100% non-blocking using our awesome API

api.php

@@ -80,6 +80,10 @@
         $data = array_merge($data, getGravity());
     }
 
+    if (isset($_GET['tailLog'])) {
+        $data = array_merge($data, tailPiholeLog($_GET['tailLog']));
+    }
+
     function filterArray(&$inArray) {
 	    $outArray = array();
 	    foreach ($inArray as $key=>$value) {

data.php

@@ -293,6 +293,33 @@
         return $allQueries;
     }
 
+    function tailPiholeLog($param) {
+        // Not using SplFileObject here, since direct
+        // usage of f-streams will be much faster for
+        // files as large as the pihole.log
+        global $logListName;
+        $file = fopen($logListName,"r");
+        $offset = intval($param);
+        if($offset > 0)
+        {
+            // Seeks on the file pointer where we want to continue reading is known
+            fseek($file, $offset);
+            $lines = [];
+            while (!feof($file)) {
+                array_push($lines,fgets($file));
+            }
+            return ["offset" => ftell($file), "lines" => $lines];
+        }
+        else
+        {
+            // Locate the current position of the file read/write pointer
+            fseek($file, -1, SEEK_END);
+            // Add one to skip the very last "\n" in the log file
+            return ["offset" => ftell($file)+1];
+        }
+        fclose($file);
+    }
+
     /******** Private Members ********/
     function gravityCount() {
         global $gravityListName,$blackListFile;

js/pihole/taillog.js

@@ -1,30 +1,29 @@
-var source;
-function eventsource() {
-    var ta = $("#output");
-    source = new EventSource("php/taillog.php");
+var offset, timer, pre;
 
-    ta.html("");
-    ta.show();
+// Check every 200msec for fresh data
+var interval = 200;
 
-    source.addEventListener("message", function(e) {
-        if(e.data.indexOf("Ctrl-C") === -1)
-        {
-            // Hide the "Press Ctrl-C to exit" message
-            ta.append(e.data);
-        }
-
-    }, false);
-
-    // Will be called when script has finished
-    source.addEventListener("error", function(e) {
-        source.close();
-    }, false);
+// Function that asks the API for new data
+function reloadData(){
+  clearTimeout(timer);
+  $.getJSON("api.php?tailLog="+offset, function (data)
+    {
+      offset = data["offset"];
+      pre.append(data["lines"]);
+      console.log(offset);
+    });
+  timer = setTimeout(reloadData, interval);
 }
 
 $(function(){
-    eventsource();
+  // Get offset at first loading of page
+  $.getJSON("api.php?tailLog", function (data)
+    {
+      offset = data["offset"];
+      console.log(offset);
+    });
+  pre = $("#output");
+  // Trigger function that looks for new data
+  reloadData();
 });
 
-$(window).unload(function(){
-  source.close();
-});

php/taillog.php

@@ -1,23 +0,0 @@
-<?php
-require "password.php";
-if(!$auth) die("Not authorized");
-
-ob_end_flush();
-ini_set("output_buffering", "0");
-ob_implicit_flush(true);
-header('Content-Type: text/event-stream');
-header('Cache-Control: no-cache');
-
-function echoEvent($datatext) {
-    echo "data: ".implode("\ndata: ", explode("\n", $datatext))."\n\n";
-}
-
-// echoEvent("***START***");
-
-$proc = popen("sudo pihole -t", 'r');
-while (!feof($proc)) {
-    echoEvent(fread($proc, 4096));
-}
-
-// echoEvent("***END***");
-?>

taillog.php

@@ -6,7 +6,7 @@
     <h1>Output the last lines of the pihole.log file (live)</h1>
 </div>
 
-<pre id="output" style="width: 100%; height: 100%;" hidden="true"></pre>
+<pre id="output" style="width: 100%; height: 100%;"></pre>
 
 <?php
     require "footer.php";