PHP AMQPQueue::nack() Method: Usage and Examples

The PHP AMQPQueue::nack API performs a focused operation on an object or value. The examples below show its effect on actual data.

Negatively acknowledges a delivery and optionally requests requeueing.

What Is AMQPQueue::nack in PHP?

Negatively acknowledges a delivery and optionally requests requeueing.

This API requires a relevant extension or PHP version and cannot be reflected in the local PHP 8.4 runtime. Refer to the version or extension note below before using the examples.

Compatibility note: Install the PECL AMQP extension and configure a RabbitMQ-compatible broker before running this example.

Example 1: Basic Usage

This example uses a small input to make the main behavior visible.

<?php

$connection = new AMQPConnection([
    "host" => getenv("AMQP_HOST") ?: "127.0.0.1",
    "port" => 5672,
    "login" => getenv("AMQP_USERNAME") ?: "guest",
    "password" => getenv("AMQP_PASSWORD") ?: "guest"
]);
$connection->connect();
$channel = new AMQPChannel($connection);
$exchange = new AMQPExchange($channel);
$exchange->setName("events.exchange");
$exchange->setType(AMQP_EX_TYPE_DIRECT);
$exchange->declareExchange();
$queue = new AMQPQueue($channel);
$queue->setName("events.queue");
$queue->declareQueue();
$queue->bind($exchange->getName(), "events.created");
$exchange->publish("sample event", "events.created");
$message = $queue->get(AMQP_NOPARAM);
if ($message !== false) { $queue->nack($message->getDeliveryTag(), AMQP_REQUEUE); }
$connection->disconnect();

Negatively acknowledges a delivery and optionally requests requeueing.

Example 2: A Different Input

A different set of values shows the same operation in another situation.

<?php

$connection = new AMQPConnection([
    "host" => getenv("AMQP_HOST") ?: "127.0.0.1",
    "port" => 5672,
    "login" => getenv("AMQP_USERNAME") ?: "guest",
    "password" => getenv("AMQP_PASSWORD") ?: "guest"
]);
$connection->connect();
$channel = new AMQPChannel($connection);
$exchange = new AMQPExchange($channel);
$exchange->setName("audit.exchange");
$exchange->setType(AMQP_EX_TYPE_DIRECT);
$exchange->declareExchange();
$queue = new AMQPQueue($channel);
$queue->setName("audit.queue");
$queue->declareQueue();
$queue->bind($exchange->getName(), "events.created");
$exchange->publish("sample event", "events.created");
$message = $queue->get(AMQP_NOPARAM);
if ($message !== false) { $queue->nack($message->getDeliveryTag(), AMQP_REQUEUE); }
$connection->disconnect();

Queue operations require a configured AMQP broker; do not acknowledge before processing succeeds, and do not purge a production queue casually.

Practical Example: Applying the Feature

This example shows an application-style use of the feature, with its surrounding setup visible.

<?php

$connection = new AMQPConnection([
    "host" => getenv("AMQP_HOST") ?: "127.0.0.1",
    "port" => 5672,
    "login" => getenv("AMQP_USERNAME") ?: "guest",
    "password" => getenv("AMQP_PASSWORD") ?: "guest"
]);
$connection->connect();
$channel = new AMQPChannel($connection);
$exchange = new AMQPExchange($channel);
$exchange->setName("jobs.exchange");
$exchange->setType(AMQP_EX_TYPE_DIRECT);
$exchange->declareExchange();
$queue = new AMQPQueue($channel);
$queue->setName("jobs.queue");
$queue->declareQueue();
$queue->bind($exchange->getName(), "events.created");
$exchange->publish("sample event", "events.created");
$message = $queue->get(AMQP_NOPARAM);
if ($message !== false) { $queue->nack($message->getDeliveryTag(), AMQP_REQUEUE); }
$connection->disconnect();

The code is shown for learning. Adjust the class names, inputs and error handling to suit your application.

Important Behavior and Edge Cases

• Queue operations require a configured AMQP broker; do not acknowledge before processing succeeds, and do not purge a production queue casually.
• Negatively acknowledges a delivery and optionally requests requeueing.
• Observe differences in empty inputs, invalid states and optional extension availability where relevant.

Comparison With Related Approaches

Common Beginner Mistakes

Key Takeaways

• Negatively acknowledges a delivery and optionally requests requeueing.
• Queue operations require a configured AMQP broker; do not acknowledge before processing succeeds, and do not purge a production queue casually.
• Use the example that matches the values, runtime version and dependencies in your application.

AMQPQueue::nack is useful when its behavior matches the data structure and lifecycle of your PHP application. Choose it with a clear understanding of its preconditions and returned values.