HandlerFunc(s3APIMiddleware(api.GetObjectAttributesHandler, traceHdrsS3HFlag)).
			Queries("attributes", "")

		// CopyObjectPart
		router.Methods(http.MethodPut).Path("/{object:.+}").
			HeadersRegexp(xhttp.AmzCopySource, ".*?(\\/|%2F).*?").
			HandlerFunc(s3APIMiddleware(api.CopyObjectPartHandler)).
			Queries("partNumber", "{partNumber:.*}", "uploadId", "{uploadId:.*}")
		// PutObjectPart

	for _, apiFunction := range apiFunctions {
		switch apiFunction {
		case "PostPolicy":
			// Register PostPolicy handler.
			bucket.Methods(http.MethodPost).HeadersRegexp("Content-Type", "multipart/form-data*").HandlerFunc(api.PostPolicyBucketHandler)
		case "HeadObject":
			// Register HeadObject handler.
			bucket.Methods("Head").Path("/{object:.+}").HandlerFunc(api.HeadObjectHandler)

	}

	// Below is how CopyObjectPartHandler is registered.
	// bucket.Methods(http.MethodPut).Path("/{object:.+}").HeadersRegexp("X-Amz-Copy-Source", ".*?(\\/|%2F).*?").HandlerFunc(api.CopyObjectPartHandler).Queries("partNumber", "{partNumber:[0-9]+}", "uploadId", "{uploadId:.*}")