Using Vuer in IPython/Jupyter

IPython and Jupyter notebooks have an async event loop already running, which means Vuer works seamlessly with a simple pattern.

Quick Start (IPython/Jupyter)

The recommended approach - define your app in one cell, start it in another:

Cell 1: Define your app

python

from vuer import Vuer, VuerSession
from vuer.schemas import Scene, Box

app = Vuer()

@app.spawn()  # or @app.spawn
async def main(session: VuerSession):
    session.upsert @ Box(
        args=[0.2, 0.2, 0.2],
        position=[0, 0.1, 0],
        material=dict(color="red"),
        key="my-box",
    )
    await session.forever()

Cell 2: Start the server

python

main.start()

What happens:

Cell 2 detects IPython's event loop
Schedules the server to start in the background
Cell completes immediately
Server runs in the background
You can continue using other cells

Common Patterns

Updating the Scene Dynamically

Since the server runs in the background, you can update the scene from other cells:

python

# Cell 1: Start server
from vuer import Vuer, VuerSession
from vuer.schemas import Scene, Box

app = Vuer()

@app.spawn(start=True)
async def main(session: VuerSession):
    session.upsert @ Box(
        args=[0.2, 0.2, 0.2],
        position=[0, 0, 0],
        material=dict(color="red"),
        key="box-1",
    )
    await session.forever()

python

# Cell 2: Add more objects (run this in a separate cell)
from vuer.schemas import Sphere

# Get the session from the app
# Note: You'll need to store the session reference

Interactive Updates

For interactive updates, store the session globally:

python

from vuer import Vuer, VuerSession
from vuer.schemas import Scene, Box
import asyncio

app = Vuer()
global_session = None

@app.spawn(start=True)
async def main(session: VuerSession):
    global global_session
    global_session = session

    session.upsert @ Box(
        args=[0.2, 0.2, 0.2],
        position=[0, 0, 0],
        material=dict(color="red"),
        key="box-1",
    )

    await session.forever()

# Later, in another cell:
# global_session.upsert @ Sphere(args=[0.1], position=[0.5, 0, 0], key="sphere-1")

Differences from Regular Python

Feature	Regular Python	IPython/Jupyter
Event Loop	Created by Vuer	Already running (managed by IPython)
`start=True` behavior	Blocks until server stops	Returns immediately, server runs in background
Cell execution	Script runs start-to-finish	Can run multiple cells while server runs
Stopping server	Ctrl+C	Restart kernel or close notebook

Troubleshooting

RuntimeError: There is no current event loop

This error should no longer occur with the updated code. If you see it:

Make sure you have the latest version of Vuer
Try restarting your kernel
Use start=True instead of start=False

Server doesn't respond

If the server starts but doesn't respond:

python

# Check if server is running
import subprocess
result = subprocess.run(['lsof', '-i', ':8012'], capture_output=True, text=True)
print(result.stdout)

Restarting the server

To restart the server, you need to restart the kernel:

Jupyter: Kernel → Restart
IPython: Type exit() and start a new session

Or use a different port:

python

app = Vuer(port=8013)  # Use a different port