record_rep_weights.py

import requests
import argparse
import string
from binascii import unhexlify
from base64 import b32decode
from binascii import hexlify, unhexlify


parser = argparse.ArgumentParser(description='Generate bootstrap representative weight file.')
parser.add_argument("output", type=str, help="output weight file")
parser.add_argument("--rpc", help="node rpc host:port", default="http://[::1]:7076")
parser.add_argument("--limit", help="percentage of the active supply represented", default=0.99)
parser.add_argument("--cutoff", help="stop using bootstrap reps this many blocks before the current block height", default=250000)
args = parser.parse_args()

r = requests.post(args.rpc, data='{"action":"representatives"}')
p = r.json()

reps = [ ]
tbl = string.maketrans('13456789abcdefghijkmnopqrstuwxyz', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567')
for acc in p["representatives"]:
    reps.append({
        'account': acc,
        'weight': long(p["representatives"][acc])
    })

r = requests.post(args.rpc, data='{"action":"block_count"}')
p = r.json()
block_height = max(0, int(p["count"]) - args.cutoff)

print "cutoff block height is %d" % block_height

reps.sort(key=lambda x: x["weight"], reverse=True)

supplymax = long(0)
for rep in reps:
    supplymax += rep["weight"]

supplymax /= long('1000000000000000000000000000000')
supplymax = long(supplymax * args.limit)
supplymax *= long('1000000000000000000000000000000')

with open(args.output, 'wb') as of:
    of.write(unhexlify("%032X" % block_height))

    total = long(0)
    count = 0
    for rep in reps:
        if rep["weight"] == 0:
            break
        acc_val = long(hexlify(b32decode(rep["account"].encode("utf-8").replace("xrb_", "").translate(tbl) + "====")), 16)
        acc_bytes = unhexlify("%064X" % (((acc_val >> 36) & ((1 << 256) - 1))))
        weight_bytes = unhexlify("%032X" % rep["weight"])
        of.write(acc_bytes)
        of.write(weight_bytes)
        total += rep["weight"]
        count += 1
        if total >= supplymax:
            break

    print "wrote %d rep weights" % count

    of.close()