Sept 12-17 2004NVO Summer School1 Cone, SIAP, and OpenSkyQuery Client Development Gretchen Greene, Maria Nieto-Santisteban T HE US N ATIONAL V IRTUAL O.

Sept 12-17 2004NVO Summer School 1

Cone, SIAP, andOpenSkyQuery Client Development

Gretchen Greene, Maria Nieto-Santisteban

THE US NATIONAL VIRTUAL OBSERVATORY

Sept 12-17 2004NVO Summer School 2

This session explores

• Basic client development for standard http VO services– How-to for building tools, applications

• JAVA examples provided in course nvoss\dev files• Cone client, SIAP client, and skyportalclient tutorial on

the Twiki site (from SS program)– http://chart.stsci.edu/twiki/bin/view/Main/SummerSchoolClientSide– http://chart.stsci.edu/twiki/bin/view/Main/SummerSchoolSIAPClient

• Basic Web service clients• How to manipulate standard VO response

– XML VOTable parsing– SIAP output FITS

• Assumes some prior knowledge of service availability– Registries integration for locating services will be discussed

tomorrow (Plante/Graham)

Sept 12-17 2004NVO Summer School 3

Current Client interfaces to VO protocols

• VO DAL (Data Access Layers) returning VOTables– Cone Search: http Catalog access– Simple Image Access Protocol (SIAP)

• http retrieves image references– Simple Spectral Access Protocol (SSAP) still beta

and not presented here

• OpenSkyQuery portal– Web service (SOAP) programmatic interface

removes limitations of portal– Returns classes and operations including VOData

Sept 12-17 2004NVO Summer School 4

HTTP protocol PROS

• HTTP Interfaces return a standard VOTable– IVOA standard (current Version 1.1)– Several parsers exist: JAVOT, SAVOT, Perl, C++ http://www.ivoa.net/twiki/bin/view/IVOA/VOTableSoftware#Parsers– Suite of compatible tools available:http://www.ivoa.net/twiki/bin/view/IVOA/VOTableSoftware

#Applications

• Language independent: network protocol based

• cgi is easy to implement

Sept 12-17 2004NVO Summer School 5

HTTP protocol CONS

• Returns only VOTables – Limited simplistic Metadata, i.e. fields, UCDs, etc.

• Registries will contain more meta information yet still dependent on standard exchange– VOResource Schema design

• description level of resources/services:– e.g. Invocation methods, resource Relationships, coverage,

+

• Requires parsers• Query input parameter limited

– ra,dec,sz

Sept 12-17 2004NVO Summer School 6

Future for Client Development

• Continue to support basic http protocols: Cone, SIAP, SSAP• More Web service / SOAP based

– Contemplate DALs with Web service protocols– Wrappers for legacy services– Newer tech

• OpenSkyQuery-like tools– XSD schema can use WSDL to class auto-generation tools

• language interoperability – Receiving classes instead of fixed tables

• Complex Clients– Science applications which integrate multiple basic clients – Integrate VO standards with new and existing tools