Code to scan for BIP100 coinbase strings

bip100-fork.py

## (python3) Objective: count the number of blocks voting for BIP100 or
## using the BVnnnnnnn convention

# Requires: sudo pip3 install json-rpc

## WARNING: read and understand the following link before writing
## production JSON-parsing code for Bitcoin:
## https://en.bitcoin.it/wiki/Proper_Money_Handling_%28JSON-RPC%29

import requests
import json
from codecs import decode
import re

## Bitcoin Core by default listens on localhost:8332
url = "http://localhost:8332"

## Change this to your Bitcoin Core credentials. These are listed in the
## file .bitcoin/bitcoin.conf as the rpcuser and rpcpassword settings.
## WARNING: Be extremely careful with this information on any system
## that has a wallet or other secure/private information.
auth=('test', 'foobar')

## Prepare a couple counters for the test
bip100_blocks = 0
non_bip100_blocks = 0

## Prepare a regular expression to search binary data for the strings
## associated with BIP100
bip100 = re.compile(b'BIP100|BV[0-9]{7}')

## A simple function to get data from Bitcoin Core over JSON-RPC
def request(payload):
  return requests.post(
      url,
      data=json.dumps(payload),
      auth=auth
  ).json()

## Get the header hash of the most recent block
block = request({
  "method": "getbestblockhash"
})['result']


## Loop over the last 100 blocks and process their coinbase
## transactions. This code is not guaranteed to work with Bitcoin Core's
## default settings more than 100 blocks in the past
for i in range(0,100):
  ## Get all the data from the block
  block_data = request({
    "method": "getblock",
    "params": [ block ]
  })

  ## The header hash of the previous block, which we'll use in the next loop
  block = block_data['result']['previousblockhash']

  ## The txid of the coinbase tarnsaction
  coinbase_txid = block_data['result']['tx'][0]

  ## Each coinbase transaction has a single input; this gets it.
  ## (This special input is called the coinbase field)
  coinbase_field = request({
    "method": "getrawtransaction",
    "params": [ coinbase_txid, 1 ]
  })['result']['vin'][0]['coinbase']

  ## Convert the coinbase field to binary for searching
  coinbase_field_binary = decode(coinbase_field, 'hex')

  ## Increment counters based on matching
  if bip100.search(coinbase_field_binary):
    bip100_blocks += 1
  else:
    non_bip100_blocks += 1

## Show our results
print("BIP100 blocks: ", bip100_blocks)
print("Non-BIP100 blocks: ", non_bip100_blocks)