Update Markdown renderer to be more flexible

guides/rails_guides/markdown.rb

@@ -8,10 +8,12 @@ def initialize(view, layout)
       @view = view
       @layout = layout
       @index_counter = Hash.new(0)
+      @raw_header = ''
     end
 
     def render(body)
-      @raw_header, _, @raw_body = body.partition(/^\-{40,}$/).map(&:strip)
+      @raw_body = body
+      extract_raw_header_and_body
       generate_header
       generate_title
       generate_body
@@ -36,6 +38,12 @@ def engine
         })
       end
 
+      def extract_raw_header_and_body
+        if @raw_body =~ /^\-{40,}$/
+          @raw_header, _, @raw_body = @raw_body.partition(/^\-{40,}$/).map(&:strip)
+        end
+      end
+
       def generate_body
         @body = engine.render(@raw_body)
       end
@@ -46,6 +54,7 @@ def generate_header
 
       def generate_structure
         @raw_index = ''
+        if @body.present?
           @body = Nokogiri::HTML(@body).tap do |doc|
             hierarchy = []
 
@@ -73,8 +82,10 @@ def generate_structure
             end
           end.to_html
         end
+      end
 
       def generate_index
+        if @raw_index.present?
           @index = Nokogiri::HTML(engine.render(@raw_index)).tap do |doc|
             doc.at('ol')[:class] = 'chapters'
           end.to_html
@@ -86,9 +97,14 @@ def generate_index
           </div>
           INDEX
         end
+      end
 
       def generate_title
-        @title = "Ruby on Rails Guides: #{Nokogiri::HTML(@header).at(:h2).text}".html_safe
+        if heading = Nokogiri::HTML(@header).at(:h2)
+          @title = "Ruby on Rails Guides: #{heading.text}".html_safe
+        else
+          @title = "Ruby on Rails Guides"
+        end
       end
 
       def node_index(hierarchy)
@@ -110,7 +126,7 @@ def node_index(hierarchy)
       def render_page
         @view.content_for(:header_section) { @header }
         @view.content_for(:page_title) { @title }
-        @view.content_for(:index_section) { @index.html_safe }
+        @view.content_for(:index_section) { @index }
         @view.render(:layout => @layout, :text => @body)
       end
   end