eth_subscribe: notifications not supported

[jiebanghan]

System information

Geth version: geth version
Geth
Version: 1.5.8-unstable
OS & Version: Windows/Linux/OSX
Linux ubuntu 4.4.0-71-generic #92-Ubuntu SMP Fri Mar 24 12:59:01 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
Commit hash : (if develop)
and run geth with the command below:
./geth --identity "helloworld" --ws --wsaddr 192.168.241.128 --wsport 8545 --rpc --rpcaddr 192.168.241.128 --rpcport 8545 --rpccorsdomain "*" --datadir "$basepath/chain" --port "30303" --rpcapi "db,eth,net,ssh,miner,web3,personal,admin" --networkid 88888 console
and then

curl 192.168.241.128:8545 -X POST --data '{"id": 1, "method": "eth_subscribe", "params": ["newHeads"]}'
{"jsonrpc":"2.0","id":1,"error":{"code":-32000,"message":"notifications not supported"}}

when I　typed command changed the port to 8546:

curl 192.168.241.128:8546 -X POST --data '{"id": 1, "method": "eth_subscribe", "params": ["newHeads"]}'
bad method

I found from https://github.com/ethereum/go-ethereum/wiki/RPC-PUB-SUB : From version 1.4 geth has experimental support for pub/sub using subscriptions as defined in the JSON-RPC 2.0 specification. This allows clients to wait for events instead of polling for them.

So my geth version is higer than 1.4, So what's the problem?? Thank you.

Expected behaviour

Actual behaviour

Steps to reproduce the behaviour

Backtrace

[backtrace]

[karalabe]

Notifications require a connection oriented network protocol. Port 8545 by default is the HTTP RPC interface. HTTP does not support server push notifications, so subscriptions do not work on it.

Port 8546 by default is the WebSocket interface, which does support notifications, but you need to talk "WebSocket" with it, not plain HTTP that curl uses.

[jiebanghan]

thank you a lot.

[bas-vk]

As karalabe mentioned, either use websockets (or ipc).

[kdonthi]

I told myself I would include a code sample if I figured it out (this is just to get the blockNumber):

import json
import asyncio
from websockets import connect

async def ws_connect():
    async with connect("ws://3.235.247.246:8546") as ws:
        await ws.send(json.dumps({"id":1, "method": "eth_subscribe", "params": ["newHeads"]}))
        counter = 0
        while True:
            res = await ws.recv()
            jsonResponse = json.loads(res)
            if counter == 0:
                counter += 1
                continue
            blockNumberHex = jsonResponse["params"]["result"]["number"]
            blockNumber = int(blockNumberHex, 16)
            print(blockNumber)

asyncio.run(ws_connect())