At the heart of an App Action is the concept of an entity. These are the objects passed to Actions and returned from them, things like simple variables, more complex sets of results, or documents, photos, or text. Entities are JSON objects, so you can use familiar techniques to build and deliver App Actions, and Windows will include new APIs in WinRT ready to help you quickly add entity support to your code. It’s currently supported by a preview release of the Windows SDK, which you need to declare as part of your project.
Building an App Action starts with the entity JSON, which defines how the action is described in an agent builder, followed by inputs and outputs, and then how it’s invoked, for example via a COM GUID. You do need to write the right handlers in your code to work with the action, using an Action Provider class, which implements an asynchronous interface. Your provider uses the name defined in the App Action JSON to route inputs to the right code, sending a response back when the action has completed.
Microsoft has an App Actions Playground to test your actions. Once they’re registered with Windows, you’re able to see them in the playground. You can then send the input entities, using the playground to see the application response. Applications can then set the availability of their actions, for example, toggling them on and off when you launch and shut down your code. This ensures that applications and agents only run under user control.
