Implement tcp socket handler api

Describe the feature Additionally to "socketProxy" it would be nice to be able to add custom socket handler that lets us implement the tcp server logic ourself.
Effectively mocking the TCP connection.

Workaround Currently we can set a socketProxy and hook the window.WebSocket class to achieve this.

window.oWebSocket = window.oWebSocket || window.WebSocket;
window.WebSocket = function (url, protocols) {
  if (!/pengu\.test/.test(url)) { // Add a check which decides if we wanna hook or use the real WebSocket implementation
    return new window.oWebSocket(url, protocols);
  }

  const socket = {
    _events: new EventTarget(),
    _closed: false,

    addEventListener(...args) {
      return this._events.addEventListener(...args);
    },

    removeEventListener(...args) {
      return this._events.removeEventListener(...args);
    },

    dispatchEvent(...args) {
      return this._events.dispatchEvent(...args);
    },

    send(data) {
      if (this._closed) {
        throw new Error('WebSocket is closed');
      }

      console.log("Send: ", data); // Intercept what the client tries to send.
    },
    close(code, reason) {
      this._closed = true;
      const event = new Event('close');
      event.code = code || 1000;
      event.reason = reason || '';
      this.dispatchEvent(event);
    },
    get readyState() {
      return this._closed ? 3 : 1; // 3 = CLOSED, 1 = OPEN
    },

    get bufferedAmount() {
      return 0;
    },
    get binaryType() {
      return 'blob';
    },
    set binaryType(type) {},
    get url() {
      return url;
    },
    get protocol() {
      return protocols
        ? Array.isArray(protocols)
          ? protocols.join(',')
          : protocols
        : '';
    },
    open() {
      setTimeout(() => {
        const event = new Event('open');
        this.dispatchEvent(event);
      }, 10);
    },
  };

  // Mimic connection open
  setTimeout(() => {
    socket.open();
  }, 10);

  return socket;
};

Proposal

function exampleHandler() {
  return {
    host: "some.hostname.org",
    port: 1234,
    async connect(ctx, details) {
      console.log("Connecting to:", details.host, details.port)
      await new Promise(resolve => setTimeout(resolve, 1000) // Simulate network delay
      return true // Indicates an open connection
    },
    close(ctx, details) {
      console.log("Connection closed:", details)
    },
    async send(ctx, data) {
      console.log("Send:", data)
      await new Promise(resolve => setTimeout(resolve, 1000) // Simulate network delay
      ctx.recv("result data")
    }
  }
}

window.RufflePlayer.config = {
  socketHandler: [
    exampleHandler
  ]
}

ruffle-rs / ruffle

Implement tcp socket handler api #16674