问使用firebase函数与socket.io连接的问题及实现

EN

{
  "hosting": {
    "public": "public",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "headers": [ 

      {
        "source" : "**",
        "headers" : [ {
          "key" : "Access-Control-Allow-Headers",
          "value" : "Origin"
        } ]
      },
      {
        "source" : "**",
        "headers" : [ {
          "key" : "Access-Control-Allow-Origin",
          "value" : "http://localhost:4200"
        } ]
      }
    ],
    "rewrites": [
      {
        "source": "**",
        "function": "app"
      }
    ]
  },
  "functions": {
    "predeploy": [
      "npm --prefix \"$RESOURCE_DIR\" run lint"
    ],
    "source": "functions"
  }
}

const functions = require('firebase-functions');
const express = require('express');
var app = express();

const http = require('http').Server(express);
const socketio = require('socket.io')(http);
const cors = require('cors');


app.use(cors({credentials: true, origin: '*:*'}));
app.get('/tester', (request, response) => {

    //response.header('Access-Control-Allow-Origin', '*');
    response.send('Hello!');

    socketio.on('connection', socket => {
        connections.push(socket);
        console.log('New client connected ('+connections.length+' connections).');
        //console.log(socket);
        socket.emit('port', 'LIVE SHIT');
    });
})

exports.app = functions.https.onRequest(app)

import { Component } from '@angular/core';
import io from 'socket.io-client';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  title = 'multi-client';
  port: number = 0;
  socket: any;
  width: number = 100;
  updateVal: number = 5;
  constructor()
  {
    this.socket = io('http://localhost:5000/tester');

    this.socket.on('port', port => {
      this.port = port;
    })
  }

  updateWidth(val)
  {
    this.width += val;
  }
}