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Server Push¶
Push state updates to connected LiveView clients from anywhere in your backend: Celery tasks, management commands, cron jobs, Django signals, and more.
Quick Start¶
from djust import push_to_view
# Update state on all connected clients
push_to_view("myapp.views.DashboardView", state={"visitors": 42})
# Call a handler method on all connected clients
push_to_view("myapp.views.ChatView", handler="on_new_message",
payload={"text": "Hello from the server!"})
Push from Celery Tasks¶
The most common use case is pushing updates from background workers. Since push_to_view is synchronous, it works directly inside any Celery task.
from celery import shared_task
from djust import push_to_view
@shared_task
def refresh_metrics():
count = Order.objects.filter(status="pending").count()
push_to_view(
"dashboard.views.MetricsView",
state={"pending_orders": count},
)
Push from Management Commands¶
Useful for deployment notifications, maintenance windows, or system alerts.
from django.core.management.base import BaseCommand
from djust import push_to_view
class Command(BaseCommand):
def handle(self, *args, **options):
push_to_view(
"alerts.views.AlertView",
handler="on_alert",
payload={"level": "warning", "message": "Deploy starting"},
)
Async Push¶
For async contexts (async views, ASGI middleware, async Celery tasks), use apush_to_view:
from djust import apush_to_view
async def notify_clients():
await apush_to_view("myapp.views.FeedView", state={"new_items": True})
Periodic Tick¶
For views that need to self-update on a schedule (dashboards, live feeds), set tick_interval and override handle_tick():
from djust import LiveView
class StockTickerView(LiveView):
template_name = "ticker.html"
tick_interval = 2000 # milliseconds
def mount(self, request, **kwargs):
self.price = get_current_price()
def handle_tick(self):
self.price = get_current_price()
The view re-renders and sends VDOM patches to all connected clients after each tick. No external task runner needed.
The Broadcast Pattern¶
When multiple clients edit shared state (collaborative editing, shared dashboards), you need to broadcast changes to peers without triggering a render loop on the sender. The _broadcast / _on_broadcast pattern solves this.
from djust import LiveView
from djust.decorators import event_handler
class SharedNoteView(LiveView):
template_name = "note.html"
def mount(self, request, **kwargs):
self.content = Note.objects.get(pk=kwargs["pk"]).content
self._skip_broadcast = False
@event_handler
def update_content(self, value: str = "", **kwargs):
self.content = value
Note.objects.filter(pk=self.kwargs["pk"]).update(content=value)
self._broadcast({"content": value})
def _broadcast(self, data):
"""Push to all peers. The sender skips re-render."""
self._skip_broadcast = True
push_to_view(
"notes.views.SharedNoteView",
handler="_on_broadcast",
payload=data,
)
def _on_broadcast(self, content: str = "", **kwargs):
"""Receive broadcast from a peer."""
if self._skip_broadcast:
self._skip_broadcast = False
self._skip_render = True
return
self.content = content
The _skip_broadcast flag prevents the sender from re-rendering its own update. Peers receive the broadcast and update their state normally.
How It Works¶
- When a client connects via WebSocket, the consumer joins a channel-layer group named
djust_view_<view_path>(dots replaced with underscores). push_to_view()sends a message to that group via Django Channels.- Each connected consumer receives the message, applies state updates and/or calls the handler, re-renders, and sends DOM patches to the client.
Requirements¶
- Django Channels with a channel layer backend (Redis recommended for production).
- The
CHANNEL_LAYERSsetting must be configured insettings.py:
CHANNEL_LAYERS = {
"default": {
"BACKEND": "channels_redis.core.RedisChannelLayer",
"CONFIG": {
"hosts": [("127.0.0.1", 6379)],
},
},
}
API Reference¶
push_to_view(view_path, *, state=None, handler=None, payload=None)¶
Synchronous. Sends an update to all clients connected to view_path.
| Parameter | Type | Description |
|---|---|---|
view_path |
str |
Dotted import path of the LiveView class |
state |
dict |
Attribute names and values to set on the view |
handler |
str |
Name of a method to call on the view |
payload |
dict |
Keyword arguments passed to the handler |
apush_to_view(view_path, *, state=None, handler=None, payload=None)¶
Async version of push_to_view. Same parameters.
LiveView.tick_interval¶
Class attribute. Set to an integer (milliseconds) to enable periodic ticking.
LiveView.handle_tick()¶
Override to update state on each tick. Called every tick_interval ms.