Is it possible to temporarily disable a websockets connection in a local server environment?

Question

I have a Node.js script that uses websockets (socket.io). The script is running on my computer (e.g. local server environment) and I also tests through a browsers on my computer. I am trying to gracefully handle disconnections and reconnections. So far I have emulated network disturbances by disable/enable the WiFi on my iPad. Is it possible to disable and resume the browser's web socket connection on my local machine, i.e. through a browser plugin, third party proxy software, or some other tool?

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So fare I have tried:

• Chrome developer tool: In its Device Mode there is a Networks Conditions option, which allows me to emulate various network connectivity. Unfortunately at this point in time it only applies to HTTP-connections and not to the websocket connections.
• Charles: It records the websocket connections, but does not throttle them. (I've set bandwidth, utilisation and MTU to zero, but still receive responses trough the websocket connection).
• Fiddler: Similarly records the websocket connections, but does not block them.

Answer 1

You can try overloading the WebSocket object. Its kind of dirty, but you could capture when the websocket is trying to be created and create delays or whatever. I havent tested it, but it should be sound. Or maybe overload the WS methods themselves to interrupt when data is being sent or received.

        var WebSocket2 = WebSocket;

        WebSocket = function(addy) {
            console.log('WS: Trying to open.');
            var ws;
            if (!this.blocked) {
                console.log('WS: Not blocked, allowing.');
                ws = new WebSocket2(addy);
                this.open_sockets.push(ws);
                return ws;
            } else {
                console.log('WS: Blocked.');
            }
        };

        WebSocket.toggle = function() {
            WebSocket.prototype.blocked = !WebSocket.prototype.blocked;
            var sockets = WebSocket.prototype.open_sockets;
            if (WebSocket.prototype.blocked) {
                console.log('WS: Blocking. Removing Old Sockets.');
                sockets.forEach(function(socket, index, sockets) {
                    console.log("WS: Closing -", index);
                    socket.close();
                });
                WebSocket.prototype.open_sockets = [];
                console.log("WS: Sockets left open -", WebSocket.prototype.open_sockets.length);
            } else {
                console.log("WS: Unblocking");
            }
        };

        WebSocket.prototype.open_sockets = [];
        WebSocket.prototype.blocked = false;