hash instead of id

Question

I want to use auto-generated hash'es instead of auto-incremented integers in my activerecords as primary keys. This raises two questions:

1. how to perform this generation in most efficient way?
2. how to handle possibility that generated hash exists already in table?

Regards, Mateusz

Answer 1

If you want this because you don't want to show the id in the web url. You can use a gem like https://github.com/peterhellberg/hashids.rb

It creates a reversible hash from your database id so the hash does not need to be stored in the database.

Use it in your models to_param method.

class MyModel < ActiveRecord::Base

  def to_param
    Hashids.new("salt").encode(id)
  end
end

And decode the hash before finding the record from the database.

def show
  id = Hashids.new("salt").decode(params[:id]).try(:first)
  record = MyModel.find(id)
end