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What is Kettle?

Kettle is a framework for building server-side Web applications using JavaScript and Node.js. Originally created by the Fluid community for the Fluid Engage mobile application, Kettle is designed to provide a quick and easy way to deliver data feeds and rendered markup on the server. Kettle uses Fluid Infusion throughout, offering client-side JavaScript developers a natural starting point for building server-side code. Because it is written in JavaScript, Kettle provides the opportunity to share code between client and server seamlessly. As a result, the architectural partitioning of responsibilities between client and server can be defined and reconfigured based on the requirements of the application, not based on programming language boundaries.

There are several primary development metaphors in Kettle such as Servers and Apps. Servers represents a single instance of the Node.js HTTP server. A Server is a container for 0 or more Apps (see further). Developers have an option of deploying a number of Servers that themselves contain 0 or more Apps. The source code for the Server can be found here: Server. The App is a component that represents a single purpose application deployed within a particular Server. The source code for the App can be found here: App.

Kettle also offers built-in support for the CouchDB database, a document-based store that is a good match for JavaScript-based, collaborative Web applications.

What's the Status of Kettle?

Kettle is currently a proof-of-concept framework which has seen some limited real-world testing under load through its use as the underlying server-side layer for the GPII project and Fluid Engage mobile pilot at the McCord Museum in Montreal. It has not yet been documented (at all!), and APIs will change.

Next Steps

As part of the GPII and FLOE Projects, Kettle will be used to develop RESTful server-side data feeds and markup transformers for storing and sharing content accessibility information, user preferences, and captions.

As part of this work, Kettle will be:

  • Extended to support better URL routing and rewriting
  • Documented



Currently, Kettle is built on top of the Java Virtual Machine using Mozilla's Rhino JavaScript engine. In order to use features of Infusion and jQuery unmodified, we also use John Resig's Env.js browser compatibility environment. Kettle conforms to the JSGI spec for server-side JavaScript containers. Needless to say, Infusion is used throughout.

Moving forward, Kettle will be ported to Node.js, an event-based Web server built using Google's V8 JavaScript engine. Node's APIs are also sufficient enough to replace the handful of jQuery APIs used on the server (e.g. $.ajax()) with implementations that are not browser-encumbered. Initially, Kettle will be integrated with Node.js using the JSGI 0.3 spec, but in the future will be expanded to natively support Node's evented model.

More information about our initial technology motivations for Kettle are documented in the Engage Server-Side Technology page.

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