instiki/app/controllers/revision_sweeper.rb

class RevisionSweeper < ActionController::Caching::Sweeper
  observe Revision, Page
  
  def after_save(record)
    if record.is_a?(Revision)
      expire_caches(record.page)
    end
  end
  
  def after_delete(record)
    if record.is_a?(Page)
      expire_caches(record)
    end
  end
  
  private
  
  def expire_caches(page)
    web = page.web

    ([page.name] + WikiReference.pages_that_reference(page.name)).uniq.each do |page_name|
      expire_action :controller => 'wiki', :web => web.address,
          :action => %w(show published), :id => page_name
    end

    expire_action :controller => 'wiki', :web => web.address,
        :action => %w(authors recently_revised list)
    expire_fragment :controller => 'wiki', :web => web.address,
        :action => %w(rss_with_headlines rss_with_content)
  end

end