X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/e2fe6c0e5c1c62a37e03519590c04a5186a2cc9b..b6f73f7acffa9b2f37c78826ff6cee89987a7edc:/apps/workbench/app/controllers/projects_controller.rb

diff --git a/apps/workbench/app/controllers/projects_controller.rb b/apps/workbench/app/controllers/projects_controller.rb
index 857ab611b7..600af8d60b 100644
--- a/apps/workbench/app/controllers/projects_controller.rb
+++ b/apps/workbench/app/controllers/projects_controller.rb
@@ -183,7 +183,13 @@ class ProjectsController < ApplicationController
       # page, and use the last item on this page as a filter for
       # retrieving the next page. Ideally the API would do this for
       # us, but it doesn't (yet).
-      nextpage_operator = /\bdesc$/i =~ @order[0] ? '<' : '>'
+
+      # To avoid losing items that have the same created_at as the
+      # last item on this page, we retrieve an overlapping page with a
+      # "created_at <= last_created_at" filter, then remove duplicates
+      # with a "uuid not in [...]" filter (see below).
+      nextpage_operator = /\bdesc$/i =~ @order[0] ? '<=' : '>='
+
       @objects = []
       @name_link_for = {}
       kind_filters.each do |attr,op,val|
@@ -200,46 +206,26 @@ class ProjectsController < ApplicationController
         end
       end
       @objects = @objects.to_a.sort_by(&:created_at)
-      @objects.reverse! if nextpage_operator == '<'
+      @objects.reverse! if nextpage_operator == '<='
       @objects = @objects[0..@limit-1]
       @next_page_filters = @filters.reject do |attr,op,val|
-        attr == 'created_at' and op == nextpage_operator
-      end
-
-      # We are using created_at time slightly greater/lower than the last object created_at (see next block comment).
-      # This would mean that the server would now return the previous last item(s) with matching created_at again.
-      # Hence, we need to remove the previous last_uuids from results before displaying the rest of the results
-      # to prevent "infinite" infinite scrolling.
-      if params['last_uuids'] and @objects.any?
-        last_uuids = JSON.parse params['last_uuids']
-        @objects.reject! do |obj|
-          last_uuids.include? obj.uuid
-        end
+        (attr == 'created_at' and op == nextpage_operator) or
+          (attr == 'uuid' and op == 'not in')
       end
 
       if @objects.any?
         last_created_at = @objects.last.created_at
 
-        last_uuids = [] if (last_created_at != params[:last_created_at])
+        last_uuids = []
         @objects.each do |obj|
           last_uuids << obj.uuid if obj.created_at.eql?(last_created_at)
         end
 
-        # In order to prevent losing item(s) that have the same created_at time as the current page last item,
-        # next page should look for objects with created_at time slightly greater/lower than the current last,
-        # and remove them if they are part of previous page's last_uuids (see the previous block)
-        if nextpage_operator == '<'
-          last_created_at += 1
-        else
-          last_created_at -= 1
-        end
-
         @next_page_filters += [['created_at',
                                 nextpage_operator,
                                 last_created_at]]
+        @next_page_filters += [['uuid', 'not in', last_uuids]]
         @next_page_href = url_for(partial: :contents_rows,
-                                  last_uuids: last_uuids.to_json,
-                                  last_created_at: @objects.last.created_at,
                                   limit: @limit,
                                   filters: @next_page_filters.to_json)
       else
@@ -251,7 +237,9 @@ class ProjectsController < ApplicationController
                                   include_linked: true,
                                   filters: @filters,
                                   offset: @offset)
-      @next_page_href = next_page_href(partial: :contents_rows, filters: @filters.to_json)
+      @next_page_href = next_page_href(partial: :contents_rows,
+                                       filters: @filters.to_json,
+                                       order: @order.to_json)
     end
 
     preload_links_for_objects(@objects.to_a)