openarm_ros2/openarm_bringup/scripts/udp_recv_json.py

#!/usr/bin/env python3

import argparse
import json
import socket
import sys
from typing import Any, Dict


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Receive and print OpenArm UDP JSON joint-state packets."
    )
    parser.add_argument("--port", type=int, default=10001, help="Listen UDP port")
    parser.add_argument(
        "--bind-ip",
        default="0.0.0.0",
        help="Bind IP address (default: 0.0.0.0)",
    )
    parser.add_argument(
        "--raw",
        action="store_true",
        help="Print raw JSON text instead of formatted joint table",
    )
    return parser.parse_args()


def print_packet(packet: Dict[str, Any]) -> None:
    protocol = packet.get("protocol", "unknown")
    stamp = packet.get("stamp", {})
    sec = stamp.get("sec", "?")
    nanosec = stamp.get("nanosec", "?")
    if "joints" in packet:
        joints = packet.get("joints", [])
        left_arm = [j for j in joints if "_left_" in str(j.get("name", ""))]
        right_arm = [j for j in joints if "_right_" in str(j.get("name", ""))]
        other = [j for j in joints if j not in left_arm and j not in right_arm]
    else:
        left_arm = packet.get("left_arm", [])
        right_arm = packet.get("right_arm", [])
        other = packet.get("other", [])
        joints = left_arm + right_arm + other

    print(f"protocol={protocol} stamp={sec}.{nanosec} joints={len(joints)}")

    for group_name, group_joints in (("left_arm", left_arm), ("right_arm", right_arm), ("other", other)):
        if not group_joints:
            continue
        print(f"{group_name}:")
        for joint in group_joints:
            name = joint.get("name", "?")
            pos = joint.get("position", None)
            vel = joint.get("velocity", None)
            tor = joint.get("torque", None)
            print(f"  {name:28s}  pos={pos!s:>12s}  vel={vel!s:>12s}  tau={tor!s:>12s}")


def main() -> int:
    args = parse_args()

    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind((args.bind_ip, args.port))

    print(f"Listening JSON UDP on {args.bind_ip}:{args.port}")

    try:
        while True:
            data, addr = sock.recvfrom(65535)
            text = data.decode("utf-8", errors="replace")
            try:
                packet = json.loads(text)
            except json.JSONDecodeError as exc:
                print(f"[{addr[0]}:{addr[1]}] invalid JSON: {exc}")
                continue

            print(f"\nfrom {addr[0]}:{addr[1]}")
            if args.raw:
                print(text)
            else:
                print_packet(packet)
    except KeyboardInterrupt:
        print("\nStopped.")
    finally:
        sock.close()

    return 0


if __name__ == "__main__":
    sys.exit(main())