How to list and upload S3 bucket contents using Scala.

AWS Java SDK

You have to import the AWS Java SDK version 2, S3 package as follows:

libraryDependencies += "software.amazon.awssdk" % "s3" % "2.18.27"

List Bucket Contents

import software.amazon.awssdk.regions.Region
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider
import software.amazon.awssdk.services.s3.S3Client
import software.amazon.awssdk.services.s3.model.ListObjectsRequest
import software.amazon.awssdk.services.s3.model.ListObjectsResponse
import software.amazon.awssdk.services.s3.model.S3Exception
import software.amazon.awssdk.services.s3.model.S3Object

import java.util.List;

    val bucketName = "ojitha"
    val credentialsProvider = ProfileCredentialsProvider.create();
    val region = Region.AP_SOUTHEAST_2;
    val s3 = S3Client.builder()
            .region(region)
            .credentialsProvider(credentialsProvider)
            .build();
    val listObjects = ListObjectsRequest
                .builder()
                .bucket(bucketName)
                .build();
    val res = s3.listObjects(listObjects)
    val objects = res.contents()            
    // listBucketObjects(s3, bucketName);
    s3.close();

objects

    [S3Object(Key=philip toothbrush.jpeg, LastModified=2022-12-03T22:14:39Z, ETag="e9540d38a9b1f385182030162f5b5adb", Size=1773326, StorageClass=STANDARD, Owner=Owner(DisplayName=ojitha, ID=2e4dff4014bf54544a0e2d65e6712b142be4bfbce098f66b9f242df14372615e))]

Upload file to S3

In the following example, the file mytest.txt will be created in the local file system and upload that in to the S3 bucket.

import software.amazon.awssdk.regions.Region
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider
import software.amazon.awssdk.services.s3.S3Client
import software.amazon.awssdk.services.s3.model.ListObjectsRequest
import software.amazon.awssdk.services.s3.model.ListObjectsResponse
import software.amazon.awssdk.services.s3.model.S3Exception
import software.amazon.awssdk.services.s3.model.S3Object

import software.amazon.awssdk.services.s3.model.PutObjectRequest
import software.amazon.awssdk.core.sync.RequestBody

import java.io.PrintWriter
import java.nio.file.{Files, Paths}
import java.io.File

import java.util.HashMap
import java.util.Map

Create S3 client

val bucketName = "ojitha"
val objectKey = "mytest.txt"
val credentialsProvider = ProfileCredentialsProvider.create()
val region = Region.AP_SOUTHEAST_2

// create S3 client
val s3 = S3Client.builder()
        .region(region)
        .credentialsProvider(credentialsProvider)
        .build();

As shown in the first line, the target bucket is ojitha and the file to upload is mytest.txt.

First will create mytest.txt file locally:

// PrintWriter
val pw = new PrintWriter(new File(objectKey))
pw.write("Hello, Ojitha\n")
pw.write("How are you?\n")
pw.close

File as a byte array:

val byteArray = Files.readAllBytes(Paths.get(objectKey))

Above byte array you can upload to the S3 bucket:

val metadata = new HashMap[String, String]()
metadata.put("x-amz-meta-myVal", "test")
val putOb = PutObjectRequest.builder()
    .bucket(bucketName)
    .key(objectKey)
    .metadata(metadata)
    .build()

val response = s3.putObject(putOb, RequestBody.fromBytes(byteArray));

Now you can close the S3 client

s3.close()