Prequel

About

Prequel is a wrapper for Redis backed queues in PHP. It provides a simple and convenient API for safe access to queues.

Main features

• Multiple queues
• Simple blocking publish / wait on a queue
• Detect duplicate messages
• Safe queue processing

Quick examples

Simple publish and process

Create a queue instance on the local Redis server with name "demo":

$queue = new PrequelQueue('demo', new PredisClient('redis://127.0.0.1:6379'));

Publish a message to the queue. A message is basically a simple JSON serializable array.

$message = array(
    'body' => 'Hello world'
);
$queue->publish($message);

Wait for a message (blocking with timeout) and echo the message body:

do {
    $message = $queue->wait();
    if (is_array($message)) {
        echo $message['body'] . chr(10);
    }
} while(TRUE);

Unique messages

To prevent duplicate messages in the queue (e.g. for idempotent operations), you can specify an id key inside the message. If another message with the same identifier is published to the queue before the other message was processed, it will be ignored.

$message = array(
    'id' => 'hello-world',
    'body' => 'Hello world'
);
$queue->publish($message);

$message = array(
    'id' => 'hello-world',
    'body' => 'Hello world 2'
);
$queue->publish($message);

In this example the second message will not be published to the queue.

Dependencies

• PHP >= 5.3.0
• Predis (linked as submodule)

Links

Project

• Source code

Related

• Redis

Author

Christopher Hlubek

License

The code for Prequel is distributed under the terms of the MIT license (see LICENSE).