def add_transaction(self, transaction):
""" Add a transaction to the blockchain. Return the hash
of the transaction.
"""
if not self.current_block.is_empty():
transaction.hash_previous_transaction = hash_sha256(
str(self.current_block.transactions[-1]).encode('utf-8'))
else:
transaction.hash_previous_transaction = None
if self.current_block.is_full():
self.add_block(self.current_block)
self.current_block = Block(
id=len(self.blocks),
hash_previous_block=hash_sha256(
str(self.blocks[-1]).encode('utf-8')))
transaction.id = len(self.current_block.transactions)
if isinstance(transaction, CoinCreation):
for index, _ in enumerate(transaction.created_coins):
transaction.created_coins[index].id = CoinId(
index, transaction.id, self.current_block.id)
else:
for index, _ in enumerate(transaction.coins):
transaction.coins[index].id = CoinId(index, transaction.id,
self.current_block.id)
self.current_block.transactions.append(transaction)
return transaction
def get_hash_last_block(self):
""" Return the hash of the last block of the
blockchain. If there are not blocks, return
None.
"""
if len(self.blocks) > 0:
return hash_sha256(self.blocks[-1])
else:
return None
def add_block(self, block):
""" Add a block to the blockchain. Return the hash
of the block.
"""
if not self.is_empty():
block.hash_previous_block = hash_sha256(
str(self.blocks[-1]).encode('utf-8'))
else:
block.hash_previous_block = None
self.blocks.append(block)
return block
def check_blockchain(self):
""" Check the blockchain to find inconsistencies """
blocks = self.blocks + [self.current_block]
# The list must have at least one block (the genesis block)
if len(blocks) == 0:
return False
for ind in range(len(blocks) - 1, 0, -1):
if blocks[ind].hash_previous_block != hash_sha256(
str(blocks[ind - 1]).encode('utf-8')):
return False
return True
def __short_str__(self):
block_hash = hash_sha256(str(self).encode('utf-8'))
return f'Block ID: {self.id},Block Hash: {block_hash}, Previous Block Hash: {self.hash_previous_block}'