SRW/U
SRW (Search Retrieve Web Service) and SRU
(Search/Retrieve via URL) are web services protocols for querying indexes
and databases on the web and returning search results.
What it is
SRW (Search Retrieve Web Service) and SRU
(Search/Retrieve via URL) are web services protocols for querying indexes
and databases on the web and returning search results. The
idea behind them is similar to the older Z39.50 protocol for search and
retrieve. However, SRW/U is based on modern Web 2.0
technology and uses HTTP, web browsers, and XML. It is
therefore simpler to implement.
How it Works
In simple terms, SRW/U sends a search request to a
remote computer, and results are returned as an XML stream. If
the user has a modern web browser, the browser translates the XML into HTML
and the results are displayed.
Both SRW and SRU use Common Query Language (CQL) for
search requests. The main difference is in how queries and
results are encapsulated and transmitted. For SRU,
queries are sent as a URL using a HTTP GET request. For
SRW, SOAP is used as an extra protocol layer, and the query is sent as XML
using an HTTP POST request.
The Standard
Both standards are maintained by the US Library of
Congress and details are on the SRU web site.
SRW/U in the PALS Programmes
-
metadata+ –
NeSC developed testbed machine services for metadata discovery and
aggregation, including SRU for searching and OpenURL for linking.
Further Information