module ActiveRecord::SecureToken::ClassMethods

def has_secure_token(attribute = :token, length: MINIMUM_TOKEN_LENGTH, on: ActiveRecord.generate_secure_token_on)

starting in \Rails 7.1.
config.active_record.generate_secure_token_on, which defaults to +:initialize+
in a before_ callback. When not specified, +:on+ will use the value of
after_initialize callback, otherwise the value will be used
:initialize, the value is generated in an
The callback when the value is generated. When called with on:
[:on]

default to 24.
Length of the Secure Random, with a minimum of 24 characters. It will
[:length]

=== Options

You're encouraged to add a unique index in the database to deal with this even more unlikely scenario.
{validates_uniqueness_of}[rdoc-ref:Validations::ClassMethods#validates_uniqueness_of] can.
Note that it's still possible to generate a race condition in the database in the same way that

+SecureRandom::base58+ is used to generate at minimum a 24-character unique token, so collisions are highly unlikely.

user.regenerate_auth_token # => true
user.regenerate_token # => true
user.auth_token # => "tU9bLuZseefXQ4yQxQo8wjtBvsAfPc78os6R"
user.token # => "pX27zsMN2ViQKta1bGfLmVJE"
user.save
user = User.new

end
has_secure_token :auth_token, length: 36
has_secure_token
class User < ActiveRecord::Base
# Schema: User(token:string, auth_token:string)

Example using #has_secure_token 
def has_secure_token(attribute = :token, length: MINIMUM_TOKEN_LENGTH, on: ActiveRecord.generate_secure_token_on)
  if length < MINIMUM_TOKEN_LENGTH
    raise MinimumLengthError, "Token requires a minimum length of #{MINIMUM_TOKEN_LENGTH} characters."
  end
  # Load securerandom only when has_secure_token is used.
  require "active_support/core_ext/securerandom"
  define_method("regenerate_#{attribute}") { update! attribute => self.class.generate_unique_secure_token(length: length) }
  set_callback on, on == :initialize ? :after : :before do
    if new_record? && !query_attribute(attribute)
      send("#{attribute}=", self.class.generate_unique_secure_token(length: length))
    end
  end
end