python区块及区块链的开发详解
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【听图阁-专注于Python设计】。
