From a950ad136edf739d3d0e846e6398df46475c284d Mon Sep 17 00:00:00 2001
From: Benjamin Dauvergne <bdauvergne@entrouvert.com>
Date: Fri, 28 Sep 2018 12:36:36 +0200
Subject: [PATCH] do not refresh table when tab is invisible or user idle
 (#26804)

* refresh timer is cleared on tab invisible event
* refresh timer is cleared after 5 minutes of inactivity
* table is refreshed immediately when tab become visible and user has been inactive
more than 5 minutes
---
 wcs/qommon/static/js/wcs.listing.js | 42 +++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/wcs/qommon/static/js/wcs.listing.js b/wcs/qommon/static/js/wcs.listing.js
index c078bf00..9386c612 100644
--- a/wcs/qommon/static/js/wcs.listing.js
+++ b/wcs/qommon/static/js/wcs.listing.js
@@ -1,3 +1,26 @@
+/**
+ * vis() -> bool : is tab visible ?
+ * vis(aFunction) -> call aFunction on visibility change.
+ */
+var vis = (function(){
+    var stateKey, eventKey, keys = {
+        hidden: "visibilitychange",
+        webkitHidden: "webkitvisibilitychange",
+        mozHidden: "mozvisibilitychange",
+        msHidden: "msvisibilitychange"
+    };
+    for (stateKey in keys) {
+        if (stateKey in document) {
+            eventKey = keys[stateKey];
+            break;
+        }
+    }
+    return function(c) {
+        if (c) document.addEventListener(eventKey, c);
+        return !document[stateKey];
+    }
+})();
+
 function prepare_page_links() {
   $('#page-links a').click(function() {
     $('form#listing-settings input[name="offset"]').val($(this).data('offset'));
@@ -190,9 +213,28 @@ $(function() {
 
   if ($('#statistics').length == 0) {
     var idle_id = null;
+    var longidle_id = null;
+    vis(function () {
+      if (! vis()) {
+        /* stop refreshing in invisible tabs */
+        if (idle_id) idle_id = window.clearInterval(idle_id);
+      } else {
+        /* if tab invisible for more than 5 minutes, refresh now */
+        if (! longidle_id) autorefresh_table();
+      }
+    }
     $(window).on('mousemove keydown mousedown touchstart', function() {
+      /* if refresh timer exists, clear it */
       if (idle_id) window.clearInterval(idle_id);
+      /* if stop refresh timer exists, clear it */
+      if (longidle_id) window.clearTimeout(longidle_id);
+      /* launch timer to refresh every 30 seconds */
       idle_id = setInterval(autorefresh_table, 30000);
+      /* launch timer to stop refresh after 5 minutes idle */
+      longidle_id = setTimeout(function () {
+          if (idle_id) idle_id = window.clearInterval(idle_id);
+          longidle_id = undefined;
+      }, 300 * 1000);
     });
   }
 
-- 
2.20.1