Websocket Connection With Filter Returns No Messages

Question

I am trying to listen on a websocket connection to an optimism node for specific events on a specific contract. I am getting the message back that I am connected to the node, but even though I see events happen on chain, I get nothing from the WS in my shell. Here is my redacted code:

import asyncio
import json

from web3 import Web3
from web3.middleware import geth_poa_middleware # only needed for PoA networks like BSC
import requests
from websockets import connect
from eth_abi import decode_single, decode_abi

adapter = requests.sessions.HTTPAdapter(pool_connections=50000, pool_maxsize=50000) # pool connections and max size are for HTTP calls only, since we are using WS they are not needed. 
session = requests.Session()
w3 = Web3(Web3.WebsocketProvider("wss://opt-mainnet.g.alchemy.com/v2/REDACTED"))
w3.middleware_onion.inject(geth_poa_middleware, layer=0) # only needed for PoA networks like BSC


async def get_event():
    async with connect("wss://opt-mainnet.g.alchemy.com/v2/REDACTED") as ws:
        await ws.send(json.dumps({"id": 1, "method": "eth_subscribe", "params": ["logs", {
                    "address": ['0xREDACTED'],
                    "topics": ['0xREDACTED']}]}))
        subscription_response = await ws.recv()
        print(subscription_response)
        while True:
            try:
                message = await asyncio.wait_for(ws.recv(), timeout=60)
                print(message)
                decoded = decode_single('(address[],uint256[],uint256,address)',bytearray.fromhex(json.loads(message)['params']['result']['data'][2:]))
                print(list(decoded))
                pass
            except:
                pass
if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    while True:
        loop.run_until_complete(get_event())

For the "topics" key I am using the MethodID hash found on etherscan as a string, could that be the problem?

This is the only output I get:

{"id":1,"result":"0xf9d165f0d0edccfda86d40cf113f9bd2","jsonrpc":"2.0"}

Thanks!

Answer 1

I found the problem. When passing multiple topics into the subscribe the topics themselves need to be within a list inside the "topics" list, like so:

create_close_position_topic = '0x..70'
create_open_position_topic = '0x0..0'
execute_n_positions_with_prices_topic = '0x..7'



async def get_event():
    async with connect("wss://opt-mainnet.g.alchemy.com/v2/REDACTED") as ws:
        await ws.send(json.dumps({"id": 1, "method": "eth_subscribe", "params": ["logs", {
                    "address": ['0x..a5'],
                    "topics": [[create_close_position_topic, create_open_position_topic, execute_n_positions_with_prices_topic]]
                    }]}))

I still don't know why the method signatures are not lining up, but if I figure that out, I will update this answer as well.