The SRU package provides a framework for working with the Search and
Retrieval by URL (SRU) protocol developed by the Library of Congress. SRU
defines a web service for searching databases containing metadata and
objects. SRU often goes under the name SRW which is a SOAP version of the
protocol. You can think of SRU as a RESTful version of SRW, since all the
requests are simple URLs instead of XML documents being sent via some sort
of transport layer.
