1 files changed, 47 insertions, 0 deletions
diff --git a/lib/gitlab/markdown/filter/upload_link_filter.rb b/lib/gitlab/markdown/filter/upload_link_filter.rb
new file mode 100644
index 00000000000..fbada73ab86
--- /dev/null
+++ b/lib/gitlab/markdown/filter/upload_link_filter.rb
@@ -0,0 +1,47 @@
+require 'gitlab/markdown'
+require 'html/pipeline/filter'
+require 'uri'
+
+module Gitlab
+  module Markdown
+    # HTML filter that "fixes" relative upload links to files.
+    # Context options:
+    #   :project (required) - Current project
+    #
+    class UploadLinkFilter < HTML::Pipeline::Filter
+      def call
+        doc.search('a').each do |el|
+          process_link_attr el.attribute('href')
+        end
+
+        doc.search('img').each do |el|
+          process_link_attr el.attribute('src')
+        end
+
+        doc
+      end
+
+      protected
+
+      def process_link_attr(html_attr)
+        return if html_attr.blank?
+
+        uri = html_attr.value
+        if uri.starts_with?("/uploads/")
+          html_attr.value = build_url(uri).to_s
+        end
+      end
+
+      def build_url(uri)
+        File.join(Gitlab.config.gitlab.url, context[:project].path_with_namespace, uri)
+      end
+
+      # Ensure that a :project key exists in context
+      #
+      # Note that while the key might exist, its value could be nil!
+      def validate
+        needs :project
+      end
+    end
+  end
+end