Enabling Long Polling in Amazon SQS

Long polling reduces the number of empty responses by allowing Amazon SQS to wait a specified time for a message to become available in the queue before sending a response. Also, long polling eliminates false empty responses by querying all of the servers instead of a sampling of servers. To enable long polling, you must specify a non-zero wait time for received messages. To learn more, see Amazon SQS Long Polling.

The examples below show how to:

• Set attributes on an SQS queue to enable long polling, using SetQueueAttributes.
• Retrieve one or more messages with long polling using ReceiveMessage.
• Create a long polling queue using CreateQueue.

All the example code for the AWS SDK for PHP is available here on GitHub.

Credentials

Before running the example code, configure your AWS credentials, as described in Credentials.

Set Attributes on a Queue to Enable Long Polling

require 'vendor/autoload.php';
use Aws\Sqs\SqsClient;
use Aws\Exception\AwsException;

$queueUrl = "QUEUE_URL";
$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);
try {
    $result = $client->setQueueAttributes(array(
        'Attributes' => [
            'ReceiveMessageWaitTimeSeconds' => 20
        ],
        'QueueUrl' => $queueUrl, // REQUIRED
    ));
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}

Retrieve Messages with Long Polling

require 'vendor/autoload.php';
use Aws\Sqs\SqsClient;
use Aws\Exception\AwsException;

$queueUrl = "QUEUE_URL";
$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);
try {
    $result = $client->receiveMessage(array(
        'AttributeNames' => ['SentTimestamp'],
        'MaxNumberOfMessages' => 1,
        'MessageAttributeNames' => ['All'],
        'QueueUrl' => $queueUrl, // REQUIRED
        'WaitTimeSeconds' => 20,
    ));
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}

Create a Queue with Long Polling

require 'vendor/autoload.php';
use Aws\Sqs\SqsClient;
use Aws\Exception\AwsException;

$queueName = "QUEUE_NAME";
$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);
try {
    $result = $client->createQueue(array(
        'QueueName' => $queueName,
        'Attributes' => array(
            'ReceiveMessageWaitTimeSeconds' => 20
        ),
    ));
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}