Step 8: The Mining Endpoint

blockchain.py

import hashlib
import json

from time import time
from uuid import uuid4

from flask import Flask, jsonify, request

...

@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.
    # The sender is "0" to signify that this node has mined a new coin.
    blockchain.new_transaction(
        sender="0",
        recipient=node_identifier,
        amount=1,
    )

    # Forge the new Block by adding it to the chain
    previous_hash = blockchain.hash(last_block)
    block = blockchain.new_block(proof, previous_hash)

    response = {
        'message': "New Block Forged",
        'index': block['index'],
        'transactions': block['transactions'],
        'proof': block['proof'],
        'previous_hash': block['previous_hash'],
    }
    return jsonify(response), 200

What's node_identifier

The node_identifier defined a little bit earlier at the Step 6: Setting up Flask. Briefly, it's a unique identifier of the node (aka the miner) which successfully produced a new block: solved the mathematical problem known as proof of work. It will be rewarded with 1 coin of revenue at this example.

You could get more info regarding the mining process here: https://en.bitcoin.it/wiki/Mining#Reward

I got an error: Flask not found

from flask import Flask, jsonify, request
ModuleNotFoundError: No module named 'flask'