1 files changed, 45 insertions, 0 deletions
diff --git a/lib/gitlab/pagination/keyset/header_builder.rb b/lib/gitlab/pagination/keyset/header_builder.rb
new file mode 100644
index 00000000000..69c468207f6
--- /dev/null
+++ b/lib/gitlab/pagination/keyset/header_builder.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Pagination
+    module Keyset
+      class HeaderBuilder
+        attr_reader :request_context
+        delegate :params, :header, :request, to: :request_context
+
+        def initialize(request_context)
+          @request_context = request_context
+        end
+
+        def add_next_page_header(query_params)
+          link = next_page_link(page_href(query_params))
+          header('Links', link)
+          header('Link', link)
+        end
+
+        private
+
+        def next_page_link(href)
+          %(<#{href}>; rel="next")
+        end
+
+        def page_href(query_params)
+          base_request_uri.tap do |uri|
+            uri.query = updated_params(query_params).to_query
+          end.to_s
+        end
+
+        def base_request_uri
+          @base_request_uri ||= URI.parse(request.url).tap do |uri|
+            uri.host = Gitlab.config.gitlab.host
+            uri.port = Gitlab.config.gitlab.port
+          end
+        end
+
+        def updated_params(query_params)
+          params.merge(query_params)
+        end
+      end
+    end
+  end
+end