bacnet-ip-rest-client

An async Python client for the BACnet/IP REST proxy. It is built on httpx.

from bacnet_ip_rest_client import Client, ProxyError

async with Client("https://bacnet-proxy.example.net", token) as client:
    for obj in await client.list_objects("my-device"):
        print(obj.objid, obj.name, obj.access)

    temp = await client.read_property("my-device", "analog-input,1", "present-value")
    slots = await client.read_property("my-device", "analog-value,5", "priority-array")
    await client.write_property("my-device", "analog-value,5", "present-value", 21.5, priority=10)
    await client.write_property("my-device", "analog-value,5", "present-value", None, priority=10)  # relinquish

Authentication

Every request goes through the proxy's authentication and authorization. Pass token to Client to send it as Authorization: Bearer <token>. The token can be one of the opaque tokens configured on the proxy, or a JWT it accepts, such as a user's OIDC access token. Without a token, the proxy only allows a request if its rules grant access without one, for example by the client's IP address. A request the proxy denies raises UnauthorizedError or ForbiddenError.

Relationship to bacpypes3

Client has the same role as a bacpypes3 Application, and read_property() and write_property() take bacpypes3's arguments, with some exceptions. It doesn't try to hide the ways an HTTP proxy works differently from a BACnet/IP stack:

Errors

ProxyStatusError.is_unknown_object_or_property is true when the proxy reports a missing object or property, whether it does so as a 404 or as a 502 from the device. Code that probes for optional properties, such as priority-array, can check this one attribute.

Retries use exponential backoff as configured by RetryPolicy (default: 5 attempts, 1s doubling to at most 8s). Retry warnings are logged to the bacnet_ip_rest_client logger. Writes are retried too, since writing the same value at the same priority again has no further effect.

concurrency (default 10) caps the number of requests one Client has in flight. The proxy serializes traffic to the device itself; this cap only keeps a large read_properties() from opening hundreds of connections to the proxy.

Development

uv run pytest