Traditionally, when the user wants to share his resource on one application to another application, the user needs to give his credential to another application that causes the privacy issues. Then OAuth protocol was introduced to solve the problem without providing the user’s credential. The protocol was also designed to support mobile, desktop, and web applications. This makes OAuth protocol an essential functionality for a newly developed project. Therefore, the need of migrating the current data repositories to support authorization as an OAuth server gains more attention. However, there have been many software libraries publicly available to download; all of them focus on processing and constructing the messages that comply with the OAuth standard. None of them provides the channel that a new OAuth server could integrate the existing resources with their business logics to the service. This paper pointed the issues and proposed the object-oriented class design that can solve the problems. Then the prototype was implemented and shown that it supports reusability of the existing business logics.