init version

msgcenterpy/core/envelope.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from typing import Any, Dict, TypedDict
+
+ENVELOPE_VERSION: str = "1"
+
+
+class Properties(TypedDict, total=False):
+    ros_msg_cls_path: str
+    ros_msg_cls_namespace: str
+    json_schema: Dict[str, Any]
+
+
+class FormatMetadata(TypedDict, total=False):
+    """Additional metadata for source format, optional.
+
+    Examples: field statistics, original type descriptions, field type mappings, etc.
+    """
+
+    current_format: str
+    source_cls_name: str
+    source_cls_module: str
+    properties: Properties
+
+
+class MessageEnvelope(TypedDict, total=True):
+    """Unified message envelope format.
+
+    - version: Protocol version
+    - format: Source format (MessageType.value)
+    - type_info: Type information (applicable for ROS2, Pydantic, etc.)
+    - content: Normalized message content (dictionary)
+    - metadata: Additional metadata
+    """
+
+    version: str
+    format: str
+    content: Dict[str, Any]
+    metadata: FormatMetadata
+
+
+def create_envelope(
+    *,
+    format_name: str,
+    content: Dict[str, Any],
+    metadata: FormatMetadata,
+) -> MessageEnvelope:
+    env: MessageEnvelope = {
+        "version": ENVELOPE_VERSION,
+        "format": format_name,
+        "content": content,
+        "metadata": metadata,
+    }
+    return env