# Amazon SQS examples using the AWS SDK for PHP Version 3
<a name="sqs-examples"></a>

Amazon Simple Queue Service (SQS) is a fast, reliable, scalable, fully managed message queuing service. Amazon SQS lets you decouple the components of a cloud application. Amazon SQS includes standard queues with high throughput and at-least-once processing, and FIFO queues that provide FIFO (first>-in, first>-out) delivery and exactly-once processing.

All the example code for the AWS SDK for PHP Version 3 is available [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/php/example_code).

**Topics**
+ [Enabling long polling](sqs-examples-enable-long-polling.md)
+ [Managing visibility timeout](sqs-examples-managing-visibility-timeout.md)
+ [Sending and receiving messages](sqs-examples-send-receive-messages.md)
+ [Using dead-letter queues](sqs-examples-dead-letter-queues.md)
+ [Using queues](sqs-examples-using-queues.md)

# Enabling long polling in Amazon SQS with AWS SDK for PHP Version 3
<a name="sqs-examples-enable-long-polling"></a>

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, specify a non-zero wait time for received messages. To learn more, see [SQS Long Polling](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-long-polling.html).

The following examples show how to:
+ Set attributes on an Amazon SQS queue to enable long polling, using [SetQueueAttributes](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#setqueueattributes).
+ Retrieve one or more messages with long polling using [ReceiveMessage](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#receivemessage).
+ Create a long polling queue using [CreateQueue](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#createqueue).

All the example code for the AWS SDK for PHP is available [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/php/example_code).

## Credentials
<a name="examplecredentials"></a>

Before running the example code, configure your AWS credentials, as described in [Authenticating with AWS using AWS SDK for PHP Version 3](credentials.md). Then import the AWS SDK for PHP, as described in [Installing the AWS SDK for PHP Version 3](getting-started_installation.md).

## Set attributes on a queue to enable long polling
<a name="set-attributes-on-a-queue-to-enable-long-polling"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueUrl = "QUEUE_URL";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->setQueueAttributes([
        '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
<a name="retrieve-messages-with-long-polling"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueUrl = "QUEUE_URL";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->receiveMessage([
        '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
<a name="create-a-queue-with-long-polling"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueName = "QUEUE_NAME";


$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->createQueue([
        'QueueName' => $queueName,
        'Attributes' => [
            'ReceiveMessageWaitTimeSeconds' => 20
        ],
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

# Managing visibility timeout in Amazon SQS with AWS SDK for PHP Version 3
<a name="sqs-examples-managing-visibility-timeout"></a>

A visibility timeout is a period of time during which Amazon SQS prevents other consuming components from receiving and processing a message. To learn more, see [Visibility Timeout](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-visibility-timeout.html).

The following example shows how to:
+ Change the visibility timeout of specified messages in a queue to new values, using [ChangeMessageVisibilityBatch](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#changemessagevisibilitybatch).

All the example code for the AWS SDK for PHP is available [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/php/example_code).

## Credentials
<a name="examplecredentials"></a>

Before running the example code, configure your AWS credentials, as described in [Authenticating with AWS using AWS SDK for PHP Version 3](credentials.md). Then import the AWS SDK for PHP, as described in [Installing the AWS SDK for PHP Version 3](getting-started_installation.md).

## Change the visibility timeout of multiple messages
<a name="change-the-visibility-timeout-of-multiple-messages"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueUrl = "QUEUE_URL";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->receiveMessage(array(
        'AttributeNames' => ['SentTimestamp'],
        'MaxNumberOfMessages' => 10,
        'MessageAttributeNames' => ['All'],
        'QueueUrl' => $queueUrl, // REQUIRED
    ));
    $messages = $result->get('Messages');
    if ($messages != null) {
        $entries = array();
        for ($i = 0; $i < count($messages); $i++) {
            $entries[] = [
                'Id' => 'unique_is_msg' . $i, // REQUIRED
                'ReceiptHandle' => $messages[$i]['ReceiptHandle'], // REQUIRED
                'VisibilityTimeout' => 3600
            ];
        }
        $result = $client->changeMessageVisibilityBatch([
            'Entries' => $entries,
            'QueueUrl' => $queueUrl
        ]);

        var_dump($result);
    } else {
        echo "No messages in queue \n";
    }
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

# Sending and receiving messages in Amazon SQS with AWS SDK for PHP Version 3
<a name="sqs-examples-send-receive-messages"></a>

To learn about Amazon SQS messages, see [Sending a Message to an SQS Queue](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-send-message.html) and [Receiving and Deleting a Message from an SQS Queue](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-receive-delete-message.html.html) in the Service Quotas User Guide.

The following examples show how to:
+ Deliver a message to a specified queue using [SendMessage](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#sendmessage).
+ Retrieve one or more messages (up to 10) from a specified queue using [ReceiveMessage](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#receivemessage).
+ Delete a message from a queue using [DeleteMessage](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#deletemessage).

All the example code for the AWS SDK for PHP is available [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/php/example_code).

## Credentials
<a name="examplecredentials"></a>

Before running the example code, configure your AWS credentials, as described in [Authenticating with AWS using AWS SDK for PHP Version 3](credentials.md). Then import the AWS SDK for PHP, as described in [Installing the AWS SDK for PHP Version 3](getting-started_installation.md).

## Send a message
<a name="send-a-message"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

$params = [
    'DelaySeconds' => 10,
    'MessageAttributes' => [
        "Title" => [
            'DataType' => "String",
            'StringValue' => "The Hitchhiker's Guide to the Galaxy"
        ],
        "Author" => [
            'DataType' => "String",
            'StringValue' => "Douglas Adams."
        ],
        "WeeksOn" => [
            'DataType' => "Number",
            'StringValue' => "6"
        ]
    ],
    'MessageBody' => "Information about current NY Times fiction bestseller for week of 12/11/2016.",
    'QueueUrl' => 'QUEUE_URL'
];

try {
    $result = $client->sendMessage($params);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

## Receive and delete messages
<a name="receive-and-delete-messages"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueUrl = "QUEUE_URL";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->receiveMessage([
        'AttributeNames' => ['SentTimestamp'],
        'MaxNumberOfMessages' => 1,
        'MessageAttributeNames' => ['All'],
        'QueueUrl' => $queueUrl, // REQUIRED
        'WaitTimeSeconds' => 0,
    ]);
    if (!empty($result->get('Messages'))) {
        var_dump($result->get('Messages')[0]);
        $result = $client->deleteMessage([
            'QueueUrl' => $queueUrl, // REQUIRED
            'ReceiptHandle' => $result->get('Messages')[0]['ReceiptHandle'] // REQUIRED
        ]);
    } else {
        echo "No messages in queue. \n";
    }
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

# Using dead-letter queues in Amazon SQS with AWS SDK for PHP Version 3
<a name="sqs-examples-dead-letter-queues"></a>

A dead-letter queue is one that other (source) queues can target for messages that can’t be processed successfully. You can set aside and isolate these messages in the dead-letter queue to determine why their processing did not succeed. You must individually configure each source queue that sends messages to a dead-letter queue. Multiple queues can target a single dead-letter queue.

To learn more, see [Using SQS Dead Letter Queues](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-dead-letter-queues.html).

The following example shows how to:
+ Enable a dead-letter queue using [SetQueueAttributes](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#setqueueattributes).

All the example code for the AWS SDK for PHP is available [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/php/example_code).

## Credentials
<a name="examplecredentials"></a>

Before running the example code, configure your AWS credentials, as described in [Authenticating with AWS using AWS SDK for PHP Version 3](credentials.md). Then import the AWS SDK for PHP, as described in [Installing the AWS SDK for PHP Version 3](getting-started_installation.md).

## Enable a dead-letter queue
<a name="enable-a-dead-letter-queue"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueUrl = "QUEUE_URL";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->setQueueAttributes([
        'Attributes' => [
            'RedrivePolicy' => "{\"deadLetterTargetArn\":\"DEAD_LETTER_QUEUE_ARN\",\"maxReceiveCount\":\"10\"}"
        ],
        'QueueUrl' => $queueUrl // REQUIRED
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

# Using queues in Amazon SQS with AWS SDK for PHP Version 3
<a name="sqs-examples-using-queues"></a>

To learn about Amazon SQS queues, see [How SQS Queues Work](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-how-it-works.html).

The following examples show how to:
+ Return a list of your queues using [ListQueues](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#listqueues).
+ Create a new queue using [CreateQueue](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#createqueue).
+ Return the URL of an existing queue using [GetQueueUrl](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#getqueueurl).
+ Delete a specified queue using [DeleteQueue](https://docs.aws.amazon.com/aws-sdk-php/v3/api/api-sqs-2012-11-05.html#deletequeue).

All the example code for the AWS SDK for PHP is available [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/php/example_code).

## Credentials
<a name="examplecredentials"></a>

Before running the example code, configure your AWS credentials, as described in [Authenticating with AWS using AWS SDK for PHP Version 3](credentials.md). Then import the AWS SDK for PHP, as described in [Installing the AWS SDK for PHP Version 3](getting-started_installation.md).

## Return a list of queues
<a name="return-a-list-of-queues"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->listQueues();
    foreach ($result->get('QueueUrls') as $queueUrl) {
        echo "$queueUrl\n";
    }
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

## Create a queue
<a name="create-a-queue"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueName = "SQS_QUEUE_NAME";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->createQueue([
        'QueueName' => $queueName,
        'Attributes' => [
            'DelaySeconds' => 5,
            'MaximumMessageSize' => 4096, // 4 KB
        ],
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

## Return the URL of a queue
<a name="return-the-url-of-a-queue"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueName = "SQS_QUEUE_NAME";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->getQueueUrl([
        'QueueName' => $queueName // REQUIRED
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```

## Delete a queue
<a name="delete-a-queue"></a>

 **Imports** 

```
require 'vendor/autoload.php';

use Aws\Exception\AwsException;
use Aws\Sqs\SqsClient;
```

 **Sample Code** 

```
$queueUrl = "SQS_QUEUE_URL";

$client = new SqsClient([
    'profile' => 'default',
    'region' => 'us-west-2',
    'version' => '2012-11-05'
]);

try {
    $result = $client->deleteQueue([
        'QueueUrl' => $queueUrl // REQUIRED
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}
```