From 0fd041a35372a0b5aed12be2be2097bddb66982b Mon Sep 17 00:00:00 2001
From: davidovski <david@davidovski.xyz>
Date: Fri, 25 Aug 2023 16:23:53 +0100
Subject: [PATCH] Add timeouts for failing instances

---
 config.php.example          |  3 +++
 engines/librex/fallback.php | 39 +++++++++++++++++++++++++------------
 misc/cooldowns.php          | 20 +++++++++++++++++++
 misc/search_engine.php      |  1 +
 4 files changed, 51 insertions(+), 12 deletions(-)
 create mode 100644 misc/cooldowns.php

diff --git a/config.php.example b/config.php.example
index f906c72..599278b 100644
--- a/config.php.example
+++ b/config.php.example
@@ -20,6 +20,9 @@
         // This may greatly increase the time it takes to get a result and in some cases results in 504 errors
         "instance_fallback" => false,
 
+        // how long in minutes to put google/other instances on cooldown if they aren't responding
+        "request_cooldown" => 5,
+
         /*
             Preset privacy friendly frontends for users, these can be overwritten by users in the settings
             e.g.: Preset the invidious instance URL: "instance_url" => "https://yewtu.be",
diff --git a/engines/librex/fallback.php b/engines/librex/fallback.php
index 7d5e6a1..5244c38 100644
--- a/engines/librex/fallback.php
+++ b/engines/librex/fallback.php
@@ -15,25 +15,38 @@
             $response = json_decode($response, true);
             if (!$response)
                 return array();
-            
+
             return array_values($response);
         }
     }
 
-
-    function get_librex_results($opts) {
-        if (!$opts->do_fallback)
-            return array();
-
+    function load_instances($cooldowns) {
         $instances_json = json_decode(file_get_contents("instances.json"), true);
 
         if (empty($instances_json["instances"]))
             return array();
 
-        // TODO pick instances which aren't on cooldown
-
         $instances = array_map(fn($n) => $n['clearnet'], array_filter($instances_json['instances'], fn($n) => !is_null($n['clearnet'])));
+        $instances = array_filter($instances, fn($n) => !has_cooldown($n, $cooldowns));
         shuffle($instances);
+        return $instances;
+    }
+
+    function get_librex_results($opts) {
+        if (!$opts->do_fallback)
+            return array();
+
+        require "misc/cooldowns.php";
+
+        $cooldowns = load_cooldowns();
+        error_log("loaded" . count($cooldowns));
+        error_log(print_r($cooldowns,true));
+
+        echo "<pre>";
+        print_r($cooldowns);
+        echo "</pre>";
+
+        $instances = load_instances($cooldowns);
 
         $results = array();
         $tries = 0;
@@ -43,6 +56,7 @@
 
             $instance = array_pop($instances);
 
+            error_log($instance .  "--- " . parse_url($instance)["host"]);
             if (parse_url($instance)["host"] == parse_url($_SERVER['HTTP_HOST'])["host"])
                 continue;
 
@@ -52,12 +66,13 @@
             if (count($results) > 1)
                 return $results;
 
-        } while ( !empty($instances));
+            // on fail then do this
+            $timeout = ($opts->request_cooldown ?? "1") * 60;
+            $cooldowns = set_cooldown($instance, $timeout, $cooldowns);
 
-        if (empty($instances))
-            return array();
+        } while (!empty($instances));
 
-        return array_values($results);
+        return array();
     }
 
 ?>
diff --git a/misc/cooldowns.php b/misc/cooldowns.php
new file mode 100644
index 0000000..975afc0
--- /dev/null
+++ b/misc/cooldowns.php
@@ -0,0 +1,20 @@
+<?php
+    function load_cooldowns() {
+        return apcu_exists("cooldowns") ? apcu_fetch("cooldowns") : array();
+    }
+
+    function save_cooldowns($cooldowns) {
+        apcu_store("cooldowns", $cooldowns);
+    }
+
+    function set_cooldown($instance, $timeout, $cooldowns) {
+        $cooldowns[$instance] = time() + $timeout;
+        error_log("cooldown on instnace $instance for $timeout seconds");
+        save_cooldowns($cooldowns);
+        return $cooldowns;
+    }
+
+    function has_cooldown($instance, $cooldowns) {
+        return ($cooldowns[$instance] ?? 0) > time();
+    }
+?>
diff --git a/misc/search_engine.php b/misc/search_engine.php
index 1c1c100..0b2e221 100644
--- a/misc/search_engine.php
+++ b/misc/search_engine.php
@@ -57,6 +57,7 @@
         foreach (array_keys($opts->frontends ?? array()) as $frontend) {
             $opts->frontends[$frontend]["instance_url"] = $_COOKIE[$frontend] ?? $opts->frontends[$frontend]["instance_url"];
         }
+
         return $opts;
     }