Google Gears, taking Web apps offline

Mark Gibbs' Web site tips, plus network applications news headlines

Google’s rate of Web Application development is nothing short of amazing. Not only do they break new ground (just consider the impact that Google Maps has had), but they also redefine and re-energize concepts that have gained very little market traction.

What I’m thinking about here is the concept of using Web applications offline. There have been all sorts of attempts to address this kind of functionality but none of them have had enough market traction to become mainstream. Google Gears is the product from Google Labs that could change that.

Launched earlier this year, Gears consists of a browser extension available for Windows XP; Windows Vista; OS X; and Linux. It provides three services: A local Web server, which caches and delivers Web application resources (HTML content, JavaScript code, images, etc.) when the target server is not available; a database for application data; and a worker thread pool, a mechanism for managing computationally expensive operations in the background to make Web applications more responsive.

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Google’s rate of Web Application development is nothing short of amazing. Not only do they break new ground (just consider the impact that Google Maps has had), but they also redefine and re-energize concepts that have gained very little market traction.

What I’m thinking about here is the concept of using Web applications offline. There have been all sorts of attempts to address this kind of functionality but none of them have had enough market traction to become mainstream. Google Gears is the product from Google Labs that could change that.

Launched earlier this year, Gears consists of a browser extension available for Windows XP; Windows Vista; OS X; and Linux. It provides three services: A local Web server, which caches and delivers Web application resources (HTML content, JavaScript code, images, etc.) when the target server is not available; a database for application data; and a worker thread pool, a mechanism for managing computationally expensive operations in the background to make Web applications more responsive.

Web applications must be engineered to work with Gears: You have to create a “manifest” that specifies which files are to be available offline and upload those files and some Gears control files to your server.

One of the control files is an HTML document that tests for the presence of Gears on the browser and, if found, allows you to set up the online/offline functionality by downloading the files in the manifest to your PC. This same document also allows you to disable offline access.

After that, whenever your browser is offline the Gears system will intercept the unavailable remote URLs and serve the content from local resources. For more detail is the Gears architecture document.

Google has a full discussion of the Gears API, and if you are going to start seriously considering future production use of Gears (when it comes out of beta), you’ll need to read the discussion on Gears security.

As I noted in the beginning, the Gears project is not a new idea, but given the market power and reach of Google it could well succeed in defining how offline Web applications will work.

Editor's note: Starting the week of Nov. 12, you will notice a number of enhancements to Network World newsletters that will provide you with more resources and more news links relevant to the newsletter's subject. Beginning 'Monday, Nov. 12, the Web Applications Newsletter, written by Mark Gibbs, will be merged with the Network Applications News Alert and will be named the Web Applications Alert. You'll get Mark's Web apps pick of the day, which you will be able to read in full at NetworkWorld.com, plus links to the day's network applications news and other relevant resources. This Alert will be mailed on Mondays and Wednesdays. We hope you will enjoy the enhancements and we thank you for reading Network World newsletters.

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Mark Gibbs is a consultant, author, journalist, columnist and blogger.