Sample implementation of the SslUrlReplacer that we discussed at the whiteboard.

ssl_url_replacer.rb

# Search and replace page elements in the CMS for old SSL URLs and replace with
# a new domain.
#
# Example:
#
#   CMS::SslUrlReplacer.new(Site.first, "foo.bar.com", "foobar.example.com").perform
class CMS::SslUrlReplacer
  # Public: Initialize a new SslUrlReplacer
  #
  # site - An instance of Site
  # old_domain - A String with the old domain to search for
  # new_domain - A Stiing with the new domain to replace with
  def initialize(site, old_domain, new_domain)
    self.site = site
    self.old_domain = old_domain
    self.new_domain = new_domain
  end

  def perform
    perform_on(TextBlockElement) do |element|
      element.update_attribute(:content, replace(element.content, "https://#{old_domain}", "https://#{new_domain}"))
    end

    perform_on(DisplayCodeElement) do |element|
      element.update_attribute(:content, replace(element.content, "https://#{old_domain}", "https://#{new_domain}"))
    end

    # and so on for the simple case

    perform_on(LinkElement) do |element|
      # only perform the update for HTTPS link elements
      if element.protocol == "https" # or whatever the logic is/should be
        element.update_attribute(:domain, replace(element.domain, old_domain, new_domain))
      end
    end

    perform_on(USMapElement) do |element|
      hash = element.link_info
      hash[:url] = replace(hash.url,  "https://#{old_domain}", "https://#{new_domain}")
      element.update_attribute(:link_info, hash)
    end

    perform_on(ElementWithTwoAttributes) do |element|
      element.first_attribute = replace(element.first_attribute, old_domain, new_domain)
      element.second_attribute = replace(element.second_attribute, old_domain, new_domain)
      element.save(false)
    end
  end

  # Perform the given block on each matching element of klass
  #
  # klass - An ActiveRecord class to work with
  # &block - The block to perform the update for this class
  #
  # Example:
  #
  #   perform_on(DisplayCodeElement) do |element|
  #     element.update_attribute(:content, replace(element.content, "https://#{old_domain}", "https://#{new_domain}"))
  #   end
  def perform_on(klass)
    find_for_site(klass).find_each do |element|
      yield element
    end
  end

  def find_for_site(klass)
    klass.all_the_arel.where(:site_id => site.id)
  end

  def replace(string, search, replace)
    string.gsub(search, replace)
  end
end