Hermes-agent

plugins/google_meet/node/protocol.py

@@ -0,0 +1,124 @@
+"""Wire protocol for gateway ↔ node RPC.
+
+Everything is a JSON object with the same envelope shape:
+
+    Request:   {"type": <str>, "id": <str>, "token": <str>, "payload": <dict>}
+    Response:  {"type": "<req-type>_res", "id": <req-id>, "payload": <dict>}
+    Error:     {"type": "error", "id": <req-id>, "error": <str>}
+
+Requests must carry the shared bearer token (set up via
+``hermes meet node approve`` on the gateway and read off disk on the
+server). Mismatched tokens are rejected before dispatch.
+"""
+
+from __future__ import annotations
+
+import json
+import uuid
+from typing import Any, Dict, Tuple
+
+
+VALID_REQUEST_TYPES = frozenset({
+    "start_bot",
+    "stop",
+    "status",
+    "transcript",
+    "say",
+    "ping",
+})
+
+
+def make_request(
+    type: str,
+    token: str,
+    payload: Dict[str, Any],
+    req_id: str | None = None,
+) -> Dict[str, Any]:
+    """Construct a request envelope.
+
+    ``req_id`` is auto-generated (uuid4 hex) when not supplied so callers
+    can correlate async responses.
+    """
+    if not isinstance(type, str) or not type:
+        raise ValueError("type must be a non-empty string")
+    if type not in VALID_REQUEST_TYPES:
+        raise ValueError(f"unknown request type: {type!r}")
+    if not isinstance(token, str):
+        raise ValueError("token must be a string")
+    if not isinstance(payload, dict):
+        raise ValueError("payload must be a dict")
+    return {
+        "type": type,
+        "id": req_id or uuid.uuid4().hex,
+        "token": token,
+        "payload": payload,
+    }
+
+
+def make_response(req_id: str, payload: Dict[str, Any]) -> Dict[str, Any]:
+    """Build a success response. The caller supplies the *request* type;
+    we suffix it with ``_res`` so clients can assert they got the right
+    reply.
+
+    For simplicity we don't require the type here — clients usually just
+    key off ``id``. But we still emit a generic ``*_res`` envelope.
+    """
+    if not isinstance(payload, dict):
+        raise ValueError("payload must be a dict")
+    return {"type": "response", "id": req_id, "payload": payload}
+
+
+def make_error(req_id: str, error: str) -> Dict[str, Any]:
+    return {"type": "error", "id": req_id, "error": str(error)}
+
+
+def encode(msg: Dict[str, Any]) -> str:
+    """Serialize a message envelope to a JSON string."""
+    return json.dumps(msg, separators=(",", ":"), ensure_ascii=False)
+
+
+def decode(raw: str) -> Dict[str, Any]:
+    """Parse a JSON envelope, raising ValueError on anything malformed.
+
+    Minimal type validation: must be an object, must contain ``type`` and
+    ``id``. Heavier validation (token match, payload shape) happens in
+    :func:`validate_request` on the server side.
+    """
+    try:
+        obj = json.loads(raw)
+    except (TypeError, json.JSONDecodeError) as exc:
+        raise ValueError(f"malformed JSON: {exc}") from exc
+    if not isinstance(obj, dict):
+        raise ValueError("envelope must be a JSON object")
+    if "type" not in obj or not isinstance(obj["type"], str):
+        raise ValueError("envelope missing string 'type'")
+    if "id" not in obj or not isinstance(obj["id"], str):
+        raise ValueError("envelope missing string 'id'")
+    return obj
+
+
+def validate_request(msg: Dict[str, Any], expected_token: str) -> Tuple[bool, str]:
+    """Check a decoded request against the server's shared token.
+
+    Returns ``(True, "")`` when the envelope is acceptable or
+    ``(False, <reason>)`` otherwise. Reason strings are safe to surface
+    back to the client in an error envelope.
+    """
+    if not isinstance(msg, dict):
+        return False, "envelope must be a dict"
+    t = msg.get("type")
+    if not isinstance(t, str) or not t:
+        return False, "missing or non-string 'type'"
+    if t not in VALID_REQUEST_TYPES:
+        return False, f"unknown request type: {t!r}"
+    if not isinstance(msg.get("id"), str) or not msg.get("id"):
+        return False, "missing or non-string 'id'"
+    token = msg.get("token")
+    if not isinstance(token, str) or not token:
+        return False, "missing token"
+    if token != expected_token:
+        return False, "token mismatch"
+    payload = msg.get("payload")
+    if not isinstance(payload, dict):
+        return False, "payload must be a dict"
+    return True, ""