PrettyId

How does Stripe generate object ids?

Patrick Collison, Stripe CEO:

They're randomly generated by our Ruby application code. We use the ch_-style prefixes because we find it really useful to be able to immediately recognize the type of an ID when looking at logs or stacktraces.

source

With PrettyId you can generate Stripe-like IDs for your ActiveRecord models:

charge.id       #=> ch_xxx
user.id         #=> usr_xxx
transaction.id  #=> txn_xxx

Usage

For each model when you create table inside migration, you have to:

1. tell AR to not automatically add primary key column.
2. create id column as string
3. add unique index for id column

create_table :users, id: false do |t|
  t.string :id, null: false

  # your other columns
end

add_index(:users, :id, unique: true)

Inside model class just include PrettyId module:

class User < ActiveRecord::Base
  include PrettyId
end

By default first 3 letters of model class will be taken as id prefix. You can change it by specifying your own value:

class User < ActiveRecord::Base
  include PrettyId

  self.id_prefix = 'usr'
end

Or, if you want to add some tricky logic for id prefix (let's say for test account it should be acc_test and for live account it should be acc_live) you can provide a Proc that will return id prefix:

class Account < ActiveRecord::Base
  include PrettyId

  attr_accessor :type

  self.id_prefix = -> (model) { model.type == 'test' ? 'acc_test' : 'acc_live' }
end

account = Account.new
account.type = 'test'
account.save

account.id #=> acc_test_....

For cases when you don't want underscore (_) to be in id you can set it to nil:

class User < ActiveRecord::Base
  include PrettyId

  self.id_prefix = 'usr'
  self.id_separator = nil
end

user.id #=> usrPZUjZiIF3bnZ

Installation

Note There is another gem called 'pretty_id' so I had to rename mine into prettyid. So, be careful when you install gem and require it. It's a kind'a trick you do with 'activerecord' as well ;)

Add this line to your application's Gemfile:

gem 'prettyid', require: 'pretty_id'

And then execute:

$ bundle

Or install it yourself as:

$ gem install prettyid

Performance

If you care about performance, it's better to measure it yourself :) I have measured method that generates id (rake bm). Here are results for 1M calls:

                        user        system    total       real
PrettyId::Generator#id: 12.880000   0.020000  12.900000 ( 12.907587)                       

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/alovak/pretty_id.

License

This code is available under MIT license.

© Pavel Gabriel, 2018