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Model Versioning

#177 Model Versioning

Aug 31, 2009 | 9 minutes | Active Record, Plugins
If you need to keep track of a model's history of changes and switch between versions, consider using the vestal_versions gem like I show in this episode.
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bash 
sudo rake gems:install
script/generate vestal_versions_migration
script/generate migration version_existing_pages
rake db:migrate
config/environment.rb 
config.gem 'laserlemon-vestal_versions', :lib => 'vestal_versions', :source => 'http://gems.github.com'
models/page.rb 
class Page < ActiveRecord::Base
  versioned
end

# version_existing_pages migration
say_with_time "Setting initial version for pages" do
  Page.find_each(&:touch)
end
pages_controller.rb 
def show
  @page = Page.find(params[:id])
  @page.revert_to(params[:version].to_i) if params[:version]
end
script/console 
p = Page.all
p.versions
p.revert_to(7.minutes.ago)
p.content
p.revert_to(:last)
rhtml 
<p>
  <%= link_to "Edit", edit_page_path(@page) %>
  | Version <%= @page.version %>
  <% if @page.version > 1 %>
    | <%= link_to "Previous version", :version => @page.version-1 %>
  <% end %>
  <% if params[:version] %>
    | <%= link_to "Latest version", :version => nil %>
  <% end %>
</p>