Blockchain - Iteración 0

iteracion0.py

# Copyright 2020 Carlos Castro Martos
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
# THE SOFTWARE.

import hashlib
import json
import time

class Block:
    def __init__(self, height, timestamp, data, prev_hash):
        self.height = height
        self.timestamp = timestamp
        self.data = data
        self.prev_hash = prev_hash
        self.hash = self.make_hash()

    def make_hash(self):
        th = hashlib.sha256()
        s = str(self.height) + str(self.timestamp) + str(self.data) + str(self.prev_hash)
        bs = bytes(s, 'utf-8')
        th.update(bs)
        return th.digest().hex()
    
    def __repr__(self):
        return json.dumps(self.__dict__)


if __name__ == "__main__":
    b0 = Block(0, time.time(), 'genesis', 0)
    b1 = Block(1, time.time(), 'primero', b0.hash)
    b2 = Block(2, time.time(), 'segundo', b1.hash)
    blockchain = [b0, b1, b2]
    for b in blockchain:
        print(b)