Method AppendObject

api-append-object.go:189–244

AppendObject - S3 Express Zone https://docs.aws.amazon.com/AmazonS3/latest/userguide/directory-buckets-objects-append.html Note that appending on a server without append support may overwrite the object.

(ctx context.Context, bucketName, objectName string, reader io.Reader, objectSize int64,
	opts AppendObjectOptions,
)

// AppendObject - S3 Express Zone https://docs.aws.amazon.com/AmazonS3/latest/userguide/directory-buckets-objects-append.html
// Note that appending on a server without append support may overwrite the object.
func (c *Client) AppendObject(ctx context.Context, bucketName, objectName string, reader io.Reader, objectSize int64,
	opts AppendObjectOptions,
) (info UploadInfo, err error) {
	if objectSize < 0 && opts.ChunkSize == 0 {
		return UploadInfo{}, errors.New("object size must be provided when no chunk size is provided")
	}

	if err = opts.validate(c); err != nil {
		return UploadInfo{}, err
	}

	oinfo, err := c.StatObject(ctx, bucketName, objectName, StatObjectOptions{Checksum: true})
	if err != nil {
		return UploadInfo{}, err
	}
	if oinfo.ChecksumMode != "" && oinfo.ChecksumMode != ChecksumFullObjectMode.String() {
		return UploadInfo{}, fmt.Errorf("Append() is not allowed on objects that are not of FULL_OBJECT checksum type: %s", oinfo.ChecksumMode)
	}
	opts.setChecksumParams(oinfo)   // set the appropriate checksum params based on the existing object checksum metadata.
	opts.setWriteOffset(oinfo.Size) // First append must set the current object size as the offset.

	if opts.ChunkSize > 0 {
		finalObjSize := int64(-1)
		if objectSize > 0 {
			finalObjSize = info.Size + objectSize
		}
		totalPartsCount, partSize, lastPartSize, err := OptimalPartInfo(finalObjSize, opts.ChunkSize)
		if err != nil {
			return UploadInfo{}, err
		}
		buf := make([]byte, partSize)
		var partNumber int
		for partNumber = 1; partNumber <= totalPartsCount; partNumber++ {
			// Proceed to upload the part.
			if partNumber == totalPartsCount {
				partSize = lastPartSize
			}
			n, err := readFull(reader, buf)
			if err != nil {
				return info, err
			}
			if n != int(partSize) {
				return info, io.ErrUnexpectedEOF
			}
			rd := newHook(bytes.NewReader(buf[:n]), opts.Progress)
			uinfo, err := c.appendObjectDo(ctx, bucketName, objectName, rd, partSize, opts)
			if err != nil {
				return info, err
			}
			opts.setWriteOffset(uinfo.Size)
		}
	}

	rd := newHook(reader, opts.Progress)
	return c.appendObjectDo(ctx, bucketName, objectName, rd, objectSize, opts)
}