UUID v7

[Mike Kerner]

why would reducing randomness be desirable in an internet-facing app? isn't
the whole point to
* ensure uniqueness across the entire space
* make it nearly impossible to guess an ID?
i would think that once you make the id's sequential, you have eliminated
the ability to stop an authorized user from randomly marching through your
data.

On Fri, Sep 1, 2023 at 1:21 PM Tom Glod via use-livecode <
use-livecode at lists.runrev.com> wrote:

> Hi Folks,
>
> Sharing this because its useful, and also, more eyeballs on the code makes
> sense.
> I implemented this with the help of chatGPT.
>
> This is a handler that can generate v7 UUIDs.
> v7 UUIDs work better in databases, because they are not so random,
> improving performance.
> And they are sequential.
> They also match the format of uuid v4
> Also the specs for v7 have not yet been finalized.
>
> Here it is:
>
> function CreateUUID pVersion
>    // This Handler returns a
>    if pVersion is not 7 then
>       //Return V4 Random UUID
>       return uuid("random")
>
>    else if pVersion = 7 then
>       // return V7 Random yet sequenced UUID
>
>       local tUnixTsMs, tVer, tRandA, tTVar, tRandB, tTheID
>       -- Get the current timestamp in milliseconds
>
>       put baseConvert(the milliseconds, 10, 16) into tUnixTsMs
>       put format("%012s", tUnixTsMs) into tUnixTsMs
>
>       // Set the version field to 0b0111 (7)
>       put "7" into tVer
>
>       // Generate 12 bits of pseudo-random data for RAND A
>       put random(4095) into tRandA -- 4095 is the maximum value for 12 bits
>       put baseConvert(tRandA, 10, 16) into tRandA
>       put format("%03s", tRandA) into tRandA
>
>       // Set the variant field to 0b10
>       put "8" into tTVar -- 0b10 in hexadecimal
>
>       // Generate 62 bits of pseudo-random data for RAND B
>       repeat 16 times
>          put baseConvert(random(15), 10, 16) after tRandB -- generate one
> hex digit at a time
>       end repeat
>
>       // Combine all the bits to form the UUID
>       put tUnixTsMs & tVer & tRandA & tTVar & tRandB into tTheID
>
>       // Insert dashes to form the UUID in 8-4-4-4-12 format
>       put char 1 to 8 of tTheID & "-" & char 9 to 12 of tTheID & "-" & char
> 13 to 16 of tTheID & "-" & char 17 to 20 of tTheID & "-" & char 21 to 32 of
> tTheID into tTheID
>
>       return tTheID
>    end if
> end CreateUUID tVersion
>
> Cheers,
>
> Tom
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