Developing a Google Wave Extension

Austin Chau and Brian KennishGoogle Developer Relations

Developing a Google Wave ExtensionSilicon Valley Code Camp 2009

Topics

Writing and Deploying

Packaging

Questions

Introduction to Wave

Setting Up Your Development Environment

Troubleshooting

Introduction to Wave

Using Wave

What would email look like if it was invented today, rather than 40 years ago?

Wave combines email and many communication technologies since — instant messaging, bulletin boards, wikis, real-time document collaboration — in one place.

It's also a protocol and platform.

Developing with Wave: The Protocol

We want lots of Waves besides Google Wave, so we're drafting the protocol specification in public and open sourcing our client and server code.

http://www.waveprotocol.org/

Developing with Wave: The Platform

Embeds bring Wave to the world.

Extensions bring the world to Wave:• Gadgets let you safely run untrusted code in a wave.• Robots are automated wave participants.

Developing with Wave: Terminology

wave — A conversation and shared document in Wave.

wavelet — The unit of access control in a wave.

blip — A message in a wavelet.

Setting Up Your Development Environment

Tools

Robots are currently required to use Google App Engine. You can sign up for an account at http://appengine.google.com/.

Java robots are also required to use the Wave Java SDK (Python robots are possible too). You can download the latest JARs from http://code.google.com/p/wave-robot-java-client/downloads/list.

Using Eclipse isn't required, but we recommend doing so because the Google Plugin makes it easy to create and deploy App Engine applications. You can install the plugin via http://code.google.com/eclipse/.

Writing and Deploying

The Robot WAR File

/war/WEB-INF/web.xml binds the robot servletsto the Wave endpoints.

/war/WEB-INF/appengine-web.xml specifiesthe App Engine identifiers.

/war/_wave/capabilities.xml subscribes the robot to Wave events.

Sample Code: Hello-Worldy

hello-worldy@appspot.com

Does "hello world"-type stuff.

Appends text, echoes submittedblips, and implements form UI.

http://code.google.com/p/google-wave-resources/source/browse/trunk/samples/extensions/robots/java/hello-worldy/

Sample Code: Stocky

stocky-wave@appspot.com

Replaces stock symbols withreal-time quotes.

Incorporates third-party data intoWave.

http://code.google.com/p/google-wave-resources/source/browse/trunk/samples/extensions/robots/java/stocky/

Sample Code: Embeddy

embeddy@appspot.com

Generates code to embed awave in your webpage.

Features all three of the currentWave APIs and two-way robot-to-gadget communication.

http://code.google.com/p/google-wave-resources/source/browse/trunk/samples/extensions/robots/java/embeddy

Troubleshooting

Tips

Check your App Engine logs for errors.

Go tohttp://app-id.appspot.com/_wave/capabilities.xml tosee if your capabilities file is live.

Make sure you updated your capabilities version string after adding events.

Increase your log level in/war/WEB-INF/logging.properties, e.g., toALL.

Packaging

The Extension Installer

Extension Hooks:• NEW_WAVE_MENU• TOOLBAR

Extension Actions:• createNewWave• addParticipants

<menuHook  location="TOOLBAR"  iconUrl="http://hello-worldy.appspot.com/images/robot.jpg"  text="Add Hello-Worldy">  <addParticipants>    <participant id="hello-worldy@appspot.com" />  </addParticipants></menuHook>

Questions

Contact Us

Brian KennishGoogle Wave and Chrome

byoogle@google.comhttp://twitter.com/byoogle

Austin ChauGoogle Wave and YouTube

api.austin@google.com