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：

篡改区块链，测试模块区块链的内容，可以任意篡改，测试结果如下：

这里已经完成了数据层的部分开发，其余部分后续会完善。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。