Netstrings (1997)

(cr.yp.to)

23 points | by signa11 6 hours ago ago

10 comments

  • regularfry 5 hours ago

    Tagged Netstrings (tnetstrings) was a related proposal from 15 years ago or so. It replaces the comma with a single-character type definition so you can do JSON-like objects with a couple of recursive types: you had ',', '#', '^', '!', and '~' for strings, integers, floats, booleans, and nulls, then ']' and '}' for lists and dictionaries.

    Most of the links have bitrotted and I don't think it ever got much traction, but I did always like how simple it was. There's a copy someone grabbed of the original spec here: https://raw.githubusercontent.com/ged/tnetstrings.info/refs/...

  • weinzierl an hour ago

    Making the thing that describes the bounds of an arbitrary length thing itself arbitrary length sound like an unnecessarily risky complication to me.

    Especially since it only grows with the log of the thing it bounds. So, we could easily have s fixed length length field that covers all ever possible length values.

  • Joker_vD 2 hours ago

        if (scanf("%9lu",&len) < 1) barf();  /* >999999999 bytes is bad */
        if (getchar() != ':') barf();
        buf = malloc(len + 1);       /* malloc(0) is not portable */
        if (!buf) barf();
        if (fread(buf,1,len,stdin) < len) barf();
        if (getchar() != ',') barf();
    
    Ah, the wonders of error-handling in C. Also, I wonder what's wrong with

        buf = malloc(len ? len : 1);
  • ocrow 5 hours ago

    Seems like a coherent, sensible proposal, as one might expect from djb. Any notable protocols use them?

    • Scaevolus 5 hours ago

      BitTorrent's bencoding format, used in .torrent files, effectively uses netstrings-- but without the trailing commas, so it uses "5:hello" to represent filenames and similar.

    • asalahli 4 hours ago

      Not sure if it counts as notable, but SCGI uses it too: https://python.ca/scgi/protocol.txt

    • toast0 5 hours ago

      Php serialized uses

         s:size:value;
      
      For strings, which is pretty similar. Size is in bytes.
    • Asmod4n an hour ago

      zurl and mongrel2 are using it.

  • gnabgib 6 hours ago

    (1997) -DJB