Add go2rtc and extend camera integration for better WebRTC support (#124410)

homeassistant/components/camera/helper.py

@@ -0,0 +1,28 @@
+"""Camera helper functions."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from homeassistant.core import HomeAssistant
+from homeassistant.exceptions import HomeAssistantError
+
+from .const import DATA_COMPONENT
+
+if TYPE_CHECKING:
+    from . import Camera
+
+
+def get_camera_from_entity_id(hass: HomeAssistant, entity_id: str) -> Camera:
+    """Get camera component from entity_id."""
+    component = hass.data.get(DATA_COMPONENT)
+    if component is None:
+        raise HomeAssistantError("Camera integration not set up")
+
+    if (camera := component.get_entity(entity_id)) is None:
+        raise HomeAssistantError("Camera not found")
+
+    if not camera.is_on:
+        raise HomeAssistantError("Camera is off")
+
+    return camera