def receive_advertise_block():
jsn = request.get_json()
if "block_id" not in jsn or "peer" not in jsn:
return "Invalid request", 404
block_id = jsn.get('block_id')
if block_id <= blockchain.last_block.index:
return json.dumps({"error ": "error"})
if block_id not in blockchain.received_block_advertises:
data = {"block_id": block_id, "peer": "http://localhost:" + str(PORT)}
headers = {'Content-Type': "application/json"}
requested_block = requests.post(jsn["peer"] + '/request_block',
data=json.dumps(data),
headers=headers).json()
block = Block(
index=requested_block['index'],
transactions=requested_block['transactions'],
proof_of_verification=requested_block['proof_of_verification'],
timestamp=requested_block['timestamp'],
previous_hash=requested_block['previous_hash'])
block.hash = requested_block['hash']
verified = utils.is_valid_block(block.__dict__)
if not verified:
return json.dumps({"error ": "error"})
for transaction in block.transactions:
if transaction in blockchain.transactions:
del blockchain.transactions[transaction]
assert (requested_block["index"] == block_id)
blockchain.pending_blocks[block_id] = block
blockchain.pending_blocks_counts[block_id] = 1
blockchain.received_block_advertises.add(block_id)
for peer in blockchain.peers:
requests.post(peer + '/receive_adv_block',
data=json.dumps(data),
headers=headers)
else:
blockchain.pending_blocks_counts[block_id] += 1
if (blockchain.pending_blocks_counts[block_id] >=
(len(blockchain.peers) + 1) // 2):
if block_id in blockchain.pending_blocks:
blockchain.add_block(blockchain.pending_blocks[block_id])
del blockchain.pending_blocks[block_id]
return str(block_id)
else:
return json.dumps({"error ": "error"})
else:
return json.dumps({"error ": "error"})
def create_chain_from_dump(chain_dump):
blockchain = Blockchain(PORT)
for idx, block_data in enumerate(chain_dump):
block = Block(
block_data["index"],
block_data["transactions"],
block_data["proof_of_verification"],
block_data["timestamp"],
block_data["previous_hash"],
)
block.hash = block_data["hash"]
if idx > 0:
verified = utils.is_valid_block(block.__dict__)
added = blockchain.add_block(block, clone_mode=True)
if not added:
raise Exception("The chain dump is tampered!!")
else: # the block is a genesis block, no verification needed
blockchain.chain.append(block)
return blockchain
def add_block(self, block, clone_mode=False):
if (block.previous_hash != self.last_block.hash):
return False
if not utils.is_valid_block(block.__dict__):
return False
if block.index <= self.last_block.index:
return True
self.chain.append(block)
if clone_mode:
return True
next_index = block.index + 1
while next_index in self.pending_blocks_counts:
if (self.pending_blocks_counts[next_index] >=
(len(self.peers) + 1) // 2):
self.chain.append(block)
next_index += 1
else:
break
return True