Prefixed IDs

Generate prefixed IDs for your models with a friendly prefix. For example:

user_12345abcd
acct_23lksjdg3

This gem works by hashing the record's original :id attribute using Hashids, which transforms numbers like 347 into a string like yr8. It uses the table's name and an optional additional salt to hash values, returning a string like tablename_hashedvalue.

Inspired by Stripe's prefixed IDs in their API.

Add this line to your application's Gemfile:

gem 'prefixed_ids'

Add has_prefix_id :my_prefix to your models to autogenerate prefixed IDs.

class User < ApplicationRecord
  has_prefix_id :user
end

By default, Prefixed IDs overrides to_param in the model to use prefix IDs.

To get the prefix ID for a record:

@user.to_param
#=> "user_12345abcd"

If to_param override is disabled:

@user.prefix_id
#=> "user_12345abcd"

By default, prefixed_ids overrides find and to_param to seamlessly URLs automatically.

User.first.to_param
#=> "user_5vJjbzXq9KrLEMm32iAnOP0xGDYk6dpe"

User.find("user_5vJjbzXq9KrLEMm32iAnOP0xGDYk6dpe")
#=> #<User>

You can also use find_by_prefix_id or find_by_prefix_id! when the find override is disabled:

User.find_by_prefix_id("user_5vJjbzXq9KrLEMm32iAnOP0xGDYk6dpe") # Returns a User or nil
User.find_by_prefix_id!("user_5vJjbzXq9KrLEMm32iAnOP0xGDYk6dpe") # Raises an exception if not found

To disable find and to_param overrides, pass the following options:

class User < ApplicationRecord
  has_prefix_id :user, override_find: false, override_param: false
end

A salt is a secret value that makes it impossible to reverse engineer IDs. We recommend adding a salt to make your Prefix IDs unguessable.

# config/initializers/prefixed_ids.rb
PrefixedIds.salt = "salt"

class User
  has_prefix_id :user, salt: "usersalt"
end

Imagine you have a prefixed ID but you don't know which model it belongs to:

PrefixedIds.find("user_5vJjbzXq9KrLEMm3")
#=> #<User>

PrefixedIds.find("acct_2iAnOP0xGDYk6dpe")
#=> #<Account>

This works similarly to GlobalIDs.

You can customize the prefix, length, and attribute name for PrefixedIds.

class Account < ApplicationRecord
  has_prefix_id :acct, minimum_length: 32, override_find: false, override_param: false, salt: "", fallback: false
end

By default, find will accept both Prefix IDs and regular IDs. Setting fallback: false will disable finding by regular IDs and will only allow Prefix IDs.

After checking out the repo, run bundle install to install dependencies. Then, run rake test to run the tests. You can also run bin/rails console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/excid3/prefixed_ids. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the PrefixedIds project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.