Basics

This chapter covers everything an OST module can do without driving any INDI device — which already amounts to the bulk of the framework: the data model (properties and elements), how to react to a write, how to build or alter this model dynamically, the available element types, grids and graphs, lists of values, persistence as profiles, and how two modules collaborate (master/slave).

Each page is built around a real, minimal example module from the ost/ostmodules repository — free to read, load, and modify.

• Anatomy of a module

  Basemodule vs IndiModule, the .h/.cpp/.json triplet, the initialize() function, the event chain

• The smallest module — properties and elements

  Declaring a property and its elements in JSON: the hello module

• Reacting to a user write

  directedit, autoupdate, and how to extract a written value when the framework doesn't apply it for you

• Creating properties dynamically, in C++

  Building a property and its elements in code, at instantiation or on demand, without a JSON file

• The type catalog

  All element types, read-only vs read/write, mixing types within a property, directedit SV vs SA

• Server-side updates

  Evolving a value without a user action, organizing the display with devcat/group, isolating frequently-updated properties

• The three switch-coordination rules

  OneOfMany (radio), AtMostOne (optional radio), Any (independent) — fully declarative

• Lists of values

  The three scopes of a list of values (element, module, controller) and the constrained setting

• Profiles

  hasprofile:true — named configuration save/load, fully automatic

• Grids and graphs

  push()/clearGrid(), generic CRUD on the client side, and a graph as a plain visualization of a grid

• Master/slave relationship

  One module commanding another: declareFamily, otherModuleSetValue, onOtherModuleEvent

• Building and integrating your module

  Two ways to maintain your module: standalone, or integrated into the ost/ostmodules repository