signer

type MultipartPart struct {
	PartNumber int32
	ETag       string
}

type SignOptions struct {
	ExpiresIn time.Duration
	Method    string
}

type Signer interface {
	// SignURL signs a URL for the given resource (usually for Get or Put).
	SignURL(ctx context.Context, bucket, key string, opts SignOptions) (string, error)

	// SignDownloadPart signs a URL for downloading a specific byte range.
	SignDownloadPart(ctx context.Context, bucket, key string, start int64, end int64, opts SignOptions) (string, error)

	// InitMultipartUpload initializes a multipart upload and returns an upload ID.
	InitMultipartUpload(ctx context.Context, bucket, key string) (string, error)

	// SignMultipartPart signs a URL for uploading a specific part of a multipart upload.
	SignMultipartPart(ctx context.Context, bucket, key, uploadID string, partNumber int32) (string, error)

	// CompleteMultipartUpload finalizes a multipart upload.
	CompleteMultipartUpload(ctx context.Context, bucket, key, uploadID string, parts []MultipartPart) error
}