Heroku Nodejs诉Vercel Nodejs

Question

我有一个服务器托管在Heroku。此外，客户端(React)托管在Vercel中。这个组合很完美！但是，出于我的好奇心，我试着用Vercel主持服务器端脚本。然后，当我试图连接到Vercel托管-服务器时，客户端将返回此错误Access to XMLHttpRequest at 'https://socketio-vercel.vercel.app/socket.io/?EIO=4&transport=polling&t=NVeP_Ax' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. (我正在本地主机:3000中进行测试)。

服务器端代码(在Heroku和Vercel中都是相同的) ->

"use strict";

const express = require("express");
const socketIO = require("socket.io");

const PORT = process.env.PORT || 3000;
const INDEX = "/index.html";

const server = express()
  .use((req, res) => res.sendFile(INDEX, { root: __dirname }))
  .listen(PORT, () => console.log(`Listening on ${PORT}`));

const io = socketIO(server, {
  cors: {
    origin: "http://localhost:3000",
    methods: ["GET", "POST"],
  },
});

io.on("connection", (socket) => {
  console.log("Client connected");
  socket.on("disconnect", () => console.log("Client disconnected"));
});

setInterval(() => io.emit("time", new Date().toTimeString()), 1000);

客户端代码(如果服务器由Heroku托管)(工作) ->

useEffect(() => {
if (shouldStart) {
  axios.get("api/sync").then((response) => {
    setMessages(response.data);
    const socket = io("wss://radiant-mountain-09008.herokuapp.com");
    socket.on("connect", () => {
      console.log("connected"); // "G5p5..."
    });
    socket.on("time", (msg) => {
      console.log(msg);
    });
  });
}
}, [shouldStart]);

客户端代码(如果服务器由Vercel托管) ->

useEffect(() => {
if (shouldStart) {
  axios.get("api/sync").then((response) => {
    setMessages(response.data);
    const socket = io("wss://socketio-vercel.vercel.app");
    socket.on("connect", () => {
      console.log("connected"); // "G5p5..."
    });
    socket.on("time", (msg) => {
      console.log(msg);
    });
  });
}
}, []);

知道为什么会这样吗？谢谢！

Answer 1

据我所知，vercel只支持无服务器功能。您不能使用任何套接字，websocket库。您可以在这个官方的链接中从他们的github了解更多细节。我希望这能帮上忙。祝好运