1 files changed, 36 insertions, 0 deletions
diff --git a/lib/api/helpers/packages/dependency_proxy_helpers.rb b/lib/api/helpers/packages/dependency_proxy_helpers.rb
new file mode 100644
index 00000000000..254af7690a2
--- /dev/null
+++ b/lib/api/helpers/packages/dependency_proxy_helpers.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module API
+  module Helpers
+    module Packages
+      module DependencyProxyHelpers
+        REGISTRY_BASE_URLS = {
+          npm: 'https://registry.npmjs.org/'
+        }.freeze
+
+        def redirect_registry_request(forward_to_registry, package_type, options)
+          if forward_to_registry && redirect_registry_request_available?
+            redirect(registry_url(package_type, options))
+          else
+            yield
+          end
+        end
+
+        def registry_url(package_type, options)
+          base_url = REGISTRY_BASE_URLS[package_type]
+
+          raise ArgumentError, "Can't build registry_url for package_type #{package_type}" unless base_url
+
+          case package_type
+          when :npm
+            "#{base_url}#{options[:package_name]}"
+          end
+        end
+
+        def redirect_registry_request_available?
+          ::Gitlab::CurrentSettings.current_application_settings.npm_package_requests_forwarding
+        end
+      end
+    end
+  end
+end