From https://once.com/writebook

app/models/demo_content.rb

@@ -0,0 +1,87 @@
+class DemoContent
+  class << self
+    def create_manual(user)
+      book = create_book(user)
+      load_markdown_pages(book)
+    end
+
+    private
+      def create_book(user)
+        Book.create(title: "The Writebook Manual", author: "37signals", everyone_access: true).tap do |book|
+          with_attachment("writebook-manual.jpg") { |attachment| book.cover.attach(attachment) }
+          book.update_access(readers: [], editors: [ user.id ])
+        end
+      end
+
+      def load_markdown_pages(book)
+        pages = {}
+
+        Dir.glob(Rails.root.join("app/assets/markdown/demo/*.md")).each do |fname|
+          front_matter = FrontMatterParser::Parser.parse_file(fname)
+
+          if front_matter["class"] == "Section"
+            load_section(book, front_matter)
+          else
+            page = load_markdown_page(book, front_matter)
+            attach_images(page)
+            pages[page.leaf.slug] = page
+          end
+        end
+
+        book.leaves.pages.each { |leaf| localize_ref_links(leaf.page, pages) }
+      end
+
+      def load_markdown_page(book, front_matter)
+        book.press(Page.new(body: front_matter.content), title: front_matter["title"]).page
+      end
+
+      def load_section(book, front_matter)
+        book.press Section.new(body: front_matter.content, theme: front_matter["theme"]), title: front_matter["title"]
+      end
+
+      def attach_images(page)
+        re = %r{
+          \/u\/           # leading portion of path
+          (\S+-\w+\.\w+)  # filename including slug and extension
+        }x
+
+        body = page.body.content.gsub(re) do |match|
+          with_attachment($1) { |attachment| page.body.uploads.attach(attachment) }
+
+          attachment = page.body.uploads.attachments.last
+          attachment.analyze
+
+          "/u/" + attachment.slug
+        end
+
+        page.update!(body: body)
+      end
+
+      def localize_ref_links(page, pages)
+        re = %r{
+          (\[.+\])              # link title
+          \(                    # opening paren
+          \/\d+\/[\w-]+\/\d+\/  # leading portion of path
+          ([\w-]+)              # leaf slug
+        }x
+
+        body = page.body.content.gsub(re) do |match|
+          link_title, leaf_slug, anchor = $1, $2, $3
+          linked_page = pages[leaf_slug]
+          raise "Invalid reference link: #{page_title}" unless linked_page.present?
+
+          url = Rails.application.routes.url_helpers.leafable_slug_path(linked_page.leaf, anchor: anchor, only_path: true)
+
+          "#{link_title}(#{url}"
+        end
+
+        page.update!(body: body)
+      end
+
+      def with_attachment(filename)
+        File.open(Rails.root.join("app/assets/images/demo/#{filename}")) do |file|
+          yield io: file, filename: filename
+        end
+      end
+  end
+end