Python区块链入门项目：探索区块链技术实战应用

class Block:def __init__(self, index, timestamp, transactions, previous_hash):self.index = indexself.timestamp = timestampself.transactions = transactionsself.previous_hash = previous_hashself.hash = self.calculate_hash()def calculate_hash(self):# 计算区块的哈希值return hashlib.sha256(str(self.index) + str(self.timestamp) + str(self.transactions) + str(self.previous_hash)).hexdigest()

class Blockchain:def __init__(self):self.chain = []self.create_genesis_block()def create_genesis_block(self):# 创建创世块genesis_block = Block(0, datetime.datetime.now(), [], "0")self.chain.append(genesis_block)def add_block(self, block):# 将区块添加到区块链self.chain.append(block)def get_last_block(self):# 获取区块链中的最后一个区块return self.chain[-1]def is_valid(self):# 验证区块链的有效性for i in range(1, len(self.chain)):current_block = self.chain[i]previous_block = self.chain[i - 1]if current_block.hash != current_block.calculate_hash():return Falseif current_block.previous_hash != previous_block.hash:return Falsereturn True

class Transaction:def __init__(self, sender, receiver, amount):self.sender = senderself.receiver = receiverself.amount = amount

def main():blockchain = Blockchain()# 创建交易transaction1 = Transaction("Alice", "Bob", 10)transaction2 = Transaction("Bob", "Carol", 5)# 将交易添加到区块block = Block(blockchain.get_last_block().index + 1, datetime.datetime.now(), [transaction1, transaction2], blockchain.get_last_block().hash)# 将区块添加到区块链blockchain.add_block(block)# 查询区块链print(blockchain.chain)if __name__ == "__main__":main()