2.6 共识机制

def resolve_conflicts(self):
neighbours = self.nodes

max_len = len(self.chain)
new_chain = None

for node in neighbours:
# 遍历邻居节点，获取他们的链信息
response = requests.get(f'http://{node}/chain')
if response.status_code == 200:
length = response.json()['length']
chain = response.json()['chain']

if len(chain) > max_len and self._valid_chain(chain):
max_len = length
new_chain = chain

if not new_chain:
return False

self.chain = new_chain
return True
def _valid_chain(self, chain):
last_block = chain[0]
current_index = 1
以此遍历链上的每一个节点
while current_index < len(chain):
block = chain[current_index]
# 如果某个节点保存的上一个节点的hash值不正确，则校验不通过
if block['previous_hash'] != self.hash(last_block):
return False

# 如果某个节点不能通过工作量证明，则校验不通过
if not self._valid_proof(last_block['proof'], block['proof']):
return False

last_block = block
current_index += 1

return True

@web.route('/node/resolve', methods=['GET'])
def consensus():
replaced = block_chain.resolve_conflicts()

if replaced:
response = {
'message': 'Our chain was replaced',
'new_chain': block_chain.chain
}
else:
response = {
'message': 'Our chain is authoritative',
'chain': block_chain.chain
}

return jsonify(response)