually negligible in comparison to the performance win from going cache-first. But if you know that your service worker always has to consult the network when handling navigation requests, using navigation preload is a crucial performance win.

Oh, and those browsers that don’t yet support navigation preloads? No problem. It’s a progressive enhancement. Everything still works just like it did before. And having a service worker on your site in the first place is itself a progressive enhancement. So enabling navigation preloads is like a progressive enhancement within a progressive enhancement. It’s progressive enhancements all the way down!

By the way, if all of this service worker stuff sounds like gibberish, but you wish you understood it, I think my book, Going Offline, will prove quite valuable.

Sunday, September 2nd, 2018

Your “thread” should have been a blog post…

I’m telling you this stuff is often too important and worthy to be owned by an algorithm and lost in the stream.

Wednesday, January 3rd, 2018

Back to Bradshaw’s / Paul Robert Lloyd

I really like getting Paul’s insights into building his Bradshaw’s Guide project. Here he shares his process for typography, images and geolocation.

Thursday, October 19th, 2017

Mozilla Developer Roadshow Asia Jeremy Keith - YouTube

At the 14 minute mark I had to deal with an obstreperous member of the audience. He wasn’t heckling exactly …he just had a very bad experience with web components, and I think my talk was triggering for him.

Wednesday, September 27th, 2017

Singapore

I was in Singapore last week. It was most relaxing. Sure, it’s Disneyland With The Death Penalty but the food is wonderful.

chicken rice fishball noodles laksa grilled pork

But I wasn’t just there to sample the delights of the hawker centres. I had been invited by Mozilla to join them on the opening leg of their Developer Roadshow. We assembled in the PayPal offices one evening for a rapid-fire round of talks on emerging technologies.

We got an introduction to Quantum, the new rendering engine in Firefox. It’s looking good. And fast. Oh, and we finally get support for input type="date".

But this wasn’t a product pitch. Most of the talks were by non-Mozillians working on the cutting edge of technologies. I kicked things off with a slimmed-down version of my talk on evaluating technology. Then we heard from experts in everything from CSS to VR.

The highlight for me was meeting Hui Jing and watching her presentation on CSS layout. It was fantastic! Entertaining and informative, it was presented with gusto. I think it got everyone in the room very excited about CSS Grid.

The Singapore stop was the only I was able to make, but Hui Jing has been chronicling the whole trip. Sounds like quite a whirlwind tour. I’m so glad I was able to join in even for a portion. Thanks to Sandra and Ali for inviting me along—much appreciated.

I’ll also be speaking at Mozilla’s View Source in London in a few weeks, where I’ll be talking about building blocks of the Indie Web:

In these times of centralised services like Facebook, Twitter, and Medium, having your own website is downright disruptive. If you care about the longevity of your online presence, independent publishing is the way to go. But how can you get all the benefits of those third-party services while still owning your own data? By using the building blocks of the Indie Web, that’s how!

‘Twould be lovely to see you there.

Thursday, September 21st, 2017

Talking about talking CSS

I had the great pleasure of finally meeting Hui Jing when Mozilla invited me along to Singapore to speak at their developer roadshow. Hui Jing is speaking at each one of the events on the roadshow, and documenting the journey here.

She’s being very modest about her talk: it was superb! Entertaining and informative in equal measure, delivered with gusto. Seriously, frontend conference organisers, try to get Hui Jing to speak about CSS at your event—you won’t regret it.

Mozilla Developer Roadshow - Singapore - YouTube

I had the honour of being invited along to kick off the first leg of Mozilla’s Developer Roadshow in Singapore.

Tuesday, August 22nd, 2017

What Would Augment Reality? (with images, tweets) · lukew · Storify

Luke has been asking people to imagine ways of augmenting the world. Spimes are back, baby!

Sunday, June 11th, 2017

With New Browser Tech, Apple Preserves Privacy and Google Preserves Trackers | Electronic Frontier Foundation

It’s interesting to see how excessive surveillance is (finally!) being treated as damage and routed around. Apple seem to get it—they’re tackling the tracking issue. Meanwhile Google are focusing purely on the visibility and UX of invasive advertising, without taking steps against tracking.

There’s a huge opportunity here for Chrome’s competitors—if Firefox and Safari protect users from unwarranted tracking, that could be enough to get people to switch, regardless of the feature sets of the browsers.

Sunday, March 26th, 2017

LA Times and ads | Nelson’s log

A lot has been written about the future of journalism, the importance of businesses like the LA Times being profitable as a way to protect American democracy. I agree with that in theory. But this sort of incompetence and contempt for readers makes me completely uninterested in helping their business.

Like Craig says…

Sunday, June 26th, 2016

Making bad ads sad. Rad! - O’Reilly Media

A great talk from Bruce on the digital self-defence that ad-blockers provide. I think it’s great that Opera are building ad-blocking straight into the browser.

Tuesday, March 15th, 2016

Reasons to Use Ad-Blockers – Coyote Tracks

If you think people using ad blockers are just anti-ad or want to freeload on publishers, you’re completely missing the point. The online advertising industry has been abusing users for 20 years now, and we’re sick of it.

Wednesday, March 9th, 2016

Widespread XSS Vulnerabilities in Ad Network Code Affecting Top Tier Publishers, Retailers - Randy Westergren

An a revelation that comes as a shock to absolutely no one, the JavaScript injected by ad networks can be used as a vector for attack.

This industry-wide problem serves as a great example of how 3rd-party components can compromise the security of an otherwise secure site.

One more reason to install an ad blocker.

Sunday, November 22nd, 2015

I Turned Off JavaScript for a Whole Week and It Was Glorious | WIRED

When someone’s web browsing experience can be so drastically improved by simply switching off JavaScript, you know it’s time for an intervention with web developers.

This is our fault. Client-side JavaScript gave us enormous power and we abused that power.

Sunday, November 1st, 2015

Why It’s OK to Block Ads | Practical Ethics

In reality, ad blockers are one of the few tools that we as users have if we want to push back against the perverse design logic that has cannibalized the soul of the Web.

If enough of us used ad blockers, it could help force a systemic shift away from the attention economy altogether—and the ultimate benefit to our lives would not just be “better ads.” It would be better products: better informational environments that are fundamentally designed to be on our side, to respect our increasingly scarce attention, and to help us navigate under the stars of our own goals and values. Isn’t that what technology is for?

Given all this, the question should not be whether ad blocking is ethical, but whether it is a moral obligation.

Wednesday, August 12th, 2015

The ethics of modern web ad-blocking – Marco.org

Yes! Yes! YES!

Marco makes the same comparison I did between the dark days of pop-up windows and the current abysmal state of bloated ads and tracking on today’s web.

This won’t be a clean, easy transition. Blocking pop-ups was much more incisive: it was easy for legitimate publishers to avoid one narrowly-useful Javascript function to open new windows. But it’s completely reasonable for today’s web readers to be so fed up that they disable all ads, or even all Javascript. Web developers and standards bodies couldn’t be more out of touch with this issue, racing ahead to give browsers and Javascript even more capabilities without adequately addressing the fundamental problems that will drive many people to disable huge chunks of their browser’s functionality.

Amen!

I have one more thing to add to this list…

But publishers, advertisers, and browser vendors are all partly responsible for the situation we’re all in.

…developers. Somebody put those harm-causing script elements on those pages. Like I said: “What will you be apologising for in decades to come?”

In a few years, after the dust has settled, we’re all going to look back at today’s web’s excesses and abuses as an almost unbelievable embarrassment.

Monday, July 27th, 2015

On The Verge

Quite a few people have been linking to an article on The Verge with the inflammatory title The Mobile web sucks. In it, Nilay Patel heaps blame upon mobile browsers, Safari in particular:

But man, the web browsers on phones are terrible. They are an abomination of bad user experience, poor performance, and overall disdain for the open web that kicked off the modern tech revolution.

Les Orchard says what we’re all thinking in his detailed response The Verge’s web sucks:

Calling out browser makers for the performance of sites like his? That’s a bit much.

Nilay does acknowledge that the Verge could do better:

Now, I happen to work at a media company, and I happen to run a website that can be bloated and slow. Some of this is our fault: The Verge is ultra-complicated, we have huge images, and we serve ads from our own direct sales and a variety of programmatic networks.

But still, it sounds like the buck is being passed along. The performance issues are being treated as Somebody Else’s Problem …ad networks, trackers, etc.

The developers at Vox Media take a different, and in my opinion, more correct view. They’re declaring performance bankruptcy:

I mean, let’s cut to the chase here… our sites are friggin’ slow, okay!

But I worry about how they can possibly reconcile their desire for a faster website with a culture that accepts enormously bloated ads and trackers as the inevitable price of doing business on the web:

I’m hearing an awful lot of false dichotomies here: either you can have a performant website or you have a business model based on advertising. Here’s another false dichotomy:

If the message coming down from above is that performance concerns and business concerns are fundamentally at odds, then I just don’t know how the developers are ever going to create a culture of performance (which is a real shame, because they sound like a great bunch). It’s a particularly bizarre false dichotomy to be foisting when you consider that all the evidence points to performance as being a key differentiator when it comes to making moolah.

It’s funny, but I take almost the opposite view that Nilay puts forth in his original article. Instead of thinking “Oh, why won’t these awful browsers improve to be better at delivering our websites?”, I tend to think “Oh, why won’t these awful websites improve to be better at taking advantage of our browsers?” After all, it doesn’t seem like that long ago that web browsers on mobile really were awful; incapable of rendering the “real” web, instead only able to deal with WAP.

As Maciej says in his magnificent presentation Web Design: The First 100 Years:

As soon as a system shows signs of performance, developers will add enough abstraction to make it borderline unusable. Software forever remains at the limits of what people will put up with. Developers and designers together create overweight systems in hopes that the hardware will catch up in time and cover their mistakes.

We complained for years that browsers couldn’t do layout and javascript consistently. As soon as that got fixed, we got busy writing libraries that reimplemented the browser within itself, only slower.

I fear that if Nilay got his wish and mobile browsers made a quantum leap in performance tomorrow, the result would be even more bloated JavaScript for even more ads and trackers on websites like The Verge.

If anything, browser makers might have to take more drastic steps to route around the damage of bloated websites with invasive tracking.

We’ve been here before. When JavaScript first landed in web browsers, it was quickly adopted for three primary use cases:

  1. swapping out images when the user moused over a link,
  2. doing really bad client-side form validation, and
  3. spawning pop-up windows.

The first use case was so popular, it was moved from a procedural language (JavaScript) to a declarative language (CSS). The second use case is still with us today. The third use case was solved by browsers. They added a preference to block unwanted pop-ups.

Tracking and advertising scripts are today’s equivalent of pop-up windows. There are already plenty of tools out there to route around their damage: Ghostery, Adblock Plus, etc., along with tools like Instapaper, Readability, and Pocket.

I’m sure that business owners felt the same way about pop-up ads back in the late ’90s. Just the price of doing business. Shrug shoulders. Just the way things are. Nothing we can do to change that.

For such a young, supposedly-innovative industry, I’m often amazed at what people choose to treat as immovable, unchangeable, carved-in-stone issues. Bloated, invasive ad tracking isn’t a law of nature. It’s a choice. We can choose to change.

Every bloated advertising and tracking script on a website was added by a person. What if that person refused? I guess that person would be fired and another person would be told to add the script. What if that person refused? What if we had a web developer picket line that we collectively refused to cross?

That’s an unrealistic, drastic suggestion. But the way that the web is being destroyed by our collective culpability calls for drastic measures.

By the way, the pop-up ad was first created by Ethan Zuckerman. He has since apologised. What will you be apologising for in decades to come?

Thursday, February 20th, 2014

madgex/lazy-ads

Great stuff from James Wragg and the gang at Madgex: a way of lazy-loading ads for responsive sites without messing with the ad code.

Thursday, August 1st, 2013

Create a responsive ad unit - AdSense Help

Looks like Google are offering responsive (or at least adaptive) ad sizes.