Tags: uri

216

sparkline

Monday, April 6th, 2020

Performance, security, and ethics: influencing effectively

I wrote something recently about telling the story of performance. Sue Loh emphasis the importance of understanding what makes people tick:

Performance engineers need to be an interesting mix of data-lovers and people-whisperers.

Tuesday, March 3rd, 2020

Insecure

Universal access is at the heart of the World Wide Web. It’s also something I value when I’m building anything on the web. Whatever I’m building, I want you to be able to visit using whatever browser or device that you choose.

Just to be clear, that doesn’t mean that you’re going to have the same experience in an old browser as you are in the latest version of Firefox or Chrome. Far from it. Not only is that not feasible, I don’t believe it’s desirable either. But if you’re using an old browser, while you might not get to enjoy the newest CSS or JavaScript, you should still be able to access a website.

Applying the principle of progressive enhancement makes this emminently doable. As long as I build in a layered way, everyone gets access to the barebones HTML, even if they can’t experience newer features. Crucially, as long as I’m doing some feature detection, those newer features don’t harm older browsers.

But there’s one area where maintaining backward compatibility might well have an adverse effect on modern browsers: security.

I don’t just mean whether or not you’re serving sites over HTTPS. Even if you’re using TLS—Transport Layer Security—not all security is created equal.

Take a look at Mozilla’s very handy SSL Configuration Generator. You get to choose from three options:

  1. Modern. Services with clients that support TLS 1.3 and don’t need backward compatibility.
  2. Intermediate. General-purpose servers with a variety of clients, recommended for almost all systems.
  3. Old. Compatible with a number of very old clients, and should be used only as a last resort.

Because I value universal access, I should really go for the “old” setting. That ensures my site is accessible all the way back to Android 2.3 and Safari 1. But if I do that, I will be supporting TLS 1.0. That’s not good. My site is potentially vulnerable.

Alright then, I’ll go for “intermediate”—that’s the recommended level anyway. Now I’m no longer providing TLS 1.0 support. But that means some older browsers can no longer access my site.

This is exactly the situation I found myself in with The Session. I had a score of A+ from SSL Labs. I was feeling downright smug. Then I got emails from actual users. One had picked up an old Samsung tablet second hand. Another was using an older version of Safari. Neither could access the site.

Sure enough, if you cut off TLS 1.0, you cut off Safari below version six.

Alright, then. Can’t they just upgrade? Well …no. Apple has tied Safari to OS X. If you can’t upgrade your operating system, you can’t upgrade your browser. So if you’re using OS X Mountain Lion, you’re stuck with an insecure version of Safari.

Fortunately, you can use a different browser. It’s possible to install, say, Firefox 37 which supports TLS 1.2.

On desktop, that is. If you’re using an older iPhone or iPad and you can’t upgrade to a recent version of iOS, you’re screwed.

This isn’t an edge case. This is exactly the kind of usage that iPads excel at: you got the device a few years back just to do some web browsing and not much else. It still seems to work fine, and you have no incentive to buy a brand new iPad. And nor should you have to.

In that situation, you’re stuck using an insecure browser.

As a site owner, I can either make security my top priority, which means you’ll no longer be able to access my site. Or I can provide you access, which makes my site less secure for everyone. (That’s what I’ve done on The Session and now my score is capped at B.)

What I can’t do is tell you to install a different browser, because you literally can’t. Sure, technically you can install something called Firefox from the App Store, or you can install something called Chrome. But neither have anything to do with their desktop counterparts. They’re differently skinned versions of Safari.

Apple refuses to allow browsers with any other rendering engine to be installed. Their reasoning?

Security.

Friday, February 7th, 2020

IncrementURL

Last month I wrote some musings on default browser behaviours. When it comes to all the tasks that browsers do for us, the most fundamental is taking a URL, fetching its contents and giving us the results. As part of that process, browsers also show us the URL of the page currently loaded in a tab or window.

But even at this fundamental level, there are some differences from browser to browser.

Safari only shows you the domain name—and any subdomain names—by default. It looks like nice and tidy, but it obfuscates what page you’re on (until you click on the domain name). This is bad.

Chrome shows you the full URL, nice and straightforward. This is neutral.

Firefox, like Chrome, shows you the full URL, but with a subtle difference. The important part of the URL—usually the domain name—is subtly highlighted in a darker shade of grey. This is good.

The reason I say that what it highlights is usually the domain name is because what it actually highlights is eTLD+1.

The what now?

Well, if you’re looking at a page on adactio.com, that’s the important bit. But what if you’re looking at a page on adactio.github.io? The domain name is important, but so is the subdomain.

It turns out there’s a list out there of which sites and top level domains allow registrations like this. This is the list that Firefox is using for its shading behaviour in displaying URLs.

Safari, by the way, does not use this list. These URLs are displayed identically in Safari, the phisherman’s friend:

  • example.com
  • example.github.io
  • github.example.com

Whereas Firefox displays them as:

  • example.com
  • example.github.io
  • github.example.com

I learned all this from Jake on a recent edition of HTTP 203. Nicolas Hoizey has writen a nice little summary.

Jake acknowledges that what Apple is doing is shisuboptimal, what Firefox is doing is good, and then puts forward an idea for what Chrome could do. (But please note that this is Jake’s personal opinion; not an official proposal from the Chrome team.)

There’s some prior art here. It used to be that, if your SSL certificate included extended validation, the name would be shown in green next to the padlock symbol. So while my website—which uses regular SSL from Let’s Encrypt—would just have a padlock, Medium—which uses EV SSL—would have a padlock and the text “A Medium Corporation”.

Extended validation wasn’t quite the bulletproof verification it was cracked up to be. So browsers don’t use that interface pattern any more.

Jake suggests repurposing this pattern for all URLs. Pull out the important bit—eTLD+1—and show it next to the padlock.

Screenshots of @JaffaTheCake’s idea for separating out the eTLD+1 part of a URL in a browser’s address bar. Screenshots of @JaffaTheCake’s idea for separating out the eTLD+1 part of a URL in a browser’s address bar.

I like this. The full URL is still displayed. This proposal is more of an incremental change. An enhancement that is applied progressively, if you will.

I also like that it builds on existing interface patterns—Firefox’s URL treatment and the deprecated treatment of EV certs. In fact, I think the first step for Chrome should be to match Firefox’s current behaviour, and then go further with something like Jake’s proposal.

This kind of gradual change was exactly what Chrome did with displaying https and http domains.

Chrome treatment for HTTPS pages.

Jake mentions this in the video

We’ve already seen that you have to take small steps here, like we did with the https change.

There’s a fascinating episode of the Freakonomics podcast called In Praise of Incrementalism. I’ve huffduffed it.

I’m a great believer in the HTML design principle, Evolution Not Revolution:

It is better to evolve an existing design rather than throwing it away.

I’d love to see Chrome take the first steps to Jake’s proposal by following Firefox’s lead.

Then again, I’d love it if Chrome followed Firefox’s lead in implementing subgrid.

Wednesday, January 22nd, 2020

28c3: The Science of Insecurity - YouTube

I understand less than half of this great talk by Meredith L. Patterson, but it ticks all my boxes: Leibniz, Turing, Borges, and Postel’s Law.

(via Tim Berners-Lee)

28c3: The Science of Insecurity

Living in Alan Turing’s Future | The New Yorker

Portrait of the genius as a young man.

It is fortifying to remember that the very idea of artificial intelligence was conceived by one of the more unquantifiably original minds of the twentieth century. It is hard to imagine a computer being able to do what Alan Turing did.

Monday, January 6th, 2020

Browser defaults

I’ve been thinking about some of the default behaviours that are built into web browsers.

First off, there’s the decision that a browser makes if you enter a web address without a protocol. Let’s say you type in example.com without specifying whether you’re looking for http://example.com or https://example.com.

Browsers default to HTTP rather than HTTPS. Given that HTTP is older than HTTPS that makes sense. But given that there’s been such a push for TLS on the web, and the huge increase in sites served over HTTPS, I wonder if it’s time to reconsider that default?

Most websites that are served over HTTPS have an automatic redirect from HTTP to HTTPS (enforced with HSTS). There’s an ever so slight performance hit from that, at least for the very first visit. If, when no protocol is specified, browsers were to attempt to reach the HTTPS port first, we’d get a little bit of a speed improvement.

But would that break any existing behaviour? I don’t know. I guess there would be a bit of a performance hit in the other direction. That is, the browser would try HTTPS first, and when that doesn’t exist, go for HTTP. Sites served only over HTTP would suffer that little bit of lag.

Whatever the default behaviour, some sites are going to pay that performance penalty. Right now it’s being paid by sites that are served over HTTPS.

Here’s another browser default that Rob mentioned recently: the viewport meta tag:

I thought I might be able to get away with omitting meta name="viewport". Apparently not! Maybe someday.

This all goes back to the default behaviour of Mobile Safari when the iPhone was first released. Most sites wouldn’t display correctly if one pixel were treated as one pixel. That’s because most sites were built with the assumption that they would be viewed on monitors rather than phones. Only weirdos like me were building sites without that assumption.

So the default behaviour in Mobile Safari is assume a page width of 1024 pixels, and then shrink that down to fit on the screen …unless the developer over-rides that behaviour with a viewport meta tag. That default behaviour was adopted by other mobile browsers. I think it’s a universal default.

But the web has changed since the iPhone was released in 2007. Responsive design has swept the web. What would happen if mobile browsers were to assume width=device-width?

The viewport meta element always felt like a (proprietary) band-aid rather than a long-term solution—for one thing, it’s the kind of presentational information that belongs in CSS rather than HTML. It would be nice if we could bid it farewell.

Friday, January 3rd, 2020

Blade Runner Sketchbook (PDF)

I was sad to hear of the passing of Syd Mead last week. Here’s a sketchbook of his remarkable work for Blade Runner.

Saturday, November 16th, 2019

What would happen if we allowed blocking 3rd-Party JavaScript as an option?

This would be a fascinating experiment to run in Firefox nightly! This is in response to that post I wrote about third-party scripts.

(It’s fascinating to see how different this response is to the responses from people working at Google.)

Tuesday, November 12th, 2019

Third party

The web turned 30 this year. When I was back at CERN to mark this anniversary, there was a lot of introspection and questioning the direction that the web has taken. Everyone I know that uses the web is in agreement that tracking and surveillance are out of control. It seems only right to question whether the web has lost its way.

But here’s the thing: the technologies that enable tracking and surveillance didn’t exist in the early years of the web—JavaScript and cookies.

Without cookies, the web was stateless. This was by design. Now, I totally understand why cookies—or something like cookies—were needed. Without some way of keeping track of state, there’s no good way for a website to “remember” what’s in your shopping cart, or whether you’ve authenticated yourself.

But why would cookies ever need to work across domains? Authentication, shopping carts and all that good stuff can happen on the same domain. Third-party cookies, on the other hand, seem custom made for tracking and frankly, not much else.

Browsers allow you to disable third-party cookies, though it’s not yet the default. If enough people do it—and complain about the sites that stop working when third-party cookies are disabled—then maybe it can become the default.

Firefox is taking steps in this direction, automatically disabling some third-party cookies—the ones that known trackers. Safari is also taking steps to prevent cross-site tracking. It’s not too late to change the tide of third-party cookies.

Then there’s third-party JavaScript.

In retrospect, it seems unbelievable that third-party JavaScript is even possible. I mean, putting arbitrary code—that can then inject even more arbitrary code—onto your website? That seems like a security nightmare!

I imagine if JavaScript were being specced today, it would almost certainly be restricted to the same origin by default. But I guess the precedent had been set with images and style sheets: they could be embedded regardless of whether their domain names matched yours. Still, this is executable code we’re talking about here: that’s quite a footgun that the web has given site owners. And boy, oh boy, has it been used by the worst people to do the most damage.

Again, as with cookies, if we were to imagine what the web would be like if JavaScript was restricted by a same-domain policy, there are certainly things that would be trickier to do.

  • Embedding video, audio, and maps would get a lot finickier.
  • Analytics would need to be self-hosted. I don’t think that would bother any site owners. An analytics platform like Google Analytics that tracks people across domains is doing it for its own benefit rather than that of site owners.
  • Advertising wouldn’t be creepy and annoying. Instead of what’s so euphemistically called “personalisation”, advertisers would have to rely on serving relevant ads based on the content of the site rather than an invasive psychological profile of the user. (I honestly think that advertisers would benefit from this kind of targetting.)

It’s harder to imagine putting the genie back in the bottle when it comes to third-party JavaScript than it is with third-party cookies. All the same, I wish that browsers made it easier to experiment with it. Just as I can choose to accept all cookies, reject all cookies, or only accept same-origin cookies, I wish I could accept all JavaScript, reject all JavaScript, or only accept same-origin JavaScript.

As it is, browsers are making it harder and harder to exercise any control over JavaScript at all. So we reach for third-party tools. We don’t call them JavaScript managers though. We call them ad blockers. But honestly, most of the ad-blocker users I know—myself included—are not bothered by the advertising; we’re bothered by the tracking. We should really call them surveillance blockers.

If third-party JavaScript weren’t the norm, not only would it make the web more secure, it would make it way more performant. Read the chapter on third parties in this year’s newly-released Web Almanac. The figures are staggering.

93% of pages include at least one third-party resource, 76% of pages issue a request to an analytics domain, the median page requests content from at least 9 unique third-party domains that represent 35% of their total network activity, and the most active 10% of pages issue a whopping 175 third-party requests or more.

I don’t think all the web’s performance ills are due to third-party scripts; developers are doing a bang-up job of making their sites big and bloated with their own self-hosted frameworks and code. But as long as third-party JavaScript is allowed onto a site, there’s a limit to how much good developers can do to improve the performance of their sites.

I go to performance-related conferences and you know who I’ve never seen at those events? The people who write the JavaScript for third-party tracking scripts. Those developers are wielding an outsized influence on the health of the web.

I’m very happy to see the work being done by Mozilla and Apple to normalise the idea of rejecting third-party cookies. I’d love to see the rejection of third-party JavaScript normalised in the same way. I know that it would make my life as a developer harder. But that’s of lesser importance. It would be better for the web.

CSS for all

There have been some great new CSS properties and values shipping in Firefox recently.

Miriam Suzanne explains the difference between the newer revert value and the older inherit, initial and unset values in a video on the Mozilla Developer channel:

display: revert;

In another video, Jen describes some new properties for styling underlines (on links, for example):

text-decoration-thickness:  0.1em;
text-decoration-color: red;
text-underline-offset: 0.2em;
text-decoration-skip-ink: auto;

Great stuff!

As far as I can tell, all of these properties are available to you regardless of whether you are serving your website over HTTP or over HTTPS. That may seem like an odd observation to make, but I invite you to cast your mind back to January 2018. That’s when the Mozilla Security Blog posted about moving to secure contexts everywhere:

Effective immediately, all new features that are web-exposed are to be restricted to secure contexts. Web-exposed means that the feature is observable from a web page or server, whether through JavaScript, CSS, HTTP, media formats, etc. A feature can be anything from an extension of an existing IDL-defined object, a new CSS property, a new HTTP response header, to bigger features such as WebVR.

(emphasis mine)

Buzz Lightyear says to Woody: Secure contexts …secure contexts everywhere!

Despite that “effective immediately” clause, I haven’t observed any of the new CSS properties added in the past two years to be restricted to HTTPS. I’m glad about that. I wrote about this announcement at the time:

I am in total agreement that we should be encouraging everyone to switch to HTTPS. But requiring HTTPS in order to use CSS? The ends don’t justify the means.

If there were valid security reasons for making HTTPS a requirement, I would be all for enforcing this. But these are two totally separate areas. Enforcing HTTPS by withholding CSS support is no different to enforcing AMP by withholding search placement.

There’s no official word from the Mozilla Security Blog about any change to their two-year old “effective immediately” policy, and the original blog post hasn’t been updated. Maybe we can all just pretend it never happened.

Thursday, November 7th, 2019

Data Patterns Catalogue

I really like the work that IF are doing to document patterns around handling data:

  • Signing in to a service
  • Giving and removing consent
  • Giving access to data
  • Getting access to data
  • Understanding automated decisions
  • Doing security checks

Each pattern has a description, advantages, limitations, and examples.

Tuesday, October 29th, 2019

Periodic background sync

Yesterday I wrote about how much I’d like to see silent push for the web:

I’d really like silent push for the web—the ability to update a cache with fresh content as soon as it’s published; that would be nifty! At the same time, I understand the concerns. It feels more powerful than other permission-based APIs like notifications.

Today, John Holt Ripley responded on Twitter:

hi there, just read your blog post about Silent Push for acthe web, and wondering if Periodic Background Sync would cover a few of those use cases?

Periodic background sync looks very interesting indeed!

It’s not the same as silent push. As the name suggests, this is about your service worker waking up periodically and potentially fetching (and caching) fresh content from the network. So the service worker is polling rather than receiving a push. But I’ll take it! It’s definitely close enough for the kind of use-cases I’ve been thinking about.

Interestingly, periodic background sync also ties into the other part of what I was writing about: permissions. I mentioned that adding a site the home screen could be interpreted as a signal to potentially allow more permissions (or at least allow prompts for more permissions).

Well, Chromium has a document outlining metrics for attempting to gauge site engagement. There’s some good thinking in there.

Monday, October 28th, 2019

Silent push for the web

After Indie Web Camp in Berlin last year, I wrote about Seb’s nifty demo of push without notifications:

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.

Phil Nash left a comment on the Medium copy of my post explaining that Seb’s demo of using the Push API without showing a notification wouldn’t work for long:

The browsers allow a certain number of mistakes(?) before they start to show a generic notification to say that your site sent a push notification without showing a notification. I believe that after ~10 or so notifications, and that’s different between browsers, they run out of patience.

He also provided me with the name to describe what I’m after:

You’re looking for “silent push” as are many others.

Silent push is something that is possible in native apps. It isn’t (yet?) available on the web, presumably because of security concerns.

It’s an API that would ripe for abuse. I mean, just look at the mess we’ve made with APIs like notifications and geolocation. Sure, they require explicit user opt-in, but these opt-ins are seen so often that users are sick of seeing them. Silent push would be one more permission-based API to add to the stack of annoyances.

Still, I’d really like silent push for the web—the ability to update a cache with fresh content as soon as it’s published; that would be nifty! At the same time, I understand the concerns. It feels more powerful than other permission-based APIs like notifications.

Maybe there could be another layer of permissions. What if adding a site to your home screen was the first step? If a site is running on HTTPS, has a service worker, has a web app manifest, and has been added to the homescreen, maybe then and only then should it be allowed to prompt for permission to do silent push.

In other words, what if certain very powerful APIs were only available to progressive web apps that have successfully been added to the home screen?

Frankly, I’d be happy if the same permissions model applied to web notifications too, but I guess that ship has sailed.

Anyway, all this is pure conjecture on my part. As far as I know, silent push isn’t on the roadmap for any of the browser vendors right now. That’s fair enough. Although it does annoy me that native apps have this capability that web sites don’t.

It used to be that there was a long list of features that only native apps could do, but that list has grown shorter and shorter. The web’s hare is catching up to native’s tortoise.

Wednesday, October 2nd, 2019

Same-Site Cookies By Default | text/plain

This is good news. I have third-party cookies disabled in my browser, and I’m very happy that it will become the default.

It’s hard to believe that we ever allowed third-party cookies and scripts in the first place. Between them, they’re responsible for the worst ills of the World Wide Web.

Sunday, September 1st, 2019

Bandstands: The industry built on Victorian social engineering - BBC News

As a resident of Brighton—home to the most beautiful of bandstands—this bit of background to their history is fascinating.

Wednesday, August 7th, 2019

Turing Tumble - Build Marble-Powered Computers

Boolean logic manifested in a Turing-complete game

Tuesday, July 16th, 2019

How to Kill IE11 - What the Deaths of IE6 and IE8 Tell Us About Killing IE | Mike Sherov

An interesting look at the mortality causes for Internet Explorer 6 and Internet Explorer 8, and what they can tell us for the hoped-for death of Internet Explorer 11.

I disagree with the conclusion (that we should actively block IE11—barring any good security reasons, I don’t think that’s defensible), but I absolutely agree that we shouldn’t be shipping polyfills in production just for IE11. Give it your HTML. Give it your CSS. Withhold modern JavaScript. If you’re building with progressive enhancement (and you are, right?), then giving IE11 users a sub-par experience is absolutely fine …it’s certainly better than blocking them completely.

Monday, July 15th, 2019

Spurious Correlations

Correlation does not imply causation.

Saturday, July 6th, 2019

The Hiding Place: Inside the World’s First Long-Term Storage Facility for Highly Radioactive Nuclear Waste - Pacific Standard

Robert McFarlane’s new book is an exploration of deep time. In this extract, he visits the Onkalo nuclear waste storage facility in Finland.

Sometimes we bury materials in order that they may be preserved for the future. Sometimes we bury materials in order to preserve the future from them.

Thursday, May 30th, 2019

Is CSS Turing Complete? | Lara Schenck

This starts as a good bit of computer science nerdery, that kind of answers the question in the title:

Alone, CSS is not Turing complete. CSS plus HTML plus user input is Turing complete!

And so the takeaway here is bigger than just speculation about Turing completeness:

Given that CSS is a domain-specific language for styling user interface, this makes a lot of sense! CSS + HTML + Human = Turing complete.

At the end of that day, as CSS developers that is the language we really write. CSS is incomplete without HTML, and a styled interface is incomplete without a human to use it.