funga/scripts/web3_middleware.py

import logging
import re
import socket
import uuid
import json

from web3 import Web3, WebsocketProvider, IPCProvider


logging.basicConfig(level=logging.DEBUG)
logg = logging.getLogger('foo')


def jsonrpc_request(method, params):
    uu = uuid.uuid4()
    return {
        "jsonrpc": "2.0",
        "id": str(uu),
        "method": method,
        "params": params,
            }

class PlatformMiddleware:

    # id for the request is not available, meaning we cannot easily short-circuit
    # hack workaround
    id_seq = -1
    re_personal = re.compile('^personal_.*')
    ipcaddr = '/tmp/foo.ipc'


    def __init__(self, make_request, w3):
        self.w3 = w3 
        self.make_request = make_request

    
    # TODO: understand what format input params come in
    # single entry input gives a tuple on params, wtf...
    # dict input comes as [{}] and fails if not passed on as an array
    @staticmethod
    def _translate_params(params):
        if params.__class__.__name__ == 'tuple':
            r = []
            for p in params:
                r.append(p)
            return r

        if params.__class__.__name__ == 'list' and len(params) > 0:
            return params[0]

        return params


    def __call__(self, method, suspect_params):

        self.id_seq += 1
        logg.debug('in middleware method {} params {}'.format(method, suspect_params))

        if self.re_personal.match(method) != None:
            params = PlatformMiddleware._translate_params(suspect_params)
            # multiple providers is broken in web3.py 5.12.0
            # https://github.com/ethereum/web3.py/issues/1701
            # hack workaround
            s = socket.socket(family=socket.AF_UNIX, type=socket.SOCK_STREAM, proto=0)
            ipc_provider_workaround = s.connect(self.ipcaddr)

            logg.info('redirecting method {}  params {} original params {}'.format(method, params, suspect_params))
            o = jsonrpc_request(method, params)
            j = json.dumps(o)
            logg.debug('send {}'.format(j))
            s.send(j.encode('utf-8'))
            r = s.recv(4096)
            s.close()
            logg.debug('got recv {}'.format(str(r)))
            jr = json.loads(r)
            jr['id'] = self.id_seq
            #return str(json.dumps(jr))
            return jr

        r = self.make_request(method, suspect_params)
        return r


w3 = Web3(WebsocketProvider('ws://127.0.0.1:8546'))
w3.eth.personal = w3.geth.personal
w3.middleware_onion.add(PlatformMiddleware)
print(w3.eth.personal.newAccount('foo'))
print(w3.eth.blockNumber)
#print(w3.eth.sendTransaction({'to': '0xd3CdA913deB6f67967B99D67aCDFa1712C293601','from': '0xc305c901078781C232A2a521C2aF7980f8385ee9','value': 1000}))