learn-co-students / sending-btc-with-network-protocol-jsong-pb-sf-072618

Sending tesnet bitcoins using only the networking protocol

You have been sent some unknown amount of testnet bitcoins to your address.

Send all of it back (minus fees) to mwJn1YPMq7y5F8J3LkC5Hxg9PHyZ5K4cFv using only the networking protocol.

# Exercise 4.1

from time import sleep
from block import Block
from bloomfilter import (
    BloomFilter,
    BIP37_CONSTANT,
)
from ecc import PrivateKey
from helper import (
    bit_field_to_bytes,
    decode_base58,
    hash160,
    hash256,
    little_endian_to_int,
    murmur3,
    run,
    SIGHASH_ALL,
)
from merkleblock import MerkleBlock
from network import (
    GetDataMessage,
    GetHeadersMessage,
    HeadersMessage,
    SimpleNode,
    FILTERED_BLOCK_DATA_TYPE,
    TX_DATA_TYPE,
)
from tx import (
    Tx,
    TxIn,
    TxOut,
)
from script import p2pkh_script

last_block_hex = '<fill this in>'
last_block = bytes.fromhex(last_block_hex)
passphrase = b'<fill this in>'  # FILL THIS IN
secret = little_endian_to_int(hash256(passphrase))
private_key = PrivateKey(secret=secret)
addr = private_key.point.address(testnet=True)
print(addr)
h160 = decode_base58(addr)
target_address = 'mwJn1YPMq7y5F8J3LkC5Hxg9PHyZ5K4cFv'
filter_size = 30
filter_num_functions = 5
filter_tweak = -1  # FILL THIS IN
target_h160 = decode_base58(target_address)
target_script = p2pkh_script(target_h160)
fee = 5000  # fee in satoshis

# connect to tbtc.programmingblockchain.com in testnet mode, logging True
# create a bloom filter using variables above
# add the h160 to the bloom filter
# complete the handshake
# send the 'filterload' command with bf.filterload() as the payload

# create GetHeadersMessage with the last_block as the start_block
# send a getheaders message

# wait for the headers message
# get the stream from the headers
# parse the headers message

# initialize the GetDataMessage
# loop through the blocks in the headers message
    # check that the proof of work on the block is valid
    # check that this block's prev_block is the last block
    # set the last block to the current hash
    # add_data(FILTERED_BLOCK_DATA_TYPE, last_block) to get_data_message
# send the get_data_message

# initialize prev_tx to None
# while prev_tx is None 
    # wait for the merkleblock or tx commands
    # initialize the stream from the envelope
    # if we have the merkleblock command
        # parse the MerkleBlock
        # check that the MerkleBlock is valid
    # else we have the tx command
        # parse the tx (prev)
        # loop through the enumerated tx outs (enumerate(prev.tx_outs))
            # if our output has the same address as our address (addr) we found it
                # we found our utxo. set prev_tx, prev_index, prev_amount
                # break
# create tx_in
# calculate the output amount (prev_amount - fee)
# create tx_out
# create transaction on testnet
# sign the one input we have
# serialize and hex to see what it looks like
# send this signed transaction on the network
# wait a sec so this message goes through to the other node sleep(1) 
# now ask for this transaction from the other node
# create a GetDataMessage
# add_data (TX_DATA_TYPE, tx_obj.hash()) to get data message
# send the GetDataMessage
# now wait for a response
# if we have the tx command
    # parse the tx
    # check that the ids are the same
        # yes! we got to what we wanted