Wave Extension Installer

Once you have built your wave extension, you will need a way to install it into the user interface of the Google Wave client. A Wave Extension Installer is just that beast. You will need to create an Extension Manifest, which is an XML file describing where to find your extension, where you want it installed in the client UI and other information you want displayed.

We started out with the Wave Extension Installer Guide, but this document has some problems with the robot extension installer sample. Maybe its out of date, I don’t know.

The part that is in error is that there is no action element defined within the menuHook element. This is easily fixed by wrapping the participant element by the createNewWave element.

Once this was straightened out, we put together an extension manifest for our existing sample robot, Frakky.

Once you have your extension manifest set up for your extension, you need to make it Internet accessible. A reasonable place to put this is next to the index.html file for your robot, in the war directory. We named the file install.xml. Then whenever you upload your robot to Google App Engine, the extension manifest will be uploaded to http:/yourappname.appspot.com/install.xml. To be able to install this manifest in Google Wave Preview, you will need to install the Extension Installer. Yeah, its name is a little confusing but I am not sure that calling it Extension Installer Extension (which better describes its function) is any less confusing.

Once this is done, you can select the dropdown next to New Wave in the center panel and choose New Extension Installer. When you are asked for the Extension Manifest URL, be sure to specify the URL including the http:// portion or else you will end up receiving an error message that implies there is something wrong with the manifest instead of saying it just cannot find the manifest. This creates a wave with a puzzle piece from which you can install the manifest into the Google Wave client. Push the Install Extension button to hook it up.

Extension Almost Installed
Extension Almost Installed

You will notice that the attributes you specified in the extension element such as name, description and thumbnailURL are used to display the puzzle piece.

Now, if you check the muted wave, Extension Settings, your extension is listed at the bottom.

Installed Extension
Installed Extension

Since our manifest added a new item to the New Wave button, clicking the dropdown next to this gives us an entry that says “Creates a new Frakky wave.” Clicking this creates a new wave with our robot set as a participant.

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