how to check if user is online or not via hasura graphql and nodejs socket io
To check if a user is online or not using Hasura GraphQL and Node.js with Socket.IO, you can implement a simple presence system. Here's a high-level overview of the approach:

**Step 1: Set up Socket.IO**

In your Node.js server, set up Socket.IO to establish real-time communication with clients. When a user connects to your server, they will be assigned a unique socket ID.

**Step 2: Create a presence table in Hasura**

In your Hasura GraphQL schema, create a new table to store user presence information. This table can have columns for `user_id`, `socket_id`, and `is_online` (a boolean indicating whether the user is online or not).

**Step 3: Update presence table on socket connection/disconnection**

When a user connects to your server, update the presence table to set `is_online` to `true` for that user. When a user disconnects, update the presence table to set `is_online` to `false`.

**Step 4: Expose a GraphQL API to check user presence**

Create a GraphQL API in Hasura that allows you to query the presence table. This API can take a `user_id` as an argument and return the `is_online` status for that user.

**Step 5: Use the GraphQL API to check user presence**

In your Node.js server, use the GraphQL API to check the presence of a user whenever you need to know their online status. You
 To check if a user is online or not using Hasura GraphQL and Node.js with Socket.IO, you can follow these general steps:

1. Set up a Node.js server with Socket.IO:

First, create a new Node.js project and install the necessary dependencies:

```bash
npm init -y
npm install express socket.io hasura-client
```

Then, create a new file called `server.js` and set up a basic Socket.IO server:

```javascript
const express = require('express');
const http = require('http');
const socketIo = require('socket.io');
const { GraphQLClient } = require('graphql-request');

const app = express();
const server = http.createServer(app);
const io = socketIo(server);

app.use(express.static('public'));

io.on('connection', (socket) => {
  console.log('User connected:', socket.id);

  // Handle user disconnection
  socket.on('disconnect', () => {
    console.log('User disconnected:', socket.id);
    // Update user's online status in Hasura
    updateUserStatus(socket.id, false);
  });

  // Update user's