1 files changed, 86 insertions, 0 deletions
diff --git a/lib/gitlab/github_import/markdown/attachment.rb b/lib/gitlab/github_import/markdown/attachment.rb
new file mode 100644
index 00000000000..a5cf5ffa60e
--- /dev/null
+++ b/lib/gitlab/github_import/markdown/attachment.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module GithubImport
+    module Markdown
+      class Attachment
+        MEDIA_TYPES = %w[gif jpeg jpg mov mp4 png svg webm].freeze
+        DOC_TYPES = %w[
+          csv docx fodg fodp fods fodt gz log md odf odg odp ods
+          odt pdf pptx tgz txt xls xlsx zip
+        ].freeze
+
+        class << self
+          # markdown_node - CommonMarker::Node
+          def from_markdown(markdown_node)
+            case markdown_node.type
+            when :html, :inline_html
+              from_inline_html(markdown_node)
+            when :image
+              from_markdown_image(markdown_node)
+            when :link
+              from_markdown_link(markdown_node)
+            end
+          end
+
+          private
+
+          def from_markdown_image(markdown_node)
+            url = markdown_node.url
+
+            return unless github_url?(url, media: true)
+            return unless whitelisted_type?(url, media: true)
+
+            new(markdown_node.to_plaintext.strip, url)
+          end
+
+          def from_markdown_link(markdown_node)
+            url = markdown_node.url
+
+            return unless github_url?(url, docs: true)
+            return unless whitelisted_type?(url, docs: true)
+
+            new(markdown_node.to_plaintext.strip, url)
+          end
+
+          def from_inline_html(markdown_node)
+            img = Nokogiri::HTML.parse(markdown_node.string_content).xpath('//img')[0]
+
+            return unless img
+            return unless github_url?(img[:src], media: true)
+            return unless whitelisted_type?(img[:src], media: true)
+
+            new(img[:alt], img[:src])
+          end
+
+          def github_url?(url, docs: false, media: false)
+            if media
+              url.start_with?(::Gitlab::GithubImport::MarkdownText::GITHUB_MEDIA_CDN)
+            elsif docs
+              url.start_with?(::Gitlab::GithubImport::MarkdownText.github_url)
+            end
+          end
+
+          def whitelisted_type?(url, docs: false, media: false)
+            if media
+              MEDIA_TYPES.any? { |type| url.end_with?(type) }
+            elsif docs
+              DOC_TYPES.any? { |type| url.end_with?(type) }
+            end
+          end
+        end
+
+        attr_reader :name, :url
+
+        def initialize(name, url)
+          @name = name
+          @url = url
+        end
+
+        def inspect
+          "<#{self.class.name}: { name: #{name}, url: #{url} }>"
+        end
+      end
+    end
+  end
+end