WebsocketServer.js

import _ from "lodash";
import uws from "uws";
import Exchange from "./exchange/Exchange";

class WebsocketServer {
  constructor(server) {
    this.exchange = new Exchange();
    this.wss = new uws.Server({
      server,
      verifyClient: this.verifyClient,
      clientTracking: true
    });
  }

  broadcast = data => {
    this.wss.clients.forEach(client => {
      if (client.readyState === uws.OPEN) {
        try {
          client.send(data);
        } catch (e) {
          console.log(e);
        }
      }
    });
  };

  ping = () => {
    this.wss.clients.forEach(client => {
      if (client.readyState === uws.OPEN) {
        try {
          client.ping();
        } catch (e) {
          console.log(e);
        }
      }
    });
  };

  verifyClient = info => {
    return this.originIsAllowed(info.origin);
  };

  originIsAllowed = origin => {
    // TODO: add origin checks here
    return true;
  };

  start = () => {
    this.exchange.connect();
    this.exchange.on(
      "message",
      _.throttle(data => {
        this.broadcast(JSON.stringify(data));
      }, 1000)
    );

    setInterval(() => {
      // Ping to prevent connections from closing
      this.ping();
    }, 30000);
  };
}

export default WebsocketServer;