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Sept 12-17 2004NVO Summer School1 Cone, SIAP, and OpenSkyQuery Client Development Gretchen Greene,...
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Transcript of Sept 12-17 2004NVO Summer School1 Cone, SIAP, and OpenSkyQuery Client Development Gretchen Greene,...
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