Adds restore and ovewrite messages

jupyter_collaboration/handlers.py

@@ -209,7 +209,7 @@ async def recv(self):
         message = await self._message_queue.get()
         return message
 
-    def on_message(self, message):
+    async def on_message(self, message):
         """
         On message receive.
         """
@@ -240,6 +240,9 @@ def on_message(self, message):
                 )
                 return skip
 
+        if message_type == MessageType.ROOM:
+            await self.room.handle_msg(message[1:])
+
         if message_type == MessageType.CHAT:
             msg = message[2:].decode("utf-8")
 
@@ -316,7 +319,7 @@ async def _clean_room(self) -> None:
         file = self._file_loaders[file_id]
         if file.number_of_subscriptions == 0:
             self.log.info("Deleting file %s", file.path)
-            del self._file_loaders[file_id]
+            await self._file_loaders.remove(file_id)
             self._emit(LogLevel.INFO, "clean", "Loader deleted.")
 
     def check_origin(self, origin):

jupyter_collaboration/loaders.py

@@ -118,6 +118,26 @@ async def load_content(self, format: str, file_type: str, content: bool) -> dict
             )
 
     async def save_content(self, model: dict[str, Any]) -> dict[str, Any]:
+        """
+        Save the content of the file.
+
+            Parameters:
+                model (dict): A dictionary with format, type, last_modified, and content of the file.
+
+            Returns:
+                model (dict): A dictionary with the metadata and content of the file.
+        """
+        async with self._lock:
+            path = self.path
+            if model["type"] not in {"directory", "file", "notebook"}:
+                # fall back to file if unknown type, the content manager only knows
+                # how to handle these types
+                model["type"] = "file"
+
+            self._log.info("Saving file: %s", path)
+            return await ensure_async(self._contents_manager.save(model, path))
+
+    async def maybe_save_content(self, model: dict[str, Any]) -> dict[str, Any]:
         """
         Save the content of the file.
 

jupyter_collaboration/rooms.py

@@ -4,16 +4,24 @@
 from __future__ import annotations
 
 import asyncio
+import uuid
 from logging import Logger
 from typing import Any
 
 from jupyter_events import EventLogger
 from jupyter_ydoc import ydocs as YDOCS
 from ypy_websocket.websocket_server import YRoom
 from ypy_websocket.ystore import BaseYStore, YDocNotFound
+from ypy_websocket.yutils import write_var_uint
 
 from .loaders import FileLoader
-from .utils import JUPYTER_COLLABORATION_EVENTS_URI, LogLevel, OutOfBandChanges
+from .utils import (
+    JUPYTER_COLLABORATION_EVENTS_URI,
+    LogLevel,
+    MessageType,
+    OutOfBandChanges,
+    RoomMessages,
+)
 
 YFILE = YDOCS["file"]
 
@@ -45,9 +53,11 @@ def __init__(
         self._save_delay = save_delay
 
         self._update_lock = asyncio.Lock()
+        self._outofband_lock = asyncio.Lock()
         self._initialization_lock = asyncio.Lock()
         self._cleaner: asyncio.Task | None = None
         self._saving_document: asyncio.Task | None = None
+        self._messages: dict[str, asyncio.Lock] = {}
 
         # Listen for document changes
         self._document.observe(self._on_document_change)
@@ -149,6 +159,41 @@ async def initialize(self) -> None:
                 self.ready = True
                 self._emit(LogLevel.INFO, "initialize", "Room initialized")
 
+    async def handle_msg(self, data: bytes) -> None:
+        msg_type = data[0]
+        msg_id = data[2:].decode()
+
+        # Use a lock to prevent handling responses from multiple clients
+        # at the same time
+        async with self._messages[msg_id]:
+            # Check whether the previous client resolved the conflict
+            if msg_id not in self._messages:
+                return
+
+            try:
+                ans = None
+                if msg_type == RoomMessages.RELOAD:
+                    # Restore the room with the content from disk
+                    await self._load_document()
+                    ans = RoomMessages.DOC_OVERWRITTEN
+
+                elif msg_type == RoomMessages.OVERWRITE:
+                    # Overwrite the file with content from the room
+                    await self._save_document()
+                    ans = RoomMessages.FILE_OVERWRITTEN
+
+                if ans is not None:
+                    # Remove the lock and broadcast the resolution
+                    self._messages.pop(msg_id)
+                    data = msg_id.encode()
+                    self._outofband_lock.release()
+                    await self._broadcast_msg(
+                        bytes([MessageType.ROOM, ans]) + write_var_uint(len(data)) + data
+                    )
+
+            except Exception:
+                return
+
     def _emit(self, level: LogLevel, action: str | None = None, msg: str | None = None) -> None:
         data = {"level": level.value, "room": self._room_id, "path": self._file.path}
         if action:
@@ -187,24 +232,24 @@ async def _on_content_change(self, event: str, args: dict[str, Any]) -> None:
                 event (str): Type of change.
                 args (dict): A dictionary with format, type, last_modified.
         """
+        if self._outofband_lock.locked():
+            return
+
         if event == "metadata" and (
             self._last_modified is None or self._last_modified < args["last_modified"]
         ):
             self.log.info("Out-of-band changes. Overwriting the content in room %s", self._room_id)
             self._emit(LogLevel.INFO, "overwrite", "Out-of-band changes. Overwriting the room.")
 
-            try:
-                model = await self._file.load_content(self._file_format, self._file_type, True)
-            except Exception as e:
-                msg = f"Error loading content from file: {self._file.path}\n{e!r}"
-                self.log.error(msg, exc_info=e)
-                self._emit(LogLevel.ERROR, None, msg)
-                return None
-
-            async with self._update_lock:
-                self._document.source = model["content"]
-                self._last_modified = model["last_modified"]
-                self._document.dirty = False
+            msg_id = str(uuid.uuid4())
+            self._messages[msg_id] = asyncio.Lock()
+            await self._outofband_lock.acquire()
+            data = msg_id.encode()
+            await self._broadcast_msg(
+                bytes([MessageType.ROOM, RoomMessages.FILE_CHANGED])
+                + write_var_uint(len(data))
+                + data
+            )
 
     def _on_document_change(self, target: str, event: Any) -> None:
         """
@@ -231,6 +276,45 @@ def _on_document_change(self, target: str, event: Any) -> None:
 
         self._saving_document = asyncio.create_task(self._maybe_save_document())
 
+    async def _load_document(self) -> None:
+        try:
+            model = await self._file.load_content(self._file_format, self._file_type, True)
+        except Exception as e:
+            msg = f"Error loading content from file: {self._file.path}\n{e!r}"
+            self.log.error(msg, exc_info=e)
+            self._emit(LogLevel.ERROR, None, msg)
+            return None
+
+        async with self._update_lock:
+            self._document.source = model["content"]
+            self._last_modified = model["last_modified"]
+            self._document.dirty = False
+
+    async def _save_document(self) -> None:
+        """
+        Saves the content of the document to disk.
+        """
+        try:
+            self.log.info("Saving the content from room %s", self._room_id)
+            model = await self._file.save_content(
+                {
+                    "format": self._file_format,
+                    "type": self._file_type,
+                    "last_modified": self._last_modified,
+                    "content": self._document.source,
+                }
+            )
+            self._last_modified = model["last_modified"]
+            async with self._update_lock:
+                self._document.dirty = False
+
+            self._emit(LogLevel.INFO, "save", "Content saved.")
+
+        except Exception as e:
+            msg = f"Error saving file: {self._file.path}\n{e!r}"
+            self.log.error(msg, exc_info=e)
+            self._emit(LogLevel.ERROR, None, msg)
+
     async def _maybe_save_document(self) -> None:
         """
         Saves the content of the document to disk.
@@ -248,7 +332,7 @@ async def _maybe_save_document(self) -> None:
 
         try:
             self.log.info("Saving the content from room %s", self._room_id)
-            model = await self._file.save_content(
+            model = await self._file.maybe_save_content(
                 {
                     "format": self._file_format,
                     "type": self._file_type,
@@ -284,6 +368,10 @@ async def _maybe_save_document(self) -> None:
             self.log.error(msg, exc_info=e)
             self._emit(LogLevel.ERROR, None, msg)
 
+    async def _broadcast_msg(self, msg: bytes) -> None:
+        for client in self.clients:
+            await client.send(msg)
+
 
 class TransientRoom(YRoom):
     """A Y room for sharing state (e.g. awareness)."""

jupyter_collaboration/utils.py

@@ -12,9 +12,18 @@
 class MessageType(IntEnum):
     SYNC = 0
     AWARENESS = 1
+    ROOM = 124
     CHAT = 125
 
 
+class RoomMessages(IntEnum):
+    RELOAD = 0
+    OVERWRITE = 1
+    FILE_CHANGED = 2
+    FILE_OVERWRITTEN = 3
+    DOC_OVERWRITTEN = 4
+
+
 class LogLevel(Enum):
     INFO = "INFO"
     DEBUG = "DEBUG"

packages/docprovider/src/awareness.ts

@@ -14,12 +14,9 @@ import * as decoding from 'lib0/decoding';
 import * as encoding from 'lib0/encoding';
 import { WebsocketProvider } from 'y-websocket';
 
+import { MessageType } from './utils';
 import { IAwarenessProvider } from './tokens';
 
-export enum MessageType {
-  CHAT = 125
-}
-
 export interface IContent {
   type: string;
   body: string;

packages/docprovider/src/utils.ts

@@ -0,0 +1,17 @@
+/* -----------------------------------------------------------------------------
+| Copyright (c) Jupyter Development Team.
+| Distributed under the terms of the Modified BSD License.
+|----------------------------------------------------------------------------*/
+
+export enum MessageType {
+  ROOM = 124,
+  CHAT = 125
+}
+
+export enum RoomMessage {
+  RELOAD = 0,
+  OVERWRITE = 1,
+  FILE_CHANGED = 2,
+  FILE_OVERWRITTEN = 3,
+  DOC_OVERWRITTEN = 4
+}

packages/docprovider/src/yprovider.ts

@@ -13,10 +13,13 @@ import { Signal } from '@lumino/signaling';
 
 import { DocumentChange, YDocument } from '@jupyter/ydoc';
 
+import * as decoding from 'lib0/decoding';
+import * as encoding from 'lib0/encoding';
 import { Awareness } from 'y-protocols/awareness';
 import { WebsocketProvider as YWebsocketProvider } from 'y-websocket';
 
 import { requestDocSession } from './requests';
+import { MessageType, RoomMessage } from './utils';
 
 /**
  * An interface for a document provider.
@@ -111,6 +114,18 @@ export class WebSocketProvider implements IDocumentProvider {
 
     this._yWebsocketProvider.on('sync', this._onSync);
     this._yWebsocketProvider.on('connection-close', this._onConnectionClosed);
+
+    this._yWebsocketProvider.messageHandlers[MessageType.ROOM] = (
+      encoder,
+      decoder,
+      provider,
+      emitSynced,
+      messageType
+    ) => {
+      const msgType = decoding.readVarUint(decoder);
+      const data = decoding.readVarString(decoder);
+      this._handleRoomMessage(msgType, data);
+    };
   }
 
   private _onUserChanged(user: User.IManager): void {
@@ -138,6 +153,59 @@ export class WebSocketProvider implements IDocumentProvider {
     }
   };
 
+  private _handleRoomMessage(type: number, data: string): void {
+    switch (type) {
+      case RoomMessage.FILE_CHANGED:
+        this._handleFileChanged(data);
+        break;
+
+      case RoomMessage.DOC_OVERWRITTEN:
+      case RoomMessage.FILE_OVERWRITTEN:
+        if (this._dialog) {
+          this._dialog.close();
+          this._dialog = null;
+        }
+        break;
+    }
+  }
+
+  private _handleFileChanged(data: string): void {
+    this._dialog = new Dialog({
+      title: this._trans.__('File changed'),
+      body: this._trans.__('Do you want to overwrite the file or reload it?'),
+      buttons: [
+        Dialog.okButton({ label: 'Reload' }),
+        Dialog.warnButton({ label: 'Overwrite' })
+      ],
+      hasClose: false
+    });
+
+    this._dialog.launch().then(resp => {
+      if (resp.button.label === 'Reload') {
+        this._sendReloadMsg(data);
+      } else if (resp.button.label === 'Overwrite') {
+        this._sendOverwriteMsg(data);
+      }
+    });
+  }
+
+  private _sendReloadMsg(data: string): void {
+    const encoder = encoding.createEncoder();
+    encoding.writeVarUint(encoder, MessageType.ROOM);
+    encoding.writeVarUint(encoder, RoomMessage.RELOAD);
+    encoding.writeVarString(encoder, data);
+    this._yWebsocketProvider?.ws!.send(encoding.toUint8Array(encoder));
+  }
+
+  private _sendOverwriteMsg(data: string): void {
+    const encoder = encoding.createEncoder();
+    encoding.writeVarUint(encoder, MessageType.ROOM);
+    encoding.writeVarUint(encoder, RoomMessage.OVERWRITE);
+    encoding.writeVarString(encoder, data);
+    this._yWebsocketProvider?.ws!.send(encoding.toUint8Array(encoder));
+  }
+
+  private _dialog: Dialog<any> | null = null;
   private _awareness: Awareness;
   private _contentType: string;
   private _format: string;