Extract API pagination code to a separete module

lib/api/helpers.rb

 module API
   module Helpers
     include Gitlab::Utils
+    include Helpers::Pagination
 
     PRIVATE_TOKEN_HEADER = "HTTP_PRIVATE_TOKEN"
     PRIVATE_TOKEN_PARAM = :private_token
@@ -131,12 +132,6 @@ module API
       IssuesFinder.new(current_user, project_id: user_project.id).find(id)
     end
 
-    def paginate(relation)
-      relation.page(params[:page]).per(params[:per_page].to_i).tap do |data|
-        add_pagination_headers(data)
-      end
-    end
-
     def authenticate!
       unauthorized! unless current_user
     end
@@ -367,38 +362,6 @@ module API
 
     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
-
     def secret_token
       Gitlab::Shell.secret_token
     end

lib/api/helpers/pagination.rb

+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