新增内容：构建去中心化网络
import socket #套接字，利用三元组【ip地址，协议，端口】可以进行网络间通信
import threading #线程
import pickle# 定义一个全局列表保存所有节点
NODE_LIST = []class Node(threading.Thread): #继承与线程def __init__(self, name, port, host="localhost"):threading.Thread.__init__(self, name=name)self.host = host # 服务器地址，本地电脑都设为localhostself.port = port # 每个节点对应一个唯一的端口号self.name = name # 唯一的节点名称self.wallet = Wallet()self.blockchain = None # 用来存储一个区块链副本 账本def run(self):"""节点运行"""self.init_blockchain() # 初始化区块链# 在指定端口进行监听sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #获取TCP/ip 套接字socksock.bind((self.host, self.port)) #绑定主机，端口号到套接字sockNODE_LIST.append({"name": self.name,"host": self.host,"port": self.port})sock.listen(10) #开始TCP监听print(self.name, "运行中...")while True: # 不断处理其他节点发送的请求connection,address = sock.accept() #被动接受TCP客户的连接，(阻塞式)等待连接的到来try:print(self.name, "处理请求内容...")self.handle_request(connection)except socket.timeout: print('超时!')except Exception as e:print(e, )connection.close()def handle_request(self, connection):data = []while True: # 不断读取请求数据直至读取完成buf = connection.recv(1024) if not buf: # 若读取不到新的数据则退出breakdata.append(buf)if len(buf) < 1024: # 若读取到的数据长度小于规定长度，说明数据读取完成，退出breakt = pickle.loads(b''.join(data)) #从pickle格式的文件中读取数据并转换为Python的类型。print("数据接受完成,判断数据的 类 ：交易，区块，初始化" )if isinstance(t, Transaction): # 如果t是新交易类 消息print("处理交易请求...")if verify_sign(t.pubkey, str(t), t.signature): #验证交易，公钥验证签名# 验证交易签名没问题，生成一个新的区块print(self.name, "验证交易成功")new_block = Block(transactions=[t], prev_hash="")print(self.name, "生成新的区块...")w = ProofOfWork(new_block, self.wallet)block = w.mine() #挖矿，挖到正确的区块哈希值，此处block就是新的区块，主要是找到了符合要求的nonce值print(self.name, "将新区块添加到区块链中")self.blockchain.add_block(block)print(self.name, "将新区块广播到网络中...")self.broadcast_new_block(block)else:print(self.name, "交易验证失败！") #签名不对elif isinstance(t, Block): #如果t是新区块类 消息print("处理新区块请求...")if self.verify_block(t): print(self.name, "区块验证成功") self.blockchain.add_block(t)print(self.name, "添加新区块成功")else:print(self.name, "区块验证失败!")else: # 如果不是新区块消息，默认为初始化消息类型，返回本地区块链内容print("是我是我，我是初始化，我要返回我的区块链信息")connection.send(pickle.dumps(self.blockchain))def verify_block(self, block):"""验证区块有效性 是否是符合难度的区块哈希值，找到了正确的nonce值"""message = hashlib.sha256()message.update(str(block.prev_hash).encode('utf-8'))# 更新区块中的交易数据# message.update(str(self.block.data).encode('utf-8'))message.update(str(block.transactions).encode('utf-8'))message.update(str(block.timestamp).encode('utf-8'))message.update(str(block.nonce).encode('utf-8'))digest = message.hexdigest()prefix = '0' * DIFFICULTYreturn digest.startswith(prefix)def broadcast_new_block(self, block):"""将新生成的区块广播到网络中其他节点"""for node in NODE_LIST: #遍历节点中的每一个节点，把新的区块广播给除了自己的所有节点host =node['host']port = node['port']if host == self.host and port == self.port:print(self.name, "忽略自身节点")else:print(self.name, "广播新区块至 %s" % (node['name']))sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.connect((host, port)) # 连接到网络中的节点sock.send(pickle.dumps(block)) # 发送新区块sock.close() # 发送完成后关闭连接def init_blockchain(self):"""初始化当前节点的区块链"""#PER_BYTE = 1024if NODE_LIST: # 若当前网络中已存在其他节点，则从第一个节点从获取区块链信息host = NODE_LIST[0]['host']port = NODE_LIST[0]['port']name = NODE_LIST[0]["name"]print(self.name, "发送初始化请求 %s" % (name))print("开始让节点1发送请求")sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #获取TCP/ip套接字sock.connect((host, port)) # 连接到网络中的第一个节点sock.send(pickle.dumps('INIT')) # 发送初始化请求 pickle.dumps将Python数据转换为pickle格式的bytes字串print("请求成功")data = []print("开始接受节点1的connect返回的信息")while True: # 读取区块链信息，直至完全获取后退出buf = sock.recv(1024)print("接收中")if not buf:print("接收完毕，接空")breakdata.append(buf)if len(buf) < 1024:print("太短了，完毕")breaksock.close() # 获取完成后关闭连接# 将获取的区块链信息赋值到当前节点self.blockchain = pickle.loads(b''.join(data))print(self.name, "初始化完成.")else:# 如果是网络中的第一个节点，初始化一个创世区块block = Block(transactions=[], prev_hash="")w = ProofOfWork(block, self.wallet)genesis_block = w.mine()self.blockchain = BlockChain()self.blockchain.add_block(genesis_block)print("生成创世区块")def submit_transaction(self, transaction): #遍历节点中的每一个节点，把新的交易广播给除了自己的所有节点for node in NODE_LIST:host =node['host']port = node['port']if host == self.host and port == self.port:print(self.name, "忽略自身节点")else:print(self.name, "广播新区块至 %s:%s" % (self.host, self.port))sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((node["host"], node["port"])) sock.send(pickle.dumps(transaction)) sock.close()def get_balance(self):balance = 0for block in self.blockchain.blocks:for t in block.transactions:if t.sender == self.wallet.address.decode():balance -= t.amountelif t.recipient == self.wallet.address.decode():balance += t.amountprint("当前拥有%.1f个加密货币" % (balance))def print_blockchain(self):print("区块链包含区块个数: %d\n" % len(self.blockchain.blocks))for block in self.blockchain.blocks:print("上个区块哈希：%s" % block.prev_hash)print("区块内容：%s" % block.transactions)print("区块哈希：%s" % block.hash)print("\n")
# 初始化节点1node1 = Node("节点1", 8000)
node1.start() #启动线程 调用 start() 方法是用来启动线程的，轮到该线程执行时，会自动调用 run()；直接调用 run() 方法
node1.print_blockchain() #输出区块信息
node2 = Node("节点2", 8001)
node2.start()
node2.print_blockchain()
node1.get_balance()
node2.get_balance()
#创建交易
new_transaction = Transaction(sender=node1.wallet.address,recipient=node2.wallet.address,amount=0.3
)
sig = node1.wallet.sign(str(new_transaction)) #私钥签名
new_transaction.set_sign(sig, node1.wallet.pubkey)#发送公钥，和签名，给验证者验证
node1.submit_transaction(new_transaction) #广播交易
node1.print_blockchain()
node2.print_blockchain()
node1.get_balance()
node2.get_balance()
