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Using Gears to Run Your App Offline

Benefits of Using Gears

Running your O3D application with Gears has a number of benefits:

  • Your application works offline.
  • Performance improves because resources are cached locally.
  • Server load is lighter.

How to Use Gears

Here are the steps required to run your O3D application offline using Gears:

  1. Download gears_init.js and install it with your application.
  2. Include this script, which does the following:
    • creates a local server
    • creates a managed store for the resources used by the application
    • gives the store the list of required files
    • checks for updates to the resource files
    <script src="../assets/gears_init.js" type="text/javascript"> </script>
<script type="text/javascript">
  try {
    var localServer = google.gears.factory.create('beta.localserver');
    var store = localServer.createManagedStore('test-store');
    store.manifestUrl = 'site-manifest.txt';
    store.checkForUpdate();
  } catch (ex) {
    dump("No offline access.\n");
  }
</script>

    This script should be included in the main html file in the <head> element before anything else is loaded. The only time the script requires a server connection is when it runs the store.checkForUpdate() function.

  3. Create the site-manifest.txt file, which lists all the resources used by the application. This file uses the JSON format, with no wildcards. The file specifications need to be local references. For example:
    4. {
"betaManifestVersion": 1,
"version": "0.1",
"entries": [
{ "url": "../assets/gears_init.js" },
{ "url": "../assets/texture_b3.jpg" },
{ "url": "game.css" },
{ "url": "game.html" },
{ "url": "client.js" },
{ "url": "third_party/soundmanagerv25b-20080505/script/soundmanager2.js" },
{ "url": "third_party/soundmanagerv25b-20080505/soundmanager2.swf" },
{ "url": "third_party/soundsnap/11115901.mp3" },
{ "url": "third_party/soundsnap/11118801-modified.mp3" },
]
}

For More Information

Go to http://code.google.com/apis/gears for more information on how to use the open-source Gears API.