adaptive-lighting/custom_components/adaptive_lighting/hass_utils.py
Mario Guggenberger ed80bd7829
feat: service call adaptation (#628)
* feat: service call adaptation

* feat: toggle-on service call adaptation

* feat: prefer service call transition
2023-07-19 09:10:21 +02:00

64 lines
2.3 KiB
Python

"""Utility functions for HA core."""
from collections.abc import Awaitable
from typing import Callable
from homeassistant.core import HomeAssistant, ServiceCall
from homeassistant.util.read_only_dict import ReadOnlyDict
from .adaptation_utils import ServiceData
def setup_service_call_interceptor(
hass: HomeAssistant,
domain: str,
service: str,
intercept_func: Callable[[ServiceCall, ServiceData], Awaitable[None] | None],
) -> Callable[[], None]:
"""Inject a function into a registered service call to preprocess service data.
The injected interceptor function receives the service call and a writeable data dictionary
(the data of the service call is read-only) before the service call is executed."""
try:
# HACK: Access protected attribute of HA service registry.
# This is necessary to replace a registered service handler with our
# proxy handler to intercept calls.
registered_services = (
hass.services._services # pylint: disable=protected-access
)
except AttributeError as error:
raise RuntimeError(
"Intercept failed because registered services are no longer accessible "
"(internal API may have changed)"
) from error
if domain not in registered_services or service not in registered_services[domain]:
raise RuntimeError(
f"Intercept failed because service {domain}.{service} is not registered"
)
existing_service = registered_services[domain][service]
async def service_func_proxy(call: ServiceCall) -> None:
# Convert read-only data to writeable dictionary for modification by interceptor
data = dict(call.data)
# Call interceptor
await intercept_func(call, data)
# Convert data back to read-only
call.data = ReadOnlyDict(data)
# Call original service handler with processed data
await existing_service.job.target(call)
hass.services.async_register(
domain, service, service_func_proxy, existing_service.schema
)
def remove():
# Remove the interceptor by reinstalling the original service handler
hass.services.async_register(
domain, service, existing_service.job.target, existing_service.schema
)
return remove