Module: Sqids::Rails::Model::ClassMethods

Defined in:
lib/sqids/rails/model.rb

Instance Method Summary collapse

Instance Method Details

#generate_unique_sqid(alphabet: Sqids::Rails.alphabet, blocklist: Sqids::Rails.blocklist, min_length: Sqids::Rails.min_length) ⇒ Object 



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# File 'lib/sqids/rails/model.rb', line 95

def generate_unique_sqid(
  alphabet: Sqids::Rails.alphabet, blocklist: Sqids::Rails.blocklist, min_length: Sqids::Rails.min_length
)
  @sqids ||= {}
  @sqids[[alphabet, blocklist, min_length]] ||= Sqids.new(
    alphabet: alphabet, blocklist: blocklist, min_length: min_length
  )
  @sqids[[alphabet, blocklist, min_length]].encode([SecureRandom.random_number(Sqids.max_value)])
end

#has_sqid(attribute = :sqid, alphabet: Sqids::Rails.alphabet, blocklist: Sqids::Rails.blocklist, min_length: Sqids::Rails.min_length, on: Sqids::Rails.generate_sqid_on) ⇒ Object

Example using #has_sqid:

# Schema: User(sqid:string, long_sqid:string)
class User < ApplicationRecord
  include Sqids::Rails::Model

  has_sqid
  has_sqid :long_sqid, min_length: 24
end

user = User.new
user.save
user.sqid # => "lzNKgEb6ZuaU"
user.sqid_long # => "4y3SVm9M2aV8Olu6p4zZoGij"
user.regenerate_sqid
user.regenerate_long_sqid

SecureRandom.random_number(Sqids.max_value) is used to generate the random number to encode.

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.

See the Sqids Ruby documentation for more information on the options.

Options

:alphabet

The alphabet to use for encoding. Default is Sqids::Rails.alphabet. The minimum alphabet length is 3 characters. The alphabet cannot contain any multibyte characters.

:blocklist

The blocklist to use for encoding. Default is Sqids::Rails.blocklist.

:min_length

The minimum length of the generated sqid, from 0-255. Default is Sqids::Rails.min_length. Sqids cannot generate IDs up to a certain length, only at least a certain length.

: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 Sqids::Rails.generate_sqid_on, which defaults to :initialize.



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# File 'lib/sqids/rails/model.rb', line 55

def has_sqid(
  attribute = :sqid,
  alphabet: Sqids::Rails.alphabet,
  blocklist: Sqids::Rails.blocklist,
  min_length: Sqids::Rails.min_length,
  on: Sqids::Rails.generate_sqid_on
)
  if alphabet.length < 3
    raise AlphabetError, "Sqid requires an alphabet of at least 3 characters"
  end

  if alphabet.each_char.any? { |char| char.bytesize > 1 }
    raise AlphabetError, "Sqid alphabet cannot contain multibyte characters"
  end

  if alphabet.chars.uniq.length != alphabet.length
    raise AlphabetError, "Sqid alphabet must contain unique characters"
  end

  if min_length < 0 || min_length > 255
    raise MinimumLengthError, "Sqid requires a minimum length between 0 and 255 characters"
  end

  define_method(:"regenerate_#{attribute}") do
    update!(
      attribute => self.class.generate_unique_sqid(
        alphabet: alphabet, blocklist: blocklist, min_length: min_length
      )
    )
  end
  set_callback(on, (on == :initialize) ? :after : :before) do
    if new_record? && !query_attribute(attribute)
      send(
        :"#{attribute}=",
        self.class.generate_unique_sqid(alphabet: alphabet, blocklist: blocklist, min_length: min_length)
      )
    end
  end
end