Two ways of clearing the cache in rails... needs work

lib_user_cache.rb

module UserCache
  def self.expire_cache(id)
    @base ||= ActionController::Base.new
    fragments = [ "user_#{id}", "mini_user_#{id}",
      "admin_user_#{id}", "admin_mini_user_#{id}",
      "admin_video_user_#{id}", "video_user_#{id}",
      "archive_column", "archive",
      "admin_archive_column", "admin_archive",
      "embedded_video_#{id}"]
    fragments.each do |fragment|
        @base.expire_fragment(fragment)
     end
  end
end

user.rb

require 'lib/user_cache'
class User < ActiveRecord::Base
  after_save :expire_cache
  after_destroy :expire_cache
  # callback method #1
  def expire_cache
    UserCache.expire_cache(id)
  end
end

user_archive.html.haml

-content_for :column do
  -cache("#{prepend_if_admin?}archive_column") do
    some content
-cache("#{prepend_if_admin?}archive") do
  Some other content

user_helper.rb

module UserHelper
  def prepend_if_admin?
    (current_user && current_user.is_admin?) ? 'admin_' : ''
  end
end

user_index.html.haml

- cache('user_index_page') do
  - users.each do |user|
    - cache(user) do
      = "some stuff about #{user.name}"

user_sweeper.rb

# Sweeper / Observer callback method #2
class UserSweeper < ActionController::Caching::Sweeper
  observe User # This sweeper is going to keep an eye on the User model

  # If our sweeper detects that a User was created call this
  def after_create(user)
    expire_cache_for(user)
  end

  # If our sweeper detects that a User was updated call this
  def after_update(user)
    expire_cache_for(user)
  end

  # If our sweeper detects that a User was deleted call this
  def after_destroy(user)
    expire_cache_for(user)
  end

  private
  def expire_cache_for(user)
    # Expire the index page now that we added a new user
    # expire_page(:controller => 'users', :action => 'index')
    expire_action(:controller => 'users', :action => 'index')
    expire_action(:controller => 'users', :action => 'show', :id => user.id)

    # Expire a fragment
    expire_fragment('user_index_page')
  rescue => e
    Rails.logger.warn "DEBUGGING SWEEPER FAILURE: user #{user && user.respond_to?(:id) && user.id}: #{e.class}\t#{e.message}\t#{e.backtrace[0..4].join("\n\t")}"
  end
end

users_controller.rb

class UsersController < ApplicationController
  caches_action :index
  cache_sweeper :user_sweeper
  def index
  end
  def archive
    unless fragment_exist?("archive") and fragment_exist?("archive_column")
      # set some instance variables
    end
  end
end