hassreactor 0.2.0

Event-driven Home Assistant automations in Python

hassreactor

Event-driven Home Assistant automations in Python. No YAML, no Node-RED, no AppDaemon — just Python.

Why

Home Assistant has a powerful automation engine, but it lives in YAML or a UI. Sometimes you just want to write a Python script:

• "If living room temp > 28°C, turn on fan"
• "If front door opens, send me a Telegram message"
• "Every hour, log the temperature"

hassreactor lets you write these as plain Python files using WebSocket events — no polling, no complex setup.

Install

pip install hassreactor

Quick Start

Create a file automations.py:

from hassreactor import Reactor

app = Reactor("http://homeassistant:8123", "your-long-lived-token")

@app.when("sensor.temperatura_salotto", above=28)
async def accendi_ventilatore(event):
    """When temp goes above 28°C, turn on the fan."""
    await app.fan.turn_on(entity_id="fan.ventilatore")

@app.when("binary_sensor.porta_ingresso", to="on")
async def porta_aperta(event):
    """When front door opens, notify."""
    await app.notify.telegram(message="Porta d'ingresso aperta!")

@app.schedule("every 1h")
async def report():
    temp = await app.get_state("sensor.temperatura_salotto")
    print(f"Current temperature: {temp}°C")

if __name__ == "__main__":
    app.run()

Run it:

python automations.py

Trigger Types

Trigger	Description
@app.when(entity, above=N)	Numeric value crosses ABOVE threshold
@app.when(entity, below=N)	Numeric value crosses BELOW threshold
@app.when(entity, to="on")	State changes TO an exact value
@app.when(entity, changes=True)	ANY state change
@app.schedule("every 30m")	Run every 30 minutes
@app.schedule("every 2h")	Run every 2 hours
@app.schedule("0 9 * * *")	Cron expression (every day at 9am)

Calling Services

Any HA service is available as a method on the domain:

await app.light.turn_on(entity_id="light.kitchen", brightness=128)
await app.climate.set_temperature(entity_id="climate.home", temperature=22)
await app.switch.toggle(entity_id="switch.pump")
await app.notify.telegram(message="Hello!")

How It Works

hassreactor connects to Home Assistant via WebSocket and subscribes to state_changed events. When an entity you're watching changes state, your function runs instantly — no polling, no sleep loops.

Service calls use the REST API.

Only dependency: aiohttp.

License

MIT