diff options
| -rw-r--r-- | users/wpcarro/scratch/blockchain/default.nix | 13 | ||||
| -rw-r--r-- | users/wpcarro/scratch/blockchain/main.py | 263 | ||||
| -rw-r--r-- | users/wpcarro/scratch/blockchain/setup.py | 10 |
3 files changed, 286 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/blockchain/default.nix b/users/wpcarro/scratch/blockchain/default.nix new file mode 100644 index 000000000000..745e7a5ab490 --- /dev/null +++ b/users/wpcarro/scratch/blockchain/default.nix @@ -0,0 +1,13 @@ +{ pkgs, ... }: + +let + pypkgs = pkgs.python3Packages; +in pkgs.python3Packages.buildPythonApplication { + pname = "main"; + src = ./.; + version = "0.0.1"; + propagatedBuildInputs = with pypkgs; [ + flask + requests + ]; +} diff --git a/users/wpcarro/scratch/blockchain/main.py b/users/wpcarro/scratch/blockchain/main.py new file mode 100644 index 000000000000..e7b627613389 --- /dev/null +++ b/users/wpcarro/scratch/blockchain/main.py @@ -0,0 +1,263 @@ +from flask import Flask, jsonify, request +from hashlib import sha256 +from datetime import datetime +from urllib.parse import urlparse + +import json +import requests +import uuid + +################################################################################ +# Helper Functions +################################################################################ + +def hash(x): + return sha256(x).hexdigest() + +def is_pow_valid(guess, prev_proof): + """ + Return true if the hash of `guess` + `prev_proof` has 4x leading zeros. + """ + return hash(str(guess + prev_proof).encode("utf8"))[:4] == "0000" + +################################################################################ +# Classes +################################################################################ + +class Node(object): + def __init__(self, host="0.0.0.0", port=8000): + self.app = Flask(__name__) + self.define_api() + self.identifier = str(uuid.uuid4()) + self.blockchain = Blockchain() + self.neighbors = set() + + def add_neighbors(self, urls=None): + for url in urls: + parsed = urlparse(url) + if not parsed.netloc: + raise ValueError("Must pass valid URLs for neighbors") + self.neighbors.add(parsed.netloc) + + def decode_chain(chain_json): + return Blockchain( + blocks=[ + Block( + index=block["index"], + ts=block["ts"], + transactions=[ + Transaction( + origin=tx["origin"], + target=tx["target"], + amount=tx["amount"]) + for tx in block["ts"] + ], + proof=block["proof"], + prev_hash=block["prev_hash"]) + for block in chain_json["blocks"] + ], + transactions=[ + Transaction( + origin=tx["origin"], + target=tx["target"], + amount=tx["amount"]) + for tx in chain_json["transactions"] + ]) + + def resolve_conflicts(self): + auth_chain, auth_length = self.blockchain, len(self.blockchain) + + for neighbor in self.neighbors: + res = requests.get(f"http://{neighbor}/chain") + if res.status_code == 200 and res.json()["length"] > auth_length: + decoded_chain = decode_chain(res.json()["chain"]) + if Blockchain.is_valid(decoded_chain): + auth_length = res.json()["length"] + auth_chain = decoded_chain + + self.blockchain = auth_chain + + def define_api(self): + def msg(x): + return jsonify({"message": x}) + + ############################################################################ + # / + ############################################################################ + + @self.app.route("/healthz", methods={"GET"}) + def healthz(): + return "ok" + + @self.app.route("/reset", methods={"GET"}) + def reset(): + self.blockchain = Blockchain() + return msg("Success") + + @self.app.route("/mine", methods={"GET"}) + def mine(): + # calculate POW + proof = self.blockchain.prove_work() + + # reward miner + self.blockchain.add_transaction( + origin="0", # zero signifies that this is a newly minted coin + target=self.identifier, + amount=1) + + # publish new block + self.blockchain.add_block(proof=proof) + return msg("Success") + + ############################################################################ + # /transactions + ############################################################################ + + @self.app.route("/transactions/new", methods={"POST"}) + def new_transaction(): + payload = request.get_json() + + self.blockchain.add_transaction( + origin=payload["origin"], + target=payload["target"], + amount=payload["amount"]) + return msg("Success") + + ############################################################################ + # /blocks + ############################################################################ + + @self.app.route("/chain", methods={"GET"}) + def view_blocks(): + return jsonify({ + "length": len(self.blockchain), + "chain": self.blockchain.dictify(), + }) + + ############################################################################ + # /nodes + ############################################################################ + @self.app.route("/node/neighbors", methods={"GET"}) + def view_neighbors(): + return jsonify({"neighbors": list(self.neighbors)}) + + @self.app.route("/node/register", methods={"POST"}) + def register_nodes(): + payload = request.get_json()["neighbors"] + payload = set(payload) if payload else set() + self.add_neighbors(payload) + return msg("Success") + + @self.app.route("/node/resolve", methods={"GET"}) + def resolve_nodes(): + self.resolve_conflicts() + return msg("Success") + + def run(self): + self.app.run(host="0.0.0.0", port=8000) + + +class Blockchain(object): + def __init__(self, blocks=None, transactions=None): + self.blocks = blocks or [] + self.transactions = transactions or [] + self.add_block() + + def __len__(self): + return len(self.blocks) + + def __iter__(self): + for block in self.blocks: + yield block + + def prove_work(self): + guess, prev_proof = 0, self.blocks[-1].proof or 0 + while not is_pow_valid(guess, prev_proof): + guess += 1 + return guess + + def add_block(self, prev_hash=None, proof=None): + b = Block( + index=len(self), + transactions=self.transactions, + prev_hash=self.blocks[-1].hash() if self.blocks else None, + proof=proof) + self.blocks.append(b) + return b + + def adopt_blocks(self, json_blocks): + pass + + def add_transaction(self, origin=None, target=None, amount=None): + tx = Transaction(origin=origin, target=target, amount=amount) + self.transactions.append(tx) + + @staticmethod + def is_valid(chain): + prev_block = next(chain) + + for block in chain: + if block.prev_hash != prev_block.hash() or not is_pow_valid(prev_block.proof, block.proof): + return False + prev_block = block + + return True + + def dictify(self): + return { + "blocks": [block.dictify() for block in self.blocks], + "transactions": [tx.dictify() for tx in self.transactions], + } + + +class Block(object): + def __init__(self, index=None, ts=None, transactions=None, proof=None, prev_hash=None): + self.index = index + self.ts = ts or str(datetime.now()) + self.transactions = transactions + self.proof = proof + self.prev_hash = prev_hash + + def hash(self): + return sha256(self.jsonify().encode()).hexdigest() + + def dictify(self): + return { + "index": self.index, + "ts": self.ts, + "transactions": [tx.dictify() for tx in self.transactions], + "proof": self.proof, + "prev_hash": self.prev_hash, + } + + def jsonify(self): + return json.dumps(self.dictify(), sort_keys=True) + +class Transaction(object): + def __init__(self, origin=None, target=None, amount=None): + if None in {origin, target, amount}: + raise ValueError("To create a Transaction, you must provide origin, target, and amount") + + self.origin = origin + self.target = target + self.amount = amount + + def dictify(self): + return { + "origin": self.origin, + "target": self.target, + "amount": self.amount, + } + + def jsonify(self): + return json.dumps(self.dictify(), sort_keys=True) + +################################################################################ +# Main +################################################################################ + +def run(): + Node(host="0.0.0.0", port=8000).run() + +if __name__ == "__main__": + run() diff --git a/users/wpcarro/scratch/blockchain/setup.py b/users/wpcarro/scratch/blockchain/setup.py new file mode 100644 index 000000000000..e5310565dbbd --- /dev/null +++ b/users/wpcarro/scratch/blockchain/setup.py @@ -0,0 +1,10 @@ +from setuptools import setup + +setup( + name='main', + version='0.0.1', + py_modules=['main'], + entry_points={ + 'console_scripts': ['main = main:run'] + }, +) |