上一篇只做到單節點的功能測試，這裏繼續多節點。
import hashlib
import json
import time
from urllib.parse import urlparse
from uuid import uuid4
import requests
from flask import Flask, jsonify, request
from typing import Any, Dict, List, Optional # 數據結構
'''
typing.Optional
可選類型。
Optional[X] 等價於 Union[X, None]。也就是要麼是X，要麼是None
請注意，這不是一個可選參數的概念，它是一個具有默認值的參數。具有默認值的可選參數不需要在其類型註釋上使用 Optional 限定符（雖然如果默認值爲 None，則推斷）。
如果允許 None 的顯式值，則強制參數可以仍然具有 Optional 類型。
typing.Any
表示無約束類型的特殊類型。
每種類型都與 Any 兼容。
Any 兼容各種類型。
'''
class DadaCoinBlockChain:
def __init__(self):
self.current_transactions = [] # 交易列表
self.chain = [] # 區塊鏈
self.nodes = set() # 保存網絡節點
self.new_block(proof=100, preHash="1") # 創世區塊
##創建區塊
def new_block(self,
proof: int, # 指定參數爲int
preHash: Optional[str] # 指定上一塊的哈希數據類型爲str，默認爲None
) -> Dict[str, Any]: # 指定返回數據類型
block = {
"index": len(self.chain) + 1, # 索引
"timestamp": time.time(), # 當前時間
"transactions": self.current_transactions,
"proof": proof,
"preHash": preHash or self.hash(self.chain[-1])
}
self.current_transactions = []
self.chain.append(block)
return block
@staticmethod
def hash(block: Dict[str, Any]) -> str:
block_str = json.dumps(block, sort_keys=True).encode("utf-8")
return hashlib.sha256(block_str).hexdigest()
def new_transaction(self, sender: str, receiver: str, amount: int) -> int: # 創建交易
transaction = {
"sender": sender,
"receiver": receiver,
"amount": amount,
}
self.current_transactions.append(transaction)
return self.last_block["index"] + 1 # 索引標記交易的數量
@property
def last_block(self) -> Dict[str, Any]:
return self.chain[-1]
def proof_of_work(self, last_proof: int) -> int: # 工作量證明
proof = 0
while self.valid_proof(last_proof, proof) is False:
proof += 1
return proof
@staticmethod
def valid_proof(last_proof: int, proof: int) -> bool: # 驗證證明
guess = f'{last_proof*proof}'.encode("utf-8")
guess_hash = hashlib.sha256(guess).hexdigest()
return guess_hash[-4:] == "1234"
def register_node(self, addr: str) -> None: # 加入網絡的其他節點，用於更新
now_url = urlparse(addr)
self.nodes.add(now_url.netloc) # 增加網絡節點
pass
def valid_chain(self, chain: List[Dict[str, Any]]) -> bool: # 區塊鏈校驗
last_block = self.chain[0]
current_index = 1
while current_index < len(self.chain):
block = self.chain[current_index]
# 哈希校驗
if block["preHash"] != self.hash(last_block):
return False
# 工作量校驗
if not self.valid_proof(last_block["proof"], block["proof"]):
return False
last_block = block
current_index += 1
return True
def resolve_conflict(self) -> bool: # 同步區塊鏈
neighbours = self.nodes
new_chain = None
max_length = len(self.chain)
for node in neighbours:
response = requests.post(f'http://{node}/chain')
if response.status_code == 200:
chain = response.json()["chain"]
length = response.json()["length"]
if length > max_length and self.valid_chain(chain):
max_length = length
new_chain = chain
if new_chain:
self.chain = new_chain
return True
else:
return False
datacoin = DadaCoinBlockChain() # 創建一個網絡節點
node_id = str(uuid4()).replace("-", "") # 生成錢包地址
print("當前節點錢包地址：", node_id)
app = Flask(__name__) # 初始化
# 首頁
@app.route("/", methods=["POST"])
def index_page():
return "歡迎來到大大幣系統，你好小韭菜"
# 獲取區塊鏈
@app.route("/chain", methods=["POST"])
def index_chain():
response = {
"chain": datacoin.chain, # 區塊鏈
"length": len(datacoin.chain),
}
return jsonify(response), 200
# 創建新的交易
@app.route("/new_transaction", methods=["POST"])
def new_transaction():
values = request.get_json()
print("values:", values)
required = ["sender", "receiver", "amount"]
if not all(key in values for key in required):
return "數據不完整", 400
index = datacoin.new_transaction(values["sender"], values["receiver"], values["amount"])
response = {
"message": f'交易加入到區塊{index}',
}
return jsonify(response), 200
# 挖礦
@app.route("/mine", methods=["POST"])
def index_mine():
last_block = datacoin.last_block
last_proof = last_block["proof"]
proof = datacoin.proof_of_work(last_proof) # 挖礦計算
# 系統獎勵，挖礦產生交易
datacoin.new_transaction(sender="0", receiver=node_id, amount=10)
block = datacoin.new_block(proof, None) # 增加一個區塊
response = {
"message": "新的區塊創建",
"index": block["index"],
"transactions": block["transactions"],
"proof": block["proof"],
"preHash": block["preHash"],
}
return jsonify(response), 200
# 新增節點
@app.route("/new_node", methods=["POST"])
def new_node():
values = request.get_json()
nodes = values.get("nodes")
if nodes is None:
return "你妹的啥數據", 400
for node in nodes:
datacoin.register_node(node)
response = {
"message": f'網絡節點已被追加',
"nodes": list(datacoin.nodes),
}
return jsonify(response), 200
# 刷新節點
@app.route("/node_refresh", methods=["POST"])
def node_refresh():
replaced = datacoin.resolve_conflict() # 共識算法進行最長替換
if replaced:
response = {
"message": "區塊鏈已被替換爲最長", # 區塊鏈
"new_chain": datacoin.chain,
}
pass
else:
response = {
"message": "當前區塊鏈已是最長，無需替換", # 區塊鏈
"new_chain": datacoin.chain,
}
return jsonify(response), 200
if __name__ == "__main__":
app.run("127.0.0.1", port=5000)
這裏複製三份代碼，端口分別是5000,5002,5003，代表三個節點，全部啓動。
1,5000節點，挖礦6個區塊，5002挖礦2個區塊，5003挖礦3個區塊
2,5002添加兩個節點,
{
"nodes": ["http://127.0.0.1:5000","http://127.0.0.1:5003"]
}5003添加兩個節點
{
"nodes": ["http://127.0.0.1:5000","http://127.0.0.1:5002"]
}
3,節點同步，
順利完成前面的功能測試，這部分的開發就完成了