A Framework for Migrating Web Applications to Web Services

Abstract

Service Oriented Architecture (SOA) is an increasingly important software architecture, designed to flexibly connect separate components in response to rapid changes in the business environment. SOA focuses on the exchange of information between independent software components and on the reusability of the components by separating communication interface from internal implementation. There are several features of SOA that make legacy system modernization to SOA appealing in today’s world. These are loose coupling, abstraction of underlying logic, agility, flexibility, reusability, autonomy, statelessness, discoverability and reduced cost. Migration of legacy systems to SOA is an important problem. While migration of legacy data processing systems has been widely studied, migration of legacy web applications has not. In this thesis we review existing strategies for migration of monolithic legacy web applications to web services, noting the unique challenges due to the highly dynamic nature of the systems, poorly structured code, and weakly typed languages in web applications, and the need for automation to assist in the process. We present a new semi-automated framework for the analysis and migration of monolithic web applications to web services using source analysis and transformation techniques, and outline a set of source transformation steps that can be used to migrate existing legacy web applications to web services form. We demonstrate our framework on the analysis and automated restructuring of two large existing web applications to extract and migrate integrated internal features to independent, reusable web services.