Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- import datetime
- import hashlib
- import json
- from flask import Flask, jsonify
- # Building a Blockchain
- class Blockchain:
- def __init__(self):
- self.chain = []
- self.create_block(proof = 1, previous_hash = '0')
- def create_block(self, proof, previous_hash):
- block = {'index': len(self.chain) + 1,
- 'timestamp': str(datetime.datetime.now()),
- 'proof': proof,
- 'previous_hash': previous_hash}
- self.chain.append(block)
- return block
- def get_previous_block(self):
- return self.chain[-1]
- def proof_of_work(self, previous_proof):
- new_proof = 1
- check_proof = False
- while check_proof is False:
- hash_operation = hashlib.sha256(str(new_proof**2 - previous_proof**2).encode()).hexdigest()
- if hash_operation[:4] == '0000':
- check_proof = True
- else:
- new_proof += 1
- return new_proof
- def hash(self, block):
- encoded_block = json.dumps(block, sort_keys = True).encode()
- return hashlib.sha256(encoded_block).hexdigest()
- def is_chain_valid(self, chain):
- previous_block = chain[0]
- block_index = 1
- while block_index < len(chain):
- block = chain[block_index]
- if block['previous_hash'] != self.hash(previous_block):
- return False
- previous_proof = previous_block['proof']
- proof = block['proof']
- hash_operation = hashlib.sha256(str(proof**2 - previous_proof**2).encode()).hexdigest()
- if hash_operation[:4] != '0000':
- return False
- previous_block = block
- block_index += 1
- return True
- # Mining our Blockchain
- # Creating a Web App
- app = Flask(__name__)
- # Creating a Blockchain
- blockchain = Blockchain()
- # Mining a new block
- @app.route('/mine_block', methods = ['GET'])
- def mine_block():
- previous_block = blockchain.get_previous_block()
- previous_proof = previous_block['proof']
- proof = blockchain.proof_of_work(previous_proof)
- previous_hash = blockchain.hash(previous_block)
- block = blockchain.create_block(proof, previous_hash)
- response = {'message': 'Block Mined Successfully!',
- 'index': block['index'],
- 'timestamp': block['timestamp'],
- 'proof': block['proof'],
- 'previous_hash': block['previous_hash']}
- return jsonify(response), 200
- # 200 is the HTTP status code here and 200 is the code for SUCCESS here
- # Getting the full Blockchain
- @app.route('/get_chain', methods = ['GET'])
- def get_chain():
- response = {'chain': blockchain.chain,
- 'length': len(blockchain.chain)}
- print('here')
- return jsonify(response), 200
- # Running the app
- app.run(host = '0.0.0.0', port = 5000)
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement