Tutorial Four: Skeleton Files

This tutorial demonstrates how to use skeleton files to define properties in INDI drivers. It provides an alternative approach to defining properties compared to hard-coding them in the driver’s source code.

What You’ll Learn

  • How to use skeleton files to define INDI properties
  • How to load and use skeleton files in your driver
  • The advantages of using skeleton files for property definitions

Source Code

The source code for this tutorial can be found in the INDI library repository under the examples/tutorial_four directory.

What are Skeleton Files?

Skeleton files are XML files that define the properties of an INDI driver. They provide a way to separate the property definitions from the driver’s source code, making it easier to modify the properties without recompiling the driver.

A skeleton file contains a list of defXXX XML statements enclosed by <INDIDriver> opening and closing tags. These statements define the properties, their types, and their default values.

Code Explanation

This tutorial demonstrates:

  1. Loading Skeleton Files: How to load property definitions from an external XML file
  2. Processing Property Updates: How to handle property updates from clients
  3. Advantages of Skeleton Files: Separation of property definitions from driver logic

Running the Tutorial

To run this tutorial:

  1. Make sure the skeleton file is installed:

    # Either install to the system directory
sudo cp tutorial_four_sk.xml /usr/share/indi/

# Or set the INDISKEL environment variable
export INDISKEL=/path/to/tutorial_four_sk.xml

  2. Build the tutorial using CMake:

    cd /path/to/indi/build
make

  3. Run the INDI server with the tutorial driver:

    indiserver -v ./tutorial_four

  4. Connect to the server using an INDI client (like KStars/EKOS or INDI Control Panel).

Next Steps

This tutorial demonstrates using skeleton files for property definitions. In Tutorial Five, we’ll learn about inter-driver communication between a Rain Detector and a Dome driver.