Python Websocket Example

main.py

import websocket
import json


class WebsocketHandlers:
    def on_error(ws, error):
        print("error")
        print(error)


    def on_message(ws, message):
        obj = json.loads(message)

        if not ("time" in obj):
            print("ignoring message: ")
            print(obj)
            return

        print(f"{obj['time']} {obj['product_id']} {obj['price']}")
        #write_db(obj) // todo: custom logic



    def on_open(ws):
        print("opened")
        with open("subscription.json") as json_file:
            subscribeMessage = json.load(json_file)
            print(json.dumps(subscribeMessage))
            ws.send(json.dumps(subscribeMessage))



# websocket.enableTrace(True)

ws = websocket.WebSocketApp(
    "wss://ws-feed.pro.coinbase.com",
    on_message = WebsocketHandlers.on_message,
    on_error = WebsocketHandlers.on_error)

ws.on_open = WebsocketHandlers.on_open
ws.run_forever()

# note: websocket connection to coinbase is (currently) interrupted spontaneously 
#       It seems to be an issue on their side.
#       Same connection problem can be observed when programing with kotlin & javascript

subscription.json

{
    "type": "subscribe",
    "channels": [
        {
            "name": "ticker",
            "product_ids": [
                "LTC-EUR",
                "BTC-EUR",
                "ZRX-EUR",
                "BCH-EUR",
                "ETC-EUR"
            ]
        }
    ]
}