1 files changed, 45 insertions, 0 deletions
diff --git a/lib/api/helpers/pagination.rb b/lib/api/helpers/pagination.rb
new file mode 100644
index 00000000000..2199eea7e5f
--- /dev/null
+++ b/lib/api/helpers/pagination.rb
@@ -0,0 +1,45 @@
+module API
+  module Helpers
+    module Pagination
+      def paginate(relation)
+        relation.page(params[:page]).per(params[:per_page].to_i).tap do |data|
+          add_pagination_headers(data)
+        end
+      end
+
+      private
+
+      def add_pagination_headers(paginated_data)
+        header 'X-Total',       paginated_data.total_count.to_s
+        header 'X-Total-Pages', paginated_data.total_pages.to_s
+        header 'X-Per-Page',    paginated_data.limit_value.to_s
+        header 'X-Page',        paginated_data.current_page.to_s
+        header 'X-Next-Page',   paginated_data.next_page.to_s
+        header 'X-Prev-Page',   paginated_data.prev_page.to_s
+        header 'Link',          pagination_links(paginated_data)
+      end
+
+      def pagination_links(paginated_data)
+        request_url = request.url.split('?').first
+        request_params = params.clone
+        request_params[:per_page] = paginated_data.limit_value
+
+        links = []
+
+        request_params[:page] = paginated_data.current_page - 1
+        links << %(<#{request_url}?#{request_params.to_query}>; rel="prev") unless paginated_data.first_page?
+
+        request_params[:page] = paginated_data.current_page + 1
+        links << %(<#{request_url}?#{request_params.to_query}>; rel="next") unless paginated_data.last_page?
+
+        request_params[:page] = 1
+        links << %(<#{request_url}?#{request_params.to_query}>; rel="first")
+
+        request_params[:page] = paginated_data.total_pages
+        links << %(<#{request_url}?#{request_params.to_query}>; rel="last")
+
+        links.join(', ')
+      end
+    end
+  end
+end