Trying to Understand Drops

I’ve collected some ‘drop classes’ from Mephisto in the hope of understanding how to stitch Liquid into a Rails App.

Perhaps someone can comment on what the different drops are doing and their purpose.

Here are the ‘drops’

  class UserDrop < BaseDrop
    liquid_attributes << :login << :email
  end

Explanation of above code
Liquid accepts only a limited number of objects types i.e. Strings, Arrays, Hashes, Numerics, and Booleans. If we want to pass our Active Record object to liquid templates we have to define that logic explicitly(Liquid doesn’t provide that functionality).
Basically there are three methods/ways to define that logic http://wiki.github.com/tobi/liquid/getting-liquid-to-work-in-rails.

The above describe method will constructs a Liquid Drop with the methods you included. After including the above said stuff you will be able to access user’s email and login in the liquid template ie {{ user.email }} and {{ user.login }}. Only email and login will be available in the liquid template (all other methods will not be accessible to liquid templates i.e. user.password ).

  class ArticleDrop < BaseDrop
    include Mephisto::Liquid::UrlMethods

    timezone_dates :published_at, :updated_at
    liquid_attributes << :title << :permalink << :comments_count

    def initialize(source, options = {})
      super source
      @options        = options
      @liquid.update \
        'body'             => @source.body_html,
        'excerpt'          => (@source.excerpt_html.nil? ||
                               @source.excerpt_html.empty? ? nil : @source.excerpt_html),
        'accept_comments'  => @source.accept_comments?,
        'is_page_home'     => (options[:page] == true)
    end

    def author
      @author ||= liquify(@source.user).first
    end

    def comments
      @comments ||= liquify(*@source.comments.reject(&:new_record?))
    end

    def sections
      @sections ||= @source.sections.inject([]) { |all, s|
        s.home? ? all : all << s.to_liquid } # your days are numbered, home section!
      @sections ||= liquify(*@source.sections) { |s| s.home? ? nil : s.to_liquid }
    end

    def tags
      @tags ||= liquify(*@source.tags)
    end

    def blog_sections
      sections.select { |s| s.source.blog? }
    end

    def page_sections
      sections.select { |s| s.source.paged? }
    end

    def content
      @content ||= body_for_mode(@options[:mode] || :list)
    end

    def url
      @url ||= absolute_url(@site.permalink_for(@source))
    end

    def comments_feed_url
      @comments_feed_url ||= url + '/comments.xml'
    end

    def changes_feed_url
      @changes_feed_url ||= url + '/changes.xml'
    end

    protected
      def body_for_mode(mode)
        contents = [before_method(:excerpt), before_method(:body)]
        contents.reverse! if mode == :single
        contents.detect { |content| !content.blank? }.to_s.strip
      end
  end