Projects live at URLs, have owners, and are edited together live

A project is only ever at /p/<id>/<slug>; / is the index of the projects
you own or edit. Every project has an owner, who can name editors;
anyone with the link can view. Every edit saves itself, one request in
flight at a time, as a patch of the leaves that changed, and a websocket
(channels + daphne) carries presence and each committed write to
everyone else in the project. The first write to a leaf wins, and the
loser is told.

Undo is per person: a step undoes only if the leaves it touched still
hold what it left, so it never takes a collaborator's work with it.
Named snapshots replace saving, and restore as an ordinary write.

An empty symbol now survives the leaf round trip with `:nodes {}`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/asgi.py

@@ -1,12 +1,25 @@
 """ASGI entry point.
 
-ASGI and not only WSGI because the collaboration design in docs/architecture.md
-puts presence and document deltas on a websocket. Those consumers are out of step
-9's scope; this is the half of their setup that costs nothing now.
+HTTP is Django as usual. The websocket carries presence and the document deltas
+the server broadcasts after a write — never writes, which stay on HTTP. See
+docs/architecture.md, Collaboration.
 """
 import os
 
 from django.core.asgi import get_asgi_application
 
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "server.settings")
-application = get_asgi_application()
+django_asgi_app = get_asgi_application()
+
+from channels.auth import AuthMiddlewareStack  # noqa: E402
+from channels.routing import ProtocolTypeRouter, URLRouter  # noqa: E402
+from channels.security.websocket import AllowedHostsOriginValidator  # noqa: E402
+
+from clips.routing import websocket_urlpatterns  # noqa: E402
+
+application = ProtocolTypeRouter({
+    "http": django_asgi_app,
+    "websocket": AllowedHostsOriginValidator(
+        AuthMiddlewareStack(URLRouter(websocket_urlpatterns))
+    ),
+})

server/settings.py

@@ -32,6 +32,9 @@ CSRF_TRUSTED_ORIGINS = [
 ]
 
 INSTALLED_APPS = [
+    # First, so `runserver` is daphne's and serves the websocket too.
+    "daphne",
+    "channels",
     "django.contrib.admin",
     "django.contrib.auth",
     "django.contrib.contenttypes",
@@ -51,6 +54,10 @@ MIDDLEWARE = [
     "django.contrib.messages.middleware.MessageMiddleware",
 ]
 
+# Process-local, like the consumer's ROOMS: one worker. docs/architecture.md
+# names the move — Redis — for the day there is a second.
+CHANNEL_LAYERS = {"default": {"BACKEND": "channels.layers.InMemoryChannelLayer"}}
+
 ROOT_URLCONF = "server.urls"
 WSGI_APPLICATION = "server.wsgi.application"
 ASGI_APPLICATION = "server.asgi.application"

server/urls.py

@@ -10,6 +10,10 @@ urlpatterns = [
     # ARTHUR_URL can stay pointed at the same place and only the port moves.
     path("", views.page, name="page"),
     path("index.html", views.page),
+    # A project's own address, with its name as a slug for people to read. The
+    # same page; the client reads the id out of the path and opens it.
+    path("p/<uuid:project_id>", views.page),
+    path("p/<uuid:project_id>/<slug:slug>", views.page),
     path("api/", include("clips.urls")),
     path("blob/<str:digest>", views.blob, name="blob"),
     path("admin/", admin.site.urls),