Tags: rel

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Thursday, October 1st, 2020

AddyOsmani.com - Preload late-discovered Hero images faster

Did you know there’s an imagesrcset attribute you can put on link rel="preload" as="image" (along with an imagesizes attribute)?

I didn’t. (Until Amber pointed this out.)

Saturday, July 4th, 2020

The Machines Stop

The Situation feels like it’s changing. It’s not over, not by a long shot. But it feels like it’s entering a different, looser phase.

Throughout the lockdown, there’s been a strange symmetry between the outside world and the inside of our home. As the outside world slowed to a halt, so too did half the machinery in our flat. Our dishwasher broke shortly before the official lockdown began. So did our washing machine.

We had made plans for repairs and replacements, but as events in the world outside escalated, those plans had to be put on hold. Plumbers and engineers weren’t making any house calls, and rightly so.

We even had the gas to our stovetop cut off for a while—you can read Jessica’s account of that whole affair. All the breakdowns just added to the entropic Ballardian mood.

But the gas stovetop was fixed. And so too was the dishwasher, eventually. Just last week, we got our new washing machine installed. Piece by piece, the machinery of our interier world revived in lockstep with the resucitation of the world outside.

As of today, pubs will be open. I won’t be crossing their thresholds just yet. We know so much more about the spread of the virus now, and gatherings of people in indoor spaces are pretty much the worst environments for transmission.

I’m feeling more sanguine about outdoor spaces. Yesterday, Jessica and I went into town for Street Diner. It was the first time since March that we walked in that direction—our other excursions have been in the direction of the countryside.

It was perfectly fine. We wore masks, and while we were certainly in the minority, we were not alone. People were generally behaving responsibly.

Brighton hasn’t done too badly throughout The Situation. But still, like I said, I have no plans to head to the pub on a Saturday night. The British drinking culture is very much concentrated on weekends. Stay in all week and then on the weekend, lassen die Sau raus!, as the Germans would say.

After months of lockdown, reopening pubs on a Saturday seems like a terrible idea. Over in Ireland, pubs have been open since Monday—a sensible day to soft-launch. With plenty of precautions in place, things are going well there.

I’ve been watching The Situation in Ireland throughout. It’s where my mother lives, so I was understandably concerned. But they’ve handled everything really well. It’s not New Zealand, but it’s also not the disaster that is the UK.

It really has been like watching an A/B test run at the country level. Two very similar populations confronted with exactly the same crisis. Ireland took action early, cancelling the St. Patrick’s Day parade(!) while the UK was still merrily letting Cheltenham go ahead. Ireland had clear guidance. The UK had dilly-dallying and waffling. And when the shit really hit the fan, the Irish taoiseach rolled up his sleeves and returned to medical work. Meanwhile the UK had Dominic Cummings making a complete mockery of the sacrifices that everyone was told to endure.

What’s strange is that people here in the UK don’t seem to realise how the rest of the world, especially other European countries, have watched the response here with shock and horror. The narrative here seems to be that we all faced this thing together, and with our collective effort, we averted the worst. But the numbers tell a very different story. Comparing the numbers here with the numbers in Ireland—or pretty much any other country in Europe—is sobering.

So even though the timelines for reopenings here converge with Ireland’s, The Situation is far from over.

Even without any trips to pubs, restaurants, or other indoor spaces, I’m looking forward to making some more excursions into town. Not that it’s been bad staying at home. I’ve really quite enjoyed staying put, playing music, reading books, and watching television.

I was furloughed from work for a while in June. Normally, my work at this time of year would involve plenty of speaking at conferences. Seeing as that wasn’t happening, it made sense to take advantage of the government scheme to go into work hibernation for a bit.

I was worried I might feel at a bit of a loose end, but I actually really enjoyed it. The weather was good so I spent quite a bit of time just sitting in the back garden, reading (I am very, very grateful to have even a small garden). I listened to music. I watched movies. I surfed the web. Yes, properly surfed the web, going from link to link, get lost down rabbit holes. I tell you, this World Wide Web thing is pretty remarkable. Some days I used it to read up on science or philosophy. I spent a week immersed in Napoleonic history. I have no idea how or why. But it was great.

I’m back at work now, and have been for a couple of weeks. But I wouldn’t mind getting furloughed again. It felt kind of like being retired. I’m quite okay with the propsect of retirement now, as long as we have music and sunshine and the World Wide Web.

That’s the future. For now, The Situation continues, albeit in looser form.

I’ve really enjoyed reading other people’s accounts throughout. My RSS reader is getting a good workout. I always look forward to weeknotes from Alice, Nat, and Phil (this piece from Phil has really stuck with me). Jessica has written fifteen installments—and counting—of A Journal of the Plague Week. I know I’m biased, but I think it’s some mighty fine writing. Start here.

Thursday, June 25th, 2020

On dependency | RobWeychert.com V7

I’m very selective about how I depend on other people’s work in my personal projects. Here are the factors I consider when evaluating dependencies.

  • Complexity How complex is it, who absorbs the cost of that complexity, and is that acceptable?
  • Comprehensibility Do I understand how it works, and if not, does that matter?
  • Reliability How consistently and for how long can I expect it to work?

I really like Rob’s approach to choosing a particular kind of dependency when working on the web:

When I’m making things, that’s how I prefer to depend on others and have them depend on me: by sharing strong, simple ideas as a collective, and recombining them in novel ways with rigorous specificity as individuals.

Monday, April 20th, 2020

geoTrad - Google My Maps

Well, this is a rather wonderful mashup made with data from thesession.org:

The distribution of Irish traditional tunes which reference place names in Ireland

Monday, March 30th, 2020

Hobbies for the hell of it | Brad Frost

We should celebrate our hobbies for the joy-giving activities they are, and recognize that they don’t need to become anything bigger than that. And of course that’s not to say they those hobbies can’t turn into something bigger — it’s incredible when your passions and your occupation overlap — but it should be because you want to rather than that you feel pressured to. Not every activity you do needs to become a big official thing.

Monday, March 9th, 2020

41 hours in Galway

It was my birthday recently. I’m a firm believer in the idea that birthday celebrations should last for more than 24 hours. A week is the absolute minimum.

For the day itself, I did indeed indulge in a most luxurious evening out with Jessica at The Little Fish Market in Hove (on the street where we used to live!). The chef, Duncan Ray, is an absolute genius and his love for all things fish-related shines through in his magnificent dishes.

But to keep the celebrations going, we also went on a weekend away to Galway, where I used to live decades ago. It was a quick trip but we packed in a lot. I joked at one point that it felt like one of those travel articles headlined with “36 hours in someplace.” I ran the numbers and it turned out we were in Galway for 41 hours, but I still thought it would be fun to recount events in the imperative style of one of those articles…

A surprisingly sunny day in Galway.

Saturday, February 29th

The 3:30pm train from Dublin will get you into Galway just before 6pm. The train station is right on the doorstep of Loam, the Michelin-starred restaurant where you’ve made your reservation. Enjoy a seven course menu of local and seasonal produce. Despite the quality of the dishes, you may find the overall experience is a little cool, and the service a touch over-rehearsed.

You’ll be released sometime between 8:30pm and 9pm. Stroll through Eyre Square and down Shop Street to the Jury’s Inn, your hotel. It’s nothing luxurious but it’s functional and the location is perfect. It’s close to everything without being in the middle of the noisy weekend action. The only noise you should hear is the rushing of the incredibly fast Corrib river outside your window.

Around 9:30pm, pop ‘round to Dominick Street to enjoy a cocktail in the America Village Apothecary. It’s only open two nights a week, and it’s a showcase of botanicals gathered in Connemara. Have them make you a tasty conconction and then spend time playing guess-that-smell with their specimen jars.

By 10:30pm you should be on your way round the corner to The Crane Bar on Sea Road. Go in the side entrance and head straight upstairs where the music session will be just getting started. Marvel at how chilled out it is for a Saturday night, order a pint, and sit and listen to some lovely jigs’n’reels. Don’t forget to occassionally pester one of the musicians by asking “What was that last tune called? Lovely set!”

Checked in at The Crane Bar. Great tunes! 🎻🎶 — with Jessica

Sunday, March 1st

Skip the hotel breakfast. Instead, get your day started with a coffee from Coffeewerk + Press. Get that coffee to go and walk over to Ard Bia at Nimmos, right at the Spanish Arch. Get there before it opens at 10am. There will already be a line. Once you’re in, order one of the grand brunch options and a nice big pot of tea. The black pudding hash will set you up nicely.

Checked in at Ard Bia at Nimmos. Black pudding hash and a pot of tea — with Jessica

While the weather is far clearer and sunnier than you were expecting, take the opportunity to walk off that hearty brunch with a stroll along the sea front. That’ll blow out the cobwebs.

Galway bay. Galway bay.

When the cold gets too much, head back towards town and duck into Charlie Byrne’s, the independent bookshop. Spend some time in there browsing the shelves and don’t leave without buying something to remember it by.

By 1pm or so, it’s time for some lunch. This is the perfect opportunity to try the sushi at Wa Cafe near the harbour. They have an extensive range of irrestistable nigiri, so just go ahead and get one of everything. The standouts are the local oyster, mackerel, and salmon.

Checked in at wa cafe. Sushi — with Jessica

From there, head to Tigh Cóilí for the 2pm session. Have a Guinness and enjoy the tunes.

Checked in at Tigh Cóilí. Afternoon session — with Jessica

Spend the rest of the afternoon strolling around town. You can walk through the market at St. Nicholas Church, and check out the little Claddagh ring museum at Thomas Dillon’s—the place where you got your wedding rings at the close of the twentieth century.

Return the ring from whence it came!

If you need a pick-me-up, get another coffee from Coffeewerk + Press, but this time grab a spot at the window upstairs so you can watch the world go by outside.

By 6pm, you’ll have a hankering for some more seafood. Head over to Hooked on Henry Street. Order a plate of oysters, and a cup of seafood chowder. If they’ve got ceviche, try that too.

Checked in at Hooked. with Jessica

Walk back along the canal and stop in to The Salt House to sample a flight of beers from Galway Bay Brewery. There’ll probably be some live music.

Checked in at The Salt House. 🍺 — with Jessica

With your appetite suitably whetted, head on over to Cava Bodega for some classic tapas. Be sure to have the scallops with black pudding.

Checked in at Cava Bodega. Scallops with black pudding — with Jessica

The evening session at Tigh Cóilí starts at 8:30pm on a Sunday so you can probably still catch it. You’ll hear some top-class playing from the likes of Mick Conneely and friends.

Checked in at Tigh Cóilí. 🎶🎻 — with Jessica

And when that’s done, there’s still time to catch the session over at The Crane.

Checked in at The Crane Bar. 🎶🎻 — with Jessica

Monday, March 2nd

After a nice lie-in, check out of the hotel and head to McCambridge’s on Shop Street for some breakfast upstairs. A nice bowl of porridge will set you up nicely for the journey back to Dublin.

If you catch the 11am train, you’ll arrive in Dublin by 1:30pm—just enough time to stop off in The Winding Stair for some excellent lunch before heading on to the airport.

Checked in at The Winding Stair. Lunch in Dublin — with Jessica

Getting there

Aer Lingus flies daily from Gatwick to Dublin. Dublin’s Heuston Station has multiple trains per day going to Galway.

Friday, October 4th, 2019

Why Progressive Web Apps Are The Future of Mobile Web [2019 Research]

PWAs just work better than your typical mobile site. Period.

But bear in mind:

Maybe simply because the “A” in PWA stands for “app,” too much discussion around PWAs focuses on comparing and contrasting to native mobile applications. We believe this comparison (and the accompanying discussion) is misguided.

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, July 21st, 2019

The Simplest Way to Load CSS Asynchronously | Filament Group, Inc.

Scott re-examines the browser support for loading everything-but-the-critical-CSS asynchronously and finds that it might now be as straightforward as this one declaration:

<link rel="stylesheet" href="/path/to/my.css" media="print" onload="this.media='all'">

I love the fact the Filament Group are actively looking at how deprecate their loadCSS polyfill—exactly the right attitude for polyfills in general.

Tuesday, July 16th, 2019

Trad time

Fifteen years ago, I went to the Willie Clancy Summer School in Miltown Malbay:

I’m back from the west of Ireland. I was sorry to leave. I had a wonderful, music-filled time.

I’m not sure why it took me a decade and a half to go back, but that’s what I did last week. Myself and Jessica once again immersed ourselves in Irish tradtional music. I’ve written up a trip report over on The Session.

On the face of it, fifteen years is a long time. Last time I made the trip to county Clare, I was taking pictures on a point-and-shoot camera. I had a phone with me, but it had a T9 keyboard that I could use for texting and not much else. Also, my hair wasn’t grey.

But in some ways, fifteen years feels like the blink of an eye.

I spent my mornings at the Willie Clancy Summer School immersed in the history of Irish traditional music, with Paddy Glackin as a guide. We were discussing tradition and change in generational timescales. There was plenty of talk about technology, but we were as likely to discuss the influence of the phonograph as the influence of the internet.

Outside of the classes, there was a real feeling of lengthy timescales too. On any given day, I would find myself listening to pre-teen musicians at one point, and septegenarian masters at another.

Now that I’m back in the Clearleft studio, I’m finding it weird to adjust back in to the shorter timescales of working on the web. Progress is measured in weeks and months. Technologies are deemed outdated after just a year or two.

The one bridging point I have between these two worlds is The Session. It’s been going in one form or another for over twenty years. And while it’s very much on and of the web, it also taps into a longer tradition. Over time it has become an enormous repository of tunes, for which I feel a great sense of responsibility …but in a good way. It’s not something I take lightly. It’s also something that gives me great satisfaction, in a way that’s hard to achieve in the rapidly moving world of the web. It’s somewhat comparable to the feelings I have for my own website, where I’ve been writing for eighteen years. But whereas adactio.com is very much focused on me, thesession.org is much more of a community endeavour.

I question sometimes whether The Session is helping or hindering the Irish music tradition. “It all helps”, Paddy Glackin told me. And I have to admit, it was very gratifying to meet other musicians during Willie Clancy week who told me how much the site benefits them.

I think I benefit from The Session more than anyone though. It keeps me grounded. It gives me a perspective that I don’t think I’d otherwise get. And in a time when it feels entirely to right to question whether the internet is even providing a net gain to our world, I take comfort in being part of a project that I think uses the very best attributes of the World Wide Web.

Monday, July 15th, 2019

Spurious Correlations

Correlation does not imply causation.

Tuesday, May 28th, 2019

How Ireland became Europe’s data watchdog - BBC News

The coming GDPR storm:

Ireland’s Data Protection Commissioner, Helen Dixon, is expected to circulate her decisions on some cases by July or August, with final rulings made by the end of the year.

(That’s my sister-in-law, that is.)

Wednesday, April 24th, 2019

Preload, prefetch and other link tags: what they do and when to use them · PerfPerfPerf

Following on from Harry’s slides, here’s another round-up of thoserel attribute values that begin with pre.

More Than You Ever Wanted to Know About Resource Hints - Speaker Deck

Slides from Harry’s deep dive into rel values: preconnect, prefetch, and preload.

Wednesday, December 19th, 2018

Performance Calendar » All about prefetching

A good roundup of techniques for responsible prefetching from Katie Hempenius.

Monday, December 3rd, 2018

Voxxed Thessaloniki 2018 - Opening Keynote - Taking Back The Web - YouTube

Here’s the talk I gave recently about indie web building blocks.

There’s fifteen minutes of Q&A starting around the 35 minute mark. People asked some great questions!

Tuesday, November 6th, 2018

How to get on the #indieweb!

As well as graciously hosting Indie Web Camp Berlin on the weekend at Mozilla’s offices, Yulia has also drawn this super-cute comic.

Wednesday, September 5th, 2018

The Font Loading Checklist—zachleat.com

This checklist came in very handy during a performance-related workshop I was running today (I may have said the sentence “Always ask yourself What Would Zach Do?”).

  1. Start Important Font Downloads Earlier (Start a Web Font load)
  2. Prioritize Readable Text (Behavior while a Web Font is loading)
  3. Make Fonts Smaller (Reduce Web Font load time)
  4. Reduce Movement during Page Load (Behavior after a Web Font has loaded)

The first two are really straightforward to implement (with rel="preload" and font-display). The second two take more work (with subsetting and the font loading API).

Friday, August 10th, 2018

“Designer + Developer Workflow,” an article by Dan Mall

Dan compares the relationship between a designer and developer in the web world to the relationship between an art director and a copywriter in the ad world. He and Brad made a video to demonstrate how they collaborate.

Tuesday, July 10th, 2018

Ways to think about machine learning — Benedict Evans

This strikes me as a sensible way of thinking about machine learning: it’s like when we got relational databases—suddenly we could do more, quicker, and easier …but it doesn’t require us to treat the technology like it’s magic.

An important parallel here is that though relational databases had economy of scale effects, there were limited network or ‘winner takes all’ effects. The database being used by company A doesn’t get better if company B buys the same database software from the same vendor: Safeway’s database doesn’t get better if Caterpillar buys the same one. Much the same actually applies to machine learning: machine learning is all about data, but data is highly specific to particular applications. More handwriting data will make a handwriting recognizer better, and more gas turbine data will make a system that predicts failures in gas turbines better, but the one doesn’t help with the other. Data isn’t fungible.