Transcript GalexView Architecture

GALEXView Demo
T. Rogers, B. Shiao, P. Brown, P. McCauley,
A. Conti, M. Smith, S. Tseng, A. Volpicelli
StSci/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)
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.NET + AJAX Controls
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GWT: Google Web Toolkit
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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
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No Graphical IDE, not fully supported on all platforms/browsers.
Silverlight
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Very easy to write and debug ‘JavaScript’ for ex-Java Programmer
Difficult to perform simple Image Processing and graphics overlay on the client.
JavaFX
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Our existing .NET implementation did play well with the AJAX controls.
Image Processing still on the server
Steep learning curve.
Browser support issues.
Very fast Table Processing
Flex
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True image processing on the client
Easy To Learn IDE: ‘Flex Builder’, built on top of ‘Eclipse’
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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.
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Flex SDK, Flex Builder IDE, Flash Player
PROS:
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Flash plug-in is installed in most browsers due to ‘YouTube’ and other similar sites.
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Flex Builder IDE is very intuitive graphical development environment that makes web
development ‘fun’.
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Truly Write Once – Run Everywhere
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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:
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Flex DataGrid control performance
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Lags for displaying large number of rows and columns. (100 rows, 20 columns and beyond)
Flash Player 10 ‘Security Feature’
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Broke GalexView (and a lot of other Web Apps that download files to the client).
1 hour required to fix and re-deploy.
COST:
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Flex Builder IDE is FREE for educational research.
Flex Builder IDE is $300.00-$700.00, otherwise.
GalexView Architecture
Overview
GalexView
(Flex)
Query
XML Response:
DataTable
VoTable
Galex ‘SQL’
Web Service
(.NET)
Query
DataSet
Simple 3 tiered architecture:
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GalexView Adobe Flex 3 Client that runs inside the Flash 9.0 Player.
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Custom Galex ‘SQLs Web Service running inside IIS based on C# .NET 2005
that serves as a direct interface to the Galex Database
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Galex Database running Microsoft SQL-Server 2000
GalexView is a lightweight data client
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All queries are held in cache inside the SQL Web Service.
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Only the currently requested page of results is returned back to the client.
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All sorting, filtering and page extraction of results takes place on the server.
Galex
Database
(SqlServer)