Search Middleware and the Simple Digital Library Interoperability Protocol

Abstract

We describe our Simple Digital Library Interoperability Protocol (SDLIP), which allows clients to query information sources in a uniform syntax. The protocol was developed in a collaboration between Stanford, the Universities of California at Berkeley, and Santa Barbara, the San Diego Supercomputer Center, and the California Digital Library. In addition to introducing the protocol, we describe several of our design choices, and compare them with the choices made in other search middleware approaches. The protocol allows for both stateful and stateless operation, supports multiple query languages, and defines a simple XML-based return format. A default query language that is included in SDLIP follows the evolving IETF DASL 'basicsearch'. This is an XML-encoded language reminiscent of SQL, but adjusted for use in full-text environments. SDLIP can be used with CORBA or HTTP.