dao-governance-framework/forum-network/public/classes/forum-node.js

import { Actor } from './actor.js';
import { Action } from './action.js';
import {
  Message, PostMessage, PeerMessage, messageFromJSON,
} from './message.js';
import { CryptoUtil } from './crypto.js';
import { ForumView } from './forum-view.js';
import { PrioritizedQueue } from './prioritized-queue.js';

export class ForumNode extends Actor {
  constructor(name, scene) {
    super(name, scene);
    this.forumView = new ForumView();
    this.queue = new PrioritizedQueue();
    this.actions = {
      storePost: new Action('store post', scene),
      peerMessage: new Action('peer message', scene),
    };
  }

  // Generate a signing key pair and connect to the network
  async initialize(forumNetwork) {
    this.keyPair = await CryptoUtil.generateAsymmetricKey();
    this.forumNetwork = forumNetwork.addNode(this);
    this.status.set('Initialized');
    return this;
  }

  // Send a message to all other nodes in the network
  async broadcast(message) {
    await message.sign(this.keyPair);
    const otherForumNodes = this.forumNetwork
      .listNodes()
      .filter((forumNode) => forumNode.keyPair.publicKey !== this.keyPair.publicKey);
    for (const forumNode of otherForumNodes) {
      // For now just call receiveMessage on the target node
      this.actions.peerMessage.log(this, forumNode, null, message.content);
      await forumNode.receiveMessage(JSON.stringify(message.toJSON()));
    }
  }

  // Perform minimal processing to ingest a message.
  // Enqueue it for further processing.
  async receiveMessage(messageStr) {
    const messageJson = JSON.parse(messageStr);
    const senderReputation = this.forumView.getReputation(messageJson.publicKey) || 0;
    this.queue.add(messageJson, senderReputation);
  }

  // Process next highest priority message in the queue
  async processNextMessage() {
    const messageJson = this.queue.pop();
    if (!messageJson) {
      return null;
    }
    return this.processMessage(messageJson);
  }

  // Process a message from the queue
  async processMessage(messageJson) {
    try {
      await Message.verify(messageJson);
    } catch (e) {
      this.actions.processMessage.log(this, this, 'invalid signature', messageJson, '-x');
      console.log(`${this.name}: received message with invalid signature`);
      return;
    }

    const { publicKey } = messageJson;
    const message = messageFromJSON(messageJson);
    console.log(`${this.name}: processMessage`, message);

    if (message instanceof PostMessage) {
      await this.processPostMessage(publicKey, message.content);
    } else if (message instanceof PeerMessage) {
      await this.processPeerMessage(publicKey, message.content);
    } else {
      // Unknown message type
      // Penalize sender for wasting our time
      console.log(`${this.name}: penalizing sender for unknown message type ${message.type}`);
      this.forumView.incrementReputation(message.publicKey, -1);
    }
  }

  // Process an incoming post, received by whatever means
  processPost(authorId, post, stake) {
    if (!post.id) {
      post.id = CryptoUtil.randomUUID();
    }
    this.actions.storePost.log(this, this, null, { authorId, post, stake });
    this.forumView.addPost(authorId, post.id, post, stake);
  }

  // Process a post we received in a message
  async processPostMessage(authorId, { post, stake }) {
    this.processPost(authorId, post, stake);
    await this.broadcast(
      new PeerMessage({
        posts: [{ authorId, post, stake }],
      }),
    );
  }

  // Process a message we receive from a peer
  async processPeerMessage(peerId, { posts }) {
    // We are trusting that the peer verified the signatures of the posts they're forwarding.
    // We could instead have the peer forward the signed messages and re-verify them.
    for (const { authorId, post, stake } of posts) {
      this.processPost(authorId, post, stake);
    }
  }
}