Add linkfilter logic to existing renderers

app/helpers/markdown_helper.rb

@@ -15,6 +15,11 @@ module MarkdownHelper
     CGI.unescape_html(Sanitize.fragment(md.render(content), EVIL_TAGS)).strip
   end
 
+  def question_markdown(content)
+    md = Redcarpet::Markdown.new(QuestionMarkdown.new, MARKDOWN_OPTS)
+    Sanitize.fragment(md.render(content), EVIL_TAGS).html_safe
+  end
+
   def raw_markdown(content)
     md = Redcarpet::Markdown.new(Redcarpet::Render::HTML, RAW_MARKDOWN_OPTS)
     raw md.render content

app/services/flavored_markdown.rb

@@ -1,5 +1,6 @@
 class FlavoredMarkdown < Redcarpet::Render::HTML
   include Rails.application.routes.url_helpers
+  include SharedMarkers
 
   def preprocess(text)
     wrap_mentions(text)

app/services/shared_markers.rb

@@ -0,0 +1,9 @@
+module SharedMarkers
+  def autolink(link, _link_type)
+    if ALLOWED_HOSTS.include? URI(link).host
+      return "<a href=\"#{link}\" target=\"_blank\">#{link}</a>"
+    end
+
+    "<a href=\"#{linkfilter_path(url: link)}\" target=\"_blank\">#{link}</a>"
+  end
+end

config/initializers/redcarpet.rb

@@ -25,3 +25,8 @@ RAW_MARKDOWN_OPTS = {
   strikethrough: true,
   superscript: false
 }
+
+ALLOWED_HOSTS = [
+  APP_CONFIG['hostname'],
+  *APP_CONFIG['allowed_hosts']
+]

config/justask.yml.example

@@ -73,5 +73,12 @@ accepted_image_formats:
   - image/gif
   - .gif
 
+# This list controls which hosts are excempt from the linkfilter
+# Note: `hostname` is always included by default
+allowed_hosts:
+  - twitter.com
+  - youtube.com
+  - youtu.be
+
 # Sentry connection string
 sentry_dsn: ''