Google Wave API Overview

Welcome to Wave Development

The Google Wave API is an open platform allowing developers to extend the functionality of Google Wave itself, or extend other applications with waves. As a developer, you can think of Google Wave as three pieces:

• The Google Wave client application, the interface designed for users
• The Google Wave APIs, which are documented throughout this site
• The Google Wave Federation Protocol, the underlying network protocol for wave communication

This developer guide discusses the Wave APIs and how you can use them to augment Google Wave through extensions or augment third-party web applications by embedding Google Wave within them. This overview discusses the elements that make up the "waves" in the Google Wave model.

Wave Entities

Programming effectively using the Google Wave APIs requires understanding some basic wave concepts.

A wave is a threaded conversation, consisting of one or more participants (which may include both human participants and robots). The wave is a dynamic entity which contains state and stores historical information. A wave is a living thing, with participants communicating and modifying the wave in real time. A wave serves as a container for one or more wavelets defined below.

A wavelet is a threaded conversation that is spawned from a wave (including the initial conversation). Wavelets serve as the container for one or more messages, known as blips. The wavelet is the basic unit of access control for data in the wave. All participants on a wavelet have full read/write access to all of the content within the wavelet. As well, all events that occur within the Google Wave APIs operate on wavelet level or lower.

When you spawn a wavelet from within a wave, you do not inherit any access permissions from the parent wavelet. During the lifetime of a wave, you may spawn private conversations, which become separate wavelets, but are bundled together within the same "wave." Since events occur at the wavelet level or below, the context of an event is restricted to a single wavelet. A wavelet may be created and managed with a robot as its only participant. This allows the robot to use the wavelet effectively as a private data document. These data documents are never rendered/revealed to the user and may contain structured or unstructured data about the wavelet.

A blip is the basic unit of conversation and consists of a single messages which appears on a wavelet. Blips may either be drafts or published (by clicking "Done" within the Wave client). Blips manage their content through their document, defined below. Blips may also contain other blips as children, forming a blip hierarchy. Each wavelet always consists of at least one root blip.

A document is the content attached to a blip. This document consists of XML which can be retrieved, modified or added by the API. Generally, you manage the document through convenience methods rather than through direct manipulation of the XML data structure.

What Is the Google Wave API?

The "Wave API" actually consists of several APIs which provide different functionality (and may be combined together). Two primary types of development are available within the Wave API:

• Extensions:

  Developers can enhance Google Wave itself by authoring mini-applications (extensions) that interact with the Wave. Developers can create robots which interact with waves, or gadgets which participants may interact with (and combinations of robots and gadgets are also supported). For more information, consult the Wave Extensions Developer's Guide.

• Embeded Waves:

  Developers can enhance their existing web applications by embedding Google Wave directly in their application, allowing you to seamlessly integrate communication and collaboration. For more information, consult the Wave Embed Developer's Guide.

In addition to the developer's guide and the reference material, you may wish to check out the sample code.

Sandbox Development

Developers using Google Wave may work with two instances of Google Wave: the development version of Google Wave known as the Sandbox (available at http://wave.google.com/a/wavesandbox.com/) and the public version known as Google Wave Preview (available at http://wave.google.com/).

All initial Wave API development should take place in the sandbox. The sandbox is a developer-only instance of Google Wave where you can freely test and debug extensions you develop with other developers. You can request developer access to the sandbox using this form. When they are ready to share your application with the general population, you will want to deploy your extensions to Wave Preview. You can request a Google Wave Preview account with this form.

The sandbox is similar to the Google Wave Preview at http://wave.google.com/ in many ways, though there are some differences:

• Experimental API features may be deployed to Sandbox before Preview, allowing you to test out the API and offer suggestions for improvements before the API solidifies.
• New Wave client features are deployed to Sandbox before Preview, providing you an opportunity to test out new functionality before release to the general public.
• The Wave Sandbox provides a Debug menu which provides additional functionality for developers.
• Passing the flag &ll=debug to a Wave Sandbox URL adds a Show debug log menu item to the Debug menu, allowing you to dynamically show debug information within a special window.
• The Wave Sandbox works with Federated Wave servers, while the production version works only with Google domains (except Wave Sandbox).

Additionally, the Google Wave Preview instance provides a few bells and whistles you won't find in Wave Sandbox, including additional default Wave content, the Extensions Gallery, and operability with Wave servers running under Google Apps domains.

Once you've thoroughly experimented and tested your extensions on the Sandbox, you will want to package an extension up into an Extension Installer and test it with other developers. Once your application is ready for the real world, you can deploy it to the Google Wave Preview instance. For more information, see Deploying Extensions to Preview.

Note: Obtaining a sandbox account does not guarantee that you receive a Preview account.

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