OpenWebServer: An Adaptive Web Server Using Software Patterns

CHALLENGES FACING WEB SERVERS Current Web servers must: • Connect with various systems such as groupware, database management systems, mobile agent engines, and transaction processing monitors. • Integrate generic communication environments including Common Object Request Broker Architecture (CORBA) and Distributed Component Object Model (DCOM) • Extend server functionality by introducing additional network protocols or content data types • Change server execution policies; for example, optimizing concurrency, connection management, request handling, and cache management. • Adapt to execution environments such as ATM networks and electronic devices such as network routers, printers, or copiers Every user may not require the same functionality in a Web server. Therefore, a Web server should be flexible enough to meet a wide range of requirements on demand. Most Web servers, unfortunately, are monolithic. They provide a fixed and limited set of capabilities. When additional functionality is required, the usual solution involves shutting down the system, modifying one or more components, integrating them with existing components, and restarting the system. This solution is often difficult or expensive to maintain, and does not allow the server to be used during the upgrade. Therefore, it is typical to take the “scrap-and-build” approach for a given requirement, where the software is rewritten from scratch because it may be more economically feasible. A dynamically adaptable Web server architecture based on reusable components is an attractive alternative for extensive and intrusive changes.