带有socket.io的NodeJS应用在Heroku上不起作用

Question

我正在尝试在Heroku服务器上实现SocketIO和Express服务器。

这是服务器代码：

const express = require("express");
const path = require("path");
const app = express();
const HEROKU_PORT = process.env.PORT || 8080;

var http = require("http").Server(app);
var io = require("socket.io")(http);

var clients = {};

// API calls
app.get("/api/hello", (req, res) => {
  res.send({ express: "Hello From Express" });
});
if (process.env.NODE_ENV === "production") {
  // Serve any static files
  app.use(express.static(path.join(__dirname, "client/build")));
  // Handle React routing, return all requests to React app
  app.get("*", function(req, res) {
    res.sendFile(path.join(__dirname, "client/build", "index.html"));
  });
}
/****************************** */
io.on("connection", function(socket) {
  socket.on("I am", function(msg) {
    clients[msg] = socket.id;
    console.log(clients);
    console.log(msg, "connected");
  });
  socket.on("command", function(msg) {
    console.log(msg);
    console.log(socket.id);

    io.to(clients["Home server"]).emit("button", msg);
  });
});
/****************************** */

http.listen(HEROKU_PORT, function() {
  console.log(`SocketIO listening on port ${HEROKU_PORT}`);
});

以上代码在我的计算机上可以完美运行。但是，当我将其加载到Heroky上时，它会部分起作用。服务器响应 GET/api/hello ，但不支持SocketIO连接。