ulid-0.1.0.0: app/Main.hs

module Main where

import           Data.ULID

-- These imports only needed for cryptographically secure ULID
import qualified Crypto.Random       as CR
import qualified Data.ULID.Random    as UR
import qualified Data.ULID.TimeStamp as TS

main :: IO ()
main = do
     -- Derive a ULID using the current time and default random number generator
    ulid1 <- getULID
    print ulid1

    -- Derive a ULID using a specified time and default random number generator
    ulid2 <- getULIDTime 1469918176.385 -- POSIX Time, specified to the millisecond
    print ulid2


    -- Below only for crypographically secure ULID example

    -- This default instantiation may not be sufficiently secure, see the docs 
    -- https://hackage.haskell.org/package/crypto-api-0.13.2/docs/Crypto-Random.html
    g <- (CR.newGenIO :: IO CR.SystemRandom)

    -- Generate time stamp from current time
    t <- TS.getULIDTimeStamp

    let ulid3 = case UR.mkCryptoULIDRandom g of
            Left err        -> error $ show err
            Right (rnd, g2) -> ULID t rnd   -- use g2, etc, to continue generating secure ULIDs
    print ulid3