def _build_valid_block_data(self, num_transactions=4) -> dict:
"""
Utility method to build a dictionary with all the params needed to invoke store_block
:param num_transactions:
:return:
"""
mn_sk = Constants.Testnet.Masternodes[0]['sk']
mn_vk = ED25519Wallet.get_vk(mn_sk)
timestamp = 9000
raw_transactions = [build_test_transaction().serialize() for _ in range(num_transactions)]
tree = MerkleTree(raw_transactions)
merkle_leaves = tree.leaves_as_concat_hex_str
merkle_root = tree.root_as_hex
bc = build_test_contender(tree=tree)
prev_block_hash = '0' * 64
mn_sig = ED25519Wallet.sign(mn_sk, tree.root)
return {
'prev_block_hash': prev_block_hash,
'block_contender': bc,
'merkle_leaves': merkle_leaves,
'merkle_root': merkle_root,
'masternode_signature': mn_sig,
'masternode_vk': mn_vk,
'timestamp': timestamp
}
def store_block(cls,
block_contender: BlockContender,
raw_transactions: List[bytes],
publisher_sk: str,
timestamp: int = 0):
"""
Persist a new block to the blockchain, along with the raw transactions associated with the block. An exception
will be raised if an error occurs either validating the new block data, or storing the block. Thus, it is
recommended that this method is wrapped in a try block.
:param block_contender: A BlockContender instance
:param raw_transactions: A list of ordered raw transactions contained in the block
:param publisher_sk: The signing key of the publisher (a Masternode) who is publishing the block
:param timestamp: The time the block was published, in unix epoch time. If 0, time.time() is used
:return: None
:raises: An assertion error if invalid args are passed into this function, or a BlockStorageValidationException
if validation fails on the attempted block
TODO -- think really hard and make sure that this is 'collision proof' (extremely unlikely, but still possible)
- could there be a hash collision in the Merkle tree nodes?
- hash collision in block hash space?
- hash collision in transaction space?
"""
assert isinstance(
block_contender, BlockContender
), "Expected block_contender arg to be BlockContender instance"
assert is_valid_hex(
publisher_sk,
64), "Invalid signing key {}. Expected 64 char hex str".format(
publisher_sk)
if not timestamp:
timestamp = int(time.time())
tree = MerkleTree.from_raw_transactions(raw_transactions)
publisher_vk = ED25519Wallet.get_vk(publisher_sk)
publisher_sig = ED25519Wallet.sign(publisher_sk, tree.root)
# Build and validate block_data
block_data = {
'block_contender': block_contender,
'timestamp': timestamp,
'merkle_root': tree.root_as_hex,
'merkle_leaves': tree.leaves_as_concat_hex_str,
'prev_block_hash': cls._get_latest_block_hash(),
'masternode_signature': publisher_sig,
'masternode_vk': publisher_vk,
}
cls._validate_block_data(block_data)
# Compute block hash
block_hash = cls._compute_block_hash(block_data)
# Encode block data for serialization and finally persist the data
log.info(
"Attempting to persist new block with hash {}".format(block_hash))
block_data = cls._encode_block(block_data)
with DB() as db:
# Store block
res = db.tables.blocks.insert([{
'hash': block_hash,
**block_data
}]).run(db.ex)
if res:
log.info(
"Successfully inserted new block with number {} and hash {}"
.format(res['last_row_id'], block_hash))
else:
log.error(
"Error inserting block! Got None/False result back from insert query. Result={}"
.format(res))
return
# Store raw transactions
log.info(
"Attempting to store {} raw transactions associated with block hash {}"
.format(len(raw_transactions), block_hash))
tx_rows = [{
'hash': Hasher.hash(raw_tx),
'data': encode_tx(raw_tx),
'block_hash': block_hash
} for raw_tx in raw_transactions]
res = db.tables.transactions.insert(tx_rows).run(db.ex)
if res:
log.info("Successfully inserted {} transactions".format(
res['row_count']))
else:
log.error(
"Error inserting raw transactions! Got None from insert query. Result={}"
.format(res))