python区块及区块链的开发详解

更新时间：2020-07-11 09:18:01 作者：startmvc

接着上一篇交易记录整合交易类，这里描述区块的开发。首先我们要明白一个区块，需要的

接着上一篇交易记录整合交易类，这里描述区块的开发。

首先我们要明白一个区块，需要的内容，包括交易记录集合，时间戳，哈希，上一个区块的哈希。明白了这个，下面就容易代码开发了。


import datetime
import hashlib
from Message import DaDaMessage, InvalidMessage
from Transaction import Transaction
class Block:
 #不定参数，*args,区块集合
 def __init__(self, *args):
 self.messagelist = [] # 存储多个交易记录
 self.timestamp = None # 存储多个记录最终锁定时间
 self.hash = None
 self.preHash = None
 if args:
 for arg in args:
 self.add_message(arg)

 def add_message(self, message): # 添加 交易信息
 # 区分第一条与后面多条，是否需要链接
 if len(self.messagelist) > 0:
 message.link(self.messagelist[-1]) # 链接最后一个
 message.seal() # 密封
 message.validate() # 校验
 self.messagelist.append(message)
 def link(self, block): # 区块链接
 self.preHash = block.hash
 def seal(self): # 密封当前hash
 self.timestamp = datetime.datetime.now()
 self.hash = self.hash_block()
 def hash_block(self): # 密封上一块哈希，时间戳，交易记录的最后一个

 return hashlib.sha512(
 (str(self.timestamp) + str(self.preHash) + str(self.messagelist[-1].hash)).encode("utf-8")).hexdigest()
 def validate(self): # 校验
 for i, message in enumerate(self.messagelist): # 每个交易记录校验一下
 message.validate() #每一条交易记录校验
 if i > 0 and message.prev_hash != self.messagelist[i - 1].hash:
 raise InvalidBlock("无效的block,交易记录被修改为在第{}条记录".format(i)+str(self))
 return str(self) + "Ok"
 def __repr__(self):
 return "money block= hash:{},prehash:{},len:{},time:{}".format(self.hash, self.preHash, len(self.messagelist),
 self.timestamp)

自定义异常：


class InvalidBlock(Exception):
 def __init__(self,*args,**kwargs):
 super(Exception,self).__init__(*args,**kwargs)

编写测试模块：


if __name__=="__main__":
 t1 = Transaction("yicheng", "ddd1", 100)
 t2 = Transaction("yicheng", "ddd2", 200)
 t3 = Transaction("yicheng", "ddd3", 300)
 t4 = Transaction("yicheng", "ddd4", 400)
 m1 = DaDaMessage(t1)
 m2 = DaDaMessage(t2)
 m3 = DaDaMessage(t3)
 m4 = DaDaMessage(t4)
 try:
 block1 = Block(m1, m2, m3)
 block1.seal()
 #测试篡改数据
 #m3.data = "你妹的直播"
 #block1.messagelist[0] = m3
 print(block1.validate())
 except InvalidMessage as e: #交易记录被修改
 print(e)
 except InvalidBlock as e: #区块被修改
 print(e)

测试结果如下，为了打印需要，我改成了md5格式下的结果：

篡改区块信息的结果，可能结果不一样，因为修改的内容不一样，报的错误也不一样：

至此，已经完成了：交易记录，区块的开发，现在进行区块链的开发就比较容易了。实现代码如下：


from Block import InvalidBlock, Block
from Message import InvalidMessage, DaDaMessage
from Transaction import Transaction
# 区块链
class Dada_BlockCoin:
 def __init__(self):
 self.blocklist = [] # 装载所有区块
 def validate(self):#校验所有区块
 for i, block in enumerate(self.blocklist):
 try:
 block.validate()
 except InvalidBlockCoin as e:
 raise InvalidBlockCoin("区块校验错误，区块索引{}".format(i))
 def add_block(self, block): # 增加区块
 if len(self.blocklist) > 0:
 block.link(self.blocklist[-1]) #连接区块
 block.seal()#密封
 block.validate()#校验
 self.blocklist.append(block)#添加到区块链中
 def __repr__(self):
 return "Dada_BlockCoin:{}".format(len(self.blocklist))

自定义异常：


class InvalidBlockCoin(Exception):
 def __init__(self, *args, **kwargs):
 super(Exception, self).__init__(*args, **kwargs)

编写测试模块：


if __name__ == "__main__":
 t1 = Transaction("yicheng", "ddd1", 100)
 t2 = Transaction("yicheng", "ddd2", 200)
 t3 = Transaction("yicheng", "ddd3", 300)
 t4 = Transaction("yicheng", "ddd4", 400)
 t5 = Transaction("yicheng", "ddd5", 500)
 t6 = Transaction("yicheng", "ddd6", 600)
 m1 = DaDaMessage(t1)
 m2 = DaDaMessage(t2)
 m3 = DaDaMessage(t3)
 m4 = DaDaMessage(t4)
 m5 = DaDaMessage(t5)
 m6 = DaDaMessage(t6)
 try:
 yin1 = Block(m1, m2)
 yin1.seal()
 yin2 = Block(m3, m4)
 yin2.seal()
 yin3 = Block(m5, m6)
 yin3.seal()
 # 篡改区块
 #yin3.messagelist.append(m1)
 coin = Dada_BlockCoin() # 区块链
 coin.add_block(yin1)
 coin.add_block(yin2)
 coin.add_block(yin3)
 coin.validate()
 print(coin)
 except InvalidMessage as e:
 print(e)
 except InvalidBlock as e:
 print(e)
 except InvalidBlockCoin as e:
 print(e)

测试结果如下：