If you have lots of media content on your hard drive, but you aren't always at your PC to view it, you've probably already discovered Orb. Orb is effectively a lightweight and incredibly simple media server. The company also offers an API which lets you extend the service to your own applications. In this article, we look at how the API works and what it can — and can't — accomplish.

As an user, you install the Orb service on your PC, log on to my.orb.com, and tell the service where your local files are stored. Then you can start watching your videos, listening to your music, and browsing through pictures from any device capable of rendering a Web page or streaming through Windows Media Player, RealPlayer, or 3gp. The service itself is not particularly new, released back in 2004, but it can do some impressive stuff.

The server component handles all the decoding and re-encoding issues transparently, making it awfully easy to get to your media from just about anywhere. With the release of a API late last year, the door has opened for a variety of other functions as well. Using the API, you can write pluggable extensions that expand the existing functionality of Orb or instead to make it do entirely new things. The obvious applications are add-ons that deliver special types of media or images, but the API also allows for completely unrelated functionality, such as allowing access to unshared files or serving up your IE Favorites.

Plugging In

To run Orb, the first step is to download and install the media server, a free 10MB download from Orb.com. The API itself is also hosted there. You'll find a number of other downloads on that page, including the API documentation, a few HTML files that cover the various members of the API, and a sample add-on for you to examine. Finally, a tool that makes testing easier, called OrbAddOnManager.exe, is available; more on that later.

Once installed, you can create an account, log on, start streaming your movies, and start playing with add-ons. Unlike many other APIs, no special steps are required to generate a key to identify yourself as a developer or to register your add-on as an application with special permissions. You're free to develop your little extension to Orb, compile it, then throw it on a Web page and let folks download it. You can even charge people for the extension, if you like.

This raises some security concerns. If anyone can make and distribute any add-on they want in any way they want, users don't have any guarantees that the add-on they're downloading is safe. Additionally, the documentation contains this warning:

...use a very pecific [sic] image path that contains only the images you want to share and no other files. A good example would be C:\Add-On Images\My Add-On\Add-On\. Do not use image paths like C:\My Documents. Doing so makes it easy for other users of your add-on to access any other file in that image path and its subfolders just by modifying a URL! The default image path is images from your DLL location.

Obviously, it's very important to be conscious of the paths used in your add-on, and it's best to install everything you need into a sub-folder of the Orb installation. This may also give developers reason to pause before they allow users to share data via Orb, particularly if it involves sensitive information.