Myujth

I am trying to establish a comunication via socket.io socket between an angular 6 client and a tornado server. i get the followint errors:

on the client side:

Access to XMLHttpRequest at 'http://127.0.0.1:8888/socket.io/? 
EIO=3&transport=polling&t=MSHp-m5' from origin 'http://localhost:4200' has 
been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is 
present on the requested resource.

on the server side:

WARNING:tornado.access:404 GET /socket.io/?EIO=3&transport=polling&t=MSHp-m5 
(127.0.0.1) 1.00ms

I have a server Written in Tornado written in python 2.7, here is the code:

from tornado import websocket, web, ioloop , httpserver
import json
import socketio
from urlparse import urlparse

cl = 


class SocketHandler(websocket.WebSocketHandler):


def check_origin(self, origin):
 print "check origin"
 return True

def open(self):
 if self not in cl:
 cl.append(self)
 self.write_message("connection opened")

def on_close(self):
 if self in cl:
 cl.remove(self)
 print "connection closed"

def on_message(self, message):
 print "Message received: ".format(message)
 self.write_message("message received")

if __name__ == '__main__':
app = web.Application([
 (r'/ws', SocketHandler),
 # (r'/api', ApiHandler),
 (r'/(favicon.ico)', web.StaticFileHandler, 'path': '../'),
 (r'/(rest_api_example.png)', web.StaticFileHandler, 'path': './'),
], user_settings="websocket_allow_origin": "*")
app.listen(8888)
ioloop.IOLoop.instance().start()

I also have a client written in Angular 6 who uses socket.io to start a session with the server. the client at the moment run on localhost:4200 but in the future will run on a different machine then the server and will not be rendered by the server, means that i can't just run the client on the same port as the server because it doesn't fit my needs.

here is the angular service code from the which deals with the comunication to the server.:

import Injectable from '@angular/core';
import HttpClient from '@angular/common/http';
import Observable,BehaviorSubject from 'rxjs';
import delay,map,catchError from 'rxjs/operators';
import * as io from 'socket.io-client';
@Injectable(providedIn: 'root')
export class PysystemRunnerService 

private PDB_WEB_PORT = "23456";
private editUrl: string = 'http://127.0.0.1:' + this.PDB_WEB_PORT + 
'/l1commands/pysystem_runner_edit_list';
private socket;
private socket_port = "8888";
private socketUrl = "ws://127.0.0.1:" + this.socket_port + "/ws"

constructor(private http: HttpClient) 
 this.socket = io(this.socketUrl);


handleEdit(data) 
 var ans = this.http.post(this.editUrl, data).pipe(
 delay(100),
 map((data: any) => (data.data 

handleRun(data) 
 ///////////////socket logic////////////////


 ////////////////////////////


public getMessages = () => 
 return Observable.create((observer) => 
 this.socket.on('new-message', (message) => 
 observer.next(message);
 );
 );



//handle http errors
private handleError(error: any) 
 let errMsg = (error.message) ? error.message :
 error.status ? `$error.status - $error.statusText` : 'Server error';
 console.error(errMsg); // log to console instead
 return Observable.throw(errMsg);

I was reading the Tornado documantation and it says that making the check_origin function return True should solve the CORS issue but it didn't.