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https://github.com/haskell-github-trust/ulid
Haskell implementation of ULIDs (Unique Lexicographically Sortable Identifiers)
https://github.com/haskell-github-trust/ulid
haskell ulid uuid
Last synced: 16 days ago
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Haskell implementation of ULIDs (Unique Lexicographically Sortable Identifiers)
- Host: GitHub
- URL: https://github.com/haskell-github-trust/ulid
- Owner: haskell-github-trust
- License: bsd-3-clause
- Created: 2017-06-10T19:31:39.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2022-05-24T09:32:03.000Z (over 2 years ago)
- Last Synced: 2024-12-10T16:36:50.202Z (18 days ago)
- Topics: haskell, ulid, uuid
- Language: Haskell
- Homepage: http://hackage.haskell.org/package/ulid
- Size: 52.7 KB
- Stars: 32
- Watchers: 3
- Forks: 11
- Open Issues: 11
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ULID Implementation in Haskell
Lexicographically sortable, 128-bit identifier
with 48-bit timestamp and 80 random bits.
Canonically encoded as a 26 character string,
as opposed to the 36 character UUID.
Original implementation and spec: [github.com/alizain/ulid]
[github.com/alizain/ulid]: https://github.com/alizain/ulid/
```txt
01an4z07by 79ka1307sr9x4mv3
|----------| |----------------|
Timestamp Randomness
48 bits 80 bits
```
# Universally Unique Lexicographically Sortable Identifier
UUID can be suboptimal for many uses-cases because:
- It isn't the most character efficient way of encoding 128 bits of randomness
- UUID v1/v2 is impractical in many environments,
as it requires access to a unique, stable MAC address
- UUID v3/v5 requires a unique seed and produces randomly distributed IDs,
which can cause fragmentation in many data structures
- UUID v4 provides no other information than randomness,
which can cause fragmentation in many data structures
Instead, herein is proposed ULID:
- 128-bit compatibility with UUID
- 1.21e+24 unique ULIDs per millisecond
- Lexicographically sortable
- Canonically encoded as a 26 character string,
as opposed to the 36 character UUID
- Uses [Douglas Crockford's base 32] for better efficiency and readability
(5 bits per character)
- Case insensitive
- No special characters (URL safe)
[Douglas Crockford's base 32]: https://www.crockford.com/base32.html
## Usage
A simple usage example:
````haskell
module Main where
import Data.ULID
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, millisecond precision
print ulid2
````
As per the spec, it is also possible to use a cryptographically-secure
random number generator to contribute the randomness.
However, the programmer must manage the generator on their own.
Example:
````haskell
module Main where
import Data.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
-- This default instantiation may not be sufficiently secure.
-- See the docs at
-- hackage.haskell.org/package/crypto-api-0.13.2/docs/Crypto-Random.html
g <- (CR.newGenIO :: IO CR.SystemRandom)
-- Generate timestamp from current time
t <- TS.getULIDTimeStamp
let ulid3 = case UR.mkCryptoULIDRandom g of
Left err -> error $ show err
-- use g2, …, to continue generating secure ULIDs
Right (rnd, g2) -> ULID t rnd
print ulid3
````
## Test Suite
```sh
stack test
```
## Performance
```sh
stack bench
```
```txt
Running 1 benchmarks...
Benchmark ulid-bench: RUNNING...
217,868 op/s generate
Benchmark ulid-bench: FINISH
```