add code (#223)

backend/fastrtc/utils.py

@@ -8,6 +8,7 @@ import logging
 import tempfile
 import traceback
 from contextvars import ContextVar
+from dataclasses import dataclass
 from typing import Any, Callable, Literal, Protocol, TypedDict, cast
 
 import av
@@ -61,6 +62,22 @@ current_channel: ContextVar[DataChannel | None] = ContextVar(
 )
 
 
+@dataclass
+class Context:
+    webrtc_id: str
+
+
+current_context: ContextVar[Context | None] = ContextVar(
+    "current_context", default=None
+)
+
+
+def get_current_context() -> Context:
+    if not (ctx := current_context.get()):
+        raise RuntimeError("No context found")
+    return ctx
+
+
 def _send_log(message: str, type: str) -> None:
     async def _send(channel: DataChannel) -> None:
         channel.send(