Sugar.presence

How is data shared between activities through a D-Bus tube?

Communication in Sugar is achieved through several layers of technologies, including Sugar's own Presence Service, the D-Bus service for process communication, and various implementations of the telepathy system used for real time conversations. In order to get activity communication working between activities, your goal is to ultimately create a D-Bus tube that will handle text messaging between activities (there are also stream tubes which are discussed elsewhere).

The figure below shows a simplified conceptualization of what happens after you set up a D-Bus tube correctly.

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The activity code for each XO should handle sending text to the tube and also receiving text through a callback method that is supplied to the tube. The Activity developer will also need to define the Tube Object itself, which should be designed to send and receive text appropriately based on the type of sharing that is desired.

Let's consider a simple, but concrete example of how a D-Bus tube is used (assuming it has already been setup correctly).

Where do I get more information regarding sugar activity sharing and the technologies that support it?

• A brief tutorial on activity sharing for the OLPC laptop.