77 lines
2.1 KiB
Python
77 lines
2.1 KiB
Python
"""This file contains the class for the Blockchain."""
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from block import Block
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class Blockchain:
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"""docstring for Blockchain"""
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def __init__(self):
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self.chain = []
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self.all_transactions = []
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self.genesis_block()
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def genesis_block(self):
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"""First block of the Blockchain"""
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transactions = {}
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genesis_block = Block(transactions, '0')
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self.chain.append(genesis_block)
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return self.chain
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def print_blocks(self):
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"""Print contents of blockchain."""
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for i, current_block in enumerate(self.chain):
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print('=====')
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print(f'Block {i} {current_block}')
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current_block.print_block()
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print('=====')
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print()
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def add_block(self, transactions):
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"""Add a block to the blockchain's chain."""
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previous_block_hash = self.chain[-1].hash
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new_block = Block(transactions, previous_block_hash)
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proof = self.proof_of_work(new_block)
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new_block.proof = proof
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self.chain.append(new_block)
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return new_block
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def validate_chain(self):
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"""Check to see if blocks are linked to each other properly."""
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for i in range(1, len(self.chain)):
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current = self.chain[i]
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previous = self.chain[i - 1]
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if current.hash != current.generate_hash():
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print('WARNING!! The current hash of the block does not equal '
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'the generated hash of the block!!!')
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return False
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if current.previous_hash != previous.generate_hash():
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print('WARNING!! The previous hash of the block does not equal'
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' the generated hash of the previous block!!!')
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return False
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print('Blockchain is valid!')
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return True
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def proof_of_work(self, block, difficulty=2):
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"""Implement a proof of work in the blockchain."""
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proof = block.hash
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while not proof.startswith('0' * difficulty):
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block.nonce += 1
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proof = block.generate_hash()
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block.nonce = 0
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return proof
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