setting to exclude rel nofollow from particular domains

app/models/site_setting.rb

@@ -30,8 +30,6 @@ class SiteSetting < ActiveRecord::Base
   client_setting(:max_topic_title_length, 255)
   client_setting(:flush_timings_secs, 5)
 
-
-
   # settings only available server side
   setting(:auto_track_topics_after, 60000)
   setting(:long_polling_interval, 15000)
@@ -92,6 +90,7 @@ class SiteSetting < ActiveRecord::Base
   setting(:allow_duplicate_topic_titles, false)
 
   setting(:add_rel_nofollow_to_user_content, true)
+  setting(:exclude_rel_nofollow_domains, '')
   setting(:post_excerpt_maxlength, 300)
   setting(:post_onebox_maxlength, 500)
   setting(:best_of_score_threshold, 15)

config/locales/en.yml

@@ -220,6 +220,7 @@ en:
     category_featured_topics: "number of topics displayed in the category list"
     popup_delay: "Length of time in ms before popups appear on the screen"
     add_rel_nofollow_to_user_content: "Add rel nofollow to all submitted user content, except for internal links (including parent domains) changing this requires you update all your baked markdown"
+    exclude_rel_nofollow_domains: "A comma delimited list of domains where nofollow is not added (tld.com will automatically allow sub.tld.com as well)"
     post_excerpt_maxlength: "Maximum length in chars of a post's excerpt."
     post_onebox_maxlength: "Maximum length of a oneboxed discourse post."
     category_post_template: "The post template that appears once you create a category"

lib/pretty_text.rb

@@ -180,6 +180,11 @@ module PrettyText
   end
   
   def self.add_rel_nofollow_to_user_content(html)
+    whitelist = []
+    l = SiteSetting.exclude_rel_nofollow_domains
+    if l.present?
+      whitelist = l.split(",") 
+    end
     site_uri = nil
     doc = Nokogiri::HTML.fragment(html)
     doc.css("a").each do |l|
@@ -188,7 +193,7 @@ module PrettyText
         uri = URI(href)
         site_uri ||= URI(Discourse.base_url)
         
-        if !uri.host.present? || uri.host.ends_with?(site_uri.host)
+        if !uri.host.present? || uri.host.ends_with?(site_uri.host) || whitelist.any?{|u| uri.host.ends_with?(u)}
           # we are good no need for nofollow
         else
           l["rel"] = "nofollow"

spec/components/pretty_text_spec.rb

@@ -79,6 +79,7 @@ test
   describe "rel nofollow" do
     before do 
       SiteSetting.stubs(:add_rel_nofollow_to_user_content).returns(true)
+      SiteSetting.stubs(:exclude_rel_nofollow_domains).returns("foo.com,bar.com")
     end
 
     it "should inject nofollow in all user provided links" do 
@@ -92,6 +93,14 @@ test
     it "should not inject nofollow in all subdomain links" do 
       (PrettyText.cook("<a href='#{Discourse.base_url.sub('http://', 'http://bla.')}/test.html'>cnn</a>") !~ /nofollow/).should be_true  
     end
+
+    it "should not inject nofollow for foo.com" do
+      (PrettyText.cook("<a href='http://foo.com/test.html'>cnn</a>") !~ /nofollow/).should be_true  
+    end
+    
+    it "should not inject nofollow for bar.foo.com" do
+      (PrettyText.cook("<a href='http://bar.foo.com/test.html'>cnn</a>") !~ /nofollow/).should be_true  
+    end
   end
 
   describe "Excerpt" do