Redis + RateLimiting

Core/Objects/ConnectionData.class.php

@@ -10,12 +10,12 @@ class ConnectionData {
   private string $password;
   private array $properties;
 
-  public function __construct($host, $port, $login, $password) {
+  public function __construct(string $host, int $port, string $login, string $password) {
     $this->host = $host;
     $this->port = $port;
     $this->login = $login;
     $this->password = $password;
-    $this->properties = array();
+    $this->properties = [];
   }
 
   public function getProperties(): array {

Core/Objects/Context.class.php

@@ -4,6 +4,7 @@ namespace Core\Objects;
 
 use Core\Configuration\Configuration;
 use Core\Configuration\Settings;
+use Core\Driver\Redis\RedisConnection;
 use Core\Driver\SQL\Column\Column;
 use Core\Driver\SQL\Condition\Compare;
 use Core\Driver\SQL\Condition\CondLike;
@@ -25,6 +26,7 @@ class Context {
   private Configuration $configuration;
   private Language $language;
   public ?Router $router;
+  private ?RedisConnection $redis;
 
   private function __construct() {
 
@@ -32,6 +34,7 @@ class Context {
     $this->session = null;
     $this->user = null;
     $this->router = null;
+    $this->redis = null;
     $this->configuration = new Configuration();
     $this->setLanguage(Language::DEFAULT_LANGUAGE());
 
@@ -52,6 +55,11 @@ class Context {
       $this->sql->close();
       $this->sql = null;
     }
+
+    if ($this->redis && $this->redis->isConnected()) {
+      $this->redis->close();
+      $this->redis = null;
+    }
   }
 
   public function setLanguage(Language $language): void {
@@ -201,4 +209,18 @@ class Context {
 
     return $query->execute();
   }
+
+  public function getRedis(): ?RedisConnection {
+
+    if ($this->redis === null) {
+      $settings = $this->getSettings();
+      $connectionData = $settings->getRedisConfiguration();
+      $this->redis = new RedisConnection($this->sql);
+      if (!$this->redis->connect($connectionData)) {
+        $this->redis = null;
+      }
+    }
+
+    return $this->redis;
+  }
 }

Core/Objects/RateLimitRule.class.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Core\Objects;
+
+class RateLimitRule {
+
+  const SECOND = 0;
+  const MINUTE = 1;
+  const HOUR = 2;
+
+  private int $count;
+  private int $perSecond;
+
+  public function __construct(int $count, int $time, int $unit) {
+    $this->count = $count;
+    $this->perSecond = $time;
+    if ($unit === self::HOUR) {
+      $this->perSecond *= 60 * 60;
+    } else if ($unit === self::MINUTE) {
+      $this->perSecond *= 60;
+    }
+  }
+
+  public function getCount(): int {
+    return $this->count;
+  }
+
+  public function getWindow(): int {
+    return $this->perSecond;
+  }
+}

Core/Objects/RateLimiting.class.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace Core\Objects;
+
+use Core\Driver\Logger\Logger;
+
+class RateLimiting {
+
+  private ?RateLimitRule $anonymousRule;
+  private ?RateLimitRule $sessionRule;
+
+  public function __construct(?RateLimitRule $anonymousRule = null, ?RateLimitRule $sessionRule = null) {
+    $this->anonymousRule = $anonymousRule;
+    $this->sessionRule = $sessionRule;
+  }
+
+  public function check(Context $context, string $method): bool {
+    $session = $context->getSession();
+    $logger = new Logger("RateLimiting", $context->getSQL());
+
+    if ($session !== null) {
+      // session based rate limiting
+      $key = $session->getUUID();
+      $effectiveRule = $this->sessionRule;
+    } else {
+      // ip-based rate limiting
+      $key = $_SERVER['REMOTE_ADDR'];
+      $effectiveRule = $this->anonymousRule;
+    }
+
+    if ($effectiveRule === null) {
+      return true;
+    }
+
+    $redis = $context->getRedis();
+    if (!$redis?->isConnected()) {
+      $logger->error("Could not check rate limiting, redis is not connected.");
+      return true;
+    }
+
+    $now = time();
+    $queue = json_decode($redis->hGet($method, $key)) ?? [];
+    $pass = true;
+    $queueSize = count($queue);
+    if ($queueSize >= $effectiveRule->getCount()) {
+      // check the last n entries, whether they fit in the current window
+      $requestsInWindow = 0;
+      foreach ($queue as $accessTime) {
+        if ($accessTime >= $now - $effectiveRule->getWindow()) {
+          $requestsInWindow++;
+          if ($requestsInWindow >= $effectiveRule->getCount()) {
+            $pass = false;
+            break;
+          }
+        } else {
+          break;
+        }
+      }
+    }
+
+    if ($pass) {
+      array_unshift($queue, $now);
+      if ($queueSize + 1 > $effectiveRule->getCount()) {
+        $queue = array_slice($queue, 0, $effectiveRule->getCount());
+      }
+      $redis->hSet($method, $key, json_encode($queue));
+    }
+
+    return $pass;
+  }
+}