check-consensus-valid.py

#! /usr/bin/env python3

import argparse
import binascii
import hashlib
import io
import struct

# RPC connection stuff, from test/functional/test_framework/authproxy.py

# Copyright (c) 2011 Jeff Garzik
#
# Previous copyright, from python-jsonrpc/jsonrpc/proxy.py:
#
# Copyright (c) 2007 Jan-Klaas Kollhof
#
# This file is part of jsonrpc.
#
# jsonrpc is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# This software is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this software; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
"""HTTP proxy for opening RPC connection to bitcoind.

AuthServiceProxy has the following improvements over python-jsonrpc's
ServiceProxy class:

- HTTP connections persist for the life of the AuthServiceProxy object
  (if server supports HTTP/1.1)
- sends protocol 'version', per JSON-RPC 1.1
- sends proper, incrementing 'id'
- sends Basic HTTP authentication headers
- parses all JSON numbers that look like floats as Decimal
- uses standard Python json lib
"""

import base64
import decimal
from http import HTTPStatus
import http.client
import json
import logging
import os
import socket
import time
import urllib.parse

HTTP_TIMEOUT = 30
USER_AGENT = "AuthServiceProxy/0.1"

log = logging.getLogger("BitcoinRPC")

class JSONRPCException(Exception):
    def __init__(self, rpc_error, http_status=None):
        try:
            errmsg = '%(message)s (%(code)i)' % rpc_error
        except (KeyError, TypeError):
            errmsg = ''
        super().__init__(errmsg)
        self.error = rpc_error
        self.http_status = http_status


def EncodeDecimal(o):
    if isinstance(o, decimal.Decimal):
        return str(o)
    raise TypeError(repr(o) + " is not JSON serializable")

class AuthServiceProxy():
    __id_count = 0

    # ensure_ascii: escape unicode as \uXXXX, passed to json.dumps
    def __init__(self, service_url, service_name=None, timeout=HTTP_TIMEOUT, connection=None, ensure_ascii=True):
        self.__service_url = service_url
        self._service_name = service_name
        self.ensure_ascii = ensure_ascii  # can be toggled on the fly by tests
        self.__url = urllib.parse.urlparse(service_url)
        user = None if self.__url.username is None else self.__url.username.encode('utf8')
        passwd = None if self.__url.password is None else self.__url.password.encode('utf8')
        authpair = user + b':' + passwd
        self.__auth_header = b'Basic ' + base64.b64encode(authpair)
        self.timeout = timeout
        self._set_conn(connection)

    def __getattr__(self, name):
        if name.startswith('__') and name.endswith('__'):
            # Python internal stuff
            raise AttributeError
        if self._service_name is not None:
            name = "%s.%s" % (self._service_name, name)
        return AuthServiceProxy(self.__service_url, name, connection=self.__conn)

    def _request(self, method, path, postdata):
        '''
        Do a HTTP request, with retry if we get disconnected (e.g. due to a timeout).
        This is a workaround for https://bugs.python.org/issue3566 which is fixed in Python 3.5.
        '''
        headers = {'Host': self.__url.hostname,
                   'User-Agent': USER_AGENT,
                   'Authorization': self.__auth_header,
                   'Content-type': 'application/json'}
        if os.name == 'nt':
            # Windows somehow does not like to re-use connections
            # TODO: Find out why the connection would disconnect occasionally and make it reusable on Windows
            self._set_conn()
        try:
            self.__conn.request(method, path, postdata, headers)
            return self._get_response()
        except http.client.BadStatusLine as e:
            if e.line == "''":  # if connection was closed, try again
                self.__conn.close()
                self.__conn.request(method, path, postdata, headers)
                return self._get_response()
            else:
                raise
        except (BrokenPipeError, ConnectionResetError):
            # Python 3.5+ raises BrokenPipeError instead of BadStatusLine when the connection was reset
            # ConnectionResetError happens on FreeBSD with Python 3.4
            self.__conn.close()
            self.__conn.request(method, path, postdata, headers)
            return self._get_response()

    def get_request(self, *args, **argsn):
        AuthServiceProxy.__id_count += 1

        log.debug("-{}-> {} {}".format(
            AuthServiceProxy.__id_count,
            self._service_name,
            json.dumps(args or argsn, default=EncodeDecimal, ensure_ascii=self.ensure_ascii),
        ))
        if args and argsn:
            raise ValueError('Cannot handle both named and positional arguments')
        return {'version': '1.1',
                'method': self._service_name,
                'params': args or argsn,
                'id': AuthServiceProxy.__id_count}

    def __call__(self, *args, **argsn):
        postdata = json.dumps(self.get_request(*args, **argsn), default=EncodeDecimal, ensure_ascii=self.ensure_ascii)
        response, status = self._request('POST', self.__url.path, postdata.encode('utf-8'))
        if response['error'] is not None:
            raise JSONRPCException(response['error'], status)
        elif 'result' not in response:
            raise JSONRPCException({
                'code': -343, 'message': 'missing JSON-RPC result'}, status)
        elif status != HTTPStatus.OK:
            raise JSONRPCException({
                'code': -342, 'message': 'non-200 HTTP status code but no JSON-RPC error'}, status)
        else:
            return response['result']

    def batch(self, rpc_call_list):
        postdata = json.dumps(list(rpc_call_list), default=EncodeDecimal, ensure_ascii=self.ensure_ascii)
        log.debug("--> " + postdata)
        response, status = self._request('POST', self.__url.path, postdata.encode('utf-8'))
        if status != HTTPStatus.OK:
            raise JSONRPCException({
                'code': -342, 'message': 'non-200 HTTP status code but no JSON-RPC error'}, status)
        return response

    def _get_response(self):
        req_start_time = time.time()
        try:
            http_response = self.__conn.getresponse()
        except socket.timeout:
            raise JSONRPCException({
                'code': -344,
                'message': '%r RPC took longer than %f seconds. Consider '
                           'using larger timeout for calls that take '
                           'longer to return.' % (self._service_name,
                                                  self.__conn.timeout)})
        if http_response is None:
            raise JSONRPCException({
                'code': -342, 'message': 'missing HTTP response from server'})

        content_type = http_response.getheader('Content-Type')
        if content_type != 'application/json':
            raise JSONRPCException(
                {'code': -342, 'message': 'non-JSON HTTP response with \'%i %s\' from server' % (http_response.status, http_response.reason)},
                http_response.status)

        responsedata = http_response.read().decode('utf8')
        response = json.loads(responsedata, parse_float=decimal.Decimal)
        elapsed = time.time() - req_start_time
        if "error" in response and response["error"] is None:
            log.debug("<-%s- [%.6f] %s" % (response["id"], elapsed, json.dumps(response["result"], default=EncodeDecimal, ensure_ascii=self.ensure_ascii)))
        else:
            log.debug("<-- [%.6f] %s" % (elapsed, responsedata))
        return response, http_response.status

    def __truediv__(self, relative_uri):
        return AuthServiceProxy("{}/{}".format(self.__service_url, relative_uri), self._service_name, connection=self.__conn)

    def _set_conn(self, connection=None):
        port = 80 if self.__url.port is None else self.__url.port
        if connection:
            self.__conn = connection
            self.timeout = connection.timeout
        elif self.__url.scheme == 'https':
            self.__conn = http.client.HTTPSConnection(self.__url.hostname, port, timeout=self.timeout)
        else:
            self.__conn = http.client.HTTPConnection(self.__url.hostname, port, timeout=self.timeout)


# from test/functional/test_framework/messages.py
# Serialization/deserialization tools
def sha256(s):
    return hashlib.new('sha256', s).digest()

def hash256(s):
    return sha256(sha256(s))

def ser_compact_size(l):
    r = b""
    if l < 253:
        r = struct.pack("B", l)
    elif l < 0x10000:
        r = struct.pack("<BH", 253, l)
    elif l < 0x100000000:
        r = struct.pack("<BI", 254, l)
    else:
        r = struct.pack("<BQ", 255, l)
    return r

def deser_compact_size(f):
    nit = struct.unpack("<B", f.read(1))[0]
    if nit == 253:
        nit = struct.unpack("<H", f.read(2))[0]
    elif nit == 254:
        nit = struct.unpack("<I", f.read(4))[0]
    elif nit == 255:
        nit = struct.unpack("<Q", f.read(8))[0]
    return nit

def deser_string(f):
    nit = deser_compact_size(f)
    return f.read(nit)

def ser_string(s):
    return ser_compact_size(len(s)) + s

def deser_uint256(f):
    r = 0
    for i in range(8):
        t = struct.unpack("<I", f.read(4))[0]
        r += t << (i * 32)
    return r


def ser_uint256(u):
    rs = b""
    for i in range(8):
        rs += struct.pack("<I", u & 0xFFFFFFFF)
        u >>= 32
    return rs


def uint256_from_str(s):
    r = 0
    t = struct.unpack("<IIIIIIII", s[:32])
    for i in range(8):
        r += t[i] << (i * 32)
    return r


def uint256_from_compact(c):
    nbytes = (c >> 24) & 0xFF
    v = (c & 0xFFFFFF) << (8 * (nbytes - 3))
    return v


def deser_vector(f, c):
    nit = deser_compact_size(f)
    r = []
    for i in range(nit):
        t = c()
        t.deserialize(f)
        r.append(t)
    return r


# ser_function_name: Allow for an alternate serialization function on the
# entries in the vector (we use this for serializing the vector of transactions
# for a witness block).
def ser_vector(l, ser_function_name=None):
    r = ser_compact_size(len(l))
    for i in l:
        if ser_function_name:
            r += getattr(i, ser_function_name)()
        else:
            r += i.serialize()
    return r


def deser_uint256_vector(f):
    nit = deser_compact_size(f)
    r = []
    for i in range(nit):
        t = deser_uint256(f)
        r.append(t)
    return r


def ser_uint256_vector(l):
    r = ser_compact_size(len(l))
    for i in l:
        r += ser_uint256(i)
    return r


def deser_string_vector(f):
    nit = deser_compact_size(f)
    r = []
    for i in range(nit):
        t = deser_string(f)
        r.append(t)
    return r


def ser_string_vector(l):
    r = ser_compact_size(len(l))
    for sv in l:
        r += ser_string(sv)
    return r

class COutPoint:
    __slots__ = ("hash", "n")

    def __init__(self, hash=0, n=0):
        self.hash = hash
        self.n = n

    def deserialize(self, f):
        self.hash = deser_uint256(f)
        self.n = struct.unpack("<I", f.read(4))[0]

    def serialize(self):
        r = b""
        r += ser_uint256(self.hash)
        r += struct.pack("<I", self.n)
        return r

    def __repr__(self):
        return "COutPoint(hash=%064x n=%i)" % (self.hash, self.n)


class CTxIn:
    __slots__ = ("nSequence", "prevout", "scriptSig")

    def __init__(self, outpoint=None, scriptSig=b"", nSequence=0):
        if outpoint is None:
            self.prevout = COutPoint()
        else:
            self.prevout = outpoint
        self.scriptSig = scriptSig
        self.nSequence = nSequence

    def deserialize(self, f):
        self.prevout = COutPoint()
        self.prevout.deserialize(f)
        self.scriptSig = deser_string(f)
        self.nSequence = struct.unpack("<I", f.read(4))[0]

    def serialize(self):
        r = b""
        r += self.prevout.serialize()
        r += ser_string(self.scriptSig)
        r += struct.pack("<I", self.nSequence)
        return r

    def __repr__(self):
        return "CTxIn(prevout=%s scriptSig=%s nSequence=%i)" \
            % (repr(self.prevout), self.scriptSig.hex(),
               self.nSequence)


class CTxOut:
    __slots__ = ("nValue", "scriptPubKey")

    def __init__(self, nValue=0, scriptPubKey=b""):
        self.nValue = nValue
        self.scriptPubKey = scriptPubKey

    def deserialize(self, f):
        self.nValue = struct.unpack("<q", f.read(8))[0]
        self.scriptPubKey = deser_string(f)

    def serialize(self):
        r = b""
        r += struct.pack("<q", self.nValue)
        r += ser_string(self.scriptPubKey)
        return r

    def __repr__(self):
        return "CTxOut(nValue=%i.%08i scriptPubKey=%s)" \
            % (self.nValue // COIN, self.nValue % COIN,
               self.scriptPubKey.hex())


class CScriptWitness:
    __slots__ = ("stack",)

    def __init__(self):
        # stack is a vector of strings
        self.stack = []

    def __repr__(self):
        return "CScriptWitness(%s)" % \
               (",".join([x.hex() for x in self.stack]))

    def is_null(self):
        if self.stack:
            return False
        return True


class CTxInWitness:
    __slots__ = ("scriptWitness",)

    def __init__(self):
        self.scriptWitness = CScriptWitness()

    def deserialize(self, f):
        self.scriptWitness.stack = deser_string_vector(f)

    def serialize(self):
        return ser_string_vector(self.scriptWitness.stack)

    def __repr__(self):
        return repr(self.scriptWitness)

    def is_null(self):
        return self.scriptWitness.is_null()


class CTxWitness:
    __slots__ = ("vtxinwit",)

    def __init__(self):
        self.vtxinwit = []

    def deserialize(self, f):
        for i in range(len(self.vtxinwit)):
            self.vtxinwit[i].deserialize(f)

    def serialize(self):
        r = b""
        # This is different than the usual vector serialization --
        # we omit the length of the vector, which is required to be
        # the same length as the transaction's vin vector.
        for x in self.vtxinwit:
            r += x.serialize()
        return r

    def __repr__(self):
        return "CTxWitness(%s)" % \
               (';'.join([repr(x) for x in self.vtxinwit]))

    def is_null(self):
        for x in self.vtxinwit:
            if not x.is_null():
                return False
        return True


class CTransaction:
    __slots__ = ("hash", "nLockTime", "nVersion", "sha256", "vin", "vout",
                 "wit")

    def __init__(self, tx=None):
        if tx is None:
            self.nVersion = 1
            self.vin = []
            self.vout = []
            self.wit = CTxWitness()
            self.nLockTime = 0
            self.sha256 = None
            self.hash = None
        else:
            self.nVersion = tx.nVersion
            self.vin = copy.deepcopy(tx.vin)
            self.vout = copy.deepcopy(tx.vout)
            self.nLockTime = tx.nLockTime
            self.sha256 = tx.sha256
            self.hash = tx.hash
            self.wit = copy.deepcopy(tx.wit)

    def deserialize(self, f):
        self.nVersion = struct.unpack("<i", f.read(4))[0]
        self.vin = deser_vector(f, CTxIn)
        flags = 0
        if len(self.vin) == 0:
            flags = struct.unpack("<B", f.read(1))[0]
            # Not sure why flags can't be zero, but this
            # matches the implementation in bitcoind
            if (flags != 0):
                self.vin = deser_vector(f, CTxIn)
                self.vout = deser_vector(f, CTxOut)
        else:
            self.vout = deser_vector(f, CTxOut)
        if flags != 0:
            self.wit.vtxinwit = [CTxInWitness() for i in range(len(self.vin))]
            self.wit.deserialize(f)
        else:
            self.wit = CTxWitness()
        self.nLockTime = struct.unpack("<I", f.read(4))[0]
        self.sha256 = None
        self.hash = None

    def serialize_without_witness(self):
        r = b""
        r += struct.pack("<i", self.nVersion)
        r += ser_vector(self.vin)
        r += ser_vector(self.vout)
        r += struct.pack("<I", self.nLockTime)
        return r

    # Only serialize with witness when explicitly called for
    def serialize_with_witness(self):
        flags = 0
        if not self.wit.is_null():
            flags |= 1
        r = b""
        r += struct.pack("<i", self.nVersion)
        if flags:
            dummy = []
            r += ser_vector(dummy)
            r += struct.pack("<B", flags)
        r += ser_vector(self.vin)
        r += ser_vector(self.vout)
        if flags & 1:
            if (len(self.wit.vtxinwit) != len(self.vin)):
                # vtxinwit must have the same length as vin
                self.wit.vtxinwit = self.wit.vtxinwit[:len(self.vin)]
                for i in range(len(self.wit.vtxinwit), len(self.vin)):
                    self.wit.vtxinwit.append(CTxInWitness())
            r += self.wit.serialize()
        r += struct.pack("<I", self.nLockTime)
        return r

    # Regular serialization is with witness -- must explicitly
    # call serialize_without_witness to exclude witness data.
    def serialize(self):
        return self.serialize_with_witness()

    # Recalculate the txid (transaction hash without witness)
    def rehash(self):
        self.sha256 = None
        self.calc_sha256()
        return self.hash

    # We will only cache the serialization without witness in
    # self.sha256 and self.hash -- those are expected to be the txid.
    def calc_sha256(self, with_witness=False):
        if with_witness:
            # Don't cache the result, just return it
            return uint256_from_str(hash256(self.serialize_with_witness()))

        if self.sha256 is None:
            self.sha256 = uint256_from_str(hash256(self.serialize_without_witness()))
        self.hash = binascii.hexlify(hash256(self.serialize_without_witness())[::-1]).decode()

    def is_valid(self):
        self.calc_sha256()
        for tout in self.vout:
            if tout.nValue < 0 or tout.nValue > 21000000 * COIN:
                return False
        return True

    def __repr__(self):
        return "CTransaction(nVersion=%i vin=%s vout=%s wit=%s nLockTime=%i)" \
            % (self.nVersion, repr(self.vin), repr(self.vout), repr(self.wit), self.nLockTime)

class CBlockHeader:
    __slots__ = ("hash", "hashMerkleRoot", "hashPrevBlock", "nBits", "nNonce",
                 "nTime", "nVersion", "sha256")

    def __init__(self, header=None):
        if header is None:
            self.set_null()
        else:
            self.nVersion = header.nVersion
            self.hashPrevBlock = header.hashPrevBlock
            self.hashMerkleRoot = header.hashMerkleRoot
            self.nTime = header.nTime
            self.nBits = header.nBits
            self.nNonce = header.nNonce
            self.sha256 = header.sha256
            self.hash = header.hash
            self.calc_sha256()

    def set_null(self):
        self.nVersion = 1
        self.hashPrevBlock = 0
        self.hashMerkleRoot = 0
        self.nTime = 0
        self.nBits = 0
        self.nNonce = 0
        self.sha256 = None
        self.hash = None

    def deserialize(self, f):
        self.nVersion = struct.unpack("<i", f.read(4))[0]
        self.hashPrevBlock = deser_uint256(f)
        self.hashMerkleRoot = deser_uint256(f)
        self.nTime = struct.unpack("<I", f.read(4))[0]
        self.nBits = struct.unpack("<I", f.read(4))[0]
        self.nNonce = struct.unpack("<I", f.read(4))[0]
        self.sha256 = None
        self.hash = None

    def serialize(self):
        r = b""
        r += struct.pack("<i", self.nVersion)
        r += ser_uint256(self.hashPrevBlock)
        r += ser_uint256(self.hashMerkleRoot)
        r += struct.pack("<I", self.nTime)
        r += struct.pack("<I", self.nBits)
        r += struct.pack("<I", self.nNonce)
        return r

    def calc_sha256(self):
        if self.sha256 is None:
            r = b""
            r += struct.pack("<i", self.nVersion)
            r += ser_uint256(self.hashPrevBlock)
            r += ser_uint256(self.hashMerkleRoot)
            r += struct.pack("<I", self.nTime)
            r += struct.pack("<I", self.nBits)
            r += struct.pack("<I", self.nNonce)
            self.sha256 = uint256_from_str(hash256(r))
            self.hash = binascii.hexlify(hash256(r)[::-1]).decode()

    def rehash(self):
        self.sha256 = None
        self.calc_sha256()
        return self.sha256

    def __repr__(self):
        return "CBlockHeader(nVersion=%i hashPrevBlock=%064x hashMerkleRoot=%064x nTime=%s nBits=%08x nNonce=%08x)" \
            % (self.nVersion, self.hashPrevBlock, self.hashMerkleRoot,
               time.ctime(self.nTime), self.nBits, self.nNonce)

class CBlock(CBlockHeader):
    __slots__ = ("vtx",)

    def __init__(self, header=None):
        super(CBlock, self).__init__(header)
        self.vtx = []

    def deserialize(self, f):
        super(CBlock, self).deserialize(f)
        self.vtx = deser_vector(f, CTransaction)

    def serialize(self, with_witness=True):
        r = b""
        r += super(CBlock, self).serialize()
        if with_witness:
            r += ser_vector(self.vtx, "serialize_with_witness")
        else:
            r += ser_vector(self.vtx, "serialize_without_witness")
        return r

    # Calculate the merkle root given a vector of transaction hashes
    @classmethod
    def get_merkle_root(cls, hashes):
        while len(hashes) > 1:
            newhashes = []
            for i in range(0, len(hashes), 2):
                i2 = min(i+1, len(hashes)-1)
                newhashes.append(hash256(hashes[i] + hashes[i2]))
            hashes = newhashes
        return uint256_from_str(hashes[0])

    def calc_merkle_root(self):
        hashes = []
        for tx in self.vtx:
            tx.calc_sha256()
            hashes.append(ser_uint256(tx.sha256))
        return self.get_merkle_root(hashes)

    def calc_witness_merkle_root(self):
        # For witness root purposes, the hash of the
        # coinbase, with witness, is defined to be 0...0
        hashes = [ser_uint256(0)]

        for tx in self.vtx[1:]:
            # Calculate the hashes with witness data
            hashes.append(ser_uint256(tx.calc_sha256(True)))

        return self.get_merkle_root(hashes)

    def is_valid(self):
        self.calc_sha256()
        target = uint256_from_compact(self.nBits)
        if self.sha256 > target:
            return False
        for tx in self.vtx:
            if not tx.is_valid():
                return False
        if self.calc_merkle_root() != self.hashMerkleRoot:
            return False
        return True

    def solve(self):
        self.rehash()
        target = uint256_from_compact(self.nBits)
        while self.sha256 > target:
            self.nNonce += 1
            self.rehash()

    def __repr__(self):
        return "CBlock(nVersion=%i hashPrevBlock=%064x hashMerkleRoot=%064x nTime=%s nBits=%08x nNonce=%08x vtx=%s)" \
            % (self.nVersion, self.hashPrevBlock, self.hashMerkleRoot,
               time.ctime(self.nTime), self.nBits, self.nNonce, repr(self.vtx))

def create_coinbase(height):
    """Create a coinbase transaction with OP_TRUE output, assuming no miner fees."""
    coinbase = CTransaction()
    coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff), b'\x03' + height.to_bytes(3, byteorder='little'), 0xffffffff))
    coinbaseoutput = CTxOut()
    coinbaseoutput.nValue = 0
    coinbaseoutput.scriptPubKey = b'\x51'
    coinbase.vout = [coinbaseoutput]
    coinbase.calc_sha256()
    return coinbase

parser = argparse.ArgumentParser(description='Check whether transactions are consensus valid by submitting a block proposal to bitcoind')
parser.add_argument('rpcuser', help='The RPC username')
parser.add_argument('rpcpassword', help='The password for the RPC user')
parser.add_argument('txs', metavar='tx', nargs='+', help='The transactions to test')

args = parser.parse_args()

node = AuthServiceProxy("http://%s:%s@127.0.0.1:8332"%(args.rpcuser, args.rpcpassword))

tmpl = node.getblocktemplate({'rules': ['segwit']})

block = CBlock()
block.nVersion = tmpl["version"]
block.hashPrevBlock = int(tmpl["previousblockhash"], 16)
block.nTime = tmpl["curtime"]
block.nBits = int(tmpl["bits"], 16)
block.nNonce = 0
block.vtx = [create_coinbase(int(tmpl["height"]))]

for tx in args.txs:
    txb = binascii.unhexlify(tx)
    txf = io.BytesIO(txb)

    ctx = CTransaction()
    ctx.deserialize(txf)
    ctx.rehash()
    block.vtx.append(ctx)

withash = hash256(ser_uint256(block.calc_witness_merkle_root()) + (b'\x00' * 32))
witout = CTxOut()
witout.nValue = 0
witout.scriptPubKey = b'\x6a\x24\xaa\x21\xa9\xed' + withash
block.vtx[0].vout.append(witout)
witstack = CScriptWitness()
witstack.stack.append(b'\x00' * 32)
witin = CTxInWitness()
witin.scriptWitness = witstack
block.vtx[0].wit.vtxinwit.append(witin)
block.vtx[0].rehash()

block.hashMerkleRoot = block.calc_merkle_root()

rsp = node.getblocktemplate(template_request={'data': block.serialize().hex(), 'mode': 'proposal', 'rules': ['segwit']})

if rsp:
    print(rsp)
else:
    print("Transactions are consensus valid")