def test_transaction_to_json(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
content = transaction.to_json()
self.assertIsInstance(content, str)
self.assertGreater(len(content), 0)
def test_block_compute_hash(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
block = Block(0, [transaction.to_json()], datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"), "0")
hash_val = block.compute_hash()
self.assertIsInstance(hash_val, str)
self.assertGreater(len(hash_val), 0)
def test_block_to_dict(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
block = Block(0, [transaction.to_json()], datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"), "0")
content = block.to_dict()
self.assertIsInstance(content, dict)
self.assertEqual(list(content.keys()), ["index", "timestamp", "previous_hash", "merkle_root", "nonce", "difficulty"])
def test_block_to_json(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
block = Block(0, [transaction.to_json()], datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"), "0")
content = block.to_json()
self.assertIsInstance(content, str)
self.assertGreater(len(content), 0)
def test_blockchain_add_block_wrong_previous_hash(self):
wallet = Wallet()
blockchain = Blockchain(wallet)
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
block = Block(0, [transaction.to_json()], datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"), "Wrong")
computed_hash = blockchain.proof_of_work(block)
result = blockchain.add_block(block, computed_hash)
self.assertFalse(result)
def test_blockchain_proof_of_work_bad_block(self):
wallet = Wallet()
blockchain = Blockchain(wallet)
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
previous_hash = blockchain.last_block["hash"]
block = Block(0, [transaction.to_json()], datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"), previous_hash)
delattr(block, "transaction")
self.assertRaises(AttributeError, blockchain.proof_of_work, block)
def test_blockchain_proof_of_work(self):
wallet = Wallet()
blockchain = Blockchain(wallet)
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
previous_hash = blockchain.last_block["hash"]
block = Block(0, [transaction.to_json()], datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"), previous_hash)
computed_hash = blockchain.proof_of_work(block)
self.assertGreater(len(computed_hash), 0)
def merkle_path(self, transaction: Transaction):
'''return merkle path of given transaction'''
path = []
transactionHash = sha256(str(
transaction.to_json()).encode()).hexdigest()
block = self.search_block_with_transaction(transactionHash)
leaves = []
if block:
for trans in block['transaction']:
trans = json.loads(trans)
new_trans = Transaction(trans['sender'], trans['recipient'],
trans['value'])
if 'signature' in trans.keys():
new_trans.signature = trans['signature']
new_transHash = sha256(str(
new_trans.to_json()).encode()).hexdigest()
leaves.append(new_transHash)
path = self._merklePath(leaves, transactionHash, [])
path.append(block['merkle_root'])
return path
def add_new_transaction(self, transaction: Transaction) -> bool:
'''
add a new transaction to the block
after checking balance
'''
if transaction.verify_transaction_signature():
# Check balance and fee before confirming a transaction
total_charge = float(transaction.value) + float(transaction.fee)
if transaction.sender != "Block_Reward" and \
self.check_balance(transaction.sender) >= total_charge:
self.unconfirmed_transactions.append(transaction.to_json())
return True
return False
def partial_validation():
values = request.form
required = ['root', 'path', 'sender', 'recipient', 'value']
# Check that the required fields are in the POST data
if not all(k in values for k in required):
return 'Missing values', 400
root = values.get('root')
path = json.loads(values.get('path'))
transaction = Transaction(values.get('sender'), values.get('recipient'), values.get('value'))
if values.get('signature'):
transaction.signature = values.get('signature')
h = sha256(str(transaction.to_json()).encode()).hexdigest()
new_root = blockchain.partialValidation(path, h)
result = root == new_root
return jsonify(result), 200
def search_block_with_transaction(self, transactionHash):
'''return block that matches given transaction hash'''
fullchain = [json.loads(block) for block in self.chain]
for block in fullchain[::-1]:
for trans in block['transaction']:
trans = json.loads(trans)
new_trans = Transaction(trans['sender'], trans['recipient'],
trans['value'])
if 'signature' in trans.keys():
new_trans.signature = trans['signature']
new_transHash = sha256(str(
new_trans.to_json()).encode()).hexdigest()
if transactionHash == new_transHash:
return block
return False
def mine(self, wallet: Wallet) -> Union[Block, bool]:
'''
method to generate new blocks and claim the block reward and all the transaction fees
It confirms all unconfirmed transactions into blocks by using the proof-of-work method.
convert to JSON to store transaction in the blockchain
'''
# get all available wallet addresses in the network
addresses = self.get_addresses_from_transactions()
# create Transaction objects for interest
interest_txs = self.create_interest_transactions(addresses)
for interest_tx in interest_txs:
self.unconfirmed_transactions.insert(0, interest_tx.to_json())
# add up all the transaction fee from all unconfirmed transactions
tx_fees = [
float(json.loads(transaction)['fee'])
for transaction in self.unconfirmed_transactions
]
total_tx_fee = sum(tx_fees)
# create and add a transaction into the list of unconfirmed transactions
# for sending out a block reward, which also include all of their transaction fees
block_reward = Transaction("Block_Reward", wallet.pubkey,
str(5.0 + total_tx_fee))
self.unconfirmed_transactions.insert(0, block_reward.to_json())
# if there are no unconfirmed transactions, return False
if not self.unconfirmed_transactions:
return False
new_block = Block(
index=self.last_block['index'] + 1,
transaction=self.unconfirmed_transactions,
timestamp=datetime.datetime.now().strftime("%m/%d/%Y, %H:%M:%S"),
previous_hash=self.last_block['hash'])
new_block.difficulty = self.next_difficulty(self.last_block)
proof = self.proof_of_work(new_block)
if self.add_block(new_block, proof):
self.unconfirmed_transactions = []
return new_block
else:
return False
