python falsk socket.io.js cannot connect/error prompt WebSocket connection to 'ws://xxxxx' failed:

Problem description
Solve the error WebSocket connection to 'ws://xxxxx' failed after deploying with python falsk socketio:

Solution
Check whether your page uses http or https, or ws/wss, I use http. There is a function var uri = this.uri() in line 1568 of the front-end socket.io.js file, and the default value obtained is: ws://xxx.cn/socket.io/?EIO=4&transport=websocket&sid=P8tPESz-mqXU6QDKAAAK , if you are using http request, just replace ws: with http.

After modifying socket.io.js (replace ws://xxx.cn with http://xxx.cn)

       var uri = this.uri();
       
       //把ws：修改为http:
       if (uri){
    
    
          uri = uri.replace('ws:', 'http:')
        }

        var protocols = this.opts.protocols; // React Native only supports the 'headers' option, and will print a warning if anything else is passed

        var opts = isReactNative ? {
    
    } : pick(this.opts, "agent", "perMessageDeflate", "pfx", "key", "passphrase", "cert", "ca", "ciphers", "rejectUnauthorized", "localAddress", "protocolVersion", "origin", "maxPayload", "family", "checkServerIdentity");

        if (this.opts.extraHeaders) {
    
    
          opts.headers = this.opts.extraHeaders;
        }

        try {
    
    
          this.ws = usingBrowserWebSocket && !isReactNative ? protocols ? new WebSocket(uri, protocols) : new WebSocket(uri) : new WebSocket(uri, protocols, opts);
        } catch (err) {
    
    
          return this.emitReserved("error", err);
        }

socket.io.js before modification

       	var uri = this.uri();
        
        var protocols = this.opts.protocols; // React Native only supports the 'headers' option, and will print a warning if anything else is passed

        var opts = isReactNative ? {
    
    } : pick(this.opts, "agent", "perMessageDeflate", "pfx", "key", "passphrase", "cert", "ca", "ciphers", "rejectUnauthorized", "localAddress", "protocolVersion", "origin", "maxPayload", "family", "checkServerIdentity");

        if (this.opts.extraHeaders) {
    
    
          opts.headers = this.opts.extraHeaders;
        }

        try {
    
    
          this.ws = usingBrowserWebSocket && !isReactNative ? protocols ? new WebSocket(uri, protocols) : new WebSocket(uri) : new WebSocket(uri, protocols, opts);
        } catch (err) {
    
    
          return this.emitReserved("error", err);
        }