Module: ActiveRecord::SecureToken::ClassMethods

Relationships & Source Files
Defined in:	activerecord/lib/active_record/secure_token.rb

Instance Method Summary

#generate_unique_secure_token(length: MINIMUM_TOKEN_LENGTH)
#has_secure_token(attribute = :token, length: MINIMUM_TOKEN_LENGTH, on: ActiveRecord.generate_secure_token_on, prefix: nil)

Example using #has_secure_token

Instance Method Details

#generate_unique_secure_token(length: MINIMUM_TOKEN_LENGTH)

[ GitHub ]

# File 'activerecord/lib/active_record/secure_token.rb', line 80


def generate_unique_secure_token(length: MINIMUM_TOKEN_LENGTH)
  SecureRandom.base58(length)
end

#has_secure_token(attribute = :token, length: MINIMUM_TOKEN_LENGTH, on: ActiveRecord.generate_secure_token_on, prefix: nil)

Example using #has_secure_token

# Schema: User(token:string, auth_token:string)
class User < ActiveRecord::Base
  has_secure_token
  has_secure_token :invite_token, prefix: true
  has_secure_token :auth_token, length: 36, prefix: "auth_"
end

user = User.new
user.save
user.token # => "pX27zsMN2ViQKta1bGfLmVJE"
user.invite_token # => "invite_token_srUP2WWCb6yCtfy6CAKVdzxF"
user.auth_token # => "auth_tU9bLuZseefXQ4yQxQo8wjtBvsAfPc78os6R"
user.regenerate_token # => true
user.regenerate_invite_token # => true
user.regenerate_auth_token # => true

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

Note that it’s still possible to generate a race condition in the database in the same way that validates_uniqueness_of can. You’re encouraged to add a unique index in the database to deal with this even more unlikely scenario.

Options

:length: Length of the randomly generated token, with a minimum of 24 characters. Defaults to 24.
:on: The callback when the value is generated. When called with on: :initialize, the value is generated in an after_initialize callback, otherwise the value will be used in a before_ callback. When not specified, :on will use the value of config.active_record.generate_secure_token_on, which defaults to :initialize starting in Rails 7.1.
:prefix: An optional string prepended to the generated token. Intended primarily for keys that will be publicly visible (e.g. API keys, URLs, etc.) so that their purpose can be identified at a glance. The prefix does not count toward :length.

[ GitHub ]

# File 'activerecord/lib/active_record/secure_token.rb', line 53


def has_secure_token(attribute = :token, length: MINIMUM_TOKEN_LENGTH, on: ActiveRecord.generate_secure_token_on, prefix: nil)
  if length < MINIMUM_TOKEN_LENGTH
    raise MinimumLengthError, "Token requires a minimum length of #{MINIMUM_TOKEN_LENGTH} characters."
  end

  prefix = "#{attribute}_" if prefix == true

  if prefix
    generate_token = -> do
      token = self.generate_unique_secure_token(length: length)

      "#{prefix}#{token}"
    end
  else
    generate_token = -> { self.generate_unique_secure_token(length: length) }
  end

  # Load securerandom only when has_secure_token is used.
  require "active_support/core_ext/securerandom"
  define_method("regenerate_#{attribute}") { update! attribute => generate_token.call }
  set_callback on, on == :initialize ? :after : :before do
    if new_record? && !query_attribute(attribute)
      send("#{attribute}=", generate_token.call)
    end
  end
end