// As per "Permission" section in
			// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectGET.html
			// If the object you request does not exist,
			// the error Amazon S3 returns depends on
			// whether you also have the s3:ListBucket
			// permission.
			// * If you have the s3:ListBucket permission
			//   on the bucket, Amazon S3 will return an
			//   HTTP status code 404 ("no such key")
			//   error.

			// As per "Permission" section in
			// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectGET.html
			// If the object you request does not exist,
			// the error Amazon S3 returns depends on
			// whether you also have the s3:ListBucket
			// permission.
			// * If you have the s3:ListBucket permission
			//   on the bucket, Amazon S3 will return an
			//   HTTP status code 404 ("no such key")
			//   error.

    end
end

# TODO: provide details on different books.
def get_book_details(id, headers)
    if ENV['ENABLE_EXTERNAL_BOOK_SERVICE'] === 'true' then
      # the ISBN of one of Comedy of Errors on the Amazon
      # that has Shakespeare as the single author
        isbn = '0486424618'
        return fetch_details_from_external_service(isbn, id, headers)
    end

    return {
        'id' => id,

	}

	policyBuf, err := json.Marshal(sessionPolicy)
	if err != nil {
		return err
	}

	// https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html
	// https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html
	// The plain text that you use for both inline and managed session
	// policies shouldn't exceed maxSTSSessionPolicySize characters.

			return nil, ErrUnsignedHeaders
		}
	}
	return extractedSignedHeaders, ErrNone
}

// Trim leading and trailing spaces and replace sequential spaces with one space, following Trimall()
// in http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
func signV4TrimAll(input string) string {
	// Compress adjacent spaces (a space is determined by
	// unicode.IsSpace() internally here) to one space and return

	}

	// Content-Md5 is required should be set
	// http://docs.aws.amazon.com/AmazonS3/latest/API/multiobjectdeleteapi.html
	if _, ok := r.Header[xhttp.ContentMD5]; !ok {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrMissingContentMD5), r.URL)
		return
	}

	// Content-Length is required and should be non-zero
	// http://docs.aws.amazon.com/AmazonS3/latest/API/multiobjectdeleteapi.html
	if r.ContentLength <= 0 {

// Streaming signature clients can have custom content-encoding such as
// `aws-chunked,gzip` here we need to only save `gzip`.
// For more refer http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-streaming.html
func trimAwsChunkedContentEncoding(contentEnc string) (trimmedContentEnc string) {
	if contentEnc == "" {
		return contentEnc
	}
	var newEncs []string

// separated by periods. Each label can contain lowercase ascii
// letters, decimal digits and hyphens, but must not begin or end with
// a hyphen. See:
// http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html
func IsValidBucketName(bucket string) bool {
	// Special case when bucket is equal to one of the meta buckets.
	if isMinioMetaBucketName(bucket) {
		return true
	}

		return nil, err
	}
	return &req, nil
}

// validate a RestoreObjectRequest as per AWS S3 spec https://docs.aws.amazon.com/AmazonS3/latest/API/API_RestoreObject.html
func (r *RestoreObjectRequest) validate(ctx context.Context, objAPI ObjectLayer) error {
	if r.Type != SelectRestoreRequest && !r.SelectParameters.IsEmpty() {

}

// APIErrorCode type of error status.
type APIErrorCode int

//go:generate stringer -type=APIErrorCode -trimprefix=Err $GOFILE

// Error codes, non exhaustive list - http://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html
const (
	ErrNone APIErrorCode = iota
	ErrAccessDenied
	ErrBadDigest
	ErrEntityTooSmall
	ErrEntityTooLarge
	ErrPolicyTooLarge
	ErrIncompleteBody
	ErrInternalError