详解python实现简单区块链结构

"""
区块设计
"""
import time
import hashlib

class Block:
    # 初始化一个区块
    def __init__(self,previous_hash,data):
        self.index = 0
        self.nonce = ''
        self.previous_hash = previous_hash
        self.time_stamp = time.time()
        self.data = data
        self.hash = self.get_hash()
    # 获取区块的hash
    def get_hash(self):
        msg = hashlib.sha256()
        msg.update(str(self.previous_hash).encode('utf-8'))
        msg.update(str(self.data).encode('utf-8'))
        msg.update(str(self.time_stamp).encode('utf-8'))
        msg.update(str(self.index).encode('utf-8'))
        return msg.hexdigest()
    # 修改区块的hash值
    def set_hash(self,hash):
        self.hash = hash

# 生成创世区块，这是第一个区块，没有前一个区块
def creat_genesis_block():
    block = Block(previous_hash= '0000',data='Genesis block')
    nonce,digest = mime(block=block)
    block.nonce = nonce
    block.set_hash(digest)
    return block

def mime(block):
    """
    挖矿函数——更新区块结构，加入nonce值
        block:挖矿区块
    """
    i = 0
    prefix = '0000'
    while True:
        nonce = str(i)
        msg = hashlib.sha256()
        msg.update(str(block.previous_hash).encode('utf-8'))
        msg.update(str(block.data).encode('utf-8'))
        msg.update(str(block.time_stamp).encode('utf-8'))
        msg.update(str(block.index).encode('utf-8'))
        msg.update(nonce.encode('utf-8'))
        digest = msg.hexdigest()
        if digest.startswith(prefix):
            return nonce,digest
        i+=1

"""
区块链设计
"""
from Block import *
# 区块链
class BlockChain:
    def __init__(self):
        self.blocks = [creat_genesis_block()]
    # 添加区块到区块链上
    def add_block(self,data):
        pre_block = self.blocks[len(self.blocks)-1]
        new_block = Block(pre_block.hash,data)
        new_block.index = len(self.blocks)
        nonce,digest = mime(block=new_block)
        new_block.nonce = nonce
        new_block.set_hash(digest)
        self.blocks.append(new_block)
        return new_block

from BlockChain import *
# 创建一个区块链
bc = BlockChain()
# 添加区块
bc.add_block(data='second block')
bc.add_block(data='third block')
bc.add_block(data='fourth block')
for bl in bc.blocks:
    print("Index:{}".format(bl.index))
    print("Nonce:{}".format(bl.nonce))
    print("Hash:{}".format(bl.hash))
    print("Pre_Hash:{}".format(bl.previous_hash))
    print("Time:{}".format(bl.time_stamp))
    print("Data:{}".format(bl.data))
    print('\n')