Amazon S3 SDK: List objects

import (
	"context"
	"fmt"
	"io"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
)

func listGCSObjects(w io.Writer, bucketName string, googleAccessKeyID string, googleAccessKeySecret string) error {
	// bucketName := "your-gcs-bucket-name"
	// googleAccessKeyID := "Your Google Access Key ID"
	// googleAccessKeySecret := "Your Google Access Key Secret"

	// Create a new client and do the following:
	// 1. Change the endpoint URL to use the Google Cloud Storage XML API endpoint.
	// 2. Use Cloud Storage HMAC Credentials.
	sess := session.Must(session.NewSession(&aws.Config{
		Region:      aws.String("auto"),
		Endpoint:    aws.String("https://storage.googleapis.com"),
		Credentials: credentials.NewStaticCredentials(googleAccessKeyID, googleAccessKeySecret, ""),
	}))

	client := s3.New(sess)
	ctx := context.Background()

	result, err := client.ListObjectsWithContext(ctx, &s3.ListObjectsInput{
		Bucket: aws.String(bucketName),
	})
	if err != nil {
		return fmt.Errorf("ListObjectsWithContext: %w", err)
	}

	fmt.Fprintf(w, "Objects:")
	for _, o := range result.Contents {
		fmt.Fprintf(w, "%s\n", aws.StringValue(o.Key))
	}

	return nil
}

import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3ObjectSummary;

public class ListGcsObjects {
  public static void listGcsObjects(
      String googleAccessKeyId, String googleAccessKeySecret, String bucketName) {

    // String googleAccessKeyId = "your-google-access-key-id";
    // String googleAccessKeySecret = "your-google-access-key-secret";
    // String bucketName = "bucket-name";

    // Create a BasicAWSCredentials using Cloud Storage HMAC credentials.
    BasicAWSCredentials googleCreds =
        new BasicAWSCredentials(googleAccessKeyId, googleAccessKeySecret);

    // Create a new client and do the following:
    // 1. Change the endpoint URL to use the Google Cloud Storage XML API endpoint.
    // 2. Use Cloud Storage HMAC Credentials.
    AmazonS3 interopClient =
        AmazonS3ClientBuilder.standard()
            .withEndpointConfiguration(
                new AwsClientBuilder.EndpointConfiguration(
                    "https://storage.googleapis.com", "auto"))
            .withCredentials(new AWSStaticCredentialsProvider(googleCreds))
            .build();

    // Call GCS to list current objects
    ObjectListing objects = interopClient.listObjects(bucketName);

    // Print objects names
    System.out.println("Objects:");
    for (S3ObjectSummary object : objects.getObjectSummaries()) {
      System.out.println(object.getKey());
    }

    // Explicitly clean up client resources.
    interopClient.shutdown();
  }
}

import boto3  # type: ignore


def list_gcs_objects(
    google_access_key_id: str, google_access_key_secret: str, bucket_name: str
) -> List[str]:
    """Lists all Cloud Storage objects using AWS SDK for Python (boto3)
    Positional arguments:
        google_access_key_id: hash-based message authentication code (HMAC) access ID
        google_access_key_secret: HMAC access secret
        bucket_name: name of Cloud Storage bucket

    Returned value is a list of strings, one for each object in the bucket.

    To use this sample:
    1. Create a Cloud Storage HMAC key: https://cloud.google.com/storage/docs/authentication/managing-hmackeys#create
    2. Change endpoint_url to a Google Cloud Storage XML API endpoint.

    To learn more about HMAC: https://cloud.google.com/storage/docs/authentication/hmackeys#overview
    """
    client = boto3.client(
        "s3",
        region_name="auto",
        endpoint_url="https://storage.googleapis.com",
        aws_access_key_id=google_access_key_id,
        aws_secret_access_key=google_access_key_secret,
    )

    # Call GCS to list objects in bucket_name
    response = client.list_objects(Bucket=bucket_name)

    # Return list of object names in bucket
    results = []
    for blob in response["Contents"]:
        results.append(blob["Key"])
        print(blob["Key"])  # Can remove if not needed after development
    return results