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.