labthings_fastapi.decorators

Mark the Interaction Affordances of a Thing.

See Web of Things Core Concepts for definitions of Interaction Affordance and other terms.

LabThings generates a Thing Description to allow actions, properties, and events to be used by client code. The descriptions of each “interaction affordance” rely on docstrings and Python type hints to provide a full description of the parameters, so it’s important that you use these effectively.

If you have a complex datatype, it’s recommended to use a pydantic model to describe it - this is often the case for complicated properties or events. For actions, a model is created automatically based on the function’s signature: if you want to add descriptions or validators to individual arguments, you may use pydantic.Field to do this.

Actions

You can add an Action to a Thing by declaring a method, decorated with :deco:`.thing_action`. Parameters are not usually needed, but can be supplied to set various options.

Properties

As with Actions, Properties can be declared by decorating either a function, or an attribute, with :deco:`.thing_property`. You can use the decorator either on a function (in which case that function acts as the “getter” just like with Python’s :deco`property` decorator).

Events

Events are created by decorating attributes with :deco:`.thing_event`. Functions are not supported at this time.

Attributes

HTTPMethod

Valid HTTP verbs to use with fastapi_endpoint or EndpointDescriptor.

Functions

`return_type`(→ Type)	Determine the return type of a function.
`mark_thing_action`(...)	Mark a method of a Thing as an Action.

Package Contents

labthings_fastapi.decorators.HTTPMethod: Valid HTTP verbs to use with fastapi_endpoint or EndpointDescriptor.

labthings_fastapi.decorators.return_type(func: Callable) → Type

Determine the return type of a function.

Parameters:: func – a function to inspect
Returns:: the return type of the function.

labthings_fastapi.decorators.mark_thing_action(func: Callable, **kwargs) → labthings_fastapi.descriptors.ActionDescriptor

Mark a method of a Thing as an Action.

We replace the function with a descriptor that’s a subclass of ActionDescriptor

Parameters:

func – The function to be decorated.
**kwargs – Additional keyword arguments are passed to the constructor of ActionDescriptor.

Returns:

An ActionDescriptor wrapping the method.