Implementing a Redis Multi-Database Singleton Wrapper in ThinkPHP

1. Preparation: install the phpredis extension or the Predis client via Composer. composer require predis/predis 2. Configure Redis connection information in app\config\cache.php:

'redis' => [
    // driver
    'type' => 'redis',
    // host
    'host' => Env::get('redis.host'),
    // port
    'port' => Env::get('redis.port'),
];

Additional options can be set as shown:

protected $options = [
    'host'       => '127.0.0.1',
    'port'       => 6379,
    'password'   => '',
    'select'     => 0,
    'timeout'    => 0,
    'expire'     => 0,
    'persistent' => false,
    'prefix'     => '',
    'tag_prefix' => 'tag:',
    'serialize'  => [],
];

3. Create Redis.php under app\common that extends ThinkPHP's Redis driver and provides a static singleton method for each database.

<?php
namespace app\common;
use think\facade\Config;
use think\cache\driver\redis as ThinkRedis;

class Redis extends ThinkRedis {
    protected $hash;
    protected static $instance = [];

    private function __construct($db) {
        $options = Config::get('cache.stores.redis');
        $options['select'] = $db;
        $this->hash = $db;
        $this->options = array_merge($this->options, $options);
        parent::__construct();
    }

    private function __clone() {}

    public static function instance($db = 0) {
        if (!isset(self::$instance[$db])) {
            self::$instance[$db] = new self($db);
        }
        return self::$instance[$db];
    }

    public function __destruct() {
        self::$instance[$this->hash]->close();
        unset(self::$instance[$this->hash]);
    }
}

4. Use the wrapper to interact with Redis databases:

use app\common\Redis;

$redis = Redis::instance(4);
$redis->hSet('user:1', 'userName', 'admin');

Redis::instance(1)->hSet('user', 'name', 'admin1');
Redis::instance(2)->hSet('user', 'name', 'admin2');
Redis::instance(3)->hSet('user', 'name', 'admin3');

For more command references, consult the Redis command manual.