Question

I have something like:

class User
  include DataMapper::Resource

  property :id, Serial
  property :username, Text
end

I want usernames to be case-sensitive, so users can make usernames as they choose. What’s the best way to then search for usernames in a case-insensitive way?

if I make a user named ‘TestUser’, I want to be able to access it with something like

User.first(:username => 'testuser')

I thought about making a username_downcased property that uses a validates_with_method to make a downcased version of the username property for indexing, but I had problems getting that to work.

Answer 1

After a bit of finagling I found a solution, but I would be very surprised if it is the best one.

class User
  include DataMapper::Resource

  property :id, Serial
  property :username, Text
  property :username_lower, Text

  validates_with_method :lower_username
  validates_uniqueness_of :username_lower, :message => 'Username is already taken'

  def lower_username
    self.username_lower = self.username.downcase
    true
  end

end

Case-sensitive name stored in username, but case-insensitive indexing can be done on username_lower.