List objects in an Amazon S3 bucket using an AWS SDK

The following code examples show how to list objects in an S3 bucket.

.NET

AWS SDK for .NET

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

        /// <summary>
        /// Shows how to list the objects in an Amazon S3 bucket.
        /// </summary>
        /// <param name="client">An initialized Amazon S3 client object.</param>
        /// <param name="bucketName">The name of the bucket for which to list
        /// the contents.</param>
        /// <returns>A boolean value indicating the success or failure of the
        /// copy operation.</returns>
        public static async Task<bool> ListBucketContentsAsync(IAmazonS3 client, string bucketName)
        {
            try
            {
                var request = new ListObjectsV2Request
                {
                    BucketName = bucketName,
                    MaxKeys = 5,
                };

                Console.WriteLine("--------------------------------------");
                Console.WriteLine($"Listing the contents of {bucketName}:");
                Console.WriteLine("--------------------------------------");

                ListObjectsV2Response response;

                do
                {
                    response = await client.ListObjectsV2Async(request);

                    response.S3Objects
                        .ForEach(obj => Console.WriteLine($"{obj.Key,-35}{obj.LastModified.ToShortDateString(),10}{obj.Size,10}"));

                    // If the response is truncated, set the request ContinuationToken
                    // from the NextContinuationToken property of the response.
                    request.ContinuationToken = response.NextContinuationToken;
                }
                while (response.IsTruncated);

                return true;
            }
            catch (AmazonS3Exception ex)
            {
                Console.WriteLine($"Error encountered on server. Message:'{ex.Message}' getting list of objects.");
                return false;
            }
        }

List objects with a paginator.

    using System;
    using System.Threading.Tasks;
    using Amazon.S3;
    using Amazon.S3.Model;

    /// <summary>
    /// The following example lists objects in an Amazon Simple Storage
    /// Service (Amazon S3) bucket. It was created using AWS SDK for .NET 3.5
    /// and .NET Core 5.0.
    /// </summary>
    public class ListObjectsPaginator
    {
        private const string BucketName = "doc-example-bucket";

        public static async Task Main()
        {
            IAmazonS3 s3Client = new AmazonS3Client();

            Console.WriteLine($"Listing the objects contained in {BucketName}:\n");
            await ListingObjectsAsync(s3Client, BucketName);
        }

        /// <summary>
        /// This method uses a paginator to retrieve the list of objects in an
        /// an Amazon S3 bucket.
        /// </summary>
        /// <param name="client">An Amazon S3 client object.</param>
        /// <param name="bucketName">The name of the S3 bucket whose objects
        /// you want to list.</param>
        public static async Task ListingObjectsAsync(IAmazonS3 client, string bucketName)
        {
            var listObjectsV2Paginator = client.Paginators.ListObjectsV2(new ListObjectsV2Request
            {
                BucketName = bucketName,
            });

            await foreach (var response in listObjectsV2Paginator.Responses)
            {
                Console.WriteLine($"HttpStatusCode: {response.HttpStatusCode}");
                Console.WriteLine($"Number of Keys: {response.KeyCount}");
                foreach (var entry in response.S3Objects)
                {
                    Console.WriteLine($"Key = {entry.Key} Size = {entry.Size}");
                }
            }
        }
    }

• For API details, see ListObjects in AWS SDK for .NET API Reference.

C++

SDK for C++

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

bool AwsDoc::S3::ListObjects(const Aws::String &bucketName,
                             const Aws::Client::ClientConfiguration &clientConfig) {
    Aws::S3::S3Client s3_client(clientConfig);

    Aws::S3::Model::ListObjectsRequest request;
    request.WithBucket(bucketName);

    auto outcome = s3_client.ListObjects(request);

    if (!outcome.IsSuccess()) {
        std::cerr << "Error: ListObjects: " <<
                  outcome.GetError().GetMessage() << std::endl;
    }
    else {
        Aws::Vector<Aws::S3::Model::Object> objects =
                outcome.GetResult().GetContents();

        for (Aws::S3::Model::Object &object: objects) {
            std::cout << object.GetKey() << std::endl;
        }
    }

    return outcome.IsSuccess();
}

• For API details, see ListObjects in AWS SDK for C++ API Reference.

Go

SDK for Go V2

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// ListObjects lists the objects in a bucket.
func (basics BucketBasics) ListObjects(bucketName string) ([]types.Object, error) {
	result, err := basics.S3Client.ListObjectsV2(context.TODO(), &s3.ListObjectsV2Input{
		Bucket: aws.String(bucketName),
	})
	var contents []types.Object
	if err != nil {
		log.Printf("Couldn't list objects in bucket %v. Here's why: %v\n", bucketName, err)
	} else {
		contents = result.Contents
	}
	return contents, err
}

• For API details, see ListObjects in AWS SDK for Go API Reference.

Java

SDK for Java 2.x

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public static void listBucketObjects(S3Client s3, String bucketName ) {

        try {
            ListObjectsRequest listObjects = ListObjectsRequest
                .builder()
                .bucket(bucketName)
                .build();

            ListObjectsResponse res = s3.listObjects(listObjects);
            List<S3Object> objects = res.contents();
            for (S3Object myValue : objects) {
                System.out.print("\n The name of the key is " + myValue.key());
                System.out.print("\n The object is " + calKb(myValue.size()) + " KBs");
                System.out.print("\n The owner is " + myValue.owner());
            }

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    //convert bytes to kbs.
    private static long calKb(Long val) {
        return val/1024;
    }

List objects using pagination.

    public static void listBucketObjects(S3Client s3, String bucketName ) {
        try {
            ListObjectsV2Request listReq = ListObjectsV2Request.builder()
                .bucket(bucketName)
                .maxKeys(1)
                .build();

            ListObjectsV2Iterable listRes = s3.listObjectsV2Paginator(listReq);
            listRes.stream()
                .flatMap(r -> r.contents().stream())
                .forEach(content -> System.out.println(" Key: " + content.key() + " size = " + content.size()));

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

• For API details, see ListObjects in AWS SDK for Java 2.x API Reference.

JavaScript

SDK for JavaScript (v3)

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

List all of the objects in your bucket. If there is more than one object, IsTruncated and NextContinuationToken will be used to iterate over the full list.

import {
  S3Client,
  // This command supersedes the ListObjectsCommand and is the recommended way to list objects.
  ListObjectsV2Command,
} from "@aws-sdk/client-s3";

const client = new S3Client({});

export const main = async () => {
  const command = new ListObjectsV2Command({
    Bucket: "my-bucket",
    // The default and maximum number of keys returned is 1000. This limits it to
    // one for demonstration purposes.
    MaxKeys: 1,
  });

  try {
    let isTruncated = true;

    console.log("Your bucket contains the following objects:\n")
    let contents = "";

    while (isTruncated) {
      const { Contents, IsTruncated, NextContinuationToken } = await client.send(command);
      const contentsList = Contents.map((c) => ` • ${c.Key}`).join("\n");
      contents += contentsList + "\n";
      isTruncated = IsTruncated;
      command.input.ContinuationToken = NextContinuationToken;
    }
    console.log(contents);

  } catch (err) {
    console.error(err);
  }
};

• For API details, see ListObjects in AWS SDK for JavaScript API Reference.

Kotlin

SDK for Kotlin

Note

This is prerelease documentation for a feature in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

suspend fun listBucketObjects(bucketName: String) {

    val request = ListObjectsRequest {
        bucket = bucketName
    }

    S3Client { region = "us-east-1" }.use { s3 ->

        val response = s3.listObjects(request)
        response.contents?.forEach { myObject ->
            println("The name of the key is ${myObject.key}")
            println("The object is ${calKb(myObject.size)} KBs")
            println("The owner is ${myObject.owner}")
        }
    }
}

private fun calKb(intValue: Long): Long {
    return intValue / 1024
}

• For API details, see ListObjects in AWS SDK for Kotlin API reference.

PHP

SDK for PHP

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

List objects in a bucket.

$s3client = new Aws\S3\S3Client(['region' => 'us-west-2', 'version' => 'latest']);

try {
    $contents = $s3client->listObjects([
        'Bucket' => $bucket_name,
    ]);
    echo "The contents of your bucket are: \n";
    foreach ($contents['Contents'] as $content) {
        echo $content['Key'] . "\n";
    }
} catch (Exception $exception) {
    echo "Failed to list objects in $bucket_name with error: " . $exception->getMessage();
    exit("Please fix error with listing objects before continuing.");
}

• For API details, see ListObjects in AWS SDK for PHP API Reference.

Python

SDK for Python (Boto3)

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

class ObjectWrapper:
    """Encapsulates S3 object actions."""
    def __init__(self, s3_object):
        """
        :param s3_object: A Boto3 Object resource. This is a high-level resource in Boto3
                          that wraps object actions in a class-like structure.
        """
        self.object = s3_object
        self.key = self.object.key

    @staticmethod
    def list(bucket, prefix=None):
        """
        Lists the objects in a bucket, optionally filtered by a prefix.

        :param bucket: The bucket to query. This is a Boto3 Bucket resource.
        :param prefix: When specified, only objects that start with this prefix are listed.
        :return: The list of objects.
        """
        try:
            if not prefix:
                objects = list(bucket.objects.all())
            else:
                objects = list(bucket.objects.filter(Prefix=prefix))
            logger.info("Got objects %s from bucket '%s'",
                        [o.key for o in objects], bucket.name)
        except ClientError:
            logger.exception("Couldn't get objects for bucket '%s'.", bucket.name)
            raise
        else:
            return objects

• For API details, see ListObjects in AWS SDK for Python (Boto3) API Reference.

Ruby

SDK for Ruby

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

require "aws-sdk-s3"

# Wraps Amazon S3 bucket actions.
class BucketListObjectsWrapper
  attr_reader :bucket

  # @param bucket [Aws::S3::Bucket] An existing Amazon S3 bucket.
  def initialize(bucket)
    @bucket = bucket
  end

  # Lists object in a bucket.
  #
  # @param max_objects [Integer] The maximum number of objects to list.
  # @return [Integer] The number of objects listed.
  def list_objects(max_objects)
    count = 0
    puts "The objects in #{@bucket.name} are:"
    @bucket.objects.each do |obj|
      puts "\t#{obj.key}"
      count += 1
      break if count == max_objects
    end
    count
  rescue Aws::Errors::ServiceError => e
    puts "Couldn't list objects in bucket #{bucket.name}. Here's why: #{e.message}"
    0
  end
end

def run_demo
  bucket_name = "doc-example-bucket"

  wrapper = BucketListObjectsWrapper.new(Aws::S3::Bucket.new(bucket_name))
  count = wrapper.list_objects(25)
  puts "Listed #{count} objects."
end

run_demo if $PROGRAM_NAME == __FILE__

• For API details, see ListObjects in AWS SDK for Ruby API Reference.

Rust

SDK for Rust

Note

This documentation is for an SDK in preview release. The SDK is subject to change and should not be used in production.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

pub async fn list_objects(client: &Client, bucket_name: &str) -> Result<(), Error> {
    let objects = client.list_objects_v2().bucket(bucket_name).send().await?;
    println!("Objects in bucket:");
    for obj in objects.contents().unwrap_or_default() {
        println!("{:?}", obj.key().unwrap());
    }

    Ok(())
}

• For API details, see ListObjects in AWS SDK for Rust API reference.

SAP ABAP

SDK for SAP ABAP

Note

This documentation is for an SDK in developer preview release. The SDK is subject to change and is not recommended for use in production.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    TRY.
        oo_result = lo_s3->listobjects(         " oo_result is returned for testing purposes. "
          iv_bucket = iv_bucket_name
        ).
        MESSAGE 'Retrieved list of objects in S3 bucket.' TYPE 'I'.
      CATCH /aws1/cx_s3_nosuchbucket.
        MESSAGE 'Bucket does not exist.' TYPE 'E'.
    ENDTRY.

• For API details, see ListObjects in AWS SDK for SAP ABAP API reference.

Swift

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func listBucketFiles(bucket: String) async throws -> [String] {
        let input = ListObjectsV2Input(
            bucket: bucket
        )
        let output = try await client.listObjectsV2(input: input)
        var names: [String] = []

        guard let objList = output.contents else {
            return []
        }

        for obj in objList {
            if let objName = obj.key {
                names.append(objName)
            }
        }

        return names
    }

• For API details, see ListObjects in AWS SDK for Swift API reference.

For a complete list of AWS SDK developer guides and code examples, see Using this service with an AWS SDK. This topic also includes information about getting started and details about previous SDK versions.