Developing OPML Editor Tools

Introduction – what is the OPML Editor?

The OPML Editor is an application based on the open source version of the Frontier kernel, originally developed by UserLand Software. The Frontier kernel site states that Frontier “provides high-performance web content management, an object database, and a system-level and Internet scripting environment, including source code editing and debugging”. These features provide a rich environment for developing web-based applications that run on your desktop. The OPML Editor has Macintosh and Windows versions.

Applications can be created to run within the OPML Editor. These applications are called “Tools”. A Tool is a combination of data and scripts that allows the user to access the capabilities of the Frontier kernel within the OPML Editor and create applications that can be accessed through a web browser. These applications run on the user’s local machine. The OPML Editor renders the web pages which comprise the application user interface and uses its internal web server to display the pages. This simplifies the environment for the application developer, since a web server does not have to be set up to support the application itself.

Several Tools have been released for the OPML Editor by Dave Winer, but there is little documentation available on creating a functional Tool. This series will cover basic information on how to write scripts, create user interfaces, and store data in a Tool. The series will conclude by developing a simple Tool to collect user login information, call a web service API, and display the results.

This series will cover the following topics:

• Part 1 – Installing the OPML Editor and creating a “Hello World” Tool
• Part 2 – Creating web pages and scripts
• Part 3 – Running a script from a web page
• Part 4 – Saving data in the tool database
• Part 5 – Creating an application
• Part 6 – Creating an application – Windows updates
• Part 7 – Conclusion