redis.md

Redis

• Introduction
  • Configuration
• Interacting With Redis
  • Pipelining Commands
• Pub / Sub

Introduction

Redis is an open source, advanced key-value store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets, and sorted sets. Before using Redis with Laravel, you will need to install the predis/predis package via Composer:

composer require predis/predis

Configuration

The Redis configuration for your application is located in the config/database.php configuration file. Within this file, you will see a redis array containing the Redis servers utilized by your application:

'redis' => [

    'cluster' => false,

    'default' => [
        'host' => '127.0.0.1',
        'port' => 6379,
        'database' => 0,
    ],

],

The default server configuration should suffice for development. However, you are free to modify this array based on your environment. Each Redis server defined in your configuration file is required to have a name, host, and port.

The cluster option will instruct the Laravel Redis client to perform client-side sharding across your Redis nodes, allowing you to pool nodes and create a large amount of available RAM. However, note that client-side sharding does not handle failover; therefore, is primarily suited for cached data that is available from another primary data store.

Additionally, you may define an options array value in your Redis connection definition, allowing you to specify a set of Predis client options.

If your Redis server requires authentication, you may supply a password by adding a password configuration item to your Redis server configuration array.

{note} If you have the Redis PHP extension installed via PECL, you will need to rename the alias for Redis in your config/app.php file.

Interacting With Redis

You may interact with Redis by calling various methods on the Redis facade. The Redis facade supports dynamic methods, meaning you may call any Redis command on the facade and the command will be passed directly to Redis. In this example, we will call the Redis GET command by calling the get method on the Redis facade:

<?php

namespace App\Http\Controllers;

use Illuminate\Support\Facades\Redis;
use App\Http\Controllers\Controller;

class UserController extends Controller
{
    /**
     * Show the profile for the given user.
     *
     * @param  int  $id
     * @return Response
     */
    public function showProfile($id)
    {
        $user = Redis::get('user:profile:'.$id);

        return view('user.profile', ['user' => $user]);
    }
}

Of course, as mentioned above, you may call any of the Redis commands on the Redis facade. Laravel uses magic methods to pass the commands to the Redis server, so simply pass the arguments the Redis command expects:

Redis::set('name', 'Taylor');

$values = Redis::lrange('names', 5, 10);

Alternatively, you may also pass commands to the server using the command method, which accepts the name of the command as its first argument, and an array of values as its second argument:

$values = Redis::command('lrange', ['name', 5, 10]);

Using Multiple Redis Connections

You may get a Redis instance by calling the Redis::connection method:

$redis = Redis::connection();

This will give you an instance of the default Redis server. If you are not using server clustering, you may pass the server name to the connection method to get a specific server as defined in your Redis configuration:

$redis = Redis::connection('other');

Pipelining Commands

Pipelining should be used when you need to send many commands to the server in one operation. The pipeline method accepts one argument: a Closure that receives a Redis instance. You may issue all of your commands to this Redis instance and they will all be executed within a single operation:

Redis::pipeline(function ($pipe) {
    for ($i = 0; $i < 1000; $i++) {
        $pipe->set("key:$i", $i);
    }
});

Pub / Sub

Laravel provides a convenient interface to the Redis publish and subscribe commands. These Redis commands allow you to listen for messages on a given "channel". You may publish messages to the channel from another application, or even using another programming language, allowing easy communication between applications and processes.

First, let's setup a channel listener using the subscribe method. We'll place this method call within an Artisan command since calling the subscribe method begins a long-running process:

<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\Redis;

class RedisSubscribe extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature = 'redis:subscribe';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Subscribe to a Redis channel';

    /**
     * Execute the console command.
     *
     * @return mixed
     */
    public function handle()
    {
        Redis::subscribe(['test-channel'], function($message) {
            echo $message;
        });
    }
}

Now we may publish messages to the channel using the publish method:

Route::get('publish', function () {
    // Route logic...

    Redis::publish('test-channel', json_encode(['foo' => 'bar']));
});

Wildcard Subscriptions

Using the psubscribe method, you may subscribe to a wildcard channel, which may be useful for catching all messages on all channels. The $channel name will be passed as the second argument to the provided callback Closure:

Redis::psubscribe(['*'], function($message, $channel) {
    echo $message;
});

Redis::psubscribe(['users.*'], function($message, $channel) {
    echo $message;
});