Chrome Extension for Debugging Secure Websockets on Spotify Web Player. Clone the repo, install extension as unpacked then navigate to `https://play.spotify.com/?ap=wss://ash1-linkap-a1.ap.spotify.com:443`

content_script.js

(function debugify_content_script(){
  console.log('debugify content script running');
  var nativeWebSocket = window.WebSocket;
  var requests = window.requestLog = {}; 
  var WebSocket = window.WebSocket = function(uri) {
    console.log('new WebSocket created', uri);
    this.websocket = new nativeWebSocket(uri);
    this.websocket.onopen = this.onOpen.bind(this);
    this.websocket.onmessage = this.onMessage.bind(this);
    this.listeners = {onmessage: null, onopen: null};

    if (!window._openWebSockets) window._openWebSockets = [];
    window._openWebSockets.push(this);
  };
  WebSocket.prototype.send = function(msg) {
    console.log('>>', msg);
    this.websocket.send.apply(this.websocket, arguments);
  }
  WebSocket.prototype.onOpen = function(e){
    console.log('OPEN', arguments);
    this.listeners.onopen(e);
  }
  WebSocket.prototype.onMessage = function(e){
    console.log('<<', e.data);
    this.listeners.onmessage(e);
  }
  Object.defineProperty(WebSocket.prototype, 'readyState', {
    get: function() {
      return this.websocket.readyState;
    }
  });
  Object.defineProperty(WebSocket.prototype, 'onopen', {
    get: function() {
      return this.listeners.onopen;
    },
    set: function(fn) {
      this.listeners.onopen = fn;
    }
  });
  Object.defineProperty(WebSocket.prototype, 'onclose', {
    get: function() {
      return this.websocket.onclose;
    },
    set: function(fn) {
      this.websocket.onclose = fn;
    }
  });
  Object.defineProperty(WebSocket.prototype, 'onmessage', {
    get: function() {
      return this.listeners.onmessage;
    },
    set: function(fn) {
      this.listeners.onmessage = fn;
    }
  });
  Object.defineProperty(WebSocket.prototype, 'onerror', {
    get: function() {
      return this.websocket.onerror;
    },
    set: function(fn) {
      this.websocket.onerror = fn;
    }
  });
})();

content_script_injector.js

console.log('injecting content script');
var s = document.createElement('script');
s.src = chrome.extension.getURL('content_script.js');
s.onload = function() {
    this.parentNode.removeChild(this);
};
(document.head||document.documentElement).appendChild(s);

manifest.json

{
  "name": "debugify",
  "version": "0.0.0",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": ["https://play.spotify.com/*"],
      "js": ["content_script_injector.js"],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "https://play.spotify.com/*"
  ],
  "web_accessible_resources": [
    "content_script.js"
  ]
}