Example of getting a list of unsubscribed users from Campaign Monitor using the gnumarcelo / campaigning gem, when you already know your list_ids..

campaignmonitor_cron.rb

# This script contacts Campaign Monitor, and goes through each of the three main lists looking for "unsubscribed" people.
# User accounts are then "unsubscribed" if they've done it at CM..
#
#
# Run through script/runner... 
# I know this could probably be made much nicer but it is a first attempt :)
#
#
# put in the constants set in environment of our api list ids
lists = { CAMPAIGN_MONITOR_LIST_ONE => "Type1" } # add more here, LIST_ID => User Type...

# loop through the lists and
lists.each do |list_id, user_type|
  puts "----------------------------------------------------------------"
  puts "Processing list:  #{user_type} => #{list_id}"

  #Gets a list of all subscribers for a list that have unsubscribed since the specified date.
  campaign = Campaigning::List.new(list_id)
  unsubscribe_list = campaign.find_unsubscribed(DateTime.now - 1.week) # adjust the time period to suit..

  puts "Users unsubscribed from the list in time period: #{unsubscribe_list.size}"

  # loop through the list and those which are subscribed, and unsubscribe by email and the list type ..
  counter = 0
  unsubscribe_list.each do |unsubscriber|
    user = User.find(:first, :conditions => { :email => unsubscriber.emailAddress, :type => user_type, :subscription_status => true })
    if user
      print "Unsubscribing => #{counter+=1}: #{unsubscriber.emailAddress}, #{user.id}:#{user.cognomen}"
      user.update_attribute(:subscription_status, false)
      puts "... done"
    end
  end
  puts " STATS --> FOUND: #{unsubscribe_list.size} - UNSUBSCRIBED: #{counter} "
  puts "----------------------------------------------------------------"
  puts ""

end