Redis

• Basics
  • Magic shortcut
• Pipelining
• Pub/Sub
  • Publishing
  • Subscribing
• Monitor

The Redis client provides a simple and consistent way of communicating with a Redis server.

Basics

Creating a database connection is done using the ConnectionManager::connection() method.

// Returns connection object using the "default" redis configuration defined in the config file

$redis = $this->redis->connection();

// Returns connection object using the "mydb" redis configuration defined in the config file

$redis = $this->redis->connection('mydb');

The Redis client uses the magic __call method to build commands method so every current (and future) Redis command is a valid method.

// Add some dummy data

$redis->rpush('drinks', 'water');
$redis->rpush('drinks', 'milk');
$redis->rpush('drinks', 'orange juice');

// Fetches all the drinks

$drinks = $redis->lrange('drinks', 0, -1);

// Delete data

$redis->del('drinks');

If the redis command contains spaces (CONFIG GET, CONFIG SET, etc ...) then you'll have to separate the words using camel case or underscores.

// Use camel case to separate multi word commands

$redis->configGet('*max-*-entries*');

// You can also use underscores

$redis->config_get('*max-*-entries*');

Magic shortcut

You can access the default redis connection directly without having to go through the connection method thanks to the magic __call method.

$exists = $this->redis->exists('drinks');

Pipelining

The pipeline method allows you to send multiple commands to the Redis server without having to wait for the replies. Using pipelining can be useful if you need to send a large number of commands as you will not be paying the cost of round-trip time for every single call.

$redis->set('x', 0);

$replies = $redis->pipeline(function($redis)
{
	for($i = 0; $i < 100; $i++)
	{
		$redis->incr('x');
	}
});

Note that pipelining will not work when connected to a Redis cluster unless all keys used in the pipeline are stored on the same node.

Pub/Sub

Publishing

You can publish messages to channels using the publish method. The first parameter is the channel name while the second parameter is your message. The method will return the number of subscribers that have received the message.

$redis->publish('channel1', 'Hello, World!');

Subscribing

The subscribeTo method allows you to subscribe to channels. You can also use the subscribeToPattern method if you want to subscribe using channel name patterns.

Message subscribers are blocking and should not be used in controllers. Reactor commands, however, are perfect for handling long running tasks. You should also set the timeout value of the connection used to subscribe to -1 in your redis configuration file to avoid dropped connections while waiting for new messages.

$redis->subscribeTo(['channel1', 'channel2'], function($message)
{
	$this->write($message);
});

By default the subscribers will only receive messages (message and pmessage). You can however subscribe to more messages types using the optional third parameter.

$redis->subscribeTo(['channel1', 'channel2'], function($message)
{
	$this->write($message);
}, ['message', 'subscribe', 'pong']);

You can stop subscribing at any time by returning false from the subscriber closure.

The message passed to the subscriber is an instance of the Message object. It implements the __toString method so you can treat it like a string but there are also a set of methods available if you want to access some additional information about the message.

Monitor

The monitor method can be useful when debugging applications that use Redis. Once called the server will stream back every command processed by the server.

The method should only be used in a reactor command. You should also set the timeout value of the connection used to monitor to -1 in your redis configuration file to avoid dropped connections while waiting for new commands.

$redis->monitor(function($command)
{
	$this->write($command);
});

You can stop the monitor at any time by returning false from your monitor closure.

Note that he connection is closed as soon as the monitor closure returns false.