What is web socket in flutter ?

WebSockets are a protocol for bi-directional, real-time communication between clients and servers over a single, long-lived connection. They were first standardized by the IETF in 2011 and are now widely used in web and mobile applications.

WebSockets provide a full-duplex communication channel between the client and server, allowing data to be sent and received in real-time. Unlike HTTP, which is a request-response protocol, WebSockets enable the server to push data to the client without the client needing to make a request first. This makes WebSockets ideal for applications that require real-time data updates, such as chat applications, online gaming, and stock tickers.

WebSockets work by establishing a handshake between the client and server over HTTP. Once the handshake is complete, the WebSocket connection is upgraded from HTTP to the WebSocket protocol. After the upgrade, the client and server can exchange data in real-time over the same connection.

WebSockets use a message-based protocol, where messages can be sent and received as either text or binary data. Messages are composed of one or more frames, where each frame contains a payload of data. The payload can be up to 2^64 bytes in length.

WebSockets are supported in most modern web browsers and can also be used in mobile applications. In Flutter, you can use the WebSocket class to establish a WebSocket connection with a server.

While WebSockets are a powerful tool for real-time communication, they can also pose security risks if not used correctly. It’s important to properly validate and sanitize input to prevent attacks such as cross-site scripting (XSS) and SQL injection. Additionally, WebSockets should only be used over secure connections (i.e., over HTTPS or WSS) to prevent eavesdropping and data tampering.

Flutter provides a WebSocket class that you can use to establish a WebSocket connection with a server. Here’s an example of how to use WebSocket in Flutter:

import 'dart:convert';
import 'dart:io';

void main() async {
  final socket = await WebSocket.connect('wss://echo.websocket.org');

  socket.listen((message) {
    print('Received message: $message');
  });

  socket.add(json.encode({'message': 'Hello, WebSocket!'}));

  await Future.delayed(Duration(seconds: 5));

  await socket.close();
}

In this example, we establish a WebSocket connection with the echo.websocket.org server and listen for messages from the server. We also send a JSON-encoded message to the server using the add method and close the connection after 5 seconds.

WebSockets can be used for various real-time applications, such as chat applications, multiplayer games, and stock tickers.