OpenSearchServer is a powerful, enterprise-class, search engine program. Using its Web user interface, crawlers (Web, file, database, etc.), and REST/RESTFul API, you can integrate advanced full-text search capabilities into your application.
A RESTFul Web service and a new REST crawler were added. All existing features have been dramatically improved. The build system is now based on Maven. A Ruby client library is now available.
URL: OpenSearchServer | Search Engine API