I have a form on a website that takes in some personal information from the visitor. I'm passing this information to another service and I need to assign each one of these form submits a 100 character unique hash to be stored in the DB with the record. What's the optimal way to generate this key and make sure it's unique? It's okay if the key auto-increments.
ActiveSupport::SecureRandom.hex(50)
The chance of this not being unique is astronomical.
Alternate simple "does not scale" race condition fail solution.
class MyModel < ActiveRecord::Base
before_create :assign_unique_token
private
def assign_unique_token
self.unique_token = ActiveSupport::SecureRandom.hex(50) until unique_token?
end
def unique_token?
self.class.count(:conditions => {:unique_token => unique_token}) == 0
end
end
If you really want to make sure, make an unique index on the column, and handle a DB uniqueness error by retrying, similar to my implementation above.