Add forking API (#394)

* Add forking API

* Add GET forks of root

* Add fork Jupyter events

* Replace query parameter merge=1 with merge=true

* Add fork title and description

projects/jupyter-server-ydoc/jupyter_server_ydoc/app.py

@@ -14,6 +14,7 @@
 from traitlets import Bool, Float, Type
 
 from .handlers import (
+    DocForkHandler,
     DocSessionHandler,
     TimelineHandler,
     UndoRedoHandler,
@@ -25,6 +26,7 @@
 from .utils import (
     AWARENESS_EVENTS_SCHEMA_PATH,
     EVENTS_SCHEMA_PATH,
+    FORK_EVENTS_SCHEMA_PATH,
     encode_file_path,
     room_id_from_encoded_path,
 )
@@ -85,6 +87,7 @@ def initialize(self):
         super().initialize()
         self.serverapp.event_logger.register_event_schema(EVENTS_SCHEMA_PATH)
         self.serverapp.event_logger.register_event_schema(AWARENESS_EVENTS_SCHEMA_PATH)
+        self.serverapp.event_logger.register_event_schema(FORK_EVENTS_SCHEMA_PATH)
 
     def initialize_settings(self):
         self.settings.update(
@@ -123,6 +126,13 @@ def initialize_handlers(self):
 
         self.handlers.extend(
             [
+                (
+                    r"/api/collaboration/fork/(.*)",
+                    DocForkHandler,
+                    {
+                        "ywebsocket_server": self.ywebsocket_server,
+                    },
+                ),
                 (
                     r"/api/collaboration/room/(.*)",
                     YDocWebSocketHandler,

projects/jupyter-server-ydoc/jupyter_server_ydoc/events/fork.yaml

@@ -0,0 +1,56 @@
+"$id": https://schema.jupyter.org/jupyter_collaboration/fork/v1
+"$schema": "http://json-schema.org/draft-07/schema"
+version: 1
+title: Collaborative fork events
+personal-data: true
+description: |
+  Fork events emitted from server-side during a collaborative session.
+type: object
+required:
+  - fork_roomid
+  - fork_info
+  - username
+  - action
+properties:
+  fork_roomid:
+    type: string
+    description: |
+      Fork root room ID.
+  fork_info:
+    type: object
+    description: |
+      Fork root room information.
+    required:
+      - root_roomid
+      - synchronize
+      - title
+      - description
+    properties:
+      root_roomid:
+        type: string
+        description: |
+          Root room ID. Usually composed by the file type, format and ID.
+      synchronize:
+        type: boolean
+        description: |
+          Whether the fork is kept in sync with the root.
+      title:
+        type: string
+        description: |
+          The title of the fork.
+      description:
+        type: string
+        description: |
+          The description of the fork.
+  username:
+    type: string
+    description: |
+      The name of the user who created or deleted the fork.
+  action:
+    enum:
+      - create
+      - delete
+    description: |
+      Possible values:
+      1. create
+      2. delete

projects/jupyter-server-ydoc/jupyter_server_ydoc/handlers.py

@@ -26,6 +26,7 @@
 from .utils import (
     JUPYTER_COLLABORATION_AWARENESS_EVENTS_URI,
     JUPYTER_COLLABORATION_EVENTS_URI,
+    JUPYTER_COLLABORATION_FORK_EVENTS_URI,
     LogLevel,
     MessageType,
     decode_file_path,
@@ -39,6 +40,7 @@
 
 SERVER_SESSION = str(uuid.uuid4())
 FORK_DOCUMENTS = {}
+FORK_ROOMS: dict[str, dict[str, str]] = {}
 
 
 class YDocWebSocketHandler(WebSocketHandler, JupyterHandler):
@@ -600,3 +602,101 @@ async def _cleanup_undo_manager(self, room_id: str) -> None:
         if room_id in FORK_DOCUMENTS:
             del FORK_DOCUMENTS[room_id]
             self.log.info(f"Fork Document for {room_id} has been removed.")
+
+
+class DocForkHandler(APIHandler):
+    """
+    Jupyter Server handler to:
+    - create a fork of a root document (optionally synchronizing with the root document),
+    - delete a fork of a root document (optionally merging back in the root document).
+    - get fork IDs of a root document.
+    """
+
+    auth_resource = "contents"
+
+    def initialize(
+        self,
+        ywebsocket_server: JupyterWebsocketServer,
+    ) -> None:
+        self._websocket_server = ywebsocket_server
+
+    @web.authenticated
+    @authorized
+    async def get(self, root_roomid):
+        """
+        Returns a dictionary of fork room ID to fork room information for the given root room ID.
+        """
+        self.write(
+            {
+                fork_roomid: fork_info
+                for fork_roomid, fork_info in FORK_ROOMS.items()
+                if fork_info["root_roomid"] == root_roomid
+            }
+        )
+
+    @web.authenticated
+    @authorized
+    async def put(self, root_roomid):
+        """
+        Creates a fork of a root document and returns its ID.
+        Optionally keeps the fork in sync with the root.
+        """
+        fork_roomid = uuid4().hex
+        root_room = await self._websocket_server.get_room(root_roomid)
+        update = root_room.ydoc.get_update()
+        fork_ydoc = Doc()
+        fork_ydoc.apply_update(update)
+        model = self.get_json_body()
+        synchronize = model.get("synchronize", False)
+        if synchronize:
+            root_room.ydoc.observe(lambda event: fork_ydoc.apply_update(event.update))
+        FORK_ROOMS[fork_roomid] = fork_info = {
+            "root_roomid": root_roomid,
+            "synchronize": synchronize,
+            "title": model.get("title", ""),
+            "description": model.get("description", ""),
+        }
+        fork_room = YRoom(ydoc=fork_ydoc)
+        self._websocket_server.rooms[fork_roomid] = fork_room
+        await self._websocket_server.start_room(fork_room)
+        self._emit_fork_event(self.current_user.username, fork_roomid, fork_info, "create")
+        data = json.dumps(
+            {
+                "sessionId": SERVER_SESSION,
+                "fork_roomid": fork_roomid,
+                "fork_info": fork_info,
+            }
+        )
+        self.set_status(201)
+        return self.finish(data)
+
+    @web.authenticated
+    @authorized
+    async def delete(self, fork_roomid):
+        """
+        Deletes a forked document, and optionally merges it back in the root document.
+        """
+        fork_info = FORK_ROOMS[fork_roomid]
+        root_roomid = fork_info["root_roomid"]
+        del FORK_ROOMS[fork_roomid]
+        if self.get_query_argument("merge") == "true":
+            root_room = await self._websocket_server.get_room(root_roomid)
+            root_ydoc = root_room.ydoc
+            fork_room = await self._websocket_server.get_room(fork_roomid)
+            fork_ydoc = fork_room.ydoc
+            fork_update = fork_ydoc.get_update()
+            root_ydoc.apply_update(fork_update)
+        await self._websocket_server.delete_room(name=fork_roomid)
+        self._emit_fork_event(self.current_user.username, fork_roomid, fork_info, "delete")
+        self.set_status(200)
+
+    def _emit_fork_event(
+        self, username: str, fork_roomid: str, fork_info: dict[str, str], action: str
+    ) -> None:
+        data = {
+            "username": username,
+            "fork_roomid": fork_roomid,
+            "fork_info": fork_info,
+            "action": action,
+        }
+        self.event_logger.emit(schema_id=JUPYTER_COLLABORATION_FORK_EVENTS_URI, data=data)

projects/jupyter-server-ydoc/jupyter_server_ydoc/pytest_plugin.py

@@ -145,6 +145,65 @@ async def _inner(format: str, type: str, path: str) -> Any:
     return _inner
 
 
+@pytest.fixture
+def rtc_connect_fork_client(jp_http_port, jp_base_url, rtc_fetch_session):
+    async def _inner(room_id: str) -> Any:
+        return connect(
+            f"ws://127.0.0.1:{jp_http_port}{jp_base_url}api/collaboration/room/{room_id}"
+        )
+
+    return _inner
+
+
+@pytest.fixture
+def rtc_get_forks_client(jp_fetch):
+    async def _inner(root_roomid: str) -> Any:
+        return await jp_fetch(
+            "/api/collaboration/fork",
+            root_roomid,
+            method="GET",
+        )
+
+    return _inner
+
+
+@pytest.fixture
+def rtc_create_fork_client(jp_fetch):
+    async def _inner(
+        root_roomid: str,
+        synchronize: bool,
+        title: str | None = None,
+        description: str | None = None,
+    ) -> Any:
+        return await jp_fetch(
+            "/api/collaboration/fork",
+            root_roomid,
+            method="PUT",
+            body=json.dumps(
+                {
+                    "synchronize": synchronize,
+                    "title": title,
+                    "description": description,
+                }
+            ),
+        )
+
+    return _inner
+
+
+@pytest.fixture
+def rtc_delete_fork_client(jp_fetch):
+    async def _inner(fork_roomid: str, merge: bool) -> Any:
+        return await jp_fetch(
+            "/api/collaboration/fork",
+            fork_roomid,
+            method="DELETE",
+            params={"merge": str(merge).lower()},
+        )
+
+    return _inner
+
+
 @pytest.fixture
 def rtc_add_doc_to_store(rtc_connect_doc_client):
     event = Event()

projects/jupyter-server-ydoc/jupyter_server_ydoc/utils.py

@@ -11,7 +11,9 @@
 JUPYTER_COLLABORATION_AWARENESS_EVENTS_URI = (
     "https://schema.jupyter.org/jupyter_collaboration/awareness/v1"
 )
+JUPYTER_COLLABORATION_FORK_EVENTS_URI = "https://schema.jupyter.org/jupyter_collaboration/fork/v1"
 AWARENESS_EVENTS_SCHEMA_PATH = EVENTS_FOLDER_PATH / "awareness.yaml"
+FORK_EVENTS_SCHEMA_PATH = EVENTS_FOLDER_PATH / "fork.yaml"
 
 
 class MessageType(IntEnum):

projects/jupyter-server-ydoc/pyproject.toml

@@ -41,6 +41,7 @@ dynamic = ["version"]
 [project.optional-dependencies]
 test = [
     "coverage",
+    "dirty-equals",
     "jupyter_server[test]>=2.4.0",
     "jupyter_server_fileid[test]",
     "pytest>=7.0",