PrefixedUUID

A while back I read a wonderfully useful blog post by @danschultzer

I've used a modified version of his code from the post in a few projects and as I copy/pasted the code into yet another project today, I decided to turn it into a small library. It may not be useful for anyone else, but it will make adding it to my new projects a lot easier.

Under the hood it relies on Ecto and Uniq

As Dan explains in his post, it opts to use the newer UUIDv7 instead of UUIDv4 which allow for nicieties like ordering. It also makes the UUIDs more friendly by encoding them in base62 and allowing a prefix to be assigned per schema. This allows for ids that look like user_3TUIKuXX5mNO2jSA41bsDx instead of 7232b37d-fc13-44c0-8e1b-9a5a07e24921. At a glance you know the id belongs to a user schema and while not a lot shorter, it is shorter and more compact.

Installation

The package can be installed by adding prefixed_uuid to your list of dependencies in mix.exs:

def deps do
  [
    {:prefixed_uuid, "~> 1.0.0"}
  ]
end

Usage

In your schema files, instead of use Ecto.Schema instead do use PrefixedUUID.Schema, prefix: "user"

This precludes the need for specifying @primary_key and @foreign_key_type in your schema file. If you would like to be more explicit and continue using Ecto.Schema, then you may instead opt to specify these directly.

@primary_key {:id, PrefixedUUID, prefix: "user", autogenerate: true}
@foreign_key_type PrefixedUUID

If you chose to use PrefixedUUID.Schema then you also get a type automatically set and a couple of helper functions:

• prefix/0 returns the prefix you set which allows progromatic access to the prefix.
• generate_id/0 returns a freshly generated prefixed UUID that uses the set prefix.

See the docs for the full set of functions available.