Add optional file ID to document state

jupyter_ydoc/ybasedoc.py

@@ -110,6 +110,16 @@ def path(self) -> Optional[str]:
         """
         return self._ystate.get("path")
 
+    @property
+    def file_id(self) -> Optional[str]:
+        """
+        Returns document's file ID.
+
+        :return: Document's file ID.
+        :rtype: Optional[str]
+        """
+        return self._ystate.get("file_id")
+
     @path.setter
     def path(self, value: str) -> None:
         """
@@ -121,6 +131,17 @@ def path(self, value: str) -> None:
         with self._ydoc.begin_transaction() as t:
             self._ystate.set(t, "path", value)
 
+    @file_id.setter
+    def file_id(self, value: str) -> None:
+        """
+        Sets document's file ID.
+
+        :param value: Document's file ID.
+        :type value: str
+        """
+        with self._ydoc.begin_transaction() as t:
+            self._ystate.set(t, "file_id", value)
+
     @abstractmethod
     def get(self) -> Any:
         """

jupyter_ydoc/ynotebook.py

@@ -254,7 +254,7 @@ def set(self, value: Dict) -> None:
                 self._ymeta.pop(t, key)
             if cells_len:
                 self._ycells.delete_range(t, 0, cells_len)
-            for key in [k for k in self._ystate if k not in ("dirty", "path")]:
+            for key in [k for k in self._ystate if k not in ("dirty", "path", "file_id")]:
                 self._ystate.pop(t, key)
 
             # initialize document