Open Developer Break: From Derby's OT to JavaScript in PostgreSQL

Catch up on the smaller but important notes for open source developers, from libraries to APIs and from people to posts. In this edition: ShareJS drives Derby.js, Quantifying fitness, OpenGL powers Sparrow 2.0 on iOS, cross-app-store apps on Android, V8 JavaScript in PostgreSQL, talking to Arduinos from Chrome, and how Go makes Go go.

• Writing real-time, collaborative applications? The developers of Derby have just released Derby 0.5.0, which uses OT (Operational Transformation) to synchronise multiple users. Derby 0.5.0 has been rewritten to use ShareJS, but is still on its way to becoming production code.

• Sensors are in and with devices like the FitBit and Withings scales, there are new challenges in how to get at all that data. Quantify.io is a new site and open source Rails API (MIT licence) which sets out to pull the data out of owned silos and put it under the user's control.

• Gamua have shipped Sparrow 2.0, the latest version of its open source game engine for iOS. The new architecture is based on OpenGL ES2 and iOS 5 and is up to twice as fast as the previous version.

• Android app developers are often faced with the problem of packaging for multiple app stores and supporting their in-app purchase models, especially with 36 different stores known. One Platform Foundation is setting out to fix that with AppDF which automates deployment to multiple app stores and OpenIAB for handling in-app purchases. Both are in development and are licensed under the Apache 2.0 licence.

• Want JavaScript powering your PostgreSQL application? Check out PLV8, a shared library that allows the V8 JavaScript engine to be used as PostgreSQL procedural language. The developers at Heroku liked it so much it's in all their PostgreSQL instances now.

• With browsers getting new APIs every week, its difficult to keep track. Here's a tutorial on how to use Chrome's serial device API to talk with an Arduino.

• And for the curious, ever wondered how the Go language and compilers are built? Check out this blog post on how Go builds Go with Go.

(djwm)