producers.md

Producers

Producer is an object that sends something into AMQP exchange. It can format given messages somehow, has very stupid (for now) batch messages processing and can work with both queues and exchanges as a target.

Example to warm-up an interest:

$producer = Producer::factory($connection)
    ->withExchange(Exchange::factory('test-exchange', 'fanout')->durable(true))
    ->withFormatter('json_encode');
    
$producer->produce(['field' => 'value']);

Define target

Producer has two functions to define target where to send incoming messages:

• Producer::withExchange(Definition\Exchange $exchange) declares exchange;
• Producer::withQueue(Definition\Queue $queue) declares simple queue.

Quite simple, yeah?

Every definition has only a bit of mandatory parameters (name and exchange type), all others are preset into default parameters for exchange_declare and queue_declare AMQP functions.

So, the simplest definition of exchange looks like this:

$exchange = new Definition\Exchange('test-exchange', 'fanout');
$queue = new Definition\Queue('test-queue');

Both classes support fluent interface for parameter setters and factory named constructor to avoid braces for (new Queue('test'))->durable(true).

Format messages before sending them

As you can see from Producer::produce($payload) definition it accepts everything as a parameter. That's because Producer tries to format a message before creating AMQPMessage from given object.

Default formatter is as simple as this:

function($payload) { return (string) $payload; }

But you can redefine its behavior with Producer::withFormatter($formatter) function.

$producer = Producer::factory($connection)
    ->withFormatter('json_encode');

Yes, this function accepts everything callable.

Please note, that formatters are not stacked, they are replaced by call of withFormatter().

Batch messaging

Here it is BatchProducer class, which produce function accepts everything \Traversable and arrays. The implementation of this function uses php-amqplib's batch publishing functions.

BatchProducer::factory($connection)
    ->produce(['test', 'test', 'test']);

As BatchProducer has exactly the same interface as Producer, you can use it Consumer::withProducer().

Consumer::factory($connection)
    ->withProducer(BatchProducer::factory($connection));