Redis client for PHP: Predis

Predis — a flexible Redis client for PHP

Redis is a high-performance key-value data store often used for caching, sessions, queues, and real-time applications. There are several libraries for working with Redis from PHP, and one of the most popular is Predis. It is a pure PHP client implementation that does not require installing additional extensions (unlike phpredis). Predis supports all basic Redis commands, clustering, replication, Pub/Sub, and transactions.

Installing Predis via Composer

Predis is installed in the standard way via Composer. Make sure Composer is installed in your project and run the command:

composer require predis/predis

After installation, the dependency will appear in the composer.json file, and the library will be available in the vendor folder.

Connecting to a Redis server

To get started, create an instance of the Predis client. By default, it connects to 127.0.0.1:6379, but you can specify your own parameters.

<?phprequire 'vendor/autoload.php';

use Predis\\Client;

// Connection with default parameters$client = new Client();

// Or with explicit host and port$client = new Client([    'scheme' => 'tcp',    'host'   => '127.0.0.1',    'port'   => 6379,]);

// If a password is required$client = new Client([    'host' => 'localhost',    'port' => 6379,    'password' => 'my_secret_password',]);?>

If Redis is running on a remote server or uses a UNIX socket, simply change the corresponding parameters.

Basic data operations

Predis supports all standard Redis data types: strings, hashes, lists, sets, and sorted sets. Let's look at basic examples.

Working with strings

<?php// Set a value$client->set('user:100:name', 'Ivan Petrov');

// Get a value$name = $client->get('user:100:name');echo $name; // Ivan Petrov

// Check if a key existsif ($client->exists('user:100:name')) {    echo 'Key exists';}

// Delete a key$client->del(['user:100:name']);?>

Working with hashes

Hashes are convenient for storing objects — for example, user data.

<?php// Set hash fields$client->hmset('user:100', [    'name'  => 'Anna Smirnova',    'email' => 'anna@example.com',    'age'   => 28,]);

// Get a single field$email = $client->hget('user:100', 'email');

// Get all fields$userData = $client->hgetall('user:100');print_r($userData);

// Increment a numeric field$client->hincrby('user:100', 'age', 1);?>

Working with lists

Redis lists are ideal for queues and logs.

<?php// Add elements to the beginning of the list (stack)$client->lpush('tasks', 'task1', 'task2', 'task3');

// Add to the end of the list (queue)$client->rpush('tasks', 'task4');

// Get all list elements$allTasks = $client->lrange('tasks', 0, -1);print_r($allTasks);

// Pop the first element$first = $client->lpop('tasks');echo $first; // task3?>

Setting key time-to-live (TTL)

One of the powerful features of Redis is automatic key deletion after a specified time. This is often used for caching.

<?php// Set a key with a TTL of 60 seconds$client->setex('cache:page', 60, 'Page HTML content');

// Or for an existing key$client->expire('cache:page', 120);

// Check remaining time-to-live$ttl = $client->ttl('cache:page');echo "$ttl seconds remaining";?>