mdns-termux/lib/mdns_tools/publish.py

"""Publish this device on the LAN: hostname + optional services.

Config example (config/services.example.yaml or JSON):
    hostname: movil
    services:
      - {type: _ssh._tcp, port: 8022, name: "Termux SSH"}
      - {type: _smb._tcp, port: 4450, name: "Termux SMB"}
"""
import socket
import time
from pathlib import Path

from zeroconf import Zeroconf, ServiceInfo


def _local_ipv4() -> str:
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    try:
        s.connect(("8.8.8.8", 80))
        return s.getsockname()[0]
    except OSError:
        return "127.0.0.1"
    finally:
        s.close()


def _load_config(path: str | None) -> dict:
    if not path:
        return {"hostname": "movil", "services": []}
    p = Path(path).expanduser()
    if not p.exists():
        return {"hostname": "movil", "services": []}
    text = p.read_text()
    if p.suffix in (".yml", ".yaml"):
        try:
            import yaml  # type: ignore
            return yaml.safe_load(text) or {}
        except ImportError:
            print("warning: PyYAML not installed, using minimal parser")
    import json
    try:
        return json.loads(text)
    except Exception:
        return {"hostname": "movil", "services": []}


def run(config_path: str | None = None,
        hostname: str | None = None,
        verbose: bool = True) -> None:
    """Publish hostname + services and block forever."""
    cfg = _load_config(config_path)
    host = hostname or cfg.get("hostname", "movil")
    ip = _local_ipv4()
    zc = Zeroconf()
    infos: list[ServiceInfo] = []
    # Register hostname via _workstation._tcp so the device shows up in browsers
    ws = ServiceInfo(
        type_="_workstation._tcp.local.",
        name=f"{host} [{ip.replace('.', '-')}]._workstation._tcp.local.",
        addresses=[socket.inet_aton(ip)],
        port=9,
        server=f"{host}.local.",
    )
    zc.register_service(ws)
    infos.append(ws)
    for svc in (cfg.get("services") or []):
        try:
            t = svc["type"].rstrip(".") + ".local."
            n = f'{svc.get("name", host)}.{t}'
            info = ServiceInfo(
                type_=t,
                name=n,
                addresses=[socket.inet_aton(ip)],
                port=int(svc["port"]),
                server=f"{host}.local.",
                properties=svc.get("txt", {}),
            )
            zc.register_service(info)
            infos.append(info)
        except Exception as e:
            print(f"warning: could not register {svc}: {e}")
    if verbose:
        print(f"[mdns] published {host}.local ({ip}), {len(infos)} record(s). Ctrl+C to stop.")
    try:
        while True:
            time.sleep(60)
    except KeyboardInterrupt:
        pass
    finally:
        for i in infos:
            try:
                zc.unregister_service(i)
            except Exception:
                pass
        zc.close()
        if verbose:
            print("[mdns] stopped, goodbye packets sent.")