블록체인 코드

https://bigishdata.com/2017/10/17/write-your-own-blockchain-part-1-creating-storing-syncing-displaying-mining-and-proving-work/

import datetime as d
import hashlib as hash
import os
import pymysql
class Block(object):
    def __init__(self, dictionaryV):
        """
        index
        timestamp : 생성된 시간
        data
        prev_hash
        nonce
        hash
        """
        for k, v in dictionaryV.items():
            setattr(self, k, v)

        if not hasattr(self, 'hash'):
            print ("test")
            self.hash = self.create_self_hash()
    # Block Hash generator
    def create_self_hash(self):
        sha = hash.sha256()
        sha.update(self.index +
                   self.timestamp + # 블록이 생성된 시간
                   self.data +
                   self.prev_hash) # 이전 블록의 해쉬값
        return sha.hexdigest()

    def __dict__(self):
        information = {} # type of dictionary
        information['index'] = str(self.index)
        information['timestamp'] = str(self.timestamp)
        information['data'] = str(self.data)
        information['prev_hash'] = str(self.prev_hash)
        information['hash'] = str(self.hash)
        return information

    def __str__(self):
        return "Block<prev_hash: %s, hash: %s>>" %(self.prev_hash, self.hash)

    def blockInformation(self):
        print ("==============================================================")
        print ("Block-index : {}".format(self.index))
        print ("Block-timestamp : {}".format(self.timestamp))
        print ("Block-data : {}".format(self.data))
        print ("Block-prev_hash : {}".format(self.prev_hash))
        print ("Block-hash : {}".format(self.hash))
        print ("==============================================================")

def create_first_block():
    # index zero and arbitrary previous hash
    # dictionary
    block_data = {}
    block_data['index'] = str(0).encode(encoding='utf-8')
    block_data['timestamp'] = str(d.datetime.now()).encode(encoding='utf-8')
    block_data['data'] = "Genesis block".encode(encoding='utf-8')
    block_data['prev_hash'] = "".encode(encoding='utf-8')
    block = Block(block_data)
    return block

def generate_header(index, prev_hash, data, timestamp):
    retS = str(index) + prev_hash + data + str(timestamp)
    retS = retS.encode(encoding='utf-8')
    return retS

def calculate_hash(index, prev_hash, data, timestamp):
    header_string = generate_header(index, prev_hash, data, timestamp)
    sha = hash.sha256() # hash.sha256 객체 생성
    sha.update(header_string)
    return sha.hexdigest()

def mine(last_block):
    index = int(last_block.index) + 1 # 몇 번째 블록인지
    timestamp = d.datetime.now() # 생성된 시간
    data = "I block #{indx}".format(indx = index)
    prev_hash = last_block.hash # 이전 블록의 해쉬
    block_hash=calculate_hash(index, prev_hash, data, timestamp)
    #--------------------------------------------------
    block_data = {} # type of dictionary
    block_data['index'] = index
    block_data['timestamp'] = timestamp
    block_data['data'] = data
    block_data['prev_hash'] = prev_hash
    block_data['hash'] = block_hash
    return Block(block_data)
    # --------------------------------------------------

def main():
    G = create_first_block()
    print (G)
    G.blockInformation()
    ch1 = mine(G)
    ch1.blockInformation()

    ch2 = mine(ch1)
    ch2.blockInformation()
    # 디렉토리 생성 부분____________________________
    # chaindata_dir = "chaindata"
    # if not os.path.exists(chaindata_dir):
    #     # make chaindata dir
    #     os.mkdir(path=chaindata_dir)
    #     # check if dir is empty from just creation, or empty before
    # if os.listdir(chaindata_dir) == []: # 만약 비어 있다면
    #     # create first block
    #     first_block = create_first_block()
    #     #first_block.self_save()
if __name__ == "__main__":
    main()