def test_hash_block_stringify_error(self, mock_json_dumps):
err_message = 'Could not encode block data to generate hash.'
mock_json_dumps.side_effect = Mock(side_effect=BlockError(err_message))
with self.assertRaises(BlockError) as err:
utils.hash_block(*self.arguments)
self.assertTrue(mock_json_dumps.called)
self.assertIsInstance(err, BlockError)
self.assertIn(err_message, err.message)
def proof_of_work(cls, last_block: 'Block', block: dict):
"""
Consensus protocol requiring certain computational effort to mine
a new block to be able to add it to the blockchain. The solution
is then verified by the entire network.
:param Block last_block: current last block of the blockchain.
:param dict block: block attributes except the unknown block hash.
:return dict: block data for the next block in the blockchain.
"""
block_values = block.values()
hash = utils.hash_block(*block_values)
while not utils.hex_to_binary(hash).startswith('0' * block['difficulty']):
block['nonce'] += 1
block['timestamp'] = utils.get_utcnow_timestamp()
block['difficulty'] = cls.adjust_difficulty(last_block, block['timestamp'])
hash = utils.hash_block(*block_values)
block['hash'] = hash
return block
def valid_hash(cls, value: str, values: dict, field: Field):
"""
Validate hashes values.
:param str value: provided last_hash or hash values.
:param dict values: previous fields already validated.
:param Field field: field name to validate its value.
:return str: validated last_hash or hash value.
:raise ValueError: if last_hash or hash values do not meet required conditions.
"""
match = re.match(r'^(?P<hash>[a-f0-9]{64})$', value)
if len(value) != BLOCK_HASH_LENGTH or not match:
message = f'Invalid pattern for {field.alias} value: {value}.'
logger.error(f'[BlockSchema] Validation error. {message}')
raise ValueError(message)
if field.alias == 'hash':
try:
assert hex_to_binary(value).startswith('0' * values.get('difficulty'))
assert value == hash_block(*values.values())
except AssertionError:
message = f'Invalid hash: {value}.'
logger.error(f'[BlockSchema] Validation error. {message}')
raise ValueError(message)
return value
from src.blockchain.models.utils import hash_block
# Block
BLOCK_HASH_LENGTH = 64
BLOCK_MINING_RATE = 10 * 1000 # milliseconds (10 secs)
BLOCK_TIMESTAMP_LENGTH = 13
GENESIS_BLOCK = {
'index': 0,
'timestamp': 1,
'nonce': 0,
'difficulty': 1,
'data': [],
'last_hash': 'genesis_last_hash'
}
GENESIS_BLOCK['hash'] = hash_block(*GENESIS_BLOCK.values())
# API Server
ORIGINS = [
"http://localhost:3000",
]
CORS_MIDDLEWARE_PARAMS = {
'allow_origins': ORIGINS,
'allow_credentials': True,
'allow_methods': ['GET', 'POST'],
'allow_headers': ['*']
}
# P2P Server
HEARTBEAT_RATE = 5 # seconds
def test_hash_block_different_inputs(self):
test_hash = utils.hash_block(*self.arguments)
item = random.choice(self.arguments)
self.arguments.remove(item)
test_hash_remove = utils.hash_block(*self.arguments)
self.assertNotEqual(test_hash, test_hash_remove)
def test_hash_block_same_unordered_inputs(self):
test_hash = utils.hash_block(*self.arguments)
test_hash_reverse = utils.hash_block(*reversed(self.arguments))
self.assertEqual(test_hash, test_hash_reverse)
def setUp(self):
super(BlockUtilsTest, self).setUp()
self.arguments = [
'test_index', 'test_timestamp', 'test_data', 'test_hash'
]
self.hash = utils.hash_block(self.arguments)