Day One MVP

basic_block_gp/blockchain.py

@@ -93,8 +93,12 @@ def proof_of_work(self, block):
         :return: A valid proof for the provided block
         """
         # TODO
-        pass
-        # return proof
+        proof = 0
+
+        while self.valid_proof(block, proof) is False:
+            proof += 1
+
+        return proof
 
     @staticmethod
     def valid_proof(block_string, proof):
@@ -109,8 +113,13 @@ def valid_proof(block_string, proof):
         :return: True if the resulting hash is a valid proof, False otherwise
         """
         # TODO
-        pass
+        guess = f'{block_string}{proof}'.encode()
+        guess_hash = hashlib.sha256(guess).hexdigest()
+
+        # return guess_hash[:6] == "000000"
         # return True or False
+        result = True if guess_hash[:6] == "000000" else False
+        return result
 
     def valid_chain(self, chain):
         """
@@ -131,9 +140,13 @@ def valid_chain(self, chain):
             print("\n-------------------\n")
             # Check that the hash of the block is correct
             # TODO: Return false if hash isn't correct
+            if block['previous_hash'] != self.hash(prev_block):
+                return False
 
             # Check that the Proof of Work is correct
             # TODO: Return false if proof isn't correct
+            if not self.valid_proof(prev_block['proof'], block['proof']):
+                return False
 
             prev_block = block
             current_index += 1
@@ -154,16 +167,23 @@ def valid_chain(self, chain):
 @app.route('/mine', methods=['GET'])
 def mine():
     # We run the proof of work algorithm to get the next proof...
-    proof = blockchain.proof_of_work()
+    last_block = blockchain.last_block
+    last_proof = last_block['proof']
+    proof = blockchain.proof_of_work(last_proof)
 
     # We must receive a reward for finding the proof.
     # TODO:
     # The sender is "0" to signify that this node has mine a new coin
     # The recipient is the current node, it did the mining!
     # The amount is 1 coin as a reward for mining the next block
+    blockchain.new_transaction(
+        sender='0',
+        recipient=node_identifier,
+        amount =1)
 
     # Forge the new Block by adding it to the chain
     # TODO
+    block = blockchain.new_block(proof, blockchain.hash(blockchain.last_block))
 
     # Send a response with the new block
     response = {
@@ -198,6 +218,8 @@ def new_transaction():
 def full_chain():
     response = {
         # TODO: Return the chain and its current length
+        'currentChain': blockchain.chain,
+        'length': len(blockchain.chain)
     }
     return jsonify(response), 200
 

client_mining_p/blockchain.py

@@ -1,2 +1,230 @@
-# Paste your version of blockchain.py from the basic_block_gp
-# folder here
+import hashlib
+import json
+from time import time
+from uuid import uuid4
+
+from flask import Flask, jsonify, request
+
+
+class Blockchain(object):
+    def __init__(self):
+        self.chain = []
+        self.current_transactions = []
+        self.nodes = set()
+
+        self.new_block(previous_hash=1, proof=100)
+
+    def new_block(self, proof, previous_hash=None):
+        """
+        Create a new Block in the Blockchain
+
+        :param proof: <int> The proof given by the Proof of Work algorithm
+        :param previous_hash: (Optional) <str> Hash of previous Block
+        :return: <dict> New Block
+        """
+
+        block = {
+            'index': len(self.chain) + 1,
+            'timestamp': time(),
+            'transactions': self.current_transactions,
+            'proof': proof,
+            'previous_hash': previous_hash or self.hash(self.chain[-1]),
+        }
+
+        # Reset the current list of transactions
+        self.current_transactions = []
+
+        self.chain.append(block)
+        return block
+
+    def new_transaction(self, sender, recipient, amount):
+        """
+        Creates a new transaction to go into the next mined Block
+
+        :param sender: <str> Address of the Recipient
+        :param recipient: <str> Address of the Recipient
+        :param amount: <int> Amount
+        :return: <int> The index of the BLock that will hold this transaction
+        """
+
+        self.current_transactions.append({
+            'sender': sender,
+            'recipient': recipient,
+            'amount': amount,
+        })
+
+        return self.last_block['index'] + 1
+
+    @staticmethod
+    def hash(block):
+        """
+        Creates a SHA-256 hash of a Block
+
+        :param block": <dict> Block
+        "return": <str>
+        """
+
+
+        # json.dumps converts json into a string
+        # hashlib.sha246 is used to createa hash
+        # It requires a `bytes-like` object, which is what
+        # .encode() does.  It convertes the string to bytes.
+        # We must make sure that the Dictionary is Ordered,
+        # or we'll have inconsistent hashes
+
+        block_string = json.dumps(block, sort_keys=True).encode()
+
+        # By itself, this function returns the hash in a raw string
+        # that will likely include escaped characters.
+        # This can be hard to read, but .hexdigest() converts the
+        # hash to a string using hexadecimal characters, which is
+        # easer to work with and understand.  
+        return hashlib.sha256(block_string).hexdigest()
+
+    @property
+    def last_block(self):
+        return self.chain[-1]
+
+    def proof_of_work(self, block):
+        """
+        Simple Proof of Work Algorithm
+        Find a number p such that hash(last_block_string, p) contains 6 leading
+        zeroes
+        :return: A valid proof for the provided block
+        """
+        # TODO
+        proof = 0
+
+        while self.valid_proof(block, proof) is False:
+            proof += 1
+
+        return proof
+
+    @staticmethod
+    def valid_proof(block_string, proof):
+        """
+        Validates the Proof:  Does hash(block_string, proof) contain 6
+        leading zeroes?  Return true if the proof is valid
+        :param block_string: <string> The stringified block to use to
+        check in combination with `proof`
+        :param proof: <int?> The value that when combined with the
+        stringified previous block results in a hash that has the
+        correct number of leading zeroes.
+        :return: True if the resulting hash is a valid proof, False otherwise
+        """
+        # TODO
+        guess = f'{block_string}{proof}'.encode()
+        guess_hash = hashlib.sha256(guess).hexdigest()
+
+        # return guess_hash[:6] == "000000"
+        # return True or False
+        result = True if guess_hash[:6] == "000000" else False
+        return result
+
+    def valid_chain(self, chain):
+        """
+        Determine if a given blockchain is valid.  We'll need this
+        later when we are a part of a network.
+
+        :param chain: <list> A blockchain
+        :return: <bool> True if valid, False if not
+        """
+
+        prev_block = chain[0]
+        current_index = 1
+
+        while current_index < len(chain):
+            block = chain[current_index]
+            print(f'{prev_block}')
+            print(f'{block}')
+            print("\n-------------------\n")
+            # Check that the hash of the block is correct
+            # TODO: Return false if hash isn't correct
+            if block['previous_hash'] != self.hash(prev_block):
+                return False
+
+            # Check that the Proof of Work is correct
+            # TODO: Return false if proof isn't correct
+            if not self.valid_proof(prev_block['proof'], block['proof']):
+                return False
+
+            prev_block = block
+            current_index += 1
+
+        return True
+
+
+# Instantiate our Node
+app = Flask(__name__)
+
+# Generate a globally unique address for this node
+node_identifier = str(uuid4()).replace('-', '')
+
+# Instantiate the Blockchain
+blockchain = Blockchain()
+
+
+@app.route('/mine', methods=['GET'])
+def mine():
+    # We run the proof of work algorithm to get the next proof...
+    last_block = blockchain.last_block
+    last_proof = last_block['proof']
+    proof = blockchain.proof_of_work(last_proof)
+
+    # We must receive a reward for finding the proof.
+    # TODO:
+    # The sender is "0" to signify that this node has mine a new coin
+    # The recipient is the current node, it did the mining!
+    # The amount is 1 coin as a reward for mining the next block
+    blockchain.new_transaction(
+        sender='0',
+        recipient=node_identifier,
+        amount =1)
+
+    # Forge the new Block by adding it to the chain
+    # TODO
+    block = blockchain.new_block(proof, blockchain.hash(blockchain.last_block))
+
+    # Send a response with the new block
+    response = {
+        'message': "New Block Forged",
+        'index': block['index'],
+        'transactions': block['transactions'],
+        'proof': block['proof'],
+        'previous_hash': block['previous_hash'],
+    }
+    return jsonify(response), 200
+
+
+@app.route('/transactions/new', methods=['POST'])
+def new_transaction():
+    values = request.get_json()
+
+    # Check that the required fields are in the POST'ed data
+    required = ['sender', 'recipient', 'amount']
+    if not all(k in values for k in required):
+        return 'Missing Values', 400
+
+    # Create a new Transaction
+    index = blockchain.new_transaction(values['sender'],
+                                       values['recipient'],
+                                       values['amount'])
+
+    response = {'message': f'Transaction will be added to Block {index}'}
+    return jsonify(response), 201
+
+
+@app.route('/chain', methods=['GET'])
+def full_chain():
+    response = {
+        # TODO: Return the chain and its current length
+        'currentChain': blockchain.chain,
+        'length': len(blockchain.chain)
+    }
+    return jsonify(response), 200
+
+
+# Run the program on port 5000
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=5000)
+

client_mining_p/miner.py

@@ -5,7 +5,16 @@
 
 
 # TODO: Implement functionality to search for a proof 
+def valid_proof(last_proof, proof):
+    guess = f'{last_proof}{proof}'.encode()
+    guess_hash = hashlib.sha256(guess).hexdigest()
+    return guess_hash[:6] == "000000"
 
+def proof_of_work(last_proof):
+    proof = 0
+    while valid_proof(last_proof, proof) is False:
+        proof +=1
+    return proof
 
 if __name__ == '__main__':
     # What node are we interacting with?
@@ -24,4 +33,16 @@
         # TODO: If the server responds with 'New Block Forged'
         # add 1 to the number of coins mined and print it.  Otherwise,
         # print the message from the server.
-        pass
+        last = requests.get(url=node + "/last_proof")
+        last_proof = last.json()['proof']
+        print('last proof', last_proof)
+        data = {
+            'proof': proof_of_work(last_proof)
+        }
+        print('next proof', data['proof'])
+        res = requests.post(url = f'{node}/mine', json = data)
+
+        if (res.json()['index']):
+            coins_mined+=1
+            print(f'Total Coins Mined: {coins_mined}')
+        print(res.json()['message'])