Gunakan checksum untuk bekerja dengan objek Amazon S3 menggunakan AWS SDK

Contoh kode menggunakan subset dari impor berikut.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import software.amazon.awssdk.core.exception.SdkException;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.ChecksumAlgorithm;
import software.amazon.awssdk.services.s3.model.ChecksumMode;
import software.amazon.awssdk.services.s3.model.CompletedMultipartUpload;
import software.amazon.awssdk.services.s3.model.CompletedPart;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
import software.amazon.awssdk.services.s3.model.GetObjectResponse;
import software.amazon.awssdk.services.s3.model.UploadPartRequest;
import software.amazon.awssdk.services.s3.model.UploadPartResponse;
import software.amazon.awssdk.services.s3.waiters.S3Waiter;
import software.amazon.awssdk.transfer.s3.S3TransferManager;
import software.amazon.awssdk.transfer.s3.model.FileUpload;
import software.amazon.awssdk.transfer.s3.model.UploadFileRequest;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.file.Paths;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Base64;
import java.util.List;
import java.util.Objects;
import java.util.UUID;

Tentukan algoritma checksum untuk metode putObject saat Anda membangun PutObjectRequest.

    public void putObjectWithChecksum(String bucketName, String key) {
        s3Client.putObject(b -> b
                .bucket(bucketName)
                .key(key)
                .checksumAlgorithm(ChecksumAlgorithm.CRC32),
            RequestBody.fromString("This is a test"));
    }

Verifikasi checksum untuk getObject metode saat Anda membangun. GetObjectRequest

    public GetObjectResponse getObjectWithChecksum(String bucketName, String key) {
        return s3Client.getObject(b -> b
                .bucket(bucketName)
                .key(key)
                .checksumMode(ChecksumMode.ENABLED))
            .response();
    }

Pre-calculate checksum untuk putObject metode saat Anda membangun. PutObjectRequest

    public void putObjectWithPrecalculatedChecksum(String bucketName, String key, String filePath) {
        String checksum = calculateChecksum(filePath, "SHA-256");

        s3Client.putObject((b -> b
                .bucket(bucketName)
                .key(key)
                .checksumSHA256(checksum)),
            RequestBody.fromFile(Paths.get(filePath)));
    }

Gunakan S3 Transfer Manager di atas klien AWS CRT-based S3 untuk melakukan unggahan multipart secara transparan ketika ukuran konten melebihi ambang batas. Ukuran ambang default adalah 8 MB.

Anda dapat menentukan algoritma checksum untuk SDK yang akan digunakan. Secara default, SDK menggunakan algoritma CRC32.

    public void multipartUploadWithChecksumTm(String bucketName, String key, String filePath) {
        S3TransferManager transferManager = S3TransferManager.create();
        UploadFileRequest uploadFileRequest = UploadFileRequest.builder()
            .putObjectRequest(b -> b
                .bucket(bucketName)
                .key(key)
                .checksumAlgorithm(ChecksumAlgorithm.SHA1))
            .source(Paths.get(filePath))
            .build();
        FileUpload fileUpload = transferManager.uploadFile(uploadFileRequest);
        fileUpload.completionFuture().join();
        transferManager.close();
    }

Gunakan S3Client API atau (S3AsyncClient API) untuk melakukan pengunggahan multipart. Jika Anda menentukan checksum tambahan, Anda juga harus menentukan algoritma yang akan digunakan pada inisiasi unggahan. Anda juga harus menentukan algoritma untuk setiap permintaan bagian dan memberikan checksum yang dihitung untuk setiap bagian setelah diunggah.

    public void multipartUploadWithChecksumS3Client(String bucketName, String key, String filePath) {
        ChecksumAlgorithm algorithm = ChecksumAlgorithm.CRC32;

        // Initiate the multipart upload.
        CreateMultipartUploadResponse createMultipartUploadResponse = s3Client.createMultipartUpload(b -> b
            .bucket(bucketName)
            .key(key)
            .checksumAlgorithm(algorithm)); // Checksum specified on initiation.
        String uploadId = createMultipartUploadResponse.uploadId();

        // Upload the parts of the file.
        int partNumber = 1;
        List<CompletedPart> completedParts = new ArrayList<>();
        ByteBuffer bb = ByteBuffer.allocate(1024 * 1024 * 5); // 5 MB byte buffer

        try (RandomAccessFile file = new RandomAccessFile(filePath, "r")) {
            long fileSize = file.length();
            long position = 0;
            while (position < fileSize) {
                file.seek(position);
                long read = file.getChannel().read(bb);

                bb.flip(); // Swap position and limit before reading from the buffer.
                UploadPartRequest uploadPartRequest = UploadPartRequest.builder()
                    .bucket(bucketName)
                    .key(key)
                    .uploadId(uploadId)
                    .checksumAlgorithm(algorithm) // Checksum specified on each part.
                    .partNumber(partNumber)
                    .build();

                UploadPartResponse partResponse = s3Client.uploadPart(
                    uploadPartRequest,
                    RequestBody.fromByteBuffer(bb));

                CompletedPart part = CompletedPart.builder()
                    .partNumber(partNumber)
                    .checksumCRC32(partResponse.checksumCRC32()) // Provide the calculated checksum.
                    .eTag(partResponse.eTag())
                    .build();
                completedParts.add(part);

                bb.clear();
                position += read;
                partNumber++;
            }
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }

        // Complete the multipart upload.
        s3Client.completeMultipartUpload(b -> b
            .bucket(bucketName)
            .key(key)
            .uploadId(uploadId)
            .multipartUpload(CompletedMultipartUpload.builder().parts(completedParts).build()));
    }