A Cordova plugin that uses OkHttp to provide WebSocket support in your Cordova app. It aims to mimic the WebSocket API in JavaScript, with additional features.

• ✅ WebSocket API-like interface
• ✅ Event support: onopen, onmessage, onerror, onclose
• ✅ extensions and readyState properties
• ✅ listClients() to list active connections
• ✅ Support for protocols
• ✅ Support for Custom Headers.
• ✅ Compatible with Cordova for Android

const WebSocketPlugin = cordova.websocket;

WebSocketPlugin.connect("wss://example.com/socket", ["protocol1", "protocol2"], headers)
  .then(ws => {
    ws.onopen = (e) => console.log("Connected!", e);
    ws.onmessage = (e) => console.log("Message:", e.data);
    ws.onerror = (e) => console.error("Error:", e);
    ws.onclose = (e) => console.log("Closed:", e);
    
    ws.send("Hello from Cordova!");
    ws.close();
  })
  .catch(err => console.error("WebSocket connection failed:", err));

• WebSocketPlugin.connect(url, protocols, headers, binaryType)

  • Connects to a WebSocket server.
  • url: The WebSocket server URL.
  • protocols: (Optional) An array of subprotocol strings.
  • headers: (Optional) Custom headers as key-value pairs.
  • binaryType: (Optional) Initial binary type setting.
  • Returns: A Promise that resolves to a WebSocketInstance.

• WebSocketPlugin.listClients()

  • Lists all stored webSocket instance IDs.
  • Returns: Promise that resolves to an array of instanceId strings.

• WebSocketPlugin.send(instanceId, message, binary)

  • Sends a message to the server using an instance ID.
  • instanceId: The ID of the WebSocket instance.
  • message: The message to send (string or ArrayBuffer/ArrayBufferView).
  • binary: (Optional) Whether to send the message as binary, accepts boolean
  • Returns: Promise that resolves when the message is sent.

• WebSocketPlugin.close(instanceId, code, reason)

  • same as WebSocketInstance.close(code, reason) but needs instanceId.
  • Returns: Promise that resolves.

• WebSocketInstance.send(message, binary)

  • Sends a message to the server.
  • message: The message to send (string or ArrayBuffer/ArrayBufferView).
  • binary: (Optional) Whether to send the message as binary. accepts boolean
  • Throws an error if the connection is not open.

• WebSocketInstance.close(code, reason)

  • Closes the connection.
  • code: (Optional) If unspecified, a close code for the connection is automatically set: to 1000 for a normal closure, or otherwise to another standard value in the range 1001-1015 that indicates the actual reason the connection was closed.
  • reason: A string providing a custom WebSocket connection close reason (a concise human-readable prose explanation for the closure). The value must be no longer than 123 bytes (encoded in UTF-8).

• onopen: Event listener for connection open.
• onmessage: Event listener for messages received.
• onclose: Event listener for connection close.
• onerror: Event listener for errors.
• readyState: (number) The state of the connection.
  • 0 (CONNECTING): Socket created, not yet open.
  • 1 (OPEN): Connection is open and ready.
  • 2 (CLOSING): Connection is closing.
  • 3 (CLOSED): Connection is closed or couldn't be opened.
• extensions: (string) Extensions negotiated by the server.
• binaryType: (string) Type of binary data to use ('arraybuffer' or '' (binary payload returned as strings.)).
• url: (string) The WebSocket server URL.
• instanceId: (string) Unique identifier for this WebSocket instance.

WebSocketInstance extends EventTarget, providing standard event handling methods:

• addEventListener(type, listener): Registers an event listener.
• removeEventListener(type, listener): Removes an event listener.
• dispatchEvent(event): Dispatches an event to the object.

Example of using event listeners:

const ws = await WebSocketPlugin.connect("wss://example.com/socket");

// Using on* properties
ws.onmessage = (event) => console.log("Message:", event.data);

// Using addEventListener
ws.addEventListener('message', (event) => console.log("Message:", event.data));

• WebSocketInstance.CONNECTING: 0
• WebSocketInstance.OPEN: 1
• WebSocketInstance.CLOSING: 2
• WebSocketInstance.CLOSED: 3

• Only supported on Android (via OkHttp).
• Make sure to handle connection lifecycle properly (close sockets when done).
• listClients() is useful for debugging and management.