module ActiveRecord::SignedId::ClassMethods

User.find_signed signed_id, purpose: :password_reset # => User.first
travel_back

User.find_signed signed_id, purpose: :password_reset # => nil, since the signed id has expired
travel 16.minutes

User.find_signed signed_id # => nil, since the purpose does not match

signed_id = User.first.signed_id expires_in: 15.minutes, purpose: :password_reset

==== Examples

finding. If there's a mismatch, nil is again returned.
or email verification. The purpose that was set during generation must match the purpose set when
general base model, like a User, which might have signed ids for several things, like password reset
It's possible to further restrict the use of a signed id with a purpose. This helps when you have a

the signed id will no longer be valid, and nil is returned.
signed_id(expires_in: 15.minutes). If the time has elapsed before a signed find is attempted,
You set the time period that the signed id is valid for during generation, using the instance method

a certain time period.
the bearer of the signed id to be able to interact with the underlying record, but usually only within
This is particularly useful for things like password reset or email verification, where you want
Lets you find a record based on a signed id that's safe to put into the world without risk of tampering.

def find_signed(signed_id, purpose: nil)
  raise UnknownPrimaryKey.new(self) if primary_key.nil?
  if id = signed_id_verifier.verified(signed_id, purpose: combine_signed_id_purposes(purpose))
    find_by primary_key => id
  end
end