ulid

Universally Unique Lexicographically Sortable Identifier for Crystal

UUID can be suboptimal for many use-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:

require "ulid"

ulid = Ulid::ULID.new
ulid.to_s # => "05PQXW3M5XRY8ERYNCGZWD2MCM"

• 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 Crockford's base32 for better efficiency and readability (5 bits per character)
• Case insensitive
• No special characters (URL safe)
• Monotonic sort order (correctly detects and handles the same millisecond)

For more information, see ulid specs

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     ulid:
       github: lemarsu/ulid
       version: "~> 0.1.3"

2. Run shards install

Usage

require "ulid"

ulid = Ulid::ULID.new
ulid.to_s # => "05PQXW3M5XRY8ERYNCGZWD2MCM"

ulid2 = Ulid::ULID.new "05PQXW3M5XRY8ERYNCGZWD2MCM"
ulid2 == ulid # => true

Contributing

1. Fork it (https://github.com/lemarsu/ulid/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• LeMarsu - creator and maintainer