Using "Redis.io". Redis used as PHP session "save handler". Redis client from PHP to a Redis server.

redis-client.php

<?php

// Redis client from PHP to a Redis server.

// https://marketplace.visualstudio.com/items?itemName=cweijan.vscode-database-client2

// Debian setup hints:
// sudo apt install redis
// sudo apt install pkg-php-tools # provides: pecl
// sudo apt install php-dev # provides: phpize
// sudo pecl install redis

$redis = new Redis();
$redis->connect('127.0.0.1');

// https://redis.io/docs/latest/develop/data-types/lists/

print($redis->rPush('chat_messages', 'a message')."\n");

print(json_encode($redis->lRange('chat_messages', 0, -1))."\n");

redis-session.php

<?php

// Redis used as PHP session "save handler".

// simple counter to test sessions. should increment on each page reload.
// use from a client that stores session cookies such as a web-browser,
// or something like "curl" but configured so, or "postman" or alike.

// http://localhost:8080/redis-session.php
// php -S localhost:8080

// https://marketplace.visualstudio.com/items?itemName=cweijan.vscode-database-client2

// Debian setup hints:
// sudo apt install redis
// sudo apt install php-redis

ini_set('session.save_handler', 'redis');
ini_set('session.save_path',    'tcp://127.0.0.1:6379');
// https://joshtronic.com/2013/06/20/redis-as-a-php-session-handler/

session_start(); // session cookie

$count = isset($_SESSION['count']) ? $_SESSION['count'] : 0;
$count += 1;
$_SESSION['count'] = $count;

print($count);