An apparatus and method is provided in which a server causes a client to back up a part of resource data of a server by use of an HTTP protocol. The method includes the steps of: transmitting the resource data to be backed-up to the client; determining whether or not the recovery of the resource data to be backed-up is required; transmitting, to the client, an HTTP response having a message that indicates the necessity of recovering the resource data to be backed-up, together with a message indicating that there is no update in the resource data to be backed-up, in response to the determination that indicates the necessity of recovering the resource data to be backed-up; and recovering the resource data to be backed-up by receiving a backup of the resource data to be backed-up from the client. The method of the present invention facilitates the processing of backing up, in the client, the resource data of the server and recovering the data when the resource data of the server is lost.