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| 1 | +import hashlib |
| 2 | +import json |
| 3 | +from time import time |
| 4 | +from urllib.parse import urlparse |
| 5 | +from uuid import uuid4 |
| 6 | +from collections import OrderedDict |
| 7 | + |
| 8 | +from block import Block |
| 9 | +from transaction import Transaction |
| 10 | +from wallet import Wallet |
| 11 | +from node import Node |
| 12 | + |
| 13 | +""" |
| 14 | +Lq je reçois une transaction je dois la validera avant de l'enregister dans mon block. |
| 15 | +Lq je créé une transaction, c'est différent. |
| 16 | +""" |
| 17 | + |
| 18 | +""" |
| 19 | +Our Blockchain class is responsible for managing the chain. It will store transactions and have some helper methods for adding new blocks to the chain. |
| 20 | +""" |
| 21 | + |
| 22 | +MINING_SENDER = "THE BLOCKCHAIN" |
| 23 | + |
| 24 | + |
| 25 | +class Blockchain(): |
| 26 | + |
| 27 | + def __init__(self): |
| 28 | + self.current_transactions = [] |
| 29 | + self.chain = [] |
| 30 | + self.nodes = set() |
| 31 | + |
| 32 | + # Create the genesis block |
| 33 | + self.new_block(100, '1') |
| 34 | + |
| 35 | + def register_node(self, node): |
| 36 | + """ |
| 37 | + Add a new node to the list of nodes. |
| 38 | + """ |
| 39 | + if not isinstance(node, Node): |
| 40 | + raise ValueError('node parameter should be a Node instance.') |
| 41 | + |
| 42 | + self.nodes.add(node) |
| 43 | + |
| 44 | + @property |
| 45 | + def last_block(self): |
| 46 | + return self.chain[-1] |
| 47 | + |
| 48 | + def submit_transaction(self, transaction, signature): |
| 49 | + """ |
| 50 | + Add a transaction to transactions array if the signature verified |
| 51 | + Return index of block that the transaction will be. |
| 52 | + """ |
| 53 | + if not isinstance(transaction, Transaction): |
| 54 | + raise ValueError( |
| 55 | + 'transaction parameter should be a Transaction instance.') |
| 56 | + |
| 57 | + transaction_verification = transaction.verify_signature(signature) |
| 58 | + |
| 59 | + if transaction_verification: |
| 60 | + self.current_transactions.append(transaction) |
| 61 | + return len(self.chain) + 1 |
| 62 | + |
| 63 | + return False |
| 64 | + |
| 65 | + def new_block(self, nonce, previous_hash): |
| 66 | + """ |
| 67 | + Create a new Block in the Blockchain |
| 68 | + :param nonce: The nonce given by the Proof of Work algorithm |
| 69 | + :param previous_hash: Hash of previous Block |
| 70 | + :return: New Block |
| 71 | + """ |
| 72 | + |
| 73 | + # Why we have this OR condition? Seems useless. |
| 74 | + block = Block(nonce, self.current_transactions, len(self.chain) + |
| 75 | + 1, previous_hash or Block.hash(self.chain[-1])) |
| 76 | + |
| 77 | + # Reset the current list of transactions |
| 78 | + self.current_transactions = [] |
| 79 | + |
| 80 | + self.chain.append(block) |
| 81 | + return block |
| 82 | + |
| 83 | + def valid_chain(self, chain): |
| 84 | + """ |
| 85 | + Determine if a given blockchain is valid |
| 86 | + :param chain: A blockchain |
| 87 | + :return: True if valid, False if not |
| 88 | + """ |
| 89 | + |
| 90 | + last_block = chain[0] |
| 91 | + |
| 92 | + current_index = 1 |
| 93 | + lenChain = len(chain) |
| 94 | + |
| 95 | + while current_index < lenChain: |
| 96 | + current_block = chain[current_index] |
| 97 | + |
| 98 | + # Check with last_block & current_block |
| 99 | + |
| 100 | + print(f'{last_block}') |
| 101 | + print(f'{current_block}') |
| 102 | + print("\n-----------\n") |
| 103 | + |
| 104 | + # Check that the hash of the block is correct |
| 105 | + last_block_hash = Block.hash(last_block) |
| 106 | + if current_block['previous_hash'] != last_block_hash: |
| 107 | + return False |
| 108 | + |
| 109 | + # Check that the Proof of Work is correct |
| 110 | + if not Block.valid_proof(last_block['proof'], current_block['proof'], last_block_hash): |
| 111 | + return False |
| 112 | + |
| 113 | + last_block = current_block |
| 114 | + current_index += 1 |
| 115 | + |
| 116 | + return True |
| 117 | + |
| 118 | + def mine(self): |
| 119 | + """ |
| 120 | + Take the last Block, mine it and add it to the Blockchain. |
| 121 | + """ |
| 122 | + # We run the proof of work algorithm to get the next proof... |
| 123 | + last_block = self.last_block |
| 124 | + |
| 125 | + nonce = Block.proof_of_work(last_block) |
| 126 | + |
| 127 | + # @TODO |
| 128 | + # We must receive a reward for finding the proof. |
| 129 | + # The sender is "0" to signify that this node has mined a new coin. |
| 130 | + # blockchain.new_transaction( |
| 131 | + # sender=MINING_SENDER, |
| 132 | + # recipient=node_identifier, |
| 133 | + # amount=1, |
| 134 | + # ) |
| 135 | + |
| 136 | + # Forge the new Block by adding it to the chain |
| 137 | + previous_hash = Block.hash(last_block) |
| 138 | + block = self.new_block(nonce, previous_hash) |
| 139 | + |
| 140 | + response = { |
| 141 | + 'message': "New Block Forged", |
| 142 | + 'index': block.index, |
| 143 | + 'transactions': block.transactions, |
| 144 | + 'nonce': block.nonce, |
| 145 | + 'previous_hash': block.previous_hash, |
| 146 | + } |
| 147 | + |
| 148 | + return response |
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