Refresh rate implementation

examples/dummy-web-server.pl

@@ -423,6 +423,17 @@ sub process_user_comm_led
   return content_response($r, $http->{url});
 }
 
+sub process_user_comm_voltage
+{
+  my ($http) = @_;
+
+  my $voltage = (((time - $startTime) % 60) - 30) / 30.0 + 4.0;
+  $voltage = sprintf("%.2f V", $voltage);
+  
+  my $r = '{"voltage": "' . $voltage . '"}';
+  return content_response($r, $http->{url});
+}
+
 sub process_user_comm()
 {
   my ($http) = @_;
@@ -431,4 +442,9 @@ sub process_user_comm()
   {
     return process_user_comm_led($http);
   }
+
+  if( $http->{url} eq '/Voltage.html.json' )
+  {
+    return process_user_comm_voltage($http);
+  }
 }

examples/web-server/Voltage.html

@@ -0,0 +1,10 @@
+  <meta name="refresh-rate" content="500" />
+  
+  <div class="header">
+    <h1>Voltage measurement</h1>
+  </div>
+
+  <div class="content">
+    <p id="voltage" align="center" style="font-size: 800%"/>
+  </div>
+</body></html>

html/userpage.js

@@ -1,6 +1,8 @@
 //===== Java script for user pages
 
 var loadCounter = 0;
+var refreshRate = 0;
+var refreshTimer;
 
 function notifyResponse( data )
 {
@@ -42,6 +44,14 @@ function notifyResponse( data )
       }
     }
   });
+  
+  if( refreshRate != 0 )
+  {
+    clearTimeout(refreshTimer);
+    refreshTimer = setTimeout( function () {
+      ajaxJson("GET", window.location.pathname + ".json?reason=refresh", notifyResponse );
+    }, refreshRate );
+  }
 }
 
 function notifyButtonPressed( btnId )
@@ -101,6 +111,17 @@ document.addEventListener("DOMContentLoaded", function(){
     };
   }
 
+  // collect metas
+  var metas = document.getElementsByTagName("meta");
+
+  for (ndx = 0; ndx < metas.length; ndx++) {
+    var meta = metas[ndx];
+    if( meta.getAttribute("name") == "refresh-rate" )
+    {
+      refreshRate = meta.getAttribute("content");
+    }
+  }
+
   // load variables at first time
   var loadVariables = function() {
     ajaxJson("GET", window.location.pathname + ".json?reason=load", notifyResponse,