Utilizzo ListObjectsV2 con un AWS SDK o una CLI

        /// <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;
            }
        }

Elencare gli oggetti con un impaginatore.

    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.
    /// </summary>
    public class ListObjectsPaginator
    {
        private const string BucketName = "amzn-s3-demo-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}");
                }
            }
        }
    }

###############################################################################
# function errecho
#
# This function outputs everything sent to it to STDERR (standard error output).
###############################################################################
function errecho() {
  printf "%s\n" "$*" 1>&2
}

###############################################################################
# function list_items_in_bucket
#
# This function displays a list of the files in the bucket with each file's
# size. The function uses the --query parameter to retrieve only the key and
# size fields from the Contents collection.
#
# Parameters:
#       $1 - The name of the bucket.
#
# Returns:
#       The list of files in text format.
#     And:
#       0 - If successful.
#       1 - If it fails.
###############################################################################
function list_items_in_bucket() {
  local bucket_name=$1
  local response

  response=$(aws s3api list-objects \
    --bucket "$bucket_name" \
    --output text \
    --query 'Contents[].{Key: Key, Size: Size}')

  # shellcheck disable=SC2181
  if [[ ${?} -eq 0 ]]; then
    echo "$response"
  else
    errecho "ERROR: AWS reports s3api list-objects operation failed.\n$response"
    return 1
  fi
}

bool AwsDoc::S3::listObjects(const Aws::String &bucketName,
                             Aws::Vector<Aws::String> &keysResult,
                             const Aws::S3::S3ClientConfiguration &clientConfig) {
    Aws::S3::S3Client s3Client(clientConfig);

    Aws::S3::Model::ListObjectsV2Request request;
    request.WithBucket(bucketName);

    Aws::String continuationToken; // Used for pagination.
    Aws::Vector<Aws::S3::Model::Object> allObjects;

    do {
        if (!continuationToken.empty()) {
            request.SetContinuationToken(continuationToken);
        }

        auto outcome = s3Client.ListObjectsV2(request);

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

            allObjects.insert(allObjects.end(), objects.begin(), objects.end());
            continuationToken = outcome.GetResult().GetNextContinuationToken();
        }
    } while (!continuationToken.empty());

    std::cout << allObjects.size() << " object(s) found:" << std::endl;

    for (const auto &object: allObjects) {
        std::cout << "  " << object.GetKey() << std::endl;
        keysResult.push_back(object.GetKey());
    }

    return true;
}

Per ottenere un elenco di oggetti in un bucket

L'list-objects-v2esempio seguente elenca gli oggetti nel bucket specificato.

aws s3api list-objects-v2 \
    --bucket amzn-s3-demo-bucket

Output:

{
    "Contents": [
        {
            "LastModified": "2019-11-05T23:11:50.000Z",
            "ETag": "\"621503c373607d548b37cff8778d992c\"",
            "StorageClass": "STANDARD",
            "Key": "doc1.rtf",
            "Size": 391
        },
        {
            "LastModified": "2019-11-05T23:11:50.000Z",
            "ETag": "\"a2cecc36ab7c7fe3a71a273b9d45b1b5\"",
            "StorageClass": "STANDARD",
            "Key": "doc2.rtf",
            "Size": 373
        },
        {
            "LastModified": "2019-11-05T23:11:50.000Z",
            "ETag": "\"08210852f65a2e9cb999972539a64d68\"",
            "StorageClass": "STANDARD",
            "Key": "doc3.rtf",
            "Size": 399
        },
        {
            "LastModified": "2019-11-05T23:11:50.000Z",
            "ETag": "\"d1852dd683f404306569471af106988e\"",
            "StorageClass": "STANDARD",
            "Key": "doc4.rtf",
            "Size": 6225
        }
    ]
}

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// 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(ctx context.Context, bucketName string) ([]types.Object, error) {
	var err error
	var output *s3.ListObjectsV2Output
	input := &s3.ListObjectsV2Input{
		Bucket: aws.String(bucketName),
	}
	var objects []types.Object
	objectPaginator := s3.NewListObjectsV2Paginator(basics.S3Client, input)
	for objectPaginator.HasMorePages() {
		output, err = objectPaginator.NextPage(ctx)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucketName)
				err = noBucket
			}
			break
		} else {
			objects = append(objects, output.Contents...)
		}
	}
	return objects, err
}

    /**
     * Asynchronously lists all objects in the specified S3 bucket.
     *
     * @param bucketName the name of the S3 bucket to list objects for
     * @return a {@link CompletableFuture} that completes when all objects have been listed
     */
    public CompletableFuture<Void> listAllObjectsAsync(String bucketName) {
        ListObjectsV2Request initialRequest = ListObjectsV2Request.builder()
            .bucket(bucketName)
            .maxKeys(1)
            .build();

        ListObjectsV2Publisher paginator = getAsyncClient().listObjectsV2Paginator(initialRequest);
        return paginator.subscribe(response -> {
            response.contents().forEach(s3Object -> {
                logger.info("Object key: " + s3Object.key());
            });
        }).thenRun(() -> {
            logger.info("Successfully listed all objects in the bucket: " + bucketName);
        }).exceptionally(ex -> {
            throw new RuntimeException("Failed to list objects", ex);
        });
    }

Elenca gli oggetti usando l'impaginazione.

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.paginators.ListObjectsV2Iterable;

public class ListObjectsPaginated {
    public static void main(String[] args) {
        final String usage = """

            Usage:
                <bucketName>\s

            Where:
                bucketName - The Amazon S3 bucket from which objects are read.\s
            """;

        if (args.length != 1) {
            System.out.println(usage);
            System.exit(1);
        }

        String bucketName = args[0];
        Region region = Region.US_EAST_1;
        S3Client s3 = S3Client.builder()
            .region(region)
            .build();

        listBucketObjects(s3, bucketName);
        s3.close();
    }

    /**
     * Lists the objects in the specified S3 bucket.
     *
     * @param s3 the S3Client instance used to interact with Amazon S3
     * @param bucketName the name of the S3 bucket to list the objects from
     */
    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);
        }
    }
}

Elenca tutti gli oggetti nel bucket. Se è presente più di un oggetto, IsTruncated NextContinuationToken verrà utilizzato per scorrere l'elenco completo.

import {
  S3Client,
  S3ServiceException,
  // This command supersedes the ListObjectsCommand and is the recommended way to list objects.
  paginateListObjectsV2,
} from "@aws-sdk/client-s3";

/**
 * Log all of the object keys in a bucket.
 * @param {{ bucketName: string, pageSize: string }}
 */
export const main = async ({ bucketName, pageSize }) => {
  const client = new S3Client({});
  /** @type {string[][]} */
  const objects = [];
  try {
    const paginator = paginateListObjectsV2(
      { client, /* Max items per page */ pageSize: Number.parseInt(pageSize) },
      { Bucket: bucketName },
    );

    for await (const page of paginator) {
      objects.push(page.Contents.map((o) => o.Key));
    }
    objects.forEach((objectList, pageNum) => {
      console.log(
        `Page ${pageNum + 1}\n------\n${objectList.map((o) => `• ${o}`).join("\n")}\n`,
      );
    });
  } catch (caught) {
    if (
      caught instanceof S3ServiceException &&
      caught.name === "NoSuchBucket"
    ) {
      console.error(
        `Error from S3 while listing objects for "${bucketName}". The bucket doesn't exist.`,
      );
    } else if (caught instanceof S3ServiceException) {
      console.error(
        `Error from S3 while listing objects for "${bucketName}".  ${caught.name}: ${caught.message}`,
      );
    } else {
      throw caught;
    }
  }
};

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 ${myObject.size?.let { calKb(it) }} KBs")
            println("The owner is ${myObject.owner}")
        }
    }
}

private fun calKb(intValue: Long): Long = intValue / 1024

Elenca gli oggetti in un bucket.

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

        try {
            $contents = $this->s3client->listObjectsV2([
                'Bucket' => $this->bucketName,
            ]);
            echo "The contents of your bucket are: \n";
            foreach ($contents['Contents'] as $content) {
                echo $content['Key'] . "\n";
            }
        } catch (Exception $exception) {
            echo "Failed to list objects in $this->bucketName with error: " . $exception->getMessage();
            exit("Please fix error with listing objects before continuing.");
        }

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

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

# Example usage:
def run_demo
  bucket_name = "amzn-s3-demo-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__

pub async fn list_objects(client: &aws_sdk_s3::Client, bucket: &str) -> Result<(), S3ExampleError> {
    let mut response = client
        .list_objects_v2()
        .bucket(bucket.to_owned())
        .max_keys(10) // In this example, go 10 at a time.
        .into_paginator()
        .send();

    while let Some(result) = response.next().await {
        match result {
            Ok(output) => {
                for object in output.contents() {
                    println!(" - {}", object.key().unwrap_or("Unknown"));
                }
            }
            Err(err) => {
                eprintln!("{err:?}")
            }
        }
    }

    Ok(())
}

    TRY.
        oo_result = lo_s3->listobjectsv2(         " 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.

import AWSS3

    public func listBucketFiles(bucket: String) async throws -> [String] {
        do {
            let input = ListObjectsV2Input(
                bucket: bucket
            )
            
            // Use "Paginated" to get all the objects.
            // This lets the SDK handle the 'continuationToken' in "ListObjectsV2Output".
            let output = client.listObjectsV2Paginated(input: input)
            var names: [String] = []
            
            for try await page in output {
                guard let objList = page.contents else {
                    print("ERROR: listObjectsV2Paginated returned nil contents.")
                    continue
                }
                
                for obj in objList {
                    if let objName = obj.key {
                        names.append(objName)
                    }
                }
            }
            
            
            return names
        }
        catch {
            print("ERROR: ", dump(error, name: "Listing objects."))
            throw error
        }
    }