Websockets

[sofalere]

WebSocket:

• bidirectional communication protocol that can send the data from the client to the server or from the server to the client
• using socket.io the main functions are emit and on, either one can be used in the frontend or the backend
• each connection to our app will have its own WebSocket, thats why in the server side we send the "new request" event to many sockets

server side:

• require (node:http) that is used for creating an HTTP server, this is necessary because WebSockets use the HTTP connection to establish the WebSocket connection
• the Socket.io library will create the WebSocket server
• the io object waits for connections
• emits a new event called "new request" when request hits our route to all current open sockets

  const request = await saveRequest(req);
  io.sockets.emit('new request', request);
  res.sendStatus(200);
});

client side:

• <script src="/socket.io/socket.io.js"></script>source the file before the js app file
• const socket = io(); initiates the connection to the WebSocket server
• listens for a socket event called "new request"

    const listItem = createRequestItem(request);
    requestList.appendChild(listItem);
  });