labthings_fastapi.dependencies.raw_thing

FastAPI dependency to obtain a Thing directly.

This module allows actions to obtain a Thing instance without the DirectThingClient wrapper. As a rule, it is best to use DirectThingClient where possible.

Attributes

ThingInstance

Functions

find_raw_thing_by_class(→ Callable[[fastapi.Request], ...)

Generate a function that locates the instance of a Thing subclass.

Module Contents

labthings_fastapi.dependencies.raw_thing.ThingInstance

labthings_fastapi.dependencies.raw_thing.find_raw_thing_by_class(cls: type[ThingInstance]) → Callable[[fastapi.Request], ThingInstance]

Generate a function that locates the instance of a Thing subclass.

Warning

Using a Thing directly can be tricky: unless you really need to, it is usually better to use a DirectThingClient, which provides an interface that should be identical to the HTTP thing client in Python. This is safer, and means code should be easier to translate between server and client-side.

In order to access the instance of OtherThing attached to your thing server, declare your argument type as:

OtherThingDep = Annotated[
    OtherThing, Depends(find_raw_thing_by_class(OtherThing))
]


def endpoint(other_thing: OtherThingDep):
    pass

LabThings will supply this argument automatically through the Dependencies mechanism.

Note that this function returns a dependency - it should be called with arguments inside fastapi.Depends.

Parameters:: cls – is the Thing subclass that will be returned by the dependency.
Returns:: a dependency suitable for use with fastapi.Depends (see example).