Migration Guide

This guide shows how to migrate your code to use Version 3 of the AWS SDK for PHP and how the new version differs from the Version 2 of the SDK.

Note

The basic usage pattern of the SDK (i.e., $result = $client->operation($params);) has not changed from Version 2 to Version 3, which should result in a fairly smooth migration.

Introduction

Version 3 of the SDK represents a significant effort to improve the capabilities of the SDK, incorporate over two years of customer feedback, upgrade our dependencies, improve performance, and adopt the latest PHP standards.

What's New?

  • Follows the PSR-4 and PSR-7 standards.
  • Decoupled HTTP layer.
    • Guzzle 6 is used by default to send requests, but Guzzle 5 is also supported out of the box.
    • The SDK will work in environments where cURL is not available.
    • Custom HTTP handlers are also supported.
  • Asynchronous requests.
    • Features like waiters and multipart uploaders can also be used asynchronously.
    • Asynchronous workflows can be created using promises and coroutines.
    • Improved performance of concurrent/batched requests.
  • Middleware system for customizing service client behavior.
  • Flexible paginators for iterating through paginated results.
  • Ability to query data from result and paginator objects with JMESPath.
  • Easy debugging via the 'debug' configuration option.
  • Strictly follows the SemVer standard going forward.

What's Different?

Project dependencies have been updated

The dependencies of the SDK have changed in this version.

  • The SDK now requires PHP 5.5+. We use generators liberally within the SDK code.
  • We've upgraded the SDK to use Guzzle 6 (or 5), which provides the underlying HTTP client implementation used by the SDK to send requests to the AWS services. The latest version of Guzzle brings with it a number of improvements, including asynchronous requests, swappable HTTP handlers, PSR-7 compliance, better performance, and more.
  • The PSR-7 package from the PHP-FIG (psr/http-message) defines interfaces for representing HTTP requests, HTTP responses, URLs, and streams. These interfaces are used across the SDK and Guzzle, which provides interoperability with other PSR-7 compliant packages.
  • Guzzle's PSR-7 implementation (guzzlehttp/psr7) provides an implementation of the interfaces in PSR-7, as well as a number of helpful classes and functions to go along with it. Both the SDK and Guzzle 6 rely on this package heavily.
  • Guzzle's Promises/A+ implementation (guzzlehttp/promises) is used throughout the SDK and Guzzle to provide interfaces for managing asynchronous requests and coroutines. While Guzzle's multi-cURL HTTP handler ultimately implements the non-blocking I/O model that allows for asynchronous requests, this package provides the ability to program within that paradigm. See Promises for more details.
  • The PHP implementation of JMESPath (mtdowling/jmespath.php) is used in the SDK to provide the data querying ability of the Aws\Result::search() and Aws\ResultPaginator::search() methods. See JMESPath Expressions in the SDK for more details.

Region and version options are now required

When instantiating a client for any service, you must specify the 'region' and 'version' options. In version 2 of the SDK, 'version' was completely optional, and 'region' was sometimes optional. In version 3, both are always required. Being explicit about both of these options allows you to lock into the API version and region you are coding against. When new API versions are created or new regions become available, you will be isolated from potentially breaking changes until you are ready to explicitly update your configuration.

Note

If you are not concerned with which API version you are using, then you can just set the 'version' option to 'latest'. However, it is recommended that you set the API version numbers explicitly for production code.

Not all services are available in all regions. You can find a list of available regions using the Regions and Endpoints reference.

For services only available via a single, global endpoint, e.g., Route53, IAM, and CloudFront, clients should be instantiated with their configured region set to us-east-1.

Important

The SDK also includes multi-region clients, which can dispatch requests to different regions based on a parameter (@region) supplied as a command parameter. The region used by default by these clients is specified with the region option supplied to the client constructor.

Client instantiation uses the constructor

In version 3 of the SDK, the way you instantiate a client has changed. Instead of the factory methods in version 2, you can simply instantiate a client with the new keyword.

use Aws\DynamoDb\DynamoDbClient;

// Version 2 style
$client = DynamoDbClient::factory([
    'region'  => 'us-east-2'
]);

// Version 3 style
$client = new DynamoDbClient([
    'region'  => 'us-east-2',
    'version' => '2012-08-10'
]);

Note

Instantiating a client using the factory() method still works, it is just considered deprecated.

Client configuration has changed

The client configuration options in Version 3 of the SDK have changed a little from Version 2. See the Configuration page for a description of all the supported options.

Note

One important change is that 'key' and 'secret' are no longer valid options at the root level, but you can pass them in as part of the 'credentials' option. One reason this change was made was to discourage developers from hard-coding their AWS credentials into their projects.

The SDK Object

Version 3 of the SDK introduces the Aws\Sdk object as a replacement to Aws\Common\Aws. The Sdk object acts as a client factory and is used to manage shared configuration options across multiple clients.

While Version 2's Aws class worked like a service locator (i.e., it always returned the same instance of a client), the Sdk class returns a new instance of a client every time it is used.

It also does not support the same configuration file format from Version 2 of the SDK. That configuration format was specific to Guzzle 3 and is now obsolete. Configuration can be done more simply with basic arrays, and is documented in Using the Sdk class.

Some API results have changed

In order to provide consistency in how the SDK parses the result of an API operation, Amazon ElastiCache, Amazon RDS, and Amazon RedShift now have an additional wrapping element on some API responses.

For example, calling Amazon RDS's DescribeEngineDefaultParameters result in Version 3 now includes a wrapping "EngineDefaults" element whereas in Version 2 this element was not present.

$client = new Aws\Rds\RdsClient([
    'region'  => 'us-west-1',
    'version' => '2014-09-01'
]);

// Version 2:
$result = $client->describeEngineDefaultParameters();
$family = $result['DBParameterGroupFamily'];
$marker = $result['Marker'];

// Version 3:
$result = $client->describeEngineDefaultParameters();
$family = $result['EngineDefaults']['DBParameterGroupFamily'];
$marker = $result['EngineDefaults']['Marker'];

The following operations are affected and now contain a wrapping element in the output of the result (provided below in parenthesis):

  • Amazon ElastiCache
    • AuthorizeCacheSecurityGroupIngress (CacheSecurityGroup)
    • CopySnapshot (Snapshot)
    • CreateCacheCluster (CacheCluster)
    • CreateCacheParameterGroup (CacheParameterGroup)
    • CreateCacheSecurityGroup (CacheSecurityGroup)
    • CreateCacheSubnetGroup (CacheSubnetGroup)
    • CreateReplicationGroup (ReplicationGroup)
    • CreateSnapshot (Snapshot)
    • DeleteCacheCluster (CacheCluster)
    • DeleteReplicationGroup (ReplicationGroup)
    • DeleteSnapshot (Snapshot)
    • DescribeEngineDefaultParameters (EngineDefaults)
    • ModifyCacheCluster (CacheCluster)
    • ModifyCacheSubnetGroup (CacheSubnetGroup)
    • ModifyReplicationGroup (ReplicationGroup)
    • PurchaseReservedCacheNodesOffering (ReservedCacheNode)
    • RebootCacheCluster (CacheCluster)
    • RevokeCacheSecurityGroupIngress (CacheSecurityGroup)
  • Amazon RDS
    • AddSourceIdentifierToSubscription (EventSubscription)
    • AuthorizeDBSecurityGroupIngress (DBSecurityGroup)
    • CopyDBParameterGroup (DBParameterGroup)
    • CopyDBSnapshot (DBSnapshot)
    • CopyOptionGroup (OptionGroup)
    • CreateDBInstance (DBInstance)
    • CreateDBInstanceReadReplica (DBInstance)
    • CreateDBParameterGroup (DBParameterGroup)
    • CreateDBSecurityGroup (DBSecurityGroup)
    • CreateDBSnapshot (DBSnapshot)
    • CreateDBSubnetGroup (DBSubnetGroup)
    • CreateEventSubscription (EventSubscription)
    • CreateOptionGroup (OptionGroup)
    • DeleteDBInstance (DBInstance)
    • DeleteDBSnapshot (DBSnapshot)
    • DeleteEventSubscription (EventSubscription)
    • DescribeEngineDefaultParameters (EngineDefaults)
    • ModifyDBInstance (DBInstance)
    • ModifyDBSubnetGroup (DBSubnetGroup)
    • ModifyEventSubscription (EventSubscription)
    • ModifyOptionGroup (OptionGroup)
    • PromoteReadReplica (DBInstance)
    • PurchaseReservedDBInstancesOffering (ReservedDBInstance)
    • RebootDBInstance (DBInstance)
    • RemoveSourceIdentifierFromSubscription (EventSubscription)
    • RestoreDBInstanceFromDBSnapshot (DBInstance)
    • RestoreDBInstanceToPointInTime (DBInstance)
    • RevokeDBSecurityGroupIngress (DBSecurityGroup)
  • Amazon Redshift
    • AuthorizeClusterSecurityGroupIngress (ClusterSecurityGroup)
    • AuthorizeSnapshotAccess (Snapshot)
    • CopyClusterSnapshot (Snapshot)
    • CreateCluster (Cluster)
    • CreateClusterParameterGroup (ClusterParameterGroup)
    • CreateClusterSecurityGroup (ClusterSecurityGroup)
    • CreateClusterSnapshot (Snapshot)
    • CreateClusterSubnetGroup (ClusterSubnetGroup)
    • CreateEventSubscription (EventSubscription)
    • CreateHsmClientCertificate (HsmClientCertificate)
    • CreateHsmConfiguration (HsmConfiguration)
    • DeleteCluster (Cluster)
    • DeleteClusterSnapshot (Snapshot)
    • DescribeDefaultClusterParameters (DefaultClusterParameters)
    • DisableSnapshotCopy (Cluster)
    • EnableSnapshotCopy (Cluster)
    • ModifyCluster (Cluster)
    • ModifyClusterSubnetGroup (ClusterSubnetGroup)
    • ModifyEventSubscription (EventSubscription)
    • ModifySnapshotCopyRetentionPeriod (Cluster)
    • PurchaseReservedNodeOffering (ReservedNode)
    • RebootCluster (Cluster)
    • RestoreFromClusterSnapshot (Cluster)
    • RevokeClusterSecurityGroupIngress (ClusterSecurityGroup)
    • RevokeSnapshotAccess (Snapshot)
    • RotateEncryptionKey (Cluster)

Enum classes have been removed

We have removed the Enum classes (e.g., Aws\S3\Enum\CannedAcl) that existed in Version 2 of the SDK. Enums were concrete classes within the public API of the SDK that contained constants representing groups of valid parameter values. Since these enums are specific to API versions, can change over time, can conflict with PHP reserved words, and ended up not being very useful, we have removed them in Version 3. This supports the data-driven and API version agnostic nature of Version 3.

Instead of using values from Enum objects, you should just use the literal values directly (e.g., CannedAcl::PUBLIC_READ'public-read').

Fine-grained Exception classes have been removed

We have removed the fine-grained exception classes that existed in the each of the services' namespaces (e.g., Aws\Rds\Exception\{SpecificError}Exception) for very similar reasons that we removed Enums. The exceptions thrown by service/operation are dependent on which API version is used (i.e., they can change from version to version). Also, the complete list of what exceptions can be thrown by a given operation is not available, which made Version 2's fine-grained exception classes incomplete.

You should handle errors by catching the root exception class for each service (e.g., Aws\Rds\Exception\RdsException). You can use the getAwsErrorCode() method of the exception to check for specific error codes. This is functionally equivalent to catching different exception classes, but provides that function without adding bloat to the SDK.

Static Facade classes have been removed

In Version 2, there was an obscure feature inspired by Laravel that allowed you to call enableFacades() on the Aws class to enable static access to the various service clients. This feature goes against PHP best practices, and we stopped documenting it over a year ago. In Version 3, this feature is gone completely. You should retrieve your client objects from the Aws\Sdk object and use them as object instances, not static classes.

Paginators supersede Iterators

Version 2 of the SDK had a feature called Iterators, which were objects that were used for iterating over paginated results. One complaint we had about these was that they were not flexible enough, because the iterator only emitted specific values from each result, and if there were other values you needed from the results, you could only retrieve them via event listeners.

In Version 3, Iterators have been replaced with Paginators. They are similar in purpose, but Paginators are more flexible, because they yield result objects instead of values from a response.

The following examples illustrate how Paginators are different from Iterators, by showing how to retrieve paginated results for the S3 ListObjects operation in both Version 2 and Version 3.

// Version 2
$objects = $s3Client->getIterator('ListObjects', ['Bucket' => 'my-bucket']);
foreach ($objects as $object) {
    echo $object['Key'] . "\n";
}
// Version 3
$results = $s3Client->getPaginator('ListObjects', ['Bucket' => 'my-bucket']);
foreach ($results as $result) {
    // You can extract any data that you want from the result.
    foreach ($result['Contents'] as $object) {
        echo $object['Key'] . "\n";
    }
}

Paginator objects have a search() method that allows you to use JMESPath expressions to extract data more easily from the result set.

$results = $s3Client->getPaginator('ListObjects', ['Bucket' => 'my-bucket']);
foreach ($results->search('Contents[].Key') as $key) {
    echo $key . "\n";
}

Note

The getIterator() method is still supported to allow for a smooth transition to Version 3, but encourage you to upgrade your code to use Paginators.

Many higher-level abstractions have changed

In general, many of the higher-level abstractions (service-specific helper objects aside from the clients) have been improved or updated. Some have even been removed.

  • Updated:
    • The way you use the S3 Multipart Uploader has changed. The Glacier Multipart Uploader has been changed in similar ways.
    • The way to create S3 Presigned URLs has changed.
    • The Aws\S3\Sync namespace have been replaced by the Aws\S3\Transfer class. The S3Client::uploadDirectory() and S3Client::downloadBucket() methods are still available, but have different options. See the docs for Amazon S3 Transfer Manager.
    • The Aws\S3\Model\ClearBucket and Aws\S3\Model\DeleteObjectsBatch have been replaced by Aws\S3\BatchDelete and S3Client::deleteMatchingObjects().
    • The options and behaviors for the DynamoDB Session Handler have changed slightly.
    • The Aws\DynamoDb\Model\BatchRequest namespace has been replaced by Aws\DynamoDb\WriteRequestBatch. See the docs for DynamoDB WriteRequestBatch.
  • Removed:
    • DynamoDB Item, Attribute, and ItemIterator classes - These were previously deprecated in Version 2.7.0.
    • SNS Message Validator - This is now a separate, light-weight project that does not require the SDK as a dependency. This project is, however, included in the Phar and Zip distributions of the SDK. A getting started guide can be found on the AWS PHP Development blog.
    • S3 AcpBuilder and related objects were removed.

Comparing Code Samples from Both SDKs

The following examples illustrate some of the ways in which using Version 3 of the SDK may differ from Version 2.

Example: Amazon S3 ListObjects operation

From Version 2 of the SDK

<?php

require '/path/to/vendor/autoload.php';

use Aws\S3\S3Client;
use Aws\S3\Exception\S3Exception;

$s3 = S3Client::factory([
    'profile' => 'my-credential-profile',
    'region'  => 'us-east-1'
]);

try {
    $result = $s3->listObjects([
        'Bucket' => 'my-bucket-name',
        'Key'    => 'my-object-key'
    ]);

    foreach ($result['Contents'] as $object) {
        echo $object['Key'] . "\n";
    }
} catch (S3Exception $e) {
    echo $e->getMessage() . "\n";
}

From Version 3 of the SDK

Key differences:

  • Use new instead of factory() to instantiate the client.
  • The 'version' and 'region' options are required during instantiation.
<?php

require '/path/to/vendor/autoload.php';

use Aws\S3\S3Client;
use Aws\S3\Exception\S3Exception;

$s3 = new S3Client([
    'profile' => 'my-credential-profile',
    'region'  => 'us-east-1',
    'version' => '2006-03-01'
]);

try {
    $result = $s3->listObjects([
        'Bucket' => 'my-bucket-name',
        'Key'    => 'my-object-key'
    ]);

    foreach ($result['Contents'] as $object) {
        echo $object['Key'] . "\n";
    }
} catch (S3Exception $e) {
    echo $e->getMessage() . "\n";
}

Example: Instantiating a client with global configuration

From Version 2 of the SDK

<?php return array(
    'includes' => array('_aws'),
    'services' => array(
        'default_settings' => array(
            'params' => array(
                'profile' => 'my_profile',
                'region'  => 'us-east-1'
            )
        ),
        'dynamodb' => array(
            'extends' => 'dynamodb',
            'params' => array(
                'region'  => 'us-west-2'
            )
        ),
    )
);
<?php

require '/path/to/vendor/autoload.php';

use Aws\Common\Aws;

$aws = Aws::factory('path/to/my/config.php');

$sqs = $aws->get('sqs');
// Note: SQS client will be configured for us-east-1.

$dynamodb = $aws->get('dynamodb');
// Note: DynamoDB client will be configured for us-west-2.

From Version 3 of the SDK

Key differences:

  • Use the Aws\Sdk class instead of Aws\Common\Aws.
  • No configuration file. Use an array for configuration instead.
  • The 'version' option is required during instantiation.
  • Use the create<Service>() methods instead of get('<service>').
<?php

require '/path/to/vendor/autoload.php';

$sdk = new Aws\Sdk([
    'profile' => 'my_profile',
    'region' => 'us-east-1',
    'version' => 'latest',
    'DynamoDb' => [
        'region' => 'us-west-2',
    ],
]);

$sqs = $sdk->createSqs();
// Note: SQS client will be configured for us-east-1.

$dynamodb = $sdk->createDynamoDb();
// Note: DynamoDB client will be configured for us-west-2.