Parsing millions of URLs per Second (2023)

(onlinelibrary.wiley.com)

157 points | by PaulHoule 192 days ago

11 comments

  • Thorrez 191 days ago
    > For example, the input string http://xn--6qqa088eba.xn--3ds443g/./a/../b/./c should be normalized to the string https://xn--xn6qqa088eba-l19f.xn--xn3ds-zu3b/b/c

    Why would normalization change http:// to https:// ?

    • chrismorgan 191 days ago
      There’s got to be some accidental mangling there. Somewhere. Because of that error, and still more because of the blatant error in the next sentence:

      > For example, given the base string http://example.org/foo/bar, the relative string http://example.com/ leads to the final URL http://example.org/example.com/.

      That’s just… no. I do not believe I have ever encountered any software which would parse it in that way, and I refuse to believe such software ever existed. It would be <http://example.com/>.

      But the PDF matches the HTML. I dunno, something weird is going on. Look at the hyperlinks there, too, “http://xn--ivg but not the rest of the URL that follows, and how the -- has been changed to –. Something went wrong somewhere in the editing or publication.

      • silvestrov 191 days ago
        My guess is that the html formatter changed the text "example.com" into "http://example.com" to make it a valid absolute URL.
        • chrismorgan 190 days ago
          Anything that turns </example.com/> into <http://example.com/> should be shot.

          I dislike automatic linkifiers, especially in technical contexts, because they get things wrong so often, as regards what is a link at all (and certainly never linkify if there’s no protocol! “example.com/foo” should not be turned into <http://example.com/foo>), and as regards what can be part of the link (largely around trailing punctuation). Just require explicit delimition, like <…>, or else it’s text.

          (Markdown’s […](…) is bad because ) is part of URL code points, meaning parentheses in URLs won’t be percent-encoded by a normal serialiser, so then its parser gets messy trying to compensate, assuming that parentheses will normally be paired in URLs. Your delimiter needs to not be part of the set of URL code points.)

          HN’s auto-linkifier is, most of the time, one of the better ones (it was bad ten years ago, but got fixed around punctuation inclusion a few years ago), but it still has problems. I noticed too late that it mangled something in my comment: where you get http://xn--ivg, that xn--ivg is ”, because what I actually wrote was

            … too, “http://” but not …
    • ramon156 191 days ago
      Because its 2024
      • marginalia_nu 191 days ago
        http:// is not a typo for https://. There's still a fairly large amount of web servers that do not talk https, and you simply cannot assume that they do. That will leave you with a lot of dead links. Besides, most that accept both will auto-renegotiate to https.
        • TacticalCoder 191 days ago
          > There's still a fairly large amount of web servers that do not talk https, and you simply cannot assume that they do.

          OTOH I'm browsing since years forcing HTTPS only and life goes on fine. If the absolute worse comes to worse, I can use archive.is or archive.org but it's very rare that I need that.

          Basically: if a link is HTTP to me it's not worth opening.

          The one exception would be Debian packages URLs: but these are signed and the signatures are verified.

          User _apt is the only one allowed to emit HTTP traffic.

          This prevents my ISP or anyone else injecting nasty stuff.

          • forgotmypw17 191 days ago
            Just because it is accessible to you does not mean it is accessible to everyone else. HTTPS has many failure modes which make it unreliable for essential access, such as time mismatches, certificate expirations, ssl version mismatches, etc. Security and privacy are important, and they are also not absolute. Sometimes the risk is outweighed by the importance of being able to access essential resources and reading material.
          • Analemma_ 191 days ago
            User preferences should not be encoded into parser behavior, that’s nuts. You wouldn’t just arbitrarily change an ftp:// link to an imap:// link, so why would you accept it here? That exists at a whole other layer of the stack.
            • dmd 191 days ago
              They would arbitrarily change an ftp:// link to an sftp:// link and then complain that it didn't work.
  • Cicero22 192 days ago
    This sort of work is something I wouldn't be able to do, but I can't help but point out at least one potential issue with the paper. It's a lot easier to find problems than solutions I guess.

    Are the benchmarks comparing node versions valid to conclude a real world performance increase?

    one possible confounder is the version of V8.

    https://github.com/nodejs/node/blob/v18.x/deps/v8/include/v8... https://github.com/nodejs/node/blob/v20.x/deps/v8/include/v8...

    ideally, they would've patched Node 18.15 with their changes directly and test their patch against 18.15.

  • grayhatter 191 days ago
    I wonder how much time was spent promoting this parser, vs time spent on writing it? I've seen a lot of spam for this one, and I'm not the only one.

    https://daniel.haxx.se/blog/2023/11/21/url-parser-performanc...

    • yagiznizipli 191 days ago
      Almost a year of development, 3 months of writing paper. All of the benchmarks are public. Run it before sharing someone else’s blog post.
  • beached_whale 192 days ago
    Found the easier to read/download from Arxiv link

    https://arxiv.org/abs/2311.10533

  • maartenscholl 191 days ago
    I had a lot of fun writing low latency parsers for various message standards C++. There are a lot of fun things you can do when you can take ownership of the read buffer and you can figure out how to parse in-situ (modifying the data in place as you move along)
  • youngtaff 191 days ago
    Lemire’s blog is well worth a read if you’re interested in this sort of thing https://lemire.me/blog/
  • notamy 192 days ago
    The title seems to have a few words missing. Original title:

    > Parsing millions of URLs per second

    • HL33tibCe7 192 days ago
      HN’s stupid/arrogant automatic title rewriter strikes again
      • kristianp 191 days ago
        I've never noticed a title being rewritten automatically when posting an article. Are you sure that's really a thing?
        • pests 191 days ago
          There are some auto rewrite rules. Off the top of my head: numbers in the beginning are stripped, [pdf] or [video] can be added to the end, and one more I can't remember that gets stripped off beginning and can cause confusion.

          A pdf link to "5 Reasons To Do Things" will be "Reasons To Do Things [pdf]" for example.

          • Tomte 191 days ago
            „How“ at the beginning is stripped, leading to all these strange sounding „I <verb>“ submissions.
            • TRiG_Ireland 182 days ago
              There was also an interesting article on assistive technology called "How Disabled People Use the Web", or something similar, which looked very silly with the "How" stripped.
        • Tomte 191 days ago
          Yes. And the algorithm is really incredibly stupid, but dang is opposed to even small improvements (like showing the changed title on submission beforehand, like the „x characters to long“ message).
      • PaulHoule 192 days ago
        Fixed
        • ignoramous 191 days ago
          So, suprassing 80k karma, one gets title edit rights?
          • PaulHoule 191 days ago
            I think anybody can edit a title within a short time of posting something. Or if there is a karma threshold it is way less than 80k.

            I caught that one manually but YOShInOn's tail end needs some love and could be updated so it that it fixes up titles that get mashed automatically or adds a comment sometimes to editorialize or provide an archive link.

  • trung123f 191 days ago
    u has similar repo? tks
  • TZubiri 192 days ago
    [flagged]
    • wiseowise 191 days ago
      Maybe you should’ve spent 2 minutes reading the article instead of arrogantly dismissing it with layman knowledge.
    • fabrice_d 191 days ago
      The article explains optimizations to spend less cycles parsing URLs than other libraries. Very interesting work, there's no reason not to do things efficiently when it's possible.

      Also, good luck using regex to write a RFC or WHATWG conformant URL parser.

      • TZubiri 191 days ago
        2 minutes reading an rfc about uris and I find a regex literally used in the specs:

        https://www.rfc-editor.org/rfc/rfc3986#page-7

        >> The following line is the regular expression for breaking-down a well-formed URI reference into its components.

        >> ^(([^:/?#]+):)?(//([^/?#]))?([^?#])(\?([^#]))?(#(.))?

        Did Chomsky die for nothing?

        I guess there are reasons to do things efficiently when possible, but a million URLs is not it, the adage about the root of all evil comes to mind. A billion URLs per second and it's almost interesting, but not really.

        • yagiznizipli 191 days ago
          RFC 3986 is a lot simpler than WHATWG spec. You can literally write a zero copy 3986 parser whereas you can’t with WHATWG. (And Ada is still faster than 3986 parsers)
        • switchbak 191 days ago
          Last I heard Noam Chomsky was still alive, and a quick Google doesn’t contradict that. Or is this some kind of high brow joke that went over my head?
        • runlevel1 191 days ago
          That doesn't normalize the URL nor does it handle relative URL joining logic. It also doesn't handle URLs like: `file:///foo.txt`
        • FroshKiller 191 days ago
          The spec provides an expression for "well-formed" URIs. Good luck with real-world input.
    • paulddraper 191 days ago
      That will get you only one million per second.

      And depending on the length of your URL, 4000 will not be trivial, depending on the output format.

      • metadat 191 days ago
        Correct, URLs can be something like 4,000 characters long in 15 year old Firefox. I wonder what the current maximum length is?

        Today, Chrome supports 32,768 characters.. good luck processing that in 4,000 cycles! It'd require SIMD or some other fanciness.

      • yjftsjthsd-h 191 days ago
        > That will get you only one million per second.

        But per core, right?