def parse(cls, s, version_msg=False):
# Documentation says that the `time` field ins't present in version messages ...
if version_msg:
time = None
else:
time = little_endian_to_int(s.read(4))
services = little_endian_to_int(s.read(8))
ip = little_endian_to_int(s.read(16))
port = little_endian_to_int(s.read(2))
return cls(services, ip, port, time)
def parse(cls, s):
version = little_endian_to_int(s.read(4))
#prev_block = s.read(32)[::-1] # little endian
prev_block = little_endian_to_int(s.read(32))
#merkle_root = s.read(32)[::-1] # little endian
merkle_root = little_endian_to_int(s.read(32))
timestamp = little_endian_to_int(s.read(4))
bits = s.read(4)
nonce = s.read(4)
txn_count = read_varint(s) # apparently this is always 0?
return cls(version, prev_block, merkle_root, timestamp, bits, nonce,
txn_count)
def parse(cls, s):
'''Takes a byte stream and parses the tx_input at the start
return a TxIn object
'''
# s.read(n) will return n bytes
# prev_tx is 32 bytes, little endian
prev_tx = s.read(32)[::-1]
# prev_index is 4 bytes, little endian, interpret as int
prev_index = little_endian_to_int(s.read(4))
# script_sig is a variable field (length followed by the data)
# get the length by using read_varint(s)
script_sig_length = read_varint(s)
script_sig = s.read(script_sig_length)
# sequence is 4 bytes, little-endian, interpret as int
sequence = little_endian_to_int(s.read(4))
# return an instance of the class (cls(...))
return cls(prev_tx, prev_index, script_sig, sequence)
def target(self):
'''Returns the proof-of-work target based on the bits'''
# last byte is exponent
exponent = self.bits[-1]
# the first three bytes are the coefficient in little endian
coefficient = little_endian_to_int(self.bits[:-1])
# the formula is:
# coefficient * 2**(8*(exponent-3))
return coefficient * 2**(8 * (exponent - 3))
async def read_message(reader):
magic = await reader.read(4)
if magic != NETWORK_MAGIC:
raise RuntimeError("Network Magic not at beginning of stream")
command = await reader.read(12)
payload_length = little_endian_to_int(await reader.read(4))
checksum = await reader.read(4)
payload = await reader.read(payload_length)
if double_sha256(payload)[:4] != checksum:
raise RuntimeError("Payload and Checksum do not match")
return Message(command, payload)
def parse(cls, s):
'''Takes a byte stream and parses the tx_output at the start
return a TxOut object
'''
# s.read(n) will return n bytes
# amount is 8 bytes, little endian, interpret as int
amount = little_endian_to_int(s.read(8))
# script_pubkey is a variable field (length followed by the data)
# get the length by using read_varint(s)
script_pubkey_length = read_varint(s)
script_pubkey = s.read(script_pubkey_length)
# return an instance of the class (cls(...))
return cls(amount, script_pubkey)
def parse(cls, s):
'''Takes a byte stream and parses the transaction at the start
return a Tx object
'''
# s.read(n) will return n bytes
# version has 4 bytes, little-endian, interpret as int
version = little_endian_to_int(s.read(4))
# num_inputs is a varint, use read_varint(s)
num_inputs = read_varint(s)
# each input needs parsing
inputs = []
for _ in range(num_inputs):
inputs.append(TxIn.parse(s))
# num_outputs is a varint, use read_varint(s)
num_outputs = read_varint(s)
# each output needs parsing
outputs = []
for _ in range(num_outputs):
outputs.append(TxOut.parse(s))
# locktime is 4 bytes, little-endian
locktime = little_endian_to_int(s.read(4))
# return an instance of the class (cls(...))
return cls(version, inputs, outputs, locktime)
def parse(cls, s):
version = little_endian_to_int(s.read(4))
services = little_endian_to_int(s.read(8))
timestamp = little_endian_to_int(s.read(8))
addr_recv = Address.parse(io.BytesIO(s.read(26)), version_msg=True)
addr_from = Address.parse(io.BytesIO(s.read(26)), version_msg=True)
nonce = little_endian_to_int(s.read(8))
user_agent = read_varstr(
s) # Should we convert stuff like to to strings?
start_height = little_endian_to_int(s.read(4))
relay = little_endian_to_int(s.read(1))
return cls(version, services, timestamp, addr_recv, addr_from, nonce,
user_agent, start_height, relay)
def parse(cls, s):
magic = consume_stream(s, 4)
if magic != NETWORK_MAGIC:
raise ValueError('magic is not right')
command = parse_command(consume_stream(s, 12))
payload_length = little_endian_to_int(consume_stream(s, 4))
checksum = consume_stream(s, 4)
payload = consume_stream(s, payload_length)
calculated_checksum = double_sha256(payload)[:4]
if calculated_checksum != checksum:
raise RuntimeError('checksum does not match')
if payload_length != len(payload):
raise RuntimeError(
"Tried to read {payload_length} bytes, only received {len(payload)} bytes"
)
return cls(command, payload)
def pow(self):
s = self.serialize()
sha = double_sha256(s)
return little_endian_to_int(sha)
def parse(cls, s):
type_ = little_endian_to_int(s.read(4))
hash_ = s.read(32)
return cls(type_, hash_)
