class Server:
def __init__(self,server_name="System"):
self.server_name = server_name
self.__miners = deque()
self.__blockchain = BlockChain()
self.__users = [User(self.server_name,float("inf"))]
@staticmethod
def from_dict(dict):
server = Server(dict['server_name'])
server.__blockchain = BlockChain.from_dict(dict['chain'])
if not server.__blockchain.isValid():
raise Exception("Blockchain isn't valid")
server.__users = []
for user in dict['users']:
server.__users.append(User.from_dict(user))
return server
def saveServerState(self):
self.update()
with open("server.json", 'w') as outfile:
json.dump({ 'server_name' : self.server_name,
'chain' : self.__blockchain,
'users' : self.__users
}, outfile, default=lambda o: o.__dict__, indent=4)
@property
def userCount(self):
return len(self.__users) - 1
def isExistUser(self,username):
for user in self.__users:
if user.name == username:
return True
return False
def newUser(self,username):
if not self.isExistUser(username):
self.__users.append(User(username,0))
print(f"New user {username} were created")
return True
print(f"{username} already exist")
return False
@staticmethod
def findNextNonce(prev_nonce,difficulty,nonce=0):
while hashlib.sha256(f'{prev_nonce}{nonce}'.encode()).hexdigest()[:difficulty] != "0"*difficulty:
nonce+=1
return nonce
def mineBlock(self,username):
last_nonce = self.__blockchain.getChain()[-1].nonce
nonce = self.findNextNonce(last_nonce,self.__blockchain.difficulty)
if self.__blockchain.newBlock(nonce,username):
self.__blockchain.newTransaction(Transaction(TransactionType.REWARD,self.server_name,username,self.__blockchain.difficulty/10))
self.update()
return True
return False
def mine(self,username=None):
if username:
self.__miners.append(username)
if len(self.__miners) == 0:
return
miner = self.__miners.popleft()
while self.mineBlock(miner):
print(f"{miner} mined new block!")
miner = None
if len(self.__miners) > 0:
miner = self.__miners.popleft()
else:
break
if miner is not None:
self.__miners.appendleft(miner)
def sendFromTo(self,sender_name,recipient_name,amount,message=""):
sender = self.findUserByName(sender_name)
if sender.balance >= amount:
self.__blockchain.newTransaction(Transaction(TransactionType.FROMTO,sender_name,recipient_name,amount,message))
self.update()
print(f"{sender_name} sent {recipient_name} {amount} with message \"{message}\"")
return True
print(f"{sender_name} tried to send {recipient_name} {amount} with message \"{message}\"")
return False
def buy(self,recipient_name,amount):
self.__blockchain.newTransaction(Transaction(TransactionType.BUY,self.server_name,recipient_name,amount))
self.update()
print(f"{recipient_name} bought {amount}")
def sell(self,sender_name,amount):
sender = self.findUserByName(sender_name)
if sender.balance >= amount:
self.__blockchain.newTransaction(Transaction(TransactionType.SELL,sender_name,self.server_name,amount))
self.update()
print(f"{sender_name} sold {amount}")
return True
print(f"{sender_name} tried to sell {amount}")
return False
def findUserByName(self,username):
for user in self.__users:
if user.name == username:
return user
def getRandomUser(self):
return random.choice(self.__users[1:]).name
def updateBalance(self,username,delta):
user = self.findUserByName(username)
user.balance += delta
def update(self):
blocks_count = self.__blockchain.update()
if blocks_count == 0:
return
blocks = self.__blockchain.getChain()[-blocks_count:]
for block in blocks:
for transaction in block.transactions:
if transaction.type == TransactionType.REWARD:
self.updateBalance(transaction.recipient,transaction.amount)
elif transaction.type == TransactionType.FROMTO:
self.updateBalance(transaction.recipient,transaction.amount)
self.updateBalance(transaction.sender,-transaction.amount)
elif transaction.type == TransactionType.BUY:
self.updateBalance(transaction.recipient,transaction.amount)
elif transaction.type == TransactionType.SELL:
self.updateBalance(transaction.sender,-transaction.amount)
from blockchain import BlockChain
from wallet import wallet
#Robin Danz - Joris Monnet
#He-Arc - Security
if __name__ == '__main__':
firstChain = BlockChain()
firstChain.createFirstBlock()
print(firstChain)
firstWallet = wallet.create_wallet()
secondWallet = wallet.create_wallet()
print("Second Wallet values = " + str(secondWallet))
firstChain.mine(firstWallet["address"])
firstChain.mine(secondWallet["address"])
firstChain.createTransaction(firstWallet["address"],
secondWallet["address"], 5)
print(firstChain)
secondChain = BlockChain()
secondChain.createFirstBlock()
secondChain.mine(firstWallet["address"])
secondChain.mine(firstWallet["address"])
secondChain.mine(firstWallet["address"])
print(secondChain)
firstChain.replaceChain(secondChain.getChain())
print(firstChain)
