From 02a5e7029e55d3b5d6a91a8d1949ca4a2199b35d Mon Sep 17 00:00:00 2001
From: Andreas Nedbal <git@pixelde.su>
Date: Thu, 30 Dec 2021 18:13:52 +0100
Subject: [PATCH] Add linkfilter logic to existing renderers

---
 app/helpers/markdown_helper.rb    | 5 +++++
 app/services/flavored_markdown.rb | 1 +
 app/services/shared_markers.rb    | 9 +++++++++
 config/initializers/redcarpet.rb  | 5 +++++
 config/justask.yml.example        | 7 +++++++
 5 files changed, 27 insertions(+)
 create mode 100644 app/services/shared_markers.rb

diff --git a/app/helpers/markdown_helper.rb b/app/helpers/markdown_helper.rb
index bc49c89b..23af88a1 100644
--- a/app/helpers/markdown_helper.rb
+++ b/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
diff --git a/app/services/flavored_markdown.rb b/app/services/flavored_markdown.rb
index a356d07e..0110954f 100644
--- a/app/services/flavored_markdown.rb
+++ b/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)
diff --git a/app/services/shared_markers.rb b/app/services/shared_markers.rb
new file mode 100644
index 00000000..556ce655
--- /dev/null
+++ b/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
\ No newline at end of file
diff --git a/config/initializers/redcarpet.rb b/config/initializers/redcarpet.rb
index da4a6a8e..031dcb13 100644
--- a/config/initializers/redcarpet.rb
+++ b/config/initializers/redcarpet.rb
@@ -25,3 +25,8 @@ RAW_MARKDOWN_OPTS = {
   strikethrough: true,
   superscript: false
 }
+
+ALLOWED_HOSTS = [
+  APP_CONFIG['hostname'],
+  *APP_CONFIG['allowed_hosts']
+]
\ No newline at end of file
diff --git a/config/justask.yml.example b/config/justask.yml.example
index 2d2d2f64..6a112f8e 100644
--- a/config/justask.yml.example
+++ b/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: ''