WIP: integrate into django-channels

umap/asgi.py

@@ -1,15 +1,22 @@
 import os
 
-from channels.routing import ProtocolTypeRouter
+from channels.routing import ProtocolTypeRouter, URLRouter
+from channels.security.websocket import AllowedHostsOriginValidator
 from django.core.asgi import get_asgi_application
+from django.urls import re_path
+
+from .sync import consumers
 
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "umap.settings")
 # Initialize Django ASGI application early to ensure the AppRegistry
 # is populated before importing code that may import ORM models.
 django_asgi_app = get_asgi_application()
 
+urlpatterns = (re_path(r"ws/sync/(?P<map_id>\w+)/$", consumers.SyncConsumer.as_asgi()),)
+
 application = ProtocolTypeRouter(
     {
         "http": django_asgi_app,
+        "websocket": AllowedHostsOriginValidator(URLRouter(urlpatterns)),
     }
 )

umap/settings/base.py

@@ -343,3 +343,4 @@
 WEBSOCKET_BACK_HOST = env("WEBSOCKET_BACK_HOST", default="localhost")
 WEBSOCKET_BACK_PORT = env.int("WEBSOCKET_BACK_PORT", default=8001)
 WEBSOCKET_FRONT_URI = env("WEBSOCKET_FRONT_URI", default="ws://localhost:8001")
+CHANNEL_LAYERS = {"default": {"BACKEND": "channels.layers.InMemoryChannelLayer"}}

umap/static/umap/js/modules/sync/engine.js

@@ -76,7 +76,7 @@ export class SyncEngine {
 
   start(authToken) {
     this.transport = new WebSocketTransport(
-      this._umap.properties.websocketURI,
+      Utils.template(this._umap.properties.websocketURI, { id: this._umap.id }),
       authToken,
       this
     )
@@ -124,7 +124,7 @@ export class SyncEngine {
 
     if (this.offline) return
     if (this.transport) {
-      this.transport.send('OperationMessage', message)
+      this.transport.send('OperationMessage', { sender: this.uuid, ...message })
     }
   }
 
@@ -176,6 +176,7 @@ export class SyncEngine {
    * @param {Object} payload
    */
   onOperationMessage(payload) {
+    if (payload.sender === this.uuid) return
     this._operations.storeRemoteOperations([payload])
     this._applyOperation(payload)
   }
@@ -483,7 +484,7 @@ export class Operations {
     return (
       Utils.deepEqual(local.subject, remote.subject) &&
       Utils.deepEqual(local.metadata, remote.metadata) &&
-      (!shouldCheckKey || (shouldCheckKey && local.key == remote.key))
+      (!shouldCheckKey || (shouldCheckKey && local.key === remote.key))
     )
   }
 }

umap/static/umap/js/modules/sync/websocket.js

@@ -7,7 +7,7 @@ export class WebSocketTransport {
     this.receiver = messagesReceiver
     this.closeRequested = false
 
-    this.websocket = new WebSocket(webSocketURI)
+    this.websocket = new WebSocket(`${webSocketURI}`)
 
     this.websocket.onopen = () => {
       this.send('JoinRequest', { token: authToken })
@@ -49,6 +49,7 @@ export class WebSocketTransport {
   }
 
   onMessage(wsMessage) {
+    console.log(wsMessage)
     if (wsMessage.data === 'pong') {
       this.pongReceived = true
     } else {

umap/sync/consumers.py

@@ -0,0 +1,86 @@
+import logging
+
+from channels.generic.websocket import AsyncWebsocketConsumer
+from django.core.signing import TimestampSigner
+from pydantic import ValidationError
+
+from .payloads import (
+    JoinRequest,
+    JoinResponse,
+    ListPeersResponse,
+    OperationMessage,
+    PeerMessage,
+    Request,
+)
+
+
+class SyncConsumer(AsyncWebsocketConsumer):
+    @property
+    def peers(self):
+        return self.channel_layer.groups[self.map_id].keys()
+
+    async def connect(self):
+        self.map_id = self.scope["url_route"]["kwargs"]["map_id"]
+
+        # Join room group
+        await self.channel_layer.group_add(self.map_id, self.channel_name)
+
+        self.is_authenticated = False
+        await self.accept()
+
+    async def disconnect(self, close_code):
+        await self.channel_layer.group_discard(self.map_id, self.channel_name)
+        await self.send_peers_list()
+
+    async def send_peers_list(self):
+        message = ListPeersResponse(peers=self.peers)
+        await self.broadcast(message.model_dump_json())
+
+    async def broadcast(self, message):
+        # Send to all channels (including sender!)
+        await self.channel_layer.group_send(
+            self.map_id, {"message": message, "type": "on_message"}
+        )
+
+    async def send_to(self, channel, message):
+        # Send to one given channel
+        await self.channel_layer.send(
+            channel, {"message": message, "type": "on_message"}
+        )
+
+    async def on_message(self, event):
+        # Send to self channel
+        await self.send(event["message"])
+
+    async def receive(self, text_data):
+        if not self.is_authenticated:
+            message = JoinRequest.model_validate_json(text_data)
+            signed = TimestampSigner().unsign_object(message.token, max_age=30)
+            user, map_id, permissions = signed.values()
+            if "edit" not in permissions:
+                return await self.disconnect()
+            response = JoinResponse(uuid=self.channel_name, peers=self.peers)
+            await self.send(response.model_dump_json())
+            await self.send_peers_list()
+            self.is_authenticated = True
+            return
+
+        if text_data == "ping":
+            return await self.send("pong")
+
+        try:
+            incoming = Request.model_validate_json(text_data)
+        except ValidationError as error:
+            message = (
+                f"An error occurred when receiving the following message: {text_data!r}"
+            )
+            logging.error(message, error)
+        else:
+            match incoming.root:
+                # Broadcast all operation messages to connected peers
+                case OperationMessage():
+                    await self.broadcast(text_data)
+
+                # Send peer messages to the proper peer
+                case PeerMessage():
+                    await self.send_to(incoming.root.recipient, text_data)

umap/sync/payloads.py

@@ -0,0 +1,47 @@
+from typing import Literal, Optional, Union
+
+from pydantic import BaseModel, Field, RootModel
+
+
+class JoinRequest(BaseModel):
+    kind: Literal["JoinRequest"] = "JoinRequest"
+    token: str
+
+
+class OperationMessage(BaseModel):
+    """Message sent from one peer to all the others"""
+
+    kind: Literal["OperationMessage"] = "OperationMessage"
+    verb: Literal["upsert", "update", "delete"]
+    subject: Literal["map", "datalayer", "feature"]
+    metadata: Optional[dict] = None
+    key: Optional[str] = None
+
+
+class PeerMessage(BaseModel):
+    """Message sent from a specific peer to another one"""
+
+    kind: Literal["PeerMessage"] = "PeerMessage"
+    sender: str
+    recipient: str
+    # The message can be whatever the peers want. It's not checked by the server.
+    message: dict
+
+
+class Request(RootModel):
+    """Any message coming from the websocket should be one of these, and will be rejected otherwise."""
+
+    root: Union[PeerMessage, OperationMessage] = Field(discriminator="kind")
+
+
+class JoinResponse(BaseModel):
+    """Server response containing the list of peers"""
+
+    kind: Literal["JoinResponse"] = "JoinResponse"
+    peers: list
+    uuid: str
+
+
+class ListPeersResponse(BaseModel):
+    kind: Literal["ListPeersResponse"] = "ListPeersResponse"
+    peers: list

umap/tests/integration/conftest.py

@@ -5,6 +5,7 @@
 from pathlib import Path
 
 import pytest
+from channels.testing import ChannelsLiveServerTestCase
 from playwright.sync_api import expect
 
 from ..base import mock_tiles
@@ -87,3 +88,15 @@ def websocket_server():
     yield ds_proc
     # Shut it down at the end of the pytest session
     ds_proc.terminate()
+
+
+@pytest.fixture(scope="function")
+def channels_live_server(request, settings):
+    server = ChannelsLiveServerTestCase()
+    server.serve_static = False
+    server._pre_setup()
+    settings.WEBSOCKET_FRONT_URI = f"{server.live_server_ws_url}/ws/sync/{{id}}/"
+
+    yield server
+
+    server._post_teardown()

umap/tests/integration/test_websocket_sync.py

@@ -12,7 +12,7 @@
 
 @pytest.mark.xdist_group(name="websockets")
 def test_websocket_connection_can_sync_markers(
-    new_page, live_server, websocket_server, tilelayer
+    new_page, live_server, channels_live_server, tilelayer
 ):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
@@ -80,7 +80,7 @@ def test_websocket_connection_can_sync_markers(
 
 @pytest.mark.xdist_group(name="websockets")
 def test_websocket_connection_can_sync_polygons(
-    context, live_server, websocket_server, tilelayer
+    context, live_server, channels_live_server, tilelayer
 ):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
@@ -164,7 +164,7 @@ def test_websocket_connection_can_sync_polygons(
 
 @pytest.mark.xdist_group(name="websockets")
 def test_websocket_connection_can_sync_map_properties(
-    new_page, live_server, websocket_server, tilelayer
+    new_page, live_server, channels_live_server, tilelayer
 ):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
@@ -196,7 +196,7 @@ def test_websocket_connection_can_sync_map_properties(
 
 @pytest.mark.xdist_group(name="websockets")
 def test_websocket_connection_can_sync_datalayer_properties(
-    new_page, live_server, websocket_server, tilelayer
+    new_page, live_server, channels_live_server, tilelayer
 ):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
@@ -225,7 +225,7 @@ def test_websocket_connection_can_sync_datalayer_properties(
 
 @pytest.mark.xdist_group(name="websockets")
 def test_websocket_connection_can_sync_cloned_polygons(
-    context, live_server, websocket_server, tilelayer
+    context, live_server, channels_live_server, tilelayer
 ):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
@@ -288,7 +288,7 @@ def test_websocket_connection_can_sync_cloned_polygons(
 
 @pytest.mark.xdist_group(name="websockets")
 def test_websocket_connection_can_sync_late_joining_peer(
-    new_page, live_server, websocket_server, tilelayer
+    new_page, live_server, channels_live_server, tilelayer
 ):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
@@ -349,7 +349,7 @@ def test_websocket_connection_can_sync_late_joining_peer(
 
 
 @pytest.mark.xdist_group(name="websockets")
-def test_should_sync_datalayers(new_page, live_server, websocket_server, tilelayer):
+def test_should_sync_datalayers(new_page, live_server, channels_live_server, tilelayer):
     map = MapFactory(name="sync", edit_status=Map.ANONYMOUS)
     map.settings["properties"]["syncEnabled"] = True
     map.save()
@@ -422,7 +422,7 @@ def test_should_sync_datalayers(new_page, live_server, websocket_server, tilelay
 
 @pytest.mark.xdist_group(name="websockets")
 def test_create_and_sync_map(
-    new_page, live_server, websocket_server, tilelayer, login, user
+    new_page, live_server, channels_live_server, tilelayer, login, user
 ):
     # Create a syncable map with peerA
     peerA = login(user, prefix="Page A")