Amazon S3 transfer manager in AWS SDK for PHP Version 3

The Amazon S3 transfer manager in the AWS SDK for PHP is used to upload entire directories to an Amazon S3 bucket and download entire buckets to a local directory.

Uploading a local directory to Amazon S3

The Aws\S3\Transfer object is used to perform transfers. The following example shows how to recursively upload a local directory of files to an Amazon S3 bucket.

// Create an S3 client.
$client = new \Aws\S3\S3Client([
    'region'  => 'us-west-2',
    'version' => '2006-03-01',
]);

// Where the files will be sourced from.
$source = '/path/to/source/files';

// Where the files will be transferred to.
$dest = 's3://bucket';

// Create a transfer object.
$manager = new \Aws\S3\Transfer($client, $source, $dest);

// Perform the transfer synchronously.
$manager->transfer();

In this example, we created an Amazon S3 client, created a Transfer object, and performed transfer synchronously. Using the previous example demonstrates the bare minimum amount of code needed to perform a transfer. The transfer object can perform transfers asynchronously and has various configuration options you can use to customize the transfers.

You can upload the local files to a “subfolder” of an Amazon S3 bucket by providing a key prefix in the s3:// URI. The following example uploads the local files on disk to the bucket bucket and stores the files under the foo key prefix.

$source = '/path/to/source/files';
$dest = 's3://bucket/foo';
$manager = new \Aws\S3\Transfer($client, $source, $dest);
$manager->transfer();

Downloading an Amazon S3 bucket

You can recursively download an Amazon S3 bucket to a local directory on disk by specifying the $source argument as an Amazon S3 URI (e.g., s3://bucket) and the $dest argument as the path to a local directory.

// Where the files will be sourced from.
$source = 's3://bucket';

// Where the files will be transferred to.
$dest = '/path/to/destination/dir';

$manager = new \Aws\S3\Transfer($client, $source, $dest);
$manager->transfer();

You can include a key prefix in the Amazon S3 URI after the bucket to download only objects stored under a “pseudo-folder”. The following example downloads only files stored under the “/foo” key prefix of the given bucket.

$source = 's3://bucket/foo';
$dest = '/path/to/destination/dir';
$manager = new \Aws\S3\Transfer($client, $source, $dest);
$manager->transfer();

Configuration

The Transfer object constructor accepts the following arguments.

Async transfers

The Transfer object is an instance of GuzzleHttp\Promise\PromisorInterface. This means that the transfer can occur asynchronously and is initiated by calling the promise method of the object.

$source = '/path/to/source/files';
$dest = 's3://bucket';
$manager = new \Aws\S3\Transfer($client, $source, $dest);

// Initiate the transfer and get a promise.
$promise = $manager->promise();

// Do something when the transfer is complete using the then() method.
$promise->then(function () {
    echo 'Done!';
});

The promise will be rejected if any of the files fail to transfer. You can handle the failed transfer asynchronously using the otherwise method of the promise. The otherwise function accepts a callback to invoke when an error occurs. The callback accepts the $reason for the rejection, which will typically be an instance of Aws\Exception\AwsException (although a value of any type can be delivered to the callback).

$promise->otherwise(function ($reason) {
    echo 'Transfer failed: ';
    var_dump($reason);
});

Because the Transfer object returns a promise, these transfers can occur concurrently with other asynchronous promises.

Customizing the transfer manager’s commands

Custom options can be set on the operations executed by the transfer manager via a callback passed to its constructor.

$uploader = new Transfer($s3Client, $source, $dest, [
    'before' => function (\Aws\Command $command) {
        // Commands can vary for multipart uploads, so check which command
        // is being processed.
        if (in_array($command->getName(), ['PutObject', 'CreateMultipartUpload'])) {
            // Set custom cache-control metadata.
            $command['CacheControl'] = 'max-age=3600';
            // Apply a canned ACL.
            $command['ACL'] = strpos($command['Key'], 'CONFIDENTIAL') ### false
                ? 'public-read'
                : 'private';
        }
    },
]);