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OFFLINE Web Applications Google Gears. Jia Liu [email protected]. From Online to Offline. Online applications are Great Offline are also Necessary Internet unavailable? Don’t want the data in the clouds? Response time? Fill the gaps between online and offline. Architecture. - PowerPoint PPT Presentation
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From Online to Offline
Online applications are Great
Offline are also Necessary Internet unavailable? Don’t want the data in the clouds? Response time?
Fill the gaps between online and offline
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Browser
Text
Server
Database
HTTP
Architecture
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Browser
Text
Server
Database
Install
Architecture
LocalServer
Database
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Browser
Text
Server
Database
Architecture
LocalServer
Database
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Offline ToolsIn the past
Dojo Storage, Derby/JavaDB, Zimbra
Today Adobe AIR Google Gears Microsoft Silverlight
Coming Soon FireFox 3 HTML5 Working Draft Client-side database storage
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Google GearsWhat is Google Gears? Brower-plugin
Open source library http://gears.google.com
Cost Open Source Lightweight installation necessary Application stays completely in the
browser, no extra app/start up
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Components
Local SeverLet web applications interact naturally with your desktop
DatabaseStore data locally in a fully-searchable database
WorkerPoolRun JavaScript in the background to improve performance
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LocalServer
Specialized URL Cache Requests for URLs in the LocalServer’s cache are
intercepted and served locally from the user’s disk
RecourseStore (Manual Update) ManagedResourceStore (Automatic Update)
Manifest File
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DataBaseOpen source SQLite Database
Simplified SQL Syntax
Full-text Search
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Workerpool
Time-intensive processes can be run in the background
UI stays responsive/browser doesn’t block No warning dialog “Unresponsive Script”
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Syncing
Globally Unique ID
Timestamps
When Collisions Last one wins
Lock/Check out Let user decide
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Example
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Example
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Applications
Gmail
Calendar
Maps
SpreadSheet
Reader
Google Gears
Docs
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ApplicationsGmail, Calendar… Any Web applications that can store data
enough locally to work offline will benefit from it.
Limitations Stock Trading Systems -Online connectivity is an absolute must
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CONCLUSION
Google Gears allows Web application to run offline
It opens a lot of doors to developers looking to bridge the narrowing gap between desktop and web-based applications.
