4 files changed, 67 insertions, 7 deletions
diff --git a/lib/banzai/filter/relative_link_filter.rb b/lib/banzai/filter/relative_link_filter.rb
index c78da404607..337fb50317d 100644
--- a/lib/banzai/filter/relative_link_filter.rb
+++ b/lib/banzai/filter/relative_link_filter.rb
@@ -20,7 +20,7 @@ module Banzai
           process_link_attr el.attribute('href')
         end
 
-        doc.search('img').each do |el|
+        doc.css('img, video').each do |el|
           process_link_attr el.attribute('src')
         end
 
@@ -112,8 +112,7 @@ module Banzai
       end
 
       def current_commit
-        @current_commit ||= context[:commit] ||
-          ref ? repository.commit(ref) : repository.head_commit
+        @current_commit ||= context[:commit] || ref ? repository.commit(ref) : repository.head_commit
       end
 
       def relative_url_root
diff --git a/lib/banzai/filter/video_link_filter.rb b/lib/banzai/filter/video_link_filter.rb
new file mode 100644
index 00000000000..fd8b9a6f0cc
--- /dev/null
+++ b/lib/banzai/filter/video_link_filter.rb
@@ -0,0 +1,59 @@
+module Banzai
+  module Filter
+
+    # Find every image that isn't already wrapped in an `a` tag, and that has
+    # a `src` attribute ending with a video extension, add a new video node and
+    # a "Download" link in the case the video cannot be played.
+    class VideoLinkFilter < HTML::Pipeline::Filter
+
+      def call
+        doc.xpath(query).each do |el|
+          el.replace(video_node(doc, el))
+        end
+
+        doc
+      end
+
+      private
+
+      def query
+        @query ||= begin
+          src_query = UploaderHelper::VIDEO_EXT.map do |ext|
+            "'.#{ext}' = substring(@src, string-length(@src) - #{ext.size})"
+          end
+
+          "descendant-or-self::img[not(ancestor::a) and (#{src_query.join(' or ')})]"
+        end
+      end
+
+      def video_node(doc, element)
+        container = doc.document.create_element(
+          'div',
+          class: 'video-container'
+        )
+
+        video = doc.document.create_element(
+          'video',
+          src: element['src'],
+          width: '400',
+          controls: true,
+          'data-setup' => '{}')
+
+        link = doc.document.create_element(
+          'a',
+          element['title'] || element['alt'],
+          href: element['src'],
+          target: '_blank',
+          title: "Download '#{element['title'] || element['alt']}'")
+        download_paragraph = doc.document.create_element('p')
+        download_paragraph.children = link
+
+        container.add_child(video)
+        container.add_child(download_paragraph)
+
+        container
+      end
+    end
+
+  end
+end
diff --git a/lib/banzai/pipeline/gfm_pipeline.rb b/lib/banzai/pipeline/gfm_pipeline.rb
index b27ecf3c923..8d94b199c66 100644
--- a/lib/banzai/pipeline/gfm_pipeline.rb
+++ b/lib/banzai/pipeline/gfm_pipeline.rb
@@ -7,6 +7,7 @@ module Banzai
           Filter::SanitizationFilter,
 
           Filter::UploadLinkFilter,
+          Filter::VideoLinkFilter,
           Filter::ImageLinkFilter,
           Filter::EmojiFilter,
           Filter::TableOfContentsFilter,
diff --git a/lib/banzai/reference_extractor.rb b/lib/banzai/reference_extractor.rb
index bf366962aef..b26a41a1f3b 100644
--- a/lib/banzai/reference_extractor.rb
+++ b/lib/banzai/reference_extractor.rb
@@ -2,11 +2,11 @@ module Banzai
   # Extract possible GFM references from an arbitrary String for further processing.
   class ReferenceExtractor
     def initialize
-      @texts = []
+      @texts_and_contexts = []
     end
 
     def analyze(text, context = {})
-      @texts << Renderer.render(text, context)
+      @texts_and_contexts << { text: text, context: context }
     end
 
     def references(type, project, current_user = nil)
@@ -21,9 +21,10 @@ module Banzai
     def html_documents
       # This ensures that we don't memoize anything until we have a number of
       # text blobs to parse.
-      return [] if @texts.empty?
+      return [] if @texts_and_contexts.empty?
 
-      @html_documents ||= @texts.map { |html| Nokogiri::HTML.fragment(html) }
+      @html_documents ||= Renderer.cache_collection_render(@texts_and_contexts)
+        .map { |html| Nokogiri::HTML.fragment(html) }
     end
   end
 end