在网络上实施这个 Node.js 区块链

Question

我正在查看来自 firebase 的这个区块链。 https://github.com/fireship-io/node-blockchain/blob/main/index.ts

区块链非常简单。有许多类似的区块链实施示例，但我并没有真正看到任何在网络中实际使用的示例。我正在努力为实现这一目标奠定基础，至少要从 2 个用户开始。

目前我感到困惑的是用户之间实际共享的是什么？是链条本身吗？只是新的交易？当用户 Wallet.sendMoney(5, satoshi.publicKey) 时，它会更新本地钱包，然后呢？我猜是将交易发送给网络上的其他人，但随后区块链的每个副本 adds/verifies 独立。这似乎有问题，因为一些交易可能会丢失（互联网中断或其他），这让我想知道是否发送了整个区块链，但这似乎很笨拙。

Answer 1

The thing I'm confused about at the moment is what actually gets shared between users?

您指的是 nodes 之间，而不是“用户”。所有节点都应该有相同的链和交易。所以你必须实现一个 pub-sub 系统来监听某些事件并发布交易和链。使用redis，你可以创建一个class。我在代码上解释了：

// Note that redis stores strings.
const redis = require("redis");

// create two channels to transfer data
const CHANNELS = {
  BLOCKCHAIN: "BLOCKCHAIN",
  TRANSACTION: "TRANSACTION",
};

// unlike socket, we do not need to know the address of otehr nodes

// ---------------------------HERE IS BROADCASTING STATION---------------------
// it writes multiple processes to communicate over channels.
class PubSub {
  constructor({ blockchain, transactionPool }) {
    // it is able to broadcast its chain and replacing the valid chain
    this.blockchain = blockchain;
    this.transactionPool = transactionPool;

    this.publisher = redis.createClient();
    this.subscriber = redis.createClient();
    this.subscribeToChannels();
    // this.subscriber.on("message", (channel, message) => {
    //   return this.handleMessage(channel, message);
    // });
    this.subscriber.on("message", (channel, message) =>
      this.handleMessage(channel, message)
    );
  }

  // we are listening all channels
  subscribeToChannels() {
    Object.values(CHANNELS).forEach((channel) => {
      this.subscriber.subscribe(channel);
    });
  }

  publish({ channel, message }) {
    //we unsubscrive so we dont send message to ourselves
    // we subscribe again to receive messages
    this.subscriber.unsubscribe(channel, () => {
      this.publisher.publish(channel, message, () => {
        this.subscriber.subscribe(channel);
      });
    });
  }

  // ------THIS IS WHERE BROADCASTING DONE-------------
  handleMessage(channel, message) {
    const parsedMessage = JSON.parse(message);
    switch (channel) {
      case CHANNELS.BLOCKCHAIN:
        this.blockchain.replaceChain(parsedMessage, true, () => {
          // we need to clear local transaction pool becasue we got a new chain
          this.transactionPool.clearBlockchainTransactions({
            chain: parsedMessage,
          });
        });
        break;
      case CHANNELS.TRANSACTION:
        console.log("this in pubsusb", this.transactionPool);
        this.transactionPool.setTransaction(parsedMessage);

        break;
      default:
        return;
    }
  }

  broadcastChain() {
    this.publish({
      channel: CHANNELS.BLOCKCHAIN,
      message: JSON.stringify(this.blockchain.chain),
    });
  }

  broadcastTransaction(transaction) {
    this.publish({
      channel: CHANNELS.TRANSACTION,
      message: JSON.stringify(transaction),
    });
  }
}

export default PubSub;

在网络上实施这个 Node.js 区块链

Implementing this Node.js blockhain on a network

cryptography

node.js

blockchain