看了好几个从零开始建区块链的文章，

只有以下这几个URL实在，

于是，花了一晚上，

妥妥的自已手打一次，

感觉棒棒哒~~：）

https://www.jianshu.com/p/ecfb2a9040a3

https://www.jianshu.com/p/b39c361687c1

https://www.jianshu.com/p/1e247faf8a15

ChgBlockChain.py

# coding=utf-8import hashlib
import json
import datetimefrom typing import Optional, Dict, Any, List
from urllib.parse import urlparse
import requestsclass ComplexEncoder(json.JSONEncoder):def default(self, obj):if isinstance(obj, datetime.datetime):return obj.strftime('%Y-%m-%d %H:%M:%S')else:return json.JSONEncoder.default(self, obj)class ChgBlockChain(object):def __init__(self):self.chain = []self.current_transactions = []self.nodes = set()self.new_block(proof=100, prev_hash=1)def new_block(self,proof: int,prev_hash: Optional[str])->Dict[str, Any]:block = {"index": len(self.chain) + 1,"timestamp": datetime.datetime.now(),"transactions": self.current_transactions,"proof": proof,"prev_hash": prev_hash or self.hash(self.chain[-1])}self.current_transactions = []self.chain.append(block)return blockdef new_transaction(self, sender: str, recipient: str, amount: int)->int:self.current_transactions.append({"sender": sender,"recipient": recipient,"amount": amount})return self.last_block["index"] + 1@staticmethoddef hash(block: Dict[str, Any])->str:block_str = json.dumps(block, sort_keys=True,  indent=4, cls=ComplexEncoder).encode("utf-8")return hashlib.sha256(block_str).hexdigest()@propertydef last_block(self)->Dict[str, Any]:return self.chain[-1]def proof_of_work(self, last_block)->int:last_proof = last_block["proof"]# last_hash = self.hash(last_block)proof = 0while self.valid_proof(last_proof, proof) is False:proof += 1return proof@staticmethoddef valid_proof(last_proof: int, proof: int)->bool:guess = f'{last_proof}{proof}'.encode("utf-8")guess_hash = hashlib.sha256(guess).hexdigest()return guess_hash[:4] == "0000"def register_node(self, addr: str)->None:parsed_url = urlparse(addr)if parsed_url.netloc:self.nodes.add(parsed_url.netloc)elif parsed_url.path:self.nodes.add(parsed_url.path)else:raise ValueError("url invalid!")def valid_chain(self, chain: List[Dict[str, Any]])->bool:last_block = chain[0]current_index = 1while current_index < len(chain):block = chain[current_index]if block["prev_hash"] != self.hash(last_block):return Falseif not self.valid_proof(last_block["proof"],block["proof"]):return Falselast_block = blockcurrent_index += 1return Truedef resolve_conflicts(self)->bool:neighbours = self.nodesnew_chain = Nonemax_length = len(self.chain)for node in neighbours:response = requests.get(f'http://{node}/chain')if response.status_code == 200:length = response.json()["length"]chain = response.json()["chain"]if length > max_length and self.valid_chain(chain):max_length = lengthnew_chain = chainif new_chain:return Trueelse:return False

ChgCoinBlockNode.py

# coding=utf-8from uuid import uuid4
from flask import Flask, jsonify, requestfrom ChgBlockChain import ChgBlockChainchgCoin = ChgBlockChain()
node_id = str(uuid4()).replace("-", "")
print("current node wallet address: ", node_id)app = Flask(__name__)
app.config['DEBUG'] = True
app.config['JSONIFY_PRETTYPRINT_REGULAR'] = True@app.route("/")
def index_page():return "welcome to ChgCoin..."@app.route("/chain")
def index_chain():response = {"chain": chgCoin.chain,"length": len(chgCoin.chain)}return jsonify(response), 200@app.route("/mine")
def index_mine():last_block = chgCoin.last_blockproof = chgCoin.proof_of_work(last_block)chgCoin.new_transaction(sender=0,recipient=node_id,amount=12.5)block = chgCoin.new_block(proof, chgCoin.hash(last_block))response = {"message": "new block created...","index": block["index"],"transactions": block["transactions"],"proof": block["proof"],"hash": chgCoin.hash(block),"prev_hash": block["prev_hash"]}return jsonify(response), 200@app.route("/new_transactions", methods=["POST"])
def index_new_transactions():values = request.get_json()required = ["sender", "recipient", "amount"]if not all(key in values for key in required):return "data is invalid", 400index = chgCoin.new_transaction(values["sender"],values["recipient"],values["amount"])response = {"message": f"transaction added to block{index}"}return jsonify(response), 201@app.route("/new_node", methods=["POST"])
def index_new_node():values = request.get_json()nodes = values.get("nodes")if nodes is None:return "It's empty node"for node in nodes:chgCoin.register_node(node)response = {"message": "new node added to block","nodes": list(chgCoin.nodes)}return jsonify(response), 201@app.route("/node_refresh")
def index_node_refresh():replaced = chgCoin.resolve_conflicts()print(replaced)if replaced:response = {"message": "block chain is replaced by longest chain","new chain": chgCoin.chain}else:response = {"message": "block chain is no need replaced ","chain": chgCoin.chain}return jsonify(response), 200if __name__ == '__main__':app.run("127.0.0.1", port=5005)