Optimisation no 4: cache device totals for 5min

front/php/server/devices.php

@@ -478,6 +478,14 @@ function PiaToggleArpScan() {
 //  Query total numbers of Devices by status
 //------------------------------------------------------------------------------
 function getDevicesTotals() {
+
+  $resultJSON = "";
+
+  if(getCache("getDevicesTotals") != "")
+  {
+    $resultJSON = getCache("getDevicesTotals");
+  } else
+  {
     global $db;
 
     // combined query
@@ -492,8 +500,13 @@ function getDevicesTotals() {
     ');
 
     $row = $result -> fetchArray (SQLITE3_NUM); 
+    $resultJSON = json_encode (array ($row[0], $row[1], $row[2], $row[3], $row[4], $row[5]));
 
-  echo (json_encode (array ($row[0], $row[1], $row[2], $row[3], $row[4], $row[5])));
+    // save to cache
+    setCache("getDevicesTotals", $resultJSON );
+  }  
+
+  echo ($resultJSON);
 }
 
 
@@ -798,4 +811,21 @@ function getDeviceCondition ($deviceStatus) {
   }
 }
 
+//------------------------------------------------------------------------------
+//  Simple cookie cache
+//------------------------------------------------------------------------------
+function getCache($key) {
+  if( isset($_COOKIE[$key]))
+  {
+    return $_COOKIE[$key];
+  }else
+  {
+    return "";
+  }
+}
+
+function setCache($key, $value) {
+  setcookie($key,  $value, time()+300, "/","", 0); // 5min cache
+}
+
 ?>