AttributeError: '_hashlib.HASH' 对象没有属性 'hex'

如何解决AttributeError: '_hashlib.HASH' 对象没有属性 'hex'

我正在做一个关于区块链的课程，终点工作正常，但矿块没有，我试图改变烧瓶的版本，但它不会改变结果，如果我改变了 hex()到 hexdigest() 我什至无法得到回应。有人可以帮我吗？

import hashlib
import json
import flask

from flask import Flask,jsonify

# Parte 1,criar um Blockchain

class Blockchain:
    def __init__(self):
        self.chain = []
        self.create_block(proof = 1,previous_hash = '0')
        
    def create_block(self,proof,previous_hash):
        block = {'index' : len(self.chain) + 1,'timestamp' : str(datetime.datetime.now()),'proof' : proof,'previous_hash' : previous_hash}
        self.chain.append(block)
        return block
    
    def get_previous_block(self):
        return self.chain[-1]
    
    def proof_or_work(self,previous_proof):
        new_proof = 1
        check_proof = False
        
        while check_proof is False:
            hash_operation = hashlib.sha256(str(new_proof**2 - previous_proof**2).encode()).hexdigest()
            if hash_operation[:4] == '0000':
                check_proof == True
            else:
                new_proof += 1
        return new_proof
    
    def hash(self,block):
        encoded_block = json.dumps(block,sort_keys=True).enconde()
        return hashlib.sha256(encoded_block).hexdigest()
    
    def is_chain_valid(self,chain):
        previous_block = chain[0]
        block_index = 1
        
        while block_index < len(chain):
            block = chain[block_index]
            if block['previous_hash'] != self.hash(previous_block):
                return False
            previous_proof = previous_block['proof']
            proof = block['proof']
            hash_operation = hashlib.sha256(str(proof**2 - previous_proof**2).encode()).hexdigest()
            if hash_operation[:4] != '0000':
                return False
            previous_block = block
            block_index += 1
        return True
        

app = Flask(__name__)
app.config['JSONIFY_PRETTYPRINT_REGULAR'] = False


blockchain = Blockchain()

@app.route('/mine_block',methods=['GET'])
def mine_block():
    previous_block = blockchain.get_previous_block()
    previous_proof = previous_block['proof']
    proof = blockchain.proof_or_work(previous_proof)
    previous_hash = blockchain.hash(previous_block)
    
    block = blockchain.create_block(proof,previous_hash)
    
    response = {'message' : 'Parabens voce minerou um bloco!','index': block['index'],'timestamp': block['timestamp'],'proof' : block['proof'],'previous_hash' : block['previous_hash']}
    return jsonify(response),200;

@app.route('/get_chain',methods=['GET'])
def get_chain():
    response = {'chain' : blockchain.chain,'lenght' : len(blockchain.chain)}
    return jsonify(response),200;


app.run(host= '0.0.0.0',port=5000)

• 在 http://0.0.0.0:5000/ 上运行（按 CTRL+C 退出） [2021-02-18 18:38:06,039] 应用程序错误：/mine_block [GET] 上的异常 回溯（最近一次调用最后一次）： 文件“C:\Users\Leslye\anaconda3\lib\site-packages\flask\app.py”，第 1982 行，在 wsgi_app 中 响应 = self.full_dispatch_request() 文件“C:\Users\Leslye\anaconda3\lib\site-packages\flask\app.py”，第 1614 行，在 full_dispatch_request rv = self.handle_user_exception(e) 文件“C:\Users\Leslye\anaconda3\lib\site-packages\flask\app.py”，第 1517 行，在 handle_user_exception 再加注（exc_type，exc_value，tb） 文件“C:\Users\Leslye\anaconda3\lib\site-packages\flask_compat.py”，第 33 行，重新加注 提升价值 文件“C:\Users\Leslye\anaconda3\lib\site-packages\flask\app.py”，第 1612 行，在 full_dispatch_request 中 rv = self.dispatch_request() 文件“C:\Users\Leslye\anaconda3\lib\site-packages\flask\app.py”，第 1598 行，在 dispatch_request 中 返回 self.view_functionsrule.endpoint 文件“C:\Users\Leslye\Desktop\Workspace\Blockchain\Modulo 1 - Criar Blockchain\blockchain.py”，第 70 行，在 mine_block 证明 = blockchain.proof_or_work(previous_proof) 文件“C:\Users\Leslye\Desktop\Workspace\Blockchain\Modulo 1 - Criar Blockchain\blockchain.py”，第 31 行，在 proof_or_work hash_operation = hashlib.sha256(str(new_proof2 - previous_proof2).encode()).hex() AttributeError: '_hashlib.HASH' 对象没有属性 'hex' 127.0.0.1 - - [18/Feb/2021 18:38:06] "GET /mine_block HTTP/1.1" 500 -