discourse/lib/onebox/engine/discourse_local_onebox.rb

module Onebox
  module Engine
    class DiscourseLocalOnebox
      include Engine

      matches_regexp Regexp.new("^#{Discourse.base_url.gsub(".","\\.")}.*$", true)

      # Use this onebox before others
      def self.priority
        1
      end

      def self.===(other)
        if other.kind_of?(URI)
          uri = other
          begin
            route = Rails.application.routes.recognize_path(uri.path)
            case route[:controller]
            when 'topics'
              # super will use matches_regexp to match the domain name
              super
            else
              false
            end
          rescue ActionController::RoutingError
            false
          end
        else
          super
        end
      end

      def to_html
        uri = URI::parse(@url)
        route = Rails.application.routes.recognize_path(uri.path)


        # Figure out what kind of onebox to show based on the URL
        case route[:controller]
        when 'topics'

          linked = "<a href='#{@url}'>#{@url}</a>"
          if route[:post_number].present? && route[:post_number].to_i > 1
            # Post Link
            post = Post.find_by(topic_id: route[:topic_id], post_number: route[:post_number].to_i)
            return linked unless post
            return linked if post.hidden
            return linked unless Guardian.new.can_see?(post)

            topic = post.topic
            slug = Slug.for(topic.title)

            excerpt = post.excerpt(SiteSetting.post_onebox_maxlength)
            excerpt.gsub!("\n"," ")
            # hack to make it render for now
            excerpt.gsub!("[/quote]", "[quote]")
            quote = "[quote=\"#{post.user.username}, topic:#{topic.id}, slug:#{slug}, post:#{post.post_number}\"]#{excerpt}[/quote]"

            cooked = PrettyText.cook(quote)
            return cooked

          else
            # Topic Link
            topic = Topic.where(id: route[:topic_id].to_i).includes(:user).first
            return linked unless topic
            return linked unless Guardian.new.can_see?(topic)

            post = topic.posts.first

            posters = topic.posters_summary.map do |p|
              {
                username: p[:user].username,
                avatar: PrettyText.avatar_img(p[:user].avatar_template, 'tiny'),
                description: p[:description],
                extras: p[:extras]
              }
            end

            quote = post.excerpt(SiteSetting.post_onebox_maxlength)
            args = { original_url: @url,
                     title: topic.title,
                     avatar: PrettyText.avatar_img(topic.user.avatar_template, 'tiny'),
                     posts_count: topic.posts_count,
                     last_post: FreedomPatches::Rails4.time_ago_in_words(topic.last_posted_at, false, scope: :'datetime.distance_in_words_verbose'),
                     age: FreedomPatches::Rails4.time_ago_in_words(topic.created_at, false, scope: :'datetime.distance_in_words_verbose'),
                     views: topic.views,
                     posters: posters,
                     quote: quote,
                     category_html: CategoryBadge.html_for(topic.category),
                     topic: topic.id }

            return Mustache.render(File.read("#{Rails.root}/lib/onebox/templates/discourse_topic_onebox.hbs"), args)
          end
        end

      rescue ActionController::RoutingError
        nil
      end

    end
  end
end