How to generate NUUID in mongodb?

Question

As the title states, I'm looking for a way to generate a NUUID (.NET Guid compatible id) in a script for the mongodb shell.

Answer 1

Usage:

NUUID(uuid())

The uuid generator is based on this stackoverflow answer:

function uuid() {
  function s4() {
    return Math.floor((1 + Math.random()) * 0x10000).toString(16).substring(1);
  }
  return s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4();
}

The conversion from uuid to mongodb BinData is based on uuidhelpers.js:

function HexToBase64(hex) {
    var base64Digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    var base64 = "";
    var group;
    for (var i = 0; i < 30; i += 6) {
        group = parseInt(hex.substr(i, 6), 16);
        base64 += base64Digits[(group >> 18) & 0x3f];
        base64 += base64Digits[(group >> 12) & 0x3f];
        base64 += base64Digits[(group >> 6) & 0x3f];
        base64 += base64Digits[group & 0x3f];
    }
    group = parseInt(hex.substr(30, 2), 16);
    base64 += base64Digits[(group >> 2) & 0x3f];
    base64 += base64Digits[(group << 4) & 0x3f];
    base64 += "==";
    return base64;
}

function NUUID(uuid) {
    var hex = uuid.replace(/[{}-]/g, ""); // remove extra characters
    var a = hex.substr(6, 2) + hex.substr(4, 2) + hex.substr(2, 2) + hex.substr(0, 2);
    var b = hex.substr(10, 2) + hex.substr(8, 2);
    var c = hex.substr(14, 2) + hex.substr(12, 2);
    var d = hex.substr(16, 16);
    hex = a + b + c + d;
    var base64 = HexToBase64(hex);
    return new BinData(3, base64);
}