pip install django requests

class Blockchain(object):
  def __init__(self):
    self.chain = []
    self.current_transactions = []
  def new_block(self):
    # Creates a new Block and adds it to the chain
    pass
  def new_transaction(self):
    # Adds a new transaction to the list of transactions
    pass
  @staticmethod
  def hash(block):
    # Hashes a Block
    pass
  @property
  def last_block(self):
    # Returns the last Block in the chain
    pass

block = {
  'index': 1,
  'timestamp': 1506057125.900785,
  'transactions': [
    {
      'sender': "8527147fe1f5426f9dd545de4b27ee00",
      'recipient': "a77f5cdfa2934df3954a5c7c7da5df1f",
      'amount': 5,
    }
  ],
  'proof': 324984774000,
  'previous_hash': "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824"
}

class Blockchain(object):
  ...
  def new_transaction(self, sender, recipient, amount):
    """
    生成新交易信息，信息將加入到下一個(gè)待挖的區(qū)塊中
    :param sender: <str> Address of the Sender
    :param recipient: <str> Address of the Recipient
    :param amount: <int> Amount
    :return: <int> The index of the Block that will hold this transaction
    """
    self.current_transactions.append({
      'sender': sender,
      'recipient': recipient,
      'amount': amount,
    })
    return self.last_block['index'] + 1

class Blockchain(object):
  def __init__(self):
    self.chain = []
    self.current_transactions = []
    self.new_block(previous_hash=1, proof=100)
    self.nodes = set()
  def new_block(self,proof,previous_hash= None):
    block = {
      'index': len(self.chain) + 1,
      'timestamp': time(),
      'transactions': self.current_transactions,
      'proof':proof ,
      'previous_hash': previous_hash or self.hash(self.chain[-1]),
    }
    self.current_transactions = []
    self.chain.append(block)
    return block
  def new_transaction(self,sender,recipient,amount):
    self.current_transactions.append({
      'sender': sender,
      'recipient': recipient,
      'amount': amount,
    })
    return self.last_block['index']+1
  @staticmethod
  def hash(block):
    block_string = json.dumps(block, sort_keys=True).encode()
    return hashlib.sha256(block_string).hexdigest()

from hashlib import sha256
x = 5
y = 0
while sha256(str(x*y).encode()).hexdigest()[:4] != "0000":
   y += 1
   print(y,sha256(str(x*y).encode()).hexdigest()[:4])
print(y)

import hashlib
import json
from time import time
from uuid import uuid4
class Blockchain(object):
  ...
  def last_block(self):
    return self.chain[-1]
  def proof_of_work(self, last_proof):
    proof = 0
    while self.valid_proof(last_proof, proof) is False:
      proof += 1
    return proof
  @staticmethod
  def valid_proof(last_proof, proof):
    guess = str(last_proof*proof).encode()
    guess_hash = hashlib.sha256(guess).hexdigest()
    return guess_hash[:5] == "00000"

/transactions/new 創(chuàng)建一個(gè)交易并添加到區(qū)塊
/mine 告訴服務(wù)器去挖掘新的區(qū)塊
/chain 返回整個(gè)區(qū)塊鏈

node_identifier = str(uuid4()).replace('-', '')
# Instantiate the Blockchain
blockchain = Blockchain()
def mine(request):
  last_block = blockchain.last_block
  last_proof = last_block['proof']
  proof = blockchain.proof_of_work(last_proof)
  print(proof)
  blockchain.new_transaction(
     sender="0",
     recipient=node_identifier,
     amount=1,
   )
   # Forge the new Block by adding it to the chain
  block = blockchain.new_block(proof)
  response = {
     'message': "New Block Forged",
     'index': block['index'],
     'transactions': block['transactions'],
     'proof': block['proof'],
     'previous_hash': block['previous_hash'],
  }
  print(response)
  return HttpResponse(json.dumps(response))
def new_transaction(request):
  values = json.loads(request.body.decode('utf-8'))
  required = ['sender', 'recipient', 'amount']
  if not all(k in values for k in required):
    return 'Missing values'
  index = blockchain.new_transaction(values['sender'], values['recipient'], values['amount'])
  print(index)
  response = {'message': 'Transaction will be added to Block %s'%index}
  return HttpResponse(json.dumps(response))
def full_chain(request):
  response = {
    'chain': blockchain.chain,
    'length': len(blockchain.chain),
  }
  return HttpResponse(json.dumps(response))

from demo import views
urlpatterns = [
  url(r'^admin/', admin.site.urls),
  url(r'^mine', views.mine),
  url(r'^transactions/new/', views.new_transaction),
  url(r'^chain/', views.full_chain),
  url(r'^register', views.register_nodes),
  url(r'^resolve', views.consensus),
]

python manage.py runserver 127.0.0.1:8000

{
 "sender": "my address",
 "recipient": "someone else's address",
 "amount": 5
}

def proof_of_work(self, last_proof):
    proof = 0
    while self.valid_proof(last_proof, proof) is False:
      proof += 1
    return proof
  @staticmethod
  def valid_proof(last_proof, proof):
    guess = str(last_proof*proof).encode()
    guess_hash = hashlib.sha256(guess).hexdigest()
    return guess_hash[:5] == "00000"

{  "chain": [
    {
      "transactions": [],
      "proof": 100,
      "timestamp": 1520314374.7261052,
      "index": 1,
      "previous_hash": 1
    },
    {
      "transactions": [
        {
          "sender": "0",
          "recipient": "27d4aae55b2848dcae52bc722d86e0c3",
          "amount": 1
        }
      ],
      "proof": 1771087,
      "timestamp": 1520314389.5019505,
      "index": 2,
      "previous_hash": "32fa73f48240160257e95fdf8422c6df734b5d7e8ceb69a41a5578643c1d36fb"
    },
    {
      "transactions": [
        {
          "sender": "d4ee26eee15148ee92c6cd394edd9705",
          "recipient": "5",
          "amount": 500
        },
        {
          "sender": "0",
          "recipient": "27d4aae55b2848dcae52bc722d86e0c3",
          "amount": 1
        }
      ],
      "proof": 100,
      "timestamp": 1520314592.4745598,
      "index": 3,
      "previous_hash": "e6b1be488e0ed20fe3ec51135e5fafb4dfffaa28a190967106a5dd3e89e4b3aa"
    }
  ],
  "length": 3
}

/register 接收URL形式的新節(jié)點(diǎn)列表
/resolve 執(zhí)行一致性算法，解決任何沖突，確保節(jié)點(diǎn)擁有正確的鏈

from urllib.parse import urlparse
...
class Blockchain(object):
  def __init__(self):
    ...
    self.nodes = set()
    ...
  def register_node(self, address):
    parsed_url = urlparse(address)
    self.nodes.add(parsed_url.netloc)

class Blockchain(object):
  def __init__(self):
    ...
  def valid_chain(self, chain):
    last_block = chain[0]
    current_index = 1
    while current_index < len(chain):
      block = chain[current_index]
      if block['previous_hash'] != self.hash(last_block):
        return False
      # Check that the Proof of Work is correct
      if not self.valid_proof(last_block['proof'], block['proof']):
        return False
      last_block = block
      current_index += 1
    return True
  def resolve_conflicts(self):
    neighbours = self.nodes
    new_chain = None
    max_length = len(self.chain)
    for node in neighbours:
      response = requests.get('http://%s/chain' %node)
      if response.status_code == 200:
        length = json.loads(response)['length']
        chain = json.loads(response)['chain']
        # Check if the length is longer and the chain is valid
        if length > max_length and self.valid_chain(chain):
          max_length = length
          new_chain = chain
    # Replace our chain if we discovered a new, valid chain longer than ours
    if new_chain:
      self.chain = new_chain
      return True
    return False

from demo import views
urlpatterns = [
  url(r'^register', views.register_nodes),
  url(r'^resolve', views.consensus),
]