add Discord Me cache

app/App.php

@@ -128,7 +128,9 @@ HTML,
         try {
             $u = static::getU();
             if ($u === null) return null;
-            return Auth::getMe($u);
+            $cachedMe = Redis::getCachedMe($_COOKIE['u']);
+            if ($cachedMe === null) return Redis::cacheMe($_COOKIE['u'], Auth::getMe($u));
+            return $cachedMe;
         } catch (Exception) {
             error_log('Failed to getMe.');
             return null;

app/Redis.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace MingTsay\Akanyan;
+
+use MingTsay\Akanyan\Discord\Me;
+
+require_once __DIR__ . '/../env.php';
+
+class Redis
+{
+  public const PREFIX = 'akanyan:discord:me:';
+  public const TTL = 600; // 10 minutes
+    protected static ?\Redis $redis = null;
+
+    /**
+     * @throws \RedisException
+     */
+    protected static function connect(): \Redis
+    {
+        if (static::$redis === null) {
+            static::$redis = new \Redis();
+            static::$redis->connect('127.0.0.1');
+        }
+        return static::$redis;
+    }
+
+    protected static function getKey(string $u): string
+    {
+        return static::PREFIX . md5($u);
+    }
+
+    public static function getCachedMe(string $u): ?Me
+    {
+        try {
+            $redis = static::connect();
+            return unserialize($redis->get(static::getKey($u))) ?: null;
+        } catch (\RedisException $e) {
+            trigger_error($e->getMessage());
+            return null;
+        }
+    }
+
+    public static function cacheMe(string $u, ?Me $me): ?Me
+    {
+        try {
+            $redis = static::connect();
+            $redis->setEx(static::getKey($u), static::TTL, serialize($me));
+            return $me;
+        } catch (\RedisException $e) {
+            trigger_error($e->getMessage());
+            return null;
+        }
+    }
+}