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P99 0 ms* autocomplete for 240M domain names

169 pointsposted 10 hours ago

70 Comments

skybrian

9 hours ago

This autocomplete suggests domains that don't exist. You can just type garbage and it will suggest something, but then if you go there, there are no records.

It seems like one purpose of an autocomplete box is help you avoid typos, so that makes it less useful.

pul

4 hours ago

Author here.

Yes, it will autocomplete the most popular domains first, then known registered domains, and then fall back to appending popular TLDs.

The reason is that it's impossible to enumerate all domains. gTLDs (like .com, .info) mostly publish their zone files, but ccTLDs (like .cn, .de) usually don't.

But maybe you're right. After reading these comments, it's clearly confusing to people.

There are limits to how accurate you can make this. Zones like .xyz renew at 18%, so you'd expect 0.2% of those domains to expire without renewal each day. The tranco list is based on a 30 day look-back and I've seen a small percent of those domains lack name servers, even for the latest list.

Similarly, domains can be registered since the last time you downloaded your lists. So you never have a complete or accurate list.

I think it's perfectly reasonable to suggest names that have recently expired or domains that could have been recently registered. The alternative requires an NS lookup.

andai

42 minutes ago

I'm not sure I understand the reasoning behind appending the TLDs?

Can't you just append any TLD to anything and get a domain that "might" exist? Or am I missing something?

bawolff

6 hours ago

The autocomplete seemed to suggest real domains to me. If you typed in garbage it suggested the garbage plus a bunch of common TLDs - that seems like a reasonable choice to me. In any case, if your issue is the list of domains to suggest, its trivial to change that to a different list.

pierrefermat1

7 hours ago

Yes, OP seems to have completely lost touch with what is actually useful vs optimizing metrics for the sake of it.

lnenad

6 hours ago

But there is a cool blog post about it though.

1718627440

3 hours ago

That's also the old behaviour of browsers and the current one of text browsers. I fail to see how this is wrong.

    $ lynx doesnotexist2

    Looking up doesnotexist2 first
    Looking up www.doesnotexist2.com, guessing...
    Looking up www.doesnotexist2.edu, guessing...
    Looking up www.doesnotexist2.net, guessing...
    Looking up www.doesnotexist2.org, guessing...
    Can't Access `file://localhost/home/user/doesnotexist2'

Retr0id

2 hours ago

I hate this behaviour because it means if I typo an internal hostname suddenly it gets broadcast to everyone's DNS resolver, and wastes some time in the process (and in the worst case, takes me to a random website I never intended to visit). I always have to rummage around in about:config or whatever to disable it, because that behaviour is never what I expect nor intend.

addag

5 hours ago

This behavior seems to happen only when there is no more words in the list that can complete the current string. Otherwise, it shows only existing domains.

I guess this behavior helps to autocomplete the domain extension for less-known domains that are not in the search list.

Symbiote

an hour ago

It doesn't work correctly with third level domains.

speedtest.me.uk exists, but typing speedtest.me does not suggest it, and speedtest.me.u suggests speedtest.me.us first (doesn't exist).

(.me.uk is a second level domain category in .uk, intended for personal domains.)

chrismorgan

8 hours ago

Using keyup makes no sense and is inconsistent with user expectations. For triggering actions (which includes normal typing), you only ever use keydown. (Well, there’s one exception for reasons unclear to me: activating a button by pressing Space. That triggers on keyup like how clicks are on release, while Enter triggers on keydown.) Keyup is limited to things where you’re constantly reacting to the state of a key, as is common in games.

This affects the functionality, too. It is in fact introducing latency by using keyup instead of keydown. Feels bad.

danbruc

6 hours ago

For triggering actions (which includes normal typing), you only ever use keydown.

I think you have this wrong, actions generally occur on button release, until that you can move the mouse cursor to a different target, tab to another control, use [ESC] to cancel, and so on. Typing, moving a slider with the cursor keys, and similar things that make use of key repetition while holding down the key are the exception to this.

chrismorgan

5 hours ago

I am speaking specifically of keyboards. For mice, it’s release. (When I made a similar comment two months ago on Lobsters when this article came up there, I mentioned this, but decided to leave it out this time, thinking the context was clear enough. I think I was wrong.)

okamiueru

2 hours ago

If it matters, it seemed pretty clear to me. You're also explicit about it, so I'm not sure how one would think you were referring to mouse input. Unless people type by clicking on a virtual keyboard? Benefit of the doubt can only stretch so far.

okamiueru

5 hours ago

Can you give some specific examples? In my experience (which I also verified to make sure), all of the things you mention act on keydown. The exceptions are on multi-key combinations, which follow a special key that is held down while modifiers are entered, where the action is completed by releasing this special key (ALT + TAB [...TAB | SHIFT]) being a common example.

TAB is otherwise immediate, as is ESC, and the examples of typing, as well. So I'm left wondering, how do they have it wrong?

invalidusernam3

2 hours ago

Non latin characters are sometimes inputted by holding down a key. For example on my keyboard holding down z shows ź,ž and ż with a corresponding number to select which one I would like to type. I haven't checked but one would assume if you're detecting keydown the input at that time will be z, and keyup would record ž (or whatever was selected).

Xirdus

an hour ago

Physical keyboards and virtual keyboards are different. Traditionally, ź and ż (my keyboard doesn't have ž) are inputted on keydown X or keydown Z while Alt modifier is active.

wongarsu

5 hours ago

> all of the things you mention act on keydown

Because they listed the exceptions to the "act on keyup" rule

chrismorgan

5 hours ago

If only one case follows your rule, and everything else ever implemented from the start of personal computers is an exception, your rule is awry.

stavros

5 hours ago

The GP means that, if you hold space down on a button, you can then tab to another button without activating the first one.

hnlmorg

6 hours ago

Key down is used for events that can be duplicated by holding the key. Eg in a text editor, when you want multiples of the same letters, you’d press and hold the key.

Key up is used for when it’s important to only have one occurrence of that event.

Technically you could write code that made key down only react once. But the logical separation makes some sense.

chrismorgan

5 hours ago

Give me an example. Any example beyond this Space one we’re discussing; because I don’t know of any.

youngtaff

4 hours ago

I can see both viewpoints here and don’t have a strong personal view

But for reference browsers fire the keypress event on keyup

chrismorgan

4 hours ago

The keypress event is an ancient mistake that I think never had any legitimate use case, and has been deprecated for quite some time now.

zxexz

8 hours ago

As a user, I’ve not thought too much about this before now. I agree with you mostly, but the keyup on space behaviour actually feels so innate I’d hate any change to it. Keydown on space is “jump”; nothing else.

chrismorgan

8 hours ago

I’d just like to hear an explanation of why it is. Because if you handled “is key currently pressed” events with polling rather than events (which is how people almost always consume them logically), it would be the only thing in the entire world that I can think of that would/should use keyup.

Edit: I think people are misunderstanding me. I’m asking for an explanation of why, when you have a button focused, pressing Space activates on key up, rather than key down like literally everything else on the keyboard, including Enter on a focused button. (Mouse activates on release.)

Rygian

7 hours ago

Because in those contexts, the Space key is being used as a physical mirror of the on-screen button, and on-screen buttons are UX'd to perform action when released.

These two interactions should behave identically:

- Hover over a button, press mouse button 1, release button 1.

- Tab over to a button, press spacebar, release spacebar.

Why on-screen buttons are UX'd to behave this way is a logical follow-up question. I'd wager that it gives a means to bail out of the clicking (e.g. by moving the mouse out of the on-screen button before releasing mousebutton 1, or by pressing Esc while having spacebar still depressed).

regularfry

7 hours ago

Yes, the bailing-out explanation is right. With a mouse it's intentional that you should be able to push the pointer off the button with the mouse button still pressed to cancel.

chrismorgan

6 hours ago

(Esc while Space is held doesn’t cancel, but Tab does.)

You’re only answering half of the inconsistency: because Enter activates buttons like any other key, on keydown.

b112

5 hours ago

Just diving in without full context, but, enter is often a completion action. Historically often a full carriage return. It often means "submit data".

So this could be the oddity

podocarp

7 hours ago

It just matches real life. What about lmb to shoot? You don't fire a gun on trigger release, you fire it on trigger down. Walking? Would be weird moving only on keyup.

wky

7 hours ago

This raises the question of why real life buttons and virtual buttons behave differently. My unsubstantiated guess is that clicks act on release to give the opportunity to slide off the button to abort, and/or because the button would disappear while pressing if it ex. submits a form.

dangond

8 hours ago

Jump is keydown because many games let you adjust your jump height based on how long you hold down space after the jump starts.

flaunf221

4 hours ago

Games use keydown because it is more responsive and control responsiveness is vital to dynamic gameplay feeling good. There are some exceptions - if action can be charged, then it is on keydown. And then on gamepad sometimes actions are on release when developer has too many actions and not enough buttons, so it can be keyup vs hold.

stavros

5 hours ago

I may be wrong on this, but I think that pressing esc while space is held down cancels the button press, like moving the mouse off the key while holding down the click does. I'd need to test this, though.

dawnerd

5 hours ago

That’s where the input event is really useful as it allows for more input options than just keyboard and then you don’t have to deal with figuring out if it’s down or up.

1718627440

2 hours ago

On my own computer I can open a context menu and select an action with a single click. Whenever I need to use MS Windows, I always need two and I find that infuriating every time.

ViscountPenguin

9 hours ago

Unfortunately this approach doesn't feel that great down here in Australia, definitely a function of latency.

I think you could get a lot closer by framing this as an optimization problem, where you use the full alphabet dictionary, but add a residual prediction which aims to cover as much of the remaining domain name tree as possible weighted by popularity. This tree could then be pre-baked and stored with the same system. This would probably get you p99 0ms even in Australia.

pul

4 hours ago

Interesting, I didn't think of that yet.

I think most people search for domains they own, which doesn't correlate with Tranco popularity ranking. Treating 'popularity' not as a function of visitors, but as a function of number of known domain names with that prefix could work, though.

phil294

2 hours ago

Tangentially, I built something similar a few years back, at link-archive.org: https://web.archive.org/web/20220127233707/https://link-arch...

3B existing URLs extracted from CommonCrawl, with instant search results. It was a fun project but didn't serve much real-world purpose besides curiosity and discovery. So I eventually ditched it, primarily because the link DB was a whopping 500 GiB in size, too much to just keep hosting.

I just used SQLite FTS5 as the backend search engine. Just a few lines of code, but immediate response from a 0.5 TiB DB. SQLite is amazing.

andai

44 minutes ago

>I've designed the API to first search Tranco (the head), and then CZDS (the tail) if necessary.

How do you know if it's necessary? If Tranco returns less than eight?

whalesalad

15 minutes ago

Tranco is only top 1M domains.

oersted

8 hours ago

Why not just trigger the fetch on keyDown and show it as soon as the response arrives, as usual?

The time it takes to press a key is a reasonable target to aim at for API latency I suppose, but it is still an arbitrary target. Waiting to display until keyUp just adds more latency if your API is faster. Having it synced with keyUp doesn't make it feel more immediate to me.

s4i

8 hours ago

It’s usually good to wait for user to do KeyUp before treating the string as final. A fellow commenter explained some of the reasons: https://news.ycombinator.com/item?id=49505993

kevmo314

9 hours ago

If you’d like to reduce the network latency further you can store each trie node as a file, naming it conveniently the prefix path to that node. Then dump the few hundred million files onto R2.

Now the traversal can be done completely via CDN lookups!

pul

4 hours ago

Cloudflare R2 doesn't distribute files globally. They only cache requested files in PoPs. So then it would function the same as an API behind the Cloudflare CDN.

kevmo314

4 hours ago

It would skip the Cloudflare to server network hop that the author mentions being rather expensive for cache misses.

pul

3 hours ago

It would replace the Cloudflare to server network hop with a cloudflare PoP to R2 hop. That covers approximately the same geographical distance and results in similar latency.

(I'm the author btw)

piterrro

5 hours ago

I just typed a random sequence of the characters, long enough to be certain such domain doesnt exist. No only, the browser send an autocomplete request for every keystroke but for each request it returned a set of proposed domain names (which I'm 100% certain doesnt exist). At this point, how do I understand which results are legit and which are fake? Also, it would be nice to highlight the typed part in the result set so I can visually see what matches exactly.

addag

5 hours ago

For the nonexisting domains, it seems like it only autocomplete with the possible domain extensions, (e.g .com, .org, ....) as the search list is non-exhaustive. But it could indeed be improved by not sending autocomplete requests anymore.

pul

4 hours ago

You're not the first to mention this, so clearly users expect something different from what I've designed it for. I think I'll drop the TLD postfix suggestions.

ape4

an hour ago

How are the icons (for the domains) fetched so quickly?

camel_gopher

9 hours ago

Clever but that’s not how we measure latency.

dbalatero

9 hours ago

When it comes to UX, perceived latency is king.

wky

9 hours ago

The perceived latency starts from keydown, not keyup. Redefining latency to start at keyup reduces measured latency, not perceived latency, and delaying the visual display to keyup makes perceived latency strictly worse, not better. Even sticking with the keyup definition, just displaying the result as soon as it is available gives the possibility of negative (defined) latency.

weird-eye-issue

9 hours ago

I think you don't fully understand. They aren't just doing a search based on the key being pressed down. They already did a search based on the previous characters that returned results for all possible next characters. So by the time you type a second character it just checks results locally from the search that had likely already been returned from when you had typed the previous character.

wky

9 hours ago

They do that, yet proceed to kneecap the perceived latency by delaying the render.

> And on keyUp (the user releases the key), we render the suggestions.

weird-eye-issue

8 hours ago

There are a large number of edge cases where rendering it on key down would not be desirable (user types Ctrl+v, how accented characters are enetered, how some Asian languages get handled, backspace/delete, user holds a key down, etc). This is getting into the point of optimization where it simply does not matter and can actually harm things

wky

7 hours ago

Holding a key would indeed require both on key down and up. I'd still argue that handling rerender on key down (or to fully match whatever OS/browser semantics, oninput) makes more sense than key up. Pressing Ctrl+V for example produces feedback as soon as "V" is pressed, not when Ctrl and/or V is released.

Interestingly Ctrl+V on OP's website does update immediately when Ctrl+V is pressed.