1. Implementing VOSpace 1.0 without Axis
THE US NATIONAL VIRTUAL OBSERVATORY
Implementing VOSpace 1.0
without Axis
Matthew J. Graham (Caltech, NVO)
IVOA Beijing: Grid & Web Services 1
14 May 2007

2. IVOA Beijing: Grid & Web Services 1
Architecture
Metadata
store
Web
service
Data
server
Data
IVOA Beijing: Grid & Web Services 1
14 May 2007

3. IVOA Beijing: Grid & Web Services 1
Infrastructure
Preserve XML as much as possible
XMLBeans (xmlbeans.apache.org):
open source XML-Java binding tool based on StAX spec.
full XML Schema support and full XML Infoset fidelity
parse and generate XML documents that conform to the schema
XFire (xfire.codehaus.org):
next-generation Java SOAP framework built on StAX spec.
XMLBeans support
Virtuoso (virtuoso.openlinksw.com/wiki/main):
object-relational database for SQL, XML and RDF
supports SQL, XQuery and SQARQL
XML Infoset filelity: When unmarshalling an XML instance the full XML infoset is kept and is available to the developer. This is critical because because of the subset of XML that is not easily represented in Java. For example, order of the elements or comments might be needed in a particular application. More powerful and flexible than traditional binding tools.
IVOA Beijing: Grid & Web Services 1
14 May 2007

4. IVOA Beijing: Grid & Web Services 1
Implementation
Web service:
run as standalone service (using embedded Jetty) or deployed as Java servlet (Tomcat)
Metadata store:
interfaces for Virtuoso and MySQL
HTTP data server:
built on Apache HttpCore
supports HTTP PUT and GET (v1.1)
uses one-time URLs (1 hr lifetime)
JPARSS data server:
divides data into partitions that are sent over several parallel Java streams simultaneously using X.509 certificates and SSL
uses NVO proxy certificates from NCSA MyProxy server
Client:
simple command-line client to web service and HTTP and JPARSS data servers using Apache Axis Final
JavaScript client for browser use (work in progress)
IVOA Beijing: Grid & Web Services 1
14 May 2007

5. IVOA Beijing: Grid & Web Services 1
Status
Deployed at
Shipped as part of NVOSS 2006 and NVO Book software packages
Installation guide/tutorial in NVO Book
Tested client with ESO VOSpace implementation
Untested:
WS-Security (XFire/Virtuoso)
View conversions
WebDAV (reuse VOStore 1.0 code)
IVOA Beijing: Grid & Web Services 1
14 May 2007

6. IVOA Beijing: Grid & Web Services 1
Moving to VOSpace 1.1
Additional node types:
Containers:
Supported in VOStore reuse business logic
Assume Unix logic for “/” and children: /foo vs. /foo/
Issue about container level views - are these transfer formats?
Links
Just DataNode with no bytes
IVOA Beijing: Grid & Web Services 1
14 May 2007