ClickHouse Virtual Server

Perspective provides a built-in virtual server for ClickHouse, allowing <perspective-viewer> clients to query a ClickHouse server over WebSocket.

For browser-only usage, see the JavaScript ClickHouse guide.

Installation

pip install perspective-python clickhouse-connect

Usage

Create a server that exposes ClickHouse tables to browser clients:

import clickhouse_connect
import tornado.web
import tornado.ioloop
from perspective import ClickhouseVirtualServer
from perspective.handlers.tornado import PerspectiveTornadoHandler

# Connect to ClickHouse
client = clickhouse_connect.get_client(host="localhost")

# Create virtual server backed by ClickHouse
server = ClickhouseVirtualServer(client)

# Serve over WebSocket
app = tornado.web.Application([
    (r"/websocket", PerspectiveTornadoHandler, {"perspective_server": server}),
])

app.listen(8080)
tornado.ioloop.IOLoop.current().start()

Connect from the browser:

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

Supported features

The ClickHouse virtual server supports:

• group_by — aggregation via ClickHouse’s GROUP BY
• sort — ordering results
• filter — standard filter operators (==, !=, >, <, >=, <=, LIKE, IS NOT NULL, etc.)
• expressions — computed columns via ClickHouse SQL expressions

Note that split_by is not currently supported with ClickHouse.

Examples

• Python ClickHouse example