{
    "timestamp": "1572185927665", 
    "source": "香肠加工", 
    "recorder": "小詹"
}

from hashlib import sha256
data = "TEST".encode("utf-8")
print(sha256(data).hexdigest())

from hashlib import sha256
import json
class Block: 
    def compute_hash(self):  
        """ 
        对区块进行哈希计算
        """ 
        block_string = json.dumps(self.__dict__, sort_keys=True) 
        return sha256(block_string.encode()).hexdigest()

from hashlib import sha256
import json
class Block: 
    def __init__(self, index, data, timestamp, previous_hash):
        self.index = index 
        self.data = data
        self.timestamp = timestamp
        self.previous_hash = previous_hash 

    def compute_hash(self):  
        """ 
        对区块进行哈希计算
        """ 
        block_string = json.dumps(self.__dict__, sort_keys=True) 
        return sha256(block_string.encode()).hexdigest()

class Blockchain:
    def __init__(self): 
        self.unconfirmed_data = [] # 尚未进入区块链的数据
        self.chain = []
        self.create_genesis_block()
 
    def create_genesis_block(self): 
        """
        生成创始区块(genesis block)并将其附加到链中的函数。
        该块的索引为0,previous_hash为0，并且是一个有效的散列。
        """
        genesis_block = Block(0, [], time.time(), "0")
        genesis_block.hash = genesis_block.compute_hash()
        self.chain.append(genesis_block)
 
    @property
    def last_block(self): 
        return self.chain[-1]

class Blockchain: 
    # 前面的代码略
    # 难度
    difficulty = 2
    def proof_of_work(self, block): 
        """
        函数尝试不同的随机数以获得满足我们难度的块哈希。
        """
        block.nonce = 0
        computed_hash = block.compute_hash()
        while not computed_hash.startswith('0' * Blockchain.difficulty): 
            block.nonce += 1
            computed_hash = block.compute_hash()
        return computed_hash 

class Blockchain:
    # 前面的代码略
    def is_valid_proof(self, block, block_hash):
        """
        工作量证明验证，并确保previous_hash正确
        """
        return (block_hash.startswith('0' * Blockchain.difficulty) and
                block_hash == block.compute_hash())

    def add_block(self, block, proof):
        """
        在验证成功后将块链接起来
        """
        previous_hash = self.last_block.hash
        if previous_hash != block.previous_hash: 
            return False
        if not self.is_valid_proof(block, proof): 
            return False
        block.hash = proof
        self.chain.append(block)
        return True

class Blockchain:
# 前面代码略
    def add_new_data(self, data): 
        self.unconfirmed_data.append(data)
 
    def mine(self): 
        """
        此函数充当一个接口，将未决数据添加到块中并计算工作证明，
        然后将它们添加到区块链。
        """
        if not self.unconfirmed_data: 
            return False
 
        last_block = self.last_block
 
        new_block = Block(index=last_block.index + 1,
                          data=self.unconfirmed_data,
                          timestamp=time.time(),
                          previous_hash=last_block.hash)
 
        proof = self.proof_of_work(new_block)
        self.add_block(new_block, proof)
        self.unconfirmed_data = []
        return new_block.index

def new_data(data): 
    # 这里传入字典数据或json数据都可以
    required_fields = ["source", "recorder"]
    for field in required_fields: 
        if not data.get(field): 
            return "Invlaid data"
    data["timestamp"] = time.time()
    bc.add_new_data(data)
    return "Success"
bc = Blockchain()
a = new_data({"source": "香肠加工", "recorder": "小詹"})
print(a)

F:\push\20191027>python block.py
Success

def new_data(data): 
    # 这里传入字典数据或json数据都可以
    required_fields = ["source", "recorder"]
    for field in required_fields: 
        if not data.get(field): 
            return "Invlaid data"
    data["timestamp"] = time.time()
    bc.add_new_data(data)
    return "Success"
def get_chain(blockchain): 
    chain_data = []
    for block in blockchain.chain: 
        chain_data.append(block.__dict__)
    return json.dumps({"length": len(chain_data),
                       "chain": chain_data})

def mine_unconfirmed_transactions(blockchain): 
    result = blockchain.mine()
    if not result: 
        print("No data need to mine")
    print("Block #{} is mined.".format(result))

bc = Blockchain()
a = new_data({"source": "香肠加工", "recorder": "小詹"})
print(a)
mine_unconfirmed_transactions(bc)

F:\push\20191027>python block.py
Success
Block #1 is mined.

def get_chain(blockchain): 
    chain_data = []
    for block in blockchain.chain: 
        chain_data.append(block.__dict__)
    return json.dumps({"length": len(chain_data),
                       "chain": chain_data})

print(get_chain(bc)) 

F:\push\20191027>python block.py
 Success
 Block #1 is mined.
 {"length": 2, "chain": [{"index": 0, "data": [], "timestamp": 1572187230.2847784, "previous_hash": "0", "hash": "f30161fc8ffa278f26713a73780b939fe9734d9d459fe4307e72926d9eb9c3aa"}, {"index": 1, "data": [{"source": "\u9999\u80a0\u52a0\u5de5", "recorder": "\u5c0f\u8a79", "timestamp": 1572187230.2847784}], "timestamp": 1572187230.2847784, "previous_hash": "f30161fc8ffa278f26713a73780b939fe9734d9d459fe4307e72926d9eb9c3aa", "nonce": 0, "hash": "0026b22937fdcb24978814dd26cdf64a6210966c26914e66b73ca68805f1cd5a"}]}