knxrpc

knxrpc

Documentation

Description

knxrpc provides a ConnectRPC handler and server for RPCs interacting with a KNX bus in smart homes.

You can either integrate it as a http.Handler in your own code or run the included server which has swagger and metrics support.

You can find the protobuf-spec in groupaddressservice.proto.

You can access Swagger UI (if enabled via config) via: http://localhost:8080/swagger.

knxrpc API client using golang

You can use the generated golang code and helper funcs to build your own API client.

Take this as an example:

package main

import (
    "github.com/choopm/knxrpc"
    v1 "github.com/choopm/knxrpc/knx/groupaddress/v1"

    "github.com/vapourismo/knx-go/knx/dpt"
    // ...
)

func main() {
    // build ctx
    ctx, cancel := context.WithTimeout(context.Background(), time.Second() * 3)
    defer cancel()

    // construct knxrpc client
    client, err := knxrpc.NewClient(knxrpc.ClientConfig{
        Host: "127.0.0.1",
        Port: 8080,
    })
    if err != nil {
        panic(fmt.Errorf("knxrpc: %s", err))
    }

    // publish a message
    _, err := client.Publish(ctx, connect.NewRequest(&v1.PublishRequest{
        GroupAddress: "1/2/3",
        Data:         dpt.DPT_1002(true).Pack(),
        Event:        v1.Event_EVENT_WRITE,
    }))
    if err != nil {
        panic(fmt.Errorf("unable to send: %s", err))
    }

    // connect stream to receive bus messages for specific group addresses
    stream, err := client.Subscribe(ctx, connect.NewRequest(&v1.SubscribeRequest{
        GroupAddresses: []string{"1/2/3", "4/5/6"},
        Event:          v1.Event_EVENT_UNSPECIFIED,
    }))
    if err != nil {
        panic(fmt.Errorf("stream open: %s", err))
    }
    defer stream.Close()

    // start receiver loop
    for stream.Receive() {
        res := stream.Msg()
        // TODO handle res message here
        fmt.Println(res.GroupAddress)
        fmt.Println(res.Event)
        fmt.Println(res.Data)
        // ...
    }
    if connectErr := new(connect.Error); errors.As(err, &connectErr) &&
        !errors.Is(connectErr, context.Canceled) &&
        !errors.Is(connectErr, context.DeadlineExceeded) {
        panic(fmt.Errorf("stream closed: %s", stream.Err()))
    }
}

knxrpc binary - server mode

Starting the container will run the knxrpc binary in server mode using the argument server.

This will provide a ConnectRPC server to handle the RPCs defined at groupaddressservice.proto.

You will have to configure your KNX gatewayHost and port in the YAML config. You can also override the defaults using environment variables whiceh are derived from the YAML path such as:

• KNXRPC_KNX_GATWAYHOST=192.168.1.2
• KNXRPC_RPC_AUTH_ENABLED=true
• KNXRPC_RPC_AUTH_SECRETKEY=password

Note the prefix KNXRPC when setting environment variables from YAML paths.

If enabled and configured in knxrpc.yaml, you will be able to use the SwaggerUI for testing RPCs.

When deploying to public or production, make sure to use TLS and authorization as otherwise you would be allowing public access to the KNX bus.

knxrpc binary - client publish/subscribe

You can also run the subcommands subscribe or publish to directly interact with any running RPC server.

This is useful when you are already running a knxrpc server. The client commands will use the knxrpc: section from YAML for connecting to the knxrpc server.

publishing

# send the data '\x01' (hex string) to group address 0/4/0
/usr/bin/knxrpc publish 0/4/0 01

# send the hex-string of 'hello world' to group address 1/2/3
/usr/bin/knxrpc publish 1/2/3 68656c6c6f20776f726c64

# send a read request
/usr/bin/knxrpc publish 0/5/6

# send a response message
/usr/bin/knxrpc publish --event response 0/5/6 fffd

subscribing

# subscribe to all bus messages by not providing a filter
/usr/bin/knxrpc subscribe

# subscribe to all response messages (which are send as a result to previous read requests)
/usr/bin/knxrpc subscribe --event response

# subscribe to specific group address(es)
/usr/bin/knxrpc subscribe 0/5/6 0/4/0 1/2/3

JSON client

Publishing a write event

This example sends BASE64-encoded hex data \x01 to the groupAddress 0/5/6.

curl -X 'POST' \
  'http://localhost:8080/knx.groupaddress.v1.GroupAddressService/Publish' \
  -H 'accept: application/json' \
  -H 'Authorization: Bearer CHANGEME' \
  -H 'Content-Type: application/json' \
  -d '{
  "groupAddress": "0/5/6",
  "event": "EVENT_WRITE",
  "data": "AQo="
}'

Publishing a read event

In this example a read-event is send to the groupAddress 0/5/6 which will trigger an asynchronous response to be read using the Subscribe-API.

curl -X 'POST' \
  'http://localhost:8080/knx.groupaddress.v1.GroupAddressService/Publish' \
  -H 'accept: application/json' \
  -H 'Authorization: Bearer CHANGEME' \
  -H 'Content-Type: application/json' \
  -d '{
  "groupAddress": "0/5/6",
  "event": "EVENT_READ"
}'

Subscribing with JSON clients

Subscription is implemented as a streming RPC and therefore an actual ConnectRPC client is required.

If you really require to use a JSON client for receiving messages, you might use wrapped SubscribeUnary API. Which internally creates the subscription stream and collects all event message for a duration of for.

# receive any messages on the bus for 10s
curl -X 'POST' \
  'http://localhost:8080/knx.groupaddress.v1.GroupAddressService/SubscribeUnary' \
  -H 'accept: application/json' \
  -H 'Authorization: Bearer CHANGEME' \
  -H 'Content-Type: application/json' \
  -d '{
  "subscribeRequest": {
    "groupAddresses": [],
    "event": "EVENT_UNSPECIFIED"
  },
  "for": "10s"
}'

If you omit the value of for, the first event message received will terminate the stream and your client will see the result immediately.

# receive the first message on the bus (missing for)
curl -X 'POST' \
  'http://localhost:8080/knx.groupaddress.v1.GroupAddressService/SubscribeUnary' \
  -H 'accept: application/json' \
  -H 'Authorization: Bearer CHANGEME' \
  -H 'Content-Type: application/json' \
  -d '{
  "subscribeRequest": {
    "groupAddresses": []
  }
}'

Development

Dev container

Open this project in Visual Studio Code and select to reopen it inside a dev container.

If you experience any issues, make sure your IDE supports dev containers: https://code.visualstudio.com/docs/devcontainers/containers

Tasks

This project uses task.

Run task --list to list all available tasks.