2 files changed, 49 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/previewer/pdf_previewer.rb b/activestorage/lib/active_storage/previewer/pdf_previewer.rb
new file mode 100644
index 0000000000..b84aefcc9c
--- /dev/null
+++ b/activestorage/lib/active_storage/previewer/pdf_previewer.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  class Previewer::PDFPreviewer < Previewer
+    class_attribute :mutool_path, default: "mutool"
+
+    def self.accept?(blob)
+      blob.content_type == "application/pdf"
+    end
+
+    def preview
+      download_blob_to_tempfile do |input|
+        draw_first_page_from input do |output|
+          yield io: output, filename: "#{blob.filename.base}.png", content_type: "image/png"
+        end
+      end
+    end
+
+    private
+      def draw_first_page_from(file, &block)
+        draw mutool_path, "draw", "-F", "png", "-o", "-", file.path, "1", &block
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/previewer/video_previewer.rb b/activestorage/lib/active_storage/previewer/video_previewer.rb
new file mode 100644
index 0000000000..5d06e33f44
--- /dev/null
+++ b/activestorage/lib/active_storage/previewer/video_previewer.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  class Previewer::VideoPreviewer < Previewer
+    class_attribute :ffmpeg_path, default: "ffmpeg"
+
+    def self.accept?(blob)
+      blob.video?
+    end
+
+    def preview
+      download_blob_to_tempfile do |input|
+        draw_relevant_frame_from input do |output|
+          yield io: output, filename: "#{blob.filename.base}.png", content_type: "image/png"
+        end
+      end
+    end
+
+    private
+      def draw_relevant_frame_from(file, &block)
+        draw ffmpeg_path, "-i", file.path, "-y", "-vcodec", "png",
+          "-vf", "thumbnail", "-vframes", "1", "-f", "image2", "-", &block
+      end
+  end
+end