Generator (like an Iterator) in Ruby on Rails

I'm creating a rails-agnostic class in ruby for getting the member photo directory.

Downloading the entire photo directory is slow. It takes a few minutes. Users don't want to wait 3 minutes to find out what is happening (success or failure, etc), but I don't want to put my model code into a library which could otherwise easily be used for non-rails apps.

The main issue here is that once the class instance is gone, so is the authentication. So it doesn't work to just store the URLs to the photos. Each photo must be downloaded. However, if the URLs to the photos are temporarily stored in the class and then downloaded one-by-one in the class, the wait for the text part of the directory to the download is acceptable (for me).

Take a look

http://secure.lds.org/units/login

/Membership Directory/.click

/with photos/i.click

The solution? A generator.

Here's a brief work snippit that shows how my solution works generically:

class Contacts
 def import_directory
   @records = []
   #... get names and photo urls
   @records << [:name => 'abc']
   @records << [:name => 'jkl']
   @records << [:name => 'xyz']
   return true
 end

 def next_contact
   if not @gen
     create_generator
   end
   return @gen.next
 end

 private
 def create_generator
   require 'generator'
   @gen = Generator.new do |g|
     for record in @records
       g.yield record
     end
     g.yield nil
   end
 end
end

contacts = Contacts.new
if not contacts.import_directory
 abort 'Invalid Import'
end

while record = contacts.next_contact
 puts record
end

I know that generators can be done in python and after a little searching I found this, which inspired me to play around and create an example class solution.

http://anthonylewis.com/2007/11/09/ruby-generators/