def mineBlock(self, user):
isChainValid, issueBlock = self.isChainValid()
if isChainValid:
miningTransaction = Transaction(fromAddress=convertToPubKey(
os.getenv("PUB_KEY")),
toAddress=user,
amount=self.minedCoinbase)
signature = rsa.sign(
str(miningTransaction).encode(encoding='utf_8'),
convertToPrivKey(os.getenv("PRIV_KEY")), "SHA-256")
miningTransaction.addSignature(signature=signature.hex())
verifiedTransactionsForBlock = []
for transaction in self.pendingTransactions:
if self._isTransactionValid(transaction=transaction):
verifiedTransactionsForBlock.append(transaction)
verifiedTransactionsForBlock.insert(0, miningTransaction)
newBlock = Block(transactions=verifiedTransactionsForBlock,
previousHash=self.chain[-1].hashVal,
miningDifficulty=self.miningDifficulty)
self.chain.append(newBlock)
self.pendingTransactions = self.pendingTransactions - set(
verifiedTransactionsForBlock)
else:
print(
f"Chain is not valid! Someone tampered with the data! Issue with block {issueBlock}. Removing block {issueBlock} ..."
)
if self.debug:
print("\nBlock which is being removed is:\n")
print(self.chain[issueBlock])
self.chain = self.chain[:issueBlock]
def mineBlock(pubKeyStr):
blockchainNetwork.blockchain.mineBlock(user=convertToPubKey(pubKeyStr))
for node in blockchainNetwork.blockchain.nodes:
try:
requests.post(f'http://{node}/mine/broadcast', json={})
except Exception:
if blockchainNetwork.debug:
print(f"Node {node} not reachable...")
writeBlockchainToDb(blockchainNetwork=blockchainNetwork)
return "Block mined!", 201
def addTransaction():
data = request.get_json()
try:
valid, messageResponse = isDataValid(data)
if valid:
transaction = Transaction(
fromAddress=convertToPubKey(data["FromAddress"]),
toAddress=convertToPubKey(data["ToAddress"]),
amount=int(data["Amount"]))
signature = rsa.sign(
str(transaction).encode(encoding='utf_8'),
convertToPrivKey(data["priv_key"]), "SHA-256")
transaction.addSignature(signature=signature.hex())
result, message = blockchainNetwork.blockchain.addTransaction(
transaction=transaction)
if result:
finalMessage = message + " " + getBalance(
data["FromAddress"])[0]
writeBlockchainToDb(blockchainNetwork=blockchainNetwork)
propagateTransactionToAllNodes(
blockchainNetwork=blockchainNetwork,
transaction=transaction)
return finalMessage, 201
return message, 400
else:
return messageResponse, 500
except ValueError as e:
print(e)
return "Invalid json!", 500
except OverflowError as e:
print(e)
return "Invalid key! Please check both public and private keys", 500
except KeyError as e:
print(e)
return "Missing a field! Please check all required fields are present", 500
except Exception as e:
print(e)
return "Server error!", 500
def _isTransactionValid(self, transaction):
if transaction.signature == "":
return False, "Signature empty!"
if not isinstance(transaction, Transaction):
return False, f"Not a transaction object!\n{transaction}!\n"
if transaction in self.pendingTransactions:
return False, f"Transaction already present!\n{transaction}!\n"
userBalance = self.getBalance(transaction.fromAddress)
if userBalance < transaction.amount:
if convertToPubKey(
os.getenv("PUB_KEY")) != transaction.fromAddress:
return False, f"Insufficient balance! You only have {userBalance} coins but you are trying to send {transaction.amount}"
try:
rsa.verify(
str(transaction).encode(encoding='utf_8'),
bytes.fromhex(transaction.signature), transaction.fromAddress)
except rsa.VerificationError:
return False, f"signature not matching!"
return True, "Valid"
def getBalance(pubKeyStr):
return "Coins left: " + str(
blockchainNetwork.blockchain.getBalance(
user=convertToPubKey(pubKeyStr))), 200