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GALEXView DemoT. Rogers, B. Shiao, P. Brown, P. McCauley,
A. Conti, M. Smith, S. Tseng, A. VolpicelliStSci/MAST
GALEX (Galexy Explorer) Mission
• GALEX launched on launched on April 28, 2003. • GALEX is an all sky survey in the UV in two bands: FUV and NUV.• GALEX Archive Stats:
– Over a 100 million source objects– Over 31,000 Image ‘Tiles’– Database Size: 1.2 TB– Product Files Size: 16 TB
Background
• Existing Web site (galex.stsci.edu) developed by A. Conti, A. Volpicelli, B. Shiao using Microsoft .NET and SqlServer
• Like most HTML page-based websites, it is affective, but not engaging or highly interactive.
• So we looked into ‘Web 2.0’ Technologies to develop a more interactive web site.
Web 2.0 Technologies (We looked into as of October 2007. Your mileage may vary)
• .NET + AJAX Controls– Our existing .NET implementation did play well with the AJAX controls. – Image Processing still on the server
• GWT: Google Web Toolkit– Very easy to write and debug ‘JavaScript’ for ex-Java Programmer– Difficult to perform simple Image Processing and graphics overlay on the client.
• JavaFX– No Graphical IDE, not fully supported on all platforms/browsers.
• Silverlight– First Release (October 2007) was not a fully integrated development tool. – Creating all controls (i.e, buttons) from complete scratch. – No Data Grid Control. – Mac and Windows only.
• JavaScript/XSLT– Steep learning curve. – Browser support issues.– Very fast Table Processing
• Flex – True image processing on the client– Easy To Learn IDE: ‘Flex Builder’, built on top of ‘Eclipse’
What is Flex?• Flex is the collection of technologies developed by Adobe to build interactive web application that
run inside a Flash ‘Movie’ plug-in.– Flex SDK, Flex Builder IDE, Flash Player
PROS:• Flash plug-in is installed in most browsers due to ‘YouTube’ and other similar sites.• Flex Builder IDE is very intuitive graphical development environment that makes web
development ‘fun’. • Truly Write Once – Run Everywhere• No Browser or OS Dependencies
– (well…almost none) File Upload under Linux did not work, but resolved by forcing upgrade player to version 8.115 or above. Most browsers now have Flash version 9 and 10.
CONS:• Flex DataGrid control performance
– Lags for displaying large number of rows and columns. (100 rows, 20 columns and beyond)• Flash Player 10 ‘Security Feature’
– Broke GalexView (and a lot of other Web Apps that download files to the client). – 1 hour required to fix and re-deploy.
COST:• Flex Builder IDE is FREE for educational research. • Flex Builder IDE is $300.00-$700.00, otherwise.
GalexView ArchitectureOverview
GalexView(Flex)
Galex ‘SQL’Web Service
(.NET)
Galex Database
(SqlServer)
Query
XML Response:DataTable VoTable
DataSet
Query
Simple 3 tiered architecture:• GalexView Adobe Flex 3 Client that runs inside the Flash 9.0 Player.• Custom Galex ‘SQLs Web Service running inside IIS based on C# .NET 2005
that serves as a direct interface to the Galex Database• Galex Database running Microsoft SQL-Server 2000
GalexView is a lightweight data client• All queries are held in cache inside the SQL Web Service. • Only the currently requested page of results is returned back to the client.• All sorting, filtering and page extraction of results takes place on the server.