fess
Open source enterprise search server for websites, files, and data
...It enables organizations to quickly deploy a scalable search environment without requiring deep knowledge of underlying search technologies. Fess is built on top of OpenSearch and offers an integrated solution for crawling, indexing, and searching documents from websites, file systems, and various data stores. Fess includes a built-in crawler that can collect content from sources such as databases, CSV files, and shared storage, making it suitable for centralized knowledge discovery. It supports indexing and searching across many document formats including office documents, PDFs, and compressed archives. ...