optimisations #2, basic session cache for some dropdowns

back/pialert.py

@@ -1576,6 +1576,9 @@ def upgradeDB ():
       ALTER TABLE "Devices" ADD "dev_Network_Node_port" INTEGER 
       """)
 
+    # don't hog DB access  
+    closeDB ()
+
 #-------------------------------------------------------------------------------
 
 def openDB ():
@@ -1591,6 +1594,7 @@ def openDB ():
 
     # Open DB and Cursor
     sql_connection = sqlite3.connect (DB_PATH, isolation_level=None)
+    sql_connection.execute('pragma journal_mode=wal') #
     sql_connection.text_factory = str
     sql_connection.row_factory = sqlite3.Row
     sql = sql_connection.cursor()

front/deviceDetails.php

@@ -815,28 +815,34 @@ function initializeiCheck () {
 // -----------------------------------------------------------------------------
 function initializeCombos () {
   // Initialize combos with queries
-  initializeCombo ( $('#dropdownOwner')[0],                      'getOwners',       'txtOwner');
-  initializeCombo ( $('#dropdownDeviceType')[0],                 'getDeviceTypes',  'txtDeviceType');
-  initializeCombo ( $('#dropdownGroup')[0],                      'getGroups',       'txtGroup');
-  initializeCombo ( $('#dropdownLocation')[0],                   'getLocations',    'txtLocation');
-  initializeCombo ( $('#dropdownNetworkNodeMac')[0],             'getNetworkNodes', 'txtNetworkNodeMac');
+  initializeCombo ( '#dropdownOwner',                      'getOwners',       'txtOwner', true);
+  initializeCombo ( '#dropdownDeviceType',                 'getDeviceTypes',  'txtDeviceType', true);
+  initializeCombo ( '#dropdownGroup',                      'getGroups',       'txtGroup', true);
+  initializeCombo ( '#dropdownLocation',                   'getLocations',    'txtLocation', true);
+  initializeCombo ( '#dropdownNetworkNodeMac',             'getNetworkNodes', 'txtNetworkNodeMac', false);
 
   // Initialize static combos
   initializeComboSkipRepeated ();
 }
 
-function initializeCombo (HTMLelement, queryAction, txtDataField) {
+function initializeCombo (dropdownId, queryAction, txtDataField, useCache) {
+
+  // check if we have the value cached already
+  var dropdownHtmlContent = useCache ? getCache(dropdownId) : ""; 
+
+  if(dropdownHtmlContent == "")
+  {
     // get data from server
     $.get('php/server/devices.php?action='+queryAction, function(data) {
       var listData = JSON.parse(data);
       var order = 1;
       
-    HTMLelement.innerHTML = ''
+
       // for each item
       listData.forEach(function (item, index) {
         // insert line divisor
         if (order != item['order']) {
-        HTMLelement.innerHTML += '<li class="divider"></li>';
+          dropdownHtmlContent += '<li class="divider"></li>';
           order = item['order'];
         }
 
@@ -848,11 +854,46 @@ function initializeCombo (HTMLelement, queryAction, txtDataField) {
         }
 
         // add dropdown item
-      HTMLelement.innerHTML +=
+        dropdownHtmlContent +=
           '<li><a href="javascript:void(0)" onclick="setTextValue(\''+
           txtDataField +'\',\''+ id +'\')">'+ item['name'] + '</a></li>'
       });
+
+      writeDropdownHtml(dropdownId, dropdownHtmlContent)
     });
+  } else
+  {
+    writeDropdownHtml(dropdownId, dropdownHtmlContent)
+  }
+}
+
+// write out the HTML for the dropdown
+function writeDropdownHtml(dropdownId, dropdownHtmlContent)
+{
+  // cache
+  setCache(dropdownId, dropdownHtmlContent);
+
+  // write HTML for the dropdown
+  var HTMLelement = $(dropdownId)[0];
+  HTMLelement.innerHTML = ''
+  HTMLelement.innerHTML += dropdownHtmlContent;
+}
+
+function getCache(key)
+{
+  // check cache
+  if(sessionStorage.getItem(key))
+  {
+    return sessionStorage.getItem(key);
+  } else
+  {
+    return "";
+  }
+}
+
+function setCache(key, data)
+{
+  sessionStorage.setItem(key, data); 
 }