added nofollow links to all user content that dont link to coderwall

Author: mdeiters

Gemfile

@@ -38,7 +38,7 @@ source 'https://rubygems.org' do
   gem 'omniauth-twitter', '~> 0.0.16'
 
 # Markdown
-  gem 'redcarpet' #markdown processing
+  gem 'redcarpet', ">=3.3.4"
   gem 'kramdown'
   gem 'github-markdown'
 

Gemfile.lock

@@ -503,7 +503,7 @@ GEM
       ffi (>= 0.5.0)
     rdoc (3.12.2)
       json (~> 1.4)
-    redcarpet (3.3.2)
+    redcarpet (3.3.4)
     redis (3.2.1)
     redis-actionpack (3.2.4)
       actionpack (~> 3.2.0)
@@ -776,7 +776,7 @@ DEPENDENCIES
   rails_12factor!
   rails_latest!
   rakismet!
-  redcarpet!
+  redcarpet (>= 3.3.4)!
   redis-rails (= 3.2.4)!
   rest-client!
   rspec-rails!

lib/cfm.rb

@@ -5,16 +5,37 @@ module CFM
   class Markdown
     class << self
       def render(text)
-        renderer = Redcarpet::Render::HTML.new
-        extensions = {fenced_code_blocks: true, strikethrough: true, autolink: true}
+        return nil if text.nil?
+
+        extensions = {
+          fenced_code_blocks: true,
+          strikethrough: true,
+          autolink: true
+        }
+
+        renderer  = Redcarpet::Render::HTML.new(  link_attributes: {rel: "nofollow"})
         redcarpet = Redcarpet::Markdown.new(renderer, extensions)
-        redcarpet.render(render_cfm(text)) unless text.nil?
+        html      = redcarpet.render(render_cfm(text))
+        html      = add_nofollow(html)
+        html
       end
 
       USERNAME_BLACKLIST = %w(include)
 
       private
 
+      def add_nofollow( html)
+        #redcarpet isn't adding nofollow like it is suppose to.
+       html.scan(/(\<a href=["'].*?["']\>.*?\<\/a\>)/).flatten.each do |link|
+         if link.match(/\<a href=["'](http:\/\/|www){0,1}((coderwall.com)(\/.*?){0,1}|\/.*?)["']\>(.*?)\<\/a\>/)
+          else
+          link.match(/(\<a href=["'](.*?)["']\>(.*?)\<\/a\>)/)
+          html.gsub!(link, "<a href='#{$2}' rel='nofollow' >#{$3}</a>" )
+          end
+        end
+        html
+      end
+
       def render_cfm(text)
         text.lines.map do |x|
           inspect_line(x)