Perspective with FastAPI and Starlette

perspective-python includes a WebSocket handler for Starlette, and therefore FastAPI. Add one WebSocket route and every Table hosted by your perspective.Server is available to <perspective-viewer> clients in the browser.

pip install "perspective-python[starlette]" fastapi uvicorn

import uvicorn
from fastapi import FastAPI, WebSocket
from perspective import Server
from perspective.handlers.starlette import PerspectiveStarletteHandler

server = Server()
client = server.new_local_client()
table = client.table(
    {"symbol": "string", "price": "float", "time": "datetime"},
    index="symbol",
    name="prices",
)

app = FastAPI()

async def websocket_handler(websocket: WebSocket):
    handler = PerspectiveStarletteHandler(
        perspective_server=server,
        websocket=websocket,
    )

    await handler.run()

app.add_api_websocket_route("/websocket", websocket_handler)

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8080)

Anything in your application can now write to the table — a REST endpoint, a background task, a queue consumer:

@app.post("/ticks")
async def ticks(rows: list[dict]):
    table.update(rows)

In the browser:

const websocket = await perspective.websocket("ws://localhost:8080/websocket");
const table = await websocket.open_table("prices");
await document.querySelector("perspective-viewer").load(table);

Every connected viewer updates as table.update() is called.

• Hosting a WebSocket server — replicated vs server-only modes.
• Multithreading — the executor handler argument and on_poll_request.
• Real-time dashboards over WebSocket
• python-starlette example