gistfile1.rb

# This will generate something like "jfonda51", and a password like "0be21405590f",
# which is completely secure.
if client.first_name? && client.last_name?
  new_credentials = Credentials.new([client.first_name[0..0], client.last_name].join.downcase)

  # Replace the username, if it is blank
  if client.username.blank?
    # Check for existing usernames, and regenerate until unique
    until Client.exists?(:username => new_credentials.username) == false
      new_credentials = Credentials.new([client.first_name[0..0], client.last_name].join.downcase)
    end

    client.username = new_credentials.username
  end

  # Replace the password, if it is blank
  if client.crypted_password.blank?
    client.password = new_credentials.password
    client.password_confirmation = new_credentials.password
  end

  # Save the client
  client.save
end